Search

Ferrate(VI) (Fe(VI)) has been known to react with emerging organic contaminants containing electron-rich organic moieties, such as phenols, anilines, olefins, reduced sulfur and deprotonated amines. Oxidation of fluoroquinolone antibiotics, ciprofloxacin (CIP) and enrofloxacin (ENR), by Fe(VI) were investigated for their reaction products and toxicity changes as well as biodegradability of these products. Ten products were identified for both CIP and ENR reactions with Fe(VI) using a high-resolution accurate-mass Orbitrap mass analyzer. Structural changes to the CIP and ENR molecule included dealkylation, formation of alcohols and amides in piperazine ring and oxygen transfer to the double bond in quinolone structure. An enamine formation mechanism was tentatively proposed to facilitate the interpretation of CIP and ENR oxidation pathways. Toxicity evaluation using Microbial Assay for toxicity Risk Assessment (MARA) bioassay indicated that Fe(VI) oxidation products of CIP and ENR contributed negligible antibacterial potency and Fe(VI) oxidation treatment can remove the residual toxicity of CIP and ENR impacted source waters. The Fe(VI) oxidation treatment resulted in formation of relatively more biodegradable products (based on in silico assessment) than their corresponding parent compounds. The results showed that Fe(VI) has a good potential to degrade fluoroquinolone antibiotics and their antimicrobial potency in natural waters. [ABSTRACT FROM AUTHOR]

Two pesticide risk indicators, Pesticide Impact Rating Index (PIRI) and Environmental Potential Risk Indicator for Pesticides (EPRIP), were used to determine the likelihood of off-site transport to surface water of pesticides used in a cherry ( Prunus avium cultivars) and an apple ( Malus domestica cultivars) orchard. The predictions of off-site transport of some of the pesticides were verified against actual pesticide concentrations in surface water continuously monitored over two years. To our knowledge, only one other study in the published literature has attempted this. Of the chemicals monitored there was good agreement between the predictions and the field measurements from the apple orchard, but less so for the cherry orchard. In both risk indicators the attenuation factor based on the width of the buffer strip over-estimated the effectiveness of the buffer strip. There was good agreement between the EPRIP and PIRI risk assessment except for ethephon which EPRIP rated a higher risk than PIRI and dithianon which EPRIP rated a lower risk than PIRI. A strong correlation was found between the field observations and the EPRIP predicted environmental concentrations for the majority of cases. This study showed that even simple risk indicators (e.g. PIRI and EPRIP) can be good predictors for a first tier risk assessment of pesticide transport to neighbouring water bodies. [ABSTRACT FROM AUTHOR]

A survey was conducted in eight secondary schools located in two watersheds in Gujarat and Rajasthan (semi-arid region of India) to assess students’ perceptions about groundwater scarcity issues and the impact of the scarcity on their educational opportunities. Survey responses to a detailed questionnaire by a cohort of students in both watersheds; school attendance records of year 8 class students (13–14 years old) and responses gathered via a socio-economic survey involving 500 families in the study area were used in the study. In both watersheds, >90% students identified groundwater scarcity as a major issue. Required to work at home or farm, about 65% students in Gujarat and 60% in Rajasthan missed school for up to 2 days/month; and a smaller proportion (∼ 30%) missed schools for 4 or more days/month. School absenteeism was found to be linked with gender; female students missed schools more frequently than their male counterpart. The school attendance records in Rajasthan showed that the frequency of female students missing schools for 5 or more days/month was on an average 2–10 times greater than that for males. The gender difference in absenteeism in all schools was statistically significant (P < .018**). The study highlighted that groundwater scarcity in the study area, and consequent demand on their time for household work including fetching drinking water are contributing factors towards limiting their educational and economic opportunities. Groundwater scarcity can be one of the key factors that can limit inclusiveness and empowerment of women and need to be considered in policy-making. [ABSTRACT FROM PUBLISHER]

Removal of a persistent antiepileptic drug carbamazepine (CBZ) in aqueous solutions was investigated by using solar photolysis combined with free available chlorine (FAC). The combination of chlorination with simulated or natural sunlight markedly enhanced removal of CBZ in 10 mM phosphate buffer solution (pH 7.0) and river water (pH 7.0) compared with sunlight or FAC alone. Further analysis indicated that the observed enhancements in CBZ removal can be attributed to the in situ hydroxyl radical (HO ) and ozone (O 3 ) production during FAC photolysis. During 70 min simulated sunlight photolysis combined with FAC treatment, HO reaction contributed to 35.8% removal of CBZ and O 3 reaction contributed to 40.6% removal, while only 5.3% of CBZ was removed by HOCl reaction. The oxidation products of CBZ, epoxide CBZ, 10,11-dihydro-10,11-dihydroxy CBZ, 1-(2-benzaldehyde)-4-hydro-(1H,3H)-quinazoline-2-one (BQM), 1-(2-benzaldehyde)-(1H,3H)-quinazoline-2,4-dione (BQD) and 4-aldehyde-9-acridone, were mainly formed from the HO and O 3 attack at the double bond on the central heterocyclic ring of CBZ. Formation of these oxidation products did not cause any increase or decrease in toxicity to microbial species tested through Microbial Assay for Toxicity Risk Assessment (MARA). The initial FAC concentration and pH had a major influence on the removal process of CBZ during FAC photolysis, while temperature had a minor effect only. The combination of chlorination with natural sunlight could provide an effective approach for removal of CBZ and other contaminants during water treatment. [ABSTRACT FROM AUTHOR]

Canola ( Brassica napus L.) is the third largest field crop in Australia by area sown. Genetically modified (GM) and non-GM canola varieties released or being developed in Australia include Clearfield® (imidazolinone tolerant), TT (triazine tolerant), InVigor® (glufosinate-ammonium tolerant), Roundup Ready® - RR® (glyphosate tolerant) and Hyola® RT® (tolerant to both glyphosate and triazine). We used two risk assessment approaches – the Environmental Impact Quotient (EIQ) and the Pesticide Impact Rating Index (PIRI) – to compare the environmental risks associated with herbicides used in the canola varieties (GM and non-GM) that are currently grown or may be grown in the future. Risk assessments found that from an environmental impact viewpoint a number of herbicides used in the production of TT canola showed high relative risk in terms of mobility and ecotoxicity of herbicides. The EIQ field use rating values for atrazine and simazine in particular were high compared with those for glyphosate and trifluralin. Imazapic and imazapyr, which are only used in Clearfield® canola, had extremely low EIQ field use rating values, likely reflecting the very low application rates used for these chemicals (0.02 to 0.04 kg/ha) compared with those used for atrazine and simazine (1.2 to 1.5 kg/ha). The PIRI assessment showed that irrespective of the canola variety grown, trifluralin posed a high toxicity risk to fish (Rainbow trout, Oncorhynchus mykiss ), algae and Daphnia sp. While the replacement of trifluralin with propyzamide had little effect on the mobility score, it greatly decreased the ecotoxicity score to fish, algae and Daphnia sp. due to the lower LC50 values for propyzamide compared with trifluralin. This study has shown that based on likelihood of off-site transport of herbicides in surface water and potential toxicity to non-target organisms, the GM canola varieties have no advantage over non-herbicide tolerant (non HT) or Clearfield® canola. [ABSTRACT FROM AUTHOR]

Sorption of non-ionic organic compounds to soil is usually expressed as the carbon-normalized partition coefficient ( K OC ), because it is assumed that the main factor that influences the amount sorbed is the organic carbon content of the soil. However, K OC can vary by a factor of at least ten across a range of soils. We investigated two potential causes of variation in diuron K OC – organic matter–mineral interactions and organic matter chemistry – for a diverse set of 34 soils from Sri Lanka, representing a wide range of soil types. Treatment with hydrofluoric acid (HF-treatment) was used to concentrate soil organic matter. HF-treatment increased K OC for the majority of soils (average factor 2.4). We attribute this increase to the blocking of organic matter sorption sites in the whole soils by minerals. There was no significant correlation between K OC for the whole soils and K OC for the HF-treated soils, indicating that the importance of organic matter–mineral interactions varied greatly amongst these soils. There was as much variation in K OC across the HF-treated soils as there was across the whole soils, indicating that the nature of soil organic matter is also an important contributor to K OC variability. Organic matter chemistry, determined by solid-state 13 C nuclear magnetic resonance (NMR) spectroscopy, was correlated with K OC for the HF-treated soils. In particular, K OC increased with the aromatic C content ( R = 0.64, p = 1 × 10 −6 ), and decreased with O-alkyl C ( R = −0.32, p = 0.03) and alkyl C ( R = −0.41, p = 0.004) content. [ABSTRACT FROM AUTHOR]

Active pharmaceutical ingredients (APIs) can enter the natural environment during manufacture, use and/or disposal, and consequently public concern about their potential adverse impacts in the environment is growing. Despite the bulk of the human population living in Asia and Africa (mostly in low- or middle-income countries), limited work relating to research, development and regulations on APIs in the environment have so far been conducted in these regions. Also, the API manufacturing sector is gradually shifting to countries with lower production costs. This paper focuses mainly on APIs for human consumption and highlights key differences between the low-, middle- and high-income countries, covering factors such as population and demographics, manufacture, prescriptions, treatment, disposal and reuse of waste and wastewater. The striking differences in populations (both human and animal), urbanization, sewer connectivity and other factors have revealed that the environmental compartments receiving the bulk of API residues differ markedly between low- and high-income countries. High sewer connectivity in developed countries allows capture and treatment of the waste stream (point-source). However, in many low- or middle-income countries, sewerage connectivity is generally low and in some areas waste is collected predominantly in septic systems. Consequently, the diffuse-source impact, such as on groundwater from leaking septic systems or on land due to disposal of raw sewage or septage, may be of greater concern. A screening level assessment of potential burdens of APIs in urban and rural environments of countries representing low- and middle-income as well as high-income has been made. Implications for ecological risks of APIs used by humans in lower income countries are discussed. [ABSTRACT FROM AUTHOR]

Highlights: [•] Release of C60 is influenced by soil type. [•] Systems with elevated concentrations of DOC release relatively more C60. [•] Different forms of C60 have similar release behaviour. [•] Non-photoactivated formation of hydrophilic C60 appears to be a possibility in soil. [•] Apparent release of C60 from contaminated biosolids applied to soils will be limited. [Copyright &y& Elsevier]

Abstract: We studied the sorption–desorption behaviour of two herbicides (diuron and artrazine) in a soil rich in Fe and Al oxides (Ferrosol), either amended freshly with two different types of biochars or that contained biochars aged under field conditions. Standard batch sorption–desorption experiments were conducted on soil samples freshly amended with two biochars, (namely, poultry litter – PL and paper mill – PM sludge) as well on those collected from field 32months after biochar application. Soils that were freshly amended with biochars @ 10tha−1 showed a two (PM) to five (PL) fold increase in sorption of herbicides as compared with that in the unamended soil. For example, the fresh amendments with PL biochar at 10tha−1 led to a highly significant (P <0.001) increase in the Freundlich sorption coefficient (K f ) of atrazine; i.e. 20.71 (n =0.40) as compared with 4.02 (n =0.70) for the control soil. Sorption was reversible in the unamended soil but sorption–desorption hysteresis was prominent in the soil amended with fresh biochars. In contrast, the soil containing aged biochars (at 10tha−1) exhibited sorption–desorption properties that were statistically similar to that of the control soil, especially for atrazine. Ageing of biochars in the soil over a 32months period reduced the sorption capacity by 47% (PM) to 68% (PL) for diuron. These findings may have implications for herbicide efficacy in biochar amended soils. [Copyright &y& Elsevier]

Abstract: The form in which pesticides are transported off-site can have implications for their bioavailability, ecotoxicological impact and the effectiveness of any management strategies implemented to minimise their movement. We have investigated the form in which nine pesticides (carbaryl, fenarimol, azinphos methyl, penconazole, pirimicarb, chlorpyrifos, propiconazole, procymidone and bupirimate) were transported in surface water from an apple and cherry orchard in the Mt. Lofty Ranges, South Australia, over three years. The majority of pesticides monitored were found to move off-site in the dissolved (<1.2μm) phase. Only propiconazole moved off-site predominantly (70–90%) by colloidal transport in association with particulate (>1.2μm) material. Chlorpyrifos was detected in surface drainage water for several months and the predominant phase in which it moved varied between events in a year and during an event. The effectiveness of pesticide physicochemical properties as surrogates for predicting mode of transport of pesticides, in this region was determined by regression of average proportion (%) of each pesticide in the dissolved phase for each event against the relevant physicochemical parameters. There was no relationship between average proportion in the dissolved phase (<1.2μm) and any of the pesticide characteristics considered. This suggests that off-site transport of pesticides is governed by complex biological and hydrological interactions and the use of simple physicochemical properties as surrogates for predicting offsite transport may not be applicable. These results have implications for the effectiveness of management strategies, including buffer strips and sedimentation ponds, to minimise transport and suggest that, unless adequate residency time is available for sorption of the pesticides, these strategies may have limited use for minimising the transport of the pesticides used in the two land uses studied here. This study has highlighted the importance of understanding the mode of transport of pesticides for informing the choice of management strategies to minimise potential offsite transport of pesticides under different field conditions. [Copyright &y& Elsevier]

Abstract: In the Mediterranean climate of this study the growing period (and hence spraying period) for horticultural crops usually occurs from late spring to summer (i.e. October–March). However, runoff predominantly occurs in winter (late April–October) since there is insufficient rain in the spring and summer period for runoff to occur. It is therefore important to establish the runoff potential of pesticide, despite the long contact time with soil. We studied the distribution of the loads transported during individual runoff events, and the proportion of total annual load transported in each event over three seasons. Some insecticides and fungicides (pirimicarb, procymidone, carbaryl, fenarimol and penconazole) transported off-site from and apple and cherry orchard over a period of 30 months showed a strong association between peak pesticide load and peak flow during individual flow events. Others (particularly chlorpyrifos) however showed no obvious relationship between flow and load transported off-site. Throughout the year certain pesticides demonstrated behaviour characteristic of those chemicals that move in the first flush of drainage water in the season. This was particularly evident for pirimicarb, bupirimate, carbaryl and fenarimol, which all have K OC values <1000L/kg. However, for other pesticides the percentage of total annual load transported off-site either increased or remained fairly constant for several runoff events during the season which was most obvious for chlorpyrifos followed by penconazole and procymidone – all with K OC values ≥1500L/kg. Generally, the total amount of pesticide moving off-site from both orchards was <0.5% of the total mass of active ingredient applied, except fenarimol (0.54–2.1%). Only chlorpyrifos, however, showed a positive linear relationship between the load transported off-site during an event and total rainfall (R 2 =0.48, n =26). The results from this study have implications for the development of management strategies to minimise pesticide transport to waterways. [Copyright &y& Elsevier]

Abstract: Local runoff from the catchments in the Mt. Lofty Ranges provides a major source of drinking water for the city of Adelaide, South Australia, Australia. In this study two major land uses (apples and cherries) in the Mt. Lofty Ranges were monitored for off-site transport of pesticides over approximately 30 months. While fungicides have been rarely reported in the literature to be present in surface water, in our studies several fungicides (fenarimol, bupirimate, penconazole, procymidone, propiconazole) were found to be transported off-site in a persistent manner over the study period. Two pesticides (chlorpyrifos and fenarimol) from the apple orchard were of particular concern. The average chlorpyrifos concentrations in 2007 and 2009 were more than ten times the environmental guideline value (0.01μg/L), suggesting potential deleterious effects on aquatic organisms immediately downstream of the apple orchard. Fenarimol was detected in 19 water samples collected from early April to early June 2007 and in 95% of these cases the total concentration exceeded the Australian Drinking Water Quality Guideline (no environmental guidelines are available in Australia for this chemical). For pesticides such as chlorpyrifos and fenarimol at least a ten-fold dilution would be required in the receiving environment for the concentrations to be below current guideline values. Generally more pesticides were detected in drainage water leaving the apple orchard than the cherry orchard, reflecting higher pesticide use at the former. The results from this study indicate that pesticides are of concern in this catchment and strategies for minimising off-site transport need to be developed and evaluated. Data from this study show that while some pesticides move off-site predominantly with the first runoff event some pesticides continue to be transported off-site for months. Some pesticides in the Mt. Lofty Ranges are persisting in soils or on the crop canopy for considerable time periods and being detected in surface runoff water months after the last application. [Copyright &y& Elsevier]

Abstract: We evaluated wheat straw biochar produced at 450°C for its ability to influence bioavailability and persistence of two commonly used herbicides (atrazine and trifluralin) with different modes of action (photosynthesis versus root tip mitosis inhibitors) in two contrasting soils. The biochar was added to soils at 0%, 0.5% and 1.0% (w/w) and the herbicides were applied to those soil-biochar mixes at nil, half, full, two times, and four times, the recommended dosage (H4). Annual ryegrass (Lolium rigidum) was grown in biochar amended soils for 1month. Biochar had a positive impact on ryegrass survival rate and above-ground biomass at most of the application rates, and particularly at H4. Within any given biochar treatment, increasing herbicide application decreased the survival rate and fresh weight of above-ground biomass. Biomass production across the biochar treatment gradient significantly differed (p <0.01) and was more pronounced in the case of atrazine than trifluralin. For example, the dose–response analysis showed that in the presence of 1% biochar in soil, the value of GR50 (i.e. the dose required to reduce weed biomass by 50%) for atrazine increased by 3.5 times, whereas it increased only by a factor of 1.6 in the case of trifluralin. The combination of the chemical properties and the mode of action governed the extent of biochar-induced reduction in bioavailability of herbicides. The greater biomass of ryegrass in the soil containing the highest biochar (despite having the highest herbicide residues) demonstrates decreased bioavailability of the chemicals caused by the wheat straw biochar. This work clearly demonstrates decreased efficacy of herbicides in biochar amended soils. The role played by herbicide chemistry and mode of action will have major implications in choosing the appropriate application rates for biochar amended soils. [Copyright &y& Elsevier]

We studied the leaching and dissipation of atrazine (2-chloro-4-ethylamino-6-isopropylamino-1, 3, 5-s-triazine) and its two principal metabolites (desethylatrazine and desisopropylatrazine) for more than two years through soil profiles at five forestry sites across Australia (representing subtropical, temperate and Mediterranean climatic conditions with rainfall ranging from 780 to 1536 mm yr−1). Following atrazine applications at local label rates, soil cores were collected at regular intervals (up to depths of 90–150 cm), and the residues of the three compounds in soil were analysed in composite samples using liquid chromatography. Bromide was applied simultaneously with atrazine to follow the movement of the soil water. While bromide ion rapidly leached through the entire profile, in most cases the bulk of atrazine, desethylatrazine and desisopropylatrazine remained in the top 45 cm of the soil profile. However, a small fraction of residue moved deeper into the soil profile and at a subtropical site (Toolara) trace levels (ng L−1) of atrazine and one of its metabolites (DEA) were detected in perched groundwater located at a depth of 1.8 m. Data on the total residues of atrazine in soil profiles from all sites except the Tasmanian site fitted a first-order decay model. The half-life of atrazine in surface soils at the subtropical sites (Toolara and Imbil) ranged from 11 to 21 days. Four separate applications of atrazine at Toolara resulted in a narrow range of half-lives (16 ± 3.6 days), confirming relatively rapid dissipation of atrazine under subtropical conditions (Queensland). In contrast, a prominent biphasic pattern of initial rapid loss followed by very slow phase of degradation of atrazine was observed under the colder temperate climate of Highclere (Tasmania). The data showed that while its 50% (DT50) loss occurred relatively rapidly (36 days), more than 10% of herbicide residue was still detectable in the profile even a year after application (DT90 = 375 days). The rate of dissipation of atrazine at warm subtropical Queensland sites (Imbil and Toolara) was 2–3 times faster than sites located in colder climate of Tasmania. The marked contrast in DT50 values between subtropical and temperate sites suggest that climatic conditions (soil temperature) is one of the key factors affecting atrazine dissipation. At the Tasmanian site, the combination of leaching of the herbicide in subsoil and slower microbial activity at cooler temperatures would have caused a longer persistence of atrazine. [Copyright &y& Elsevier]

Abstract: Cabamazepine (CBZ), an antiepileptic pharmaceutical compound, is a pollutant of aquatic ecosystems entering via wastewater treatment plants that is considered to be persistent to degradation. An isotope exchange technique was employed using radiolabelled CBZ as a model compound, to determine the amount of isotopic exchangeability of CBZ in river sediment. The amount of isotopically exchangeable CBZ was used as an estimate of the extent of desorption hysteresis in solution from river sediment, including a treatment where the sediment was amended with black carbon. The isotopically exchangeable CBZ was measured by equilibrating 12C-CBZ with sediment for 0 to 28days followed by a 24hour equilibration with 14C-CBZ at the end of the incubation period. The isotopically exchangeable fraction of CBZ decreased over time in the sediment, particularly following amendment with black carbon. This has important implications for the fate of CBZ, which, apart from being resistant to degradation, is constantly released into aquatic ecosystems from wastewater treatment plants. This study demonstrates the availability of a relatively quick and simple alternative to batch desorption techniques for the assessment of the available fraction of organic compounds in sediments following their release into aquatic ecosystems. [Copyright &y& Elsevier]

Abstract: We report a survey on the occurrence of estrogens (estrone, E1; 17β-estradiol, E2; 17α-ethynylestradiol, EE2) and xenoestrogens (bisphenol-A, BPA; 4-t-octylphenol, 4-t-OP; 4-nonylphenols, 4-NP; and nonylphenol mono- and di-ethoxylates, NPE1 and NPE2) in effluents from five wastewater treatment plants and their receiving waters in South East Queensland. The total xenoestrogen concentrations in effluent ranged between 2446 ng/L and 6579 ng/L, with 4-NP and NPE1-2 having much higher concentration levels than BPA and 4-t-OP. The estrogen levels in effluent varied from 9.12 to 32.22 ng/L for E1, from 1.37 ng/L to 6.35 ng/L for E2 and from 0.11 ng/L to 1.20 ng/L for EE2. No significant differences (p <0.05) in the concentrations of the selected estrogenic compounds were found for the effluents from the five sewage treatment plants. The estrogens and xenoestrogens were also found in the receiving waters at relatively lower concentration levels due to dilution of effluents in the rivers. Based on the chemical analysis data and relative potency of the compound from in vitro and in vivo bioassays from the literature, the calculated in vitro EEQ values (estrogen equivalents) in the receiving river waters downstream of the effluent discharge points ranged from 1.32 to 11.79 ng/L, while the in vivo EEQ values (vitellogenin response in rainbow trout) ranged from 2.48 to 21.18 ng/L. The three estrogens accounted for the majority of the EEQ in the water samples. This study indicates that the rivers of South East Queensland are at potential risk. [Copyright &y& Elsevier]

Triclosan (TCS) antimicrobial compound is used in personal care products such as shampoos and soaps. The TCS compound can survive the treatment process and is often present in the sewage effluent and biosolids. We investigated the impact of TCS upon selected microbiological and biochemical parameters in two contrasting Australian soils. Substrate-induced respiration and nitrification, plus activities of four enzymes (relevant for carbon and nitrogen turnover), were measured using Organisation for Economic Co-operation and Development protocols after exposing soils to TCS at concentrations of 0, 1, 5, 10, 50, and 100 mg/ kg of soil. Respiration in the sandy soil was not affected by the addition of TCS, but in clay soil it decreased to TCS at 50 mg/ kg of soil. The nitrification process was affected in both soils. In the sandy soil, TCS showed a negative effect on the nitrate and nitrite production at 5 mg/kg. In contrast, in the clay soil, the effect was noticeable only at concentrations greater than 50 mg/kg. The response of four enzymes (acid and alkali phosphatase, β-glucosidase, and chitinase) in the two soils was variable, and only β-glucosidase showed some response to TCS addition. The study demonstrated that TCS at concentrations below 10 mg/kg can disturb the nitrogen cycle in some soils. A first-tier hazard assessment highlighted the need for further work on TCS impact on soil microorganisms. [ABSTRACT FROM AUTHOR]

The potential of mid-infrared (MIR) spectroscopy in combination with partial least-squares (PLS) regression was investigated to predict the soil sorption (distribution) coefficient (Kd) of a nonionic pesticide (diuron). A calibration set of 101 surface soils collected from South Australia was utilized for reference sorption data and MIR spectra. Principal component analysis (PCA) was performed on the spectra to detect spectral outliers. The MIR-PLS model was developed and validated by dividing the initial data set into four validation sets. The model resulted in a coefficient of determination (R²) of 0.69, a standard error (SE) of 5.57, and a residual predictive deviation (RPD) of 1.63. The normalized sorption coefficient for the organic compound (Koc) approach, on the other hand, resulted in R², SE, and RPD values of 0.42,7.26, and 1.25, respectively. However, the significant statistical difference between the two models was mainly due to two outliers detected via PCA. Apart from spectral outliers, the performance of the two models was essentially similar for the rest of the calibration set Outlier detection by the MIR-PLS model may gainfully be employed as a tool for improving prediction of Kd. The MIR-based model can provide a direct estimation of Kd values based on the integrated properties of organic and mineral matter reflected in the infrared spectra. [ABSTRACT FROM AUTHOR]

The fate and removal of the estrogens 17β-estradiol (E2), estrone (E1), and 17α-ethynylestradiol (EE2) and of the xenoestrogens bisphenol A (BPA), 4-tert-octylphenol (4-t-OP), 4-nonylphenol (4-NP), and nonylphenol mono- and diethoxylate (NPEO1 and NPEO2, respectively) were investigated in four South Australian sewage treatment plants (STPs; plants A-D) with different treatment technologies. The concentrations in the effluent from the two-year survey were similar to those reported in other studies. In the effluent, 4-NP, NPEO1, and NPEO2 had total concentrations up to 8 μg/L, which were much higher than those of BPA and 4-t-OP. Estrone had the highest concentrations among the three estrogens, ranging between 13.3 and 39.3 ng/L, whereas the concentrations for E2 and EE2 varied between 1.0 and 4.2 ng/L and between 0.1 and 1.3 ng/L, respectively. The removal rates for the estrogens and xenoestrogens were variable but consistent with the plant performance parameters (biochemical oxygen demand, suspended solids, and ammonia). Considering all the estrogenic compounds analyzed in the present study, plant D, with a series of anaerobic and aerobic lagoons, was the least efficient of the four STPs in the removal of these compounds. The removal rates for 4-NP, NPEO1, and NPEO2 within the plants were 92% for plant A, with conventional activated sludge treatment; 80% for plant B, with two oxidation ditches; 70% for plant C, with three bioreactors; and 64% for plant D, with 10 lagoons in series. Comparatively, the removal of estrogens was lower, with rates ranging between 47 and 68% for E2 at the four plants. Both E1 and EE2 were more persistent during treatment, especially in plants C and [ABSTRACT FROM AUTHOR]

Naturally occurring charcoals are increasingly being recognized as effective sorbents for organic compounds. In this study we investigated the sorption of benzene and toluene in single-sorbate and bi-sorbate systems on different types of charcoals produced in laboratory, employing the batch sorption technique. Air dried plant materials from Phalaris grass (Phalaris tuberosa) and Red Gum wood (Eucalyptus camadulensis) were combusted under limited oxygen supply at 250°C, 450°C, and 850°C. The resulting charcoals were characterized for their specific surface areas, total cation content, and pore size distributions (pore size distribution only for wood combusted at 450°C and 850°C). For the materials treated at 850°C not only the surface area, microporosity, and total amount of sorbed sorbate increased markedly, but also the non-linearity of the sorption isotherm. The pore size distributions and surface areas as well as an indifferent sorption behaviour and competition effects for both sorbates indicated that pore filling mechanisms were the dominating processes governing the sorption on these microporous, high temperature treated materials. For the materials treated at lower temperatures the affinity of toluene was higher compared to that of benzene. In the bi-sorbate system the overall uptake of benzene increased. These phenomena might be due to the stronger hydrophobicity of toluene, and to a varying potential for swelling of the matrix and pore deformation by the two sorbates. The significantly lower sorption capacity of the Phalaris-derived material compared to the Red Gum charcoal correlated with its smaller surface area and higher cation content. [Copyright &y& Elsevier]

Abstract: Triclosan (TCS) is an antimicrobial agent widely used in many personal care products. This study investigated the occurrence of TCS in effluents, biosolids and surface waters, and its fate in wastewater treatment plants (WWTPs). The aqueous concentrations of TCS in nineteen effluents from Australian WWTPs ranged from 23 ng/L to 434 ng/L with a median concentration of 108 ng/L, while its concentrations in nineteen biosolids ranged from 0.09 mg/kg to 16.79 mg/kg on dry weight basis with a median concentration of 2.32 mg/kg. The removal rates for TCS in five selected WWTPs were found to range between 72% and 93%. Biological degradation was believed to be the predominant removal mechanism for TCS in the WWTPs. However, adsorption onto sludge also played a significant role in the removal of TCS in the WWTPs. TCS at concentrations up to 75 ng/L was detected in surface waters (outfall, upstream, and downstream) from five rivers receiving effluent discharge from WWTPs. Preliminary risk assessment based on the worst-case scenario showed that the TCS concentrations in surface waters might lead to risks to aquatic organisms such as algae. Based on the TCS levels in the biosolids, application of biosolids on agricultural land may also cause adverse effects in the soil environment. [Copyright &y& Elsevier]

To have an effective barrier against invading termites around building structures and to assess the potential risks to the urban environment and human beings, we need to understand the fate of termiticides applied in urban soil. The movement and degradation of a new termiticide, fipronil, were investigated in Australian soils following standard termiticide treatment methods (surface application under slab and trenching treatments along walls). Surface application studies in three field sites showed slow dissipation and little movement for fipronil in all three soils under the simulated slab during a three-year period. The greatest mass of the chemical residues remained in the quartzite sand layer (thickness, 5 cm), and only small amounts of these were found to have migrated into the soil layers (depth, 0-15 cm) underneath the quartzite sand layer. Of the three metabolites (desulfinyl, sulfide, and sulfone) found in the soils, the sulfone derivative had the highest concentration. Persistence of fipronil was affected by application rate. The time for 50% loss of the total toxic components (fipronil plus its metabolites) in the quartzite sand layer (thickness, 5 cm) ranged from 200 to 326 d for the low rate (0.15 g active ingredient/m2) and from 633 to 674 d for the high application rate (3 g active ingredient/m²). One-year trenching studies at two sites in Adelaide (Roseworthy Farm [RF] and Terretfield [TF]; South Australia, Australia) showed that vertical movement and dissipation of fipronil occurred in the soils. The average concentration of fipronil in the trenches (depth, 0-30 cm) decreased from 33.7 to 14.9 mg/kg in the loam soil at the RF site and from 39.4 to 14.6 mg/kg in the clay soil at the TF site over the year. With time under the natural weather condition, fipronil and its derivatives were found in the deeper soil sections without treatment (depth, 20-30 cm). However, laboratory studies using repacked soil columns showed low mobility in the loam soil from the RF site and a variably charged clay soil from Malanda (Queensland, Australia) under intermittent wetting and drying conditions. [ABSTRACT FROM AUTHOR]

Abstract: Cadmium is perhaps environmentally the most significant heavy metal in soils. Bioavailability, remobilization and fate of Cd entering in soils are usually controlled by adsorption–desorption reactions on Fe oxides. Adsorption of Cd on soil colloids including Fe oxides has been extensively studied but Cd desorption from such soil minerals has received relatively little attention. Some factors that affect Cd adsorption on goethite include pH, temperature, aging, type of index cations, Cd concentrations, solution ionic strength and presence of organic and inorganic ions. This research was conducted to study the influence of pH, temperature and aging on Cd desorption from goethite. Batch experiments were conducted to evaluate Cd desorption from goethite with 0.01M Ca(NO3)2. In these experiments Cd desorption was observed at 20, 40 and 70°C in combination with aging for 16h, 30, 90 and 180d from goethite that adsorbed Cd from solutions containing initial Cd concentrations of 20, 80 and 180μM. Following the adsorption step Cd desorption was measured by 15 successive desorptions after aging at various temperatures. At the lowest amount of initially adsorbed Cd and equilibrium pH 5.5, cumulative Cd desorption decreased from 71% to 17% with aging from 16h to 180d and the corresponding decrease at equilibrium pH 6.0 was from 32% to 3%. There was a substantial decrease in Cd desorption with increasing equilibration temperature. For example, in goethite with the lowest amount of initial adsorption at equilibrium pH 5.5, cumulative Cd desorption decreased from 71% to 31% with increase in temperature from 20 to 70°C, even after 16h. Dissolution of Cd adsorbed goethite in 1M HCl, after 15 successive desorptions with 0.01M Ca(NO3)2, indicated that approximately 60% of the Cd was surface adsorbed. Overall, dissolution kinetics data revealed that 23% to 88% Cd could not be desorbed, which could possibly be diffused into the cracks and got entrapped in goethite crystals. At elevated temperature increased equilibrium solution pH favoured the formation of CaCO3 and CdCO3 which reasonably decreased Cd desorption. Cadmium speciation showed the formation of calcite and otavite minerals at 40 and 70°C due to increase in pH (>9.5) during aging. X-ray diffraction analysis (XRD) of these samples also revealed the formation of CaCO3 at elevated temperatures with aging. While mechanisms such as Cd diffusion and/or entrapment into fissures and cracks in goethite structure with increase in temperature and aging are possible. [Copyright &y& Elsevier]

We investigated how the NMR properties of uniformly 13C-labeled benzene molecules are influenced by sorption to charcoals produced in the laboratory and collected from the field following wildfires. Uniformly 13C-labeled benzene was sorbed to two charcoals produced in the laboratory at 450 and 850 °C. The chemical shift of benzene sorbed to the higher-temperature charcoal was 5–6 ppm lower than that of benzene sorbed to the lower-temperature charcoal. This difference was attributed to stronger diamagnetic ring currents (which cause a shift to lower ppm values) in the more condensed or ‘graphitic’ high-temperature charcoal. The chemical shift of benzene sorbed to two charcoals collected from the field following wildfires indicated a degree of charcoal graphitization intermediate between that of the two laboratory-prepared charcoals. Variable contact time and dipolar dephasing experiments showed that the molecular mobility of sorbed benzene molecules increased with increasing charcoal graphitization, and also increased with increasing benzene concentration. We propose that the chemical shift displacement of molecules sorbed to charcoal could be used to identify molecules sorbed to black carbon in heterogeneous matrixes such as soils and sediments, and to establish how condensed or ‘graphitic’ the black carbon is. [ABSTRACT FROM AUTHOR]

The Ecological Risk Assessment (ERA) workshop focused on the anthropogenic contaminants in the terrestrial environment, addressing various components of the ERA process. These included sources, exposure pathways, bioavailability, and toxicity to receptor organisms as well as risk communication. It was concluded that although the overseas experience on ERA for terrestrial ecosystems (e.g. , International Standards or guidelines from the European Union and the United States) is very useful, it is not directly applicable to Australia due to the differences in receptor organisms, contaminants, soil, and environmental conditions. Workshop discussions stressed on the need for making ERA locally relevant (in terms of choice of receptor organisms, sampling strategy, and bioavailability considerations). The workshop discussions highlighted the need of better appreciation of both the similarities and the clear differences between aquatic and terrestrial ERAs. The availability of reliable data, problems with databases, estimation of bioavailability, and extrapolations from laboratory to field were noted among the key limitations. ERA—being inherently complex and involving a range of environmental compartments, target receptor, and exposure pathways—at a minimum requires a multidisciplinary approach to address the complexities. Bringing a multidisciplinary team together often proves a major challenge in ERA. The delegates called for continued efforts in this area and formation of a network or working group in Australia. [ABSTRACT FROM AUTHOR]

A high-performance liquid chromatography method with diode-array detection (HPLC-DAD) is described for the determination of three neonicotinoid insecticides imidacloprid, thiacloprid, and thiamethoxam in soil and water. The soil samples were extracted with acetonitrile, while the water samples were extracted using C18 cartridges. The mean recoveries plus standard deviations for spiked soil samples were 82 ± 4.2% for thiamethoxam, 99 ± 4.2% for imidacloprid and 94 ± 1.4% for thiacloprid. The recoveries for water samples ranged from 87 ± 3.4% for thiamethoxam to 97 ± 3.9% for imidacloprid and 97 ± 2.6% for thiacloprid. The limits of quantitation (LOQ) were 0.1, 0.1, 0.01 mg/kg in soil (5 g), and 2, 2, 0.5 µg/L in water (50 mL) for thiamethoxam, imidacloprid, and thiacloprid, respectively. [ABSTRACT FROM AUTHOR]

We investigated bioavailability and biodegradation of carbaryl (1-naphthyl methylcarbamate) in a soil with a long history of pesticide contamination from a storage facility located at Mamoon Kanjan, Pakistan. Carbaryl is weakly sorbed and generally considered to be easily degradable in soil. Extraction studies revealed that 49% of the total carbaryl in soil (88.0 mg kg-1) was not water-extractable and also not bioavailable, as demonstrated by inoculation of the contaminated soil with a carbaryl-degrading, mixed bacterial culture. Inoculation of the contaminated soil with the carbaryl-degrading culture showed that the bacteria were capable of degrading only the available (i.e., water-extractable) fraction of the pesticide. When the soil was pulverized in a ball mill to enhance the release of residue, an additional 19% of the carbaryl became bioavailable. A significant proportion of residue (≈33%) remained unavailable. The long (>12 years) contact time between the pesticide and soil (i.e., aging), allowing possible sequestration into soil nanopores and the organic matter matrices, is suggested to have rendered the pesticide unavailable for microbial degradation. High concentration (88.0 mg kg-1) in soil facilitated its persistence and sequestration. Results from the present study demonstrate that even a weakly sorbed and easily degradable pesticide, carbaryl, is effectively sequestrated in soil with time, rendering it partly inaccessible to microorganisms and affecting the bioavailability of the compound. [ABSTRACT FROM AUTHOR]

The potential of five nonionic surfactants, Triton X-100, Brij35, Ethylan GE08, Ethylan CD127, and Ethylan CPG660 for enhancing release of carbaryl and ethion from two long-term contaminated soils was evaluated using the batch method. Incorporation of the surfactants into soils enhanced the release of both pesticides to various extents, which could be related to the type of pesticides and type and the amount of surfactants added. Release of ethion was dramatically enhanced by aqueous concentrations of surfactants above their critical micelle concentration values. This was attributed to solubility enhancement through incorporation of the highly hydrophobic compound within surfactant micelles. A concentration of 10 g L−1 of various surfactants released >70% of the total ethion from the soil irrespective of the surfactant. For carbaryl, the surfactants were effective at low concentrations and dependence on concentration was lower than in the case of ethion. The ethylan surfactants (GE08, CD127, and CPG660) had a higher potential than Triton X-100 and Brij35 for releasing the pesticides. However, there was still a significant portion of carbaryl (11% of the total) and ethion (17% of the total) left in the soil. Our study also showed that there must be an optimal concentration of each surfactant to maximize the mass transfer of pesticides. At some threshold concentration level, additional surfactant started to inhibit the mass transfer of solute from the soil into the water. The results suggested that surfactants could help remediation of soils polluted by pesticides. The choice of surfactant should be made based on the properties of pesticides. [ABSTRACT FROM AUTHOR]

Sorption and degradation of the five selected endocrine disrupting chemicals (EDCs) including bisphenol A (BPA), 17β-estradiol (E2), 17α-ethynylestradiol (EE2), 4-tert-octylphenol (4-t-OP) and 4-n-nonylphenol (4-n-NP) have been investigated in the laboratory using sediment and groundwater from an aquifer in Bolivar, South Australia. The sorption coefficients measured on the sediment were in the following order: 4-n-NP>4-t-OP>EE2>E2>BPA. The sorption coefficients (Kf values) for the five EDCs were 3.89, 21.8, 24.2, 90.9 and 195, respectively. The alkylphenols 4-t-OP and 4-n-NP had strong binding on the sediment while BPA had a weak affinity. Degradation experiments of the five EDCs showed that E2 and 4-n-NP degraded quickly under aerobic conditions with a half-life of 2 and 7 days, respectively. EE2 degraded slowly with an estimated half-life of 81 days in the aquifer material under aerobic conditions while the other two chemicals (BPA and 4-t-OP) remained almost unchanged. Little or no degradation of the five EDCs except slow degradation for E2 was observed within 70 days under anaerobic conditions in native groundwater. [Copyright &y& Elsevier]

Microbial reduction of Fe(lll) in illite was studied to evaluate the possibility of microbial utilization of Fe(lll) in sedimentary clays and to determine the effects of bioreduction on clay composition and structure. A subsurface bacterium (Shewanella putrefaciens CN32) and illite separates (<0.2 µm) from St. Peter Formation sandstone in 0gle County, IL, were used in laboratory experiments. Illite suspensions buffered at pH 7 with bicarbonate were inoculated with CN32 and provided with H[sub 2] as an electron donor. In selected treatments, anthraquinone-2,6-disulfonate (AQDS), was included as an electron shuttle to facilitate the bioreduction. Fe(ll) production in inoculated treatments was determined by extraction with 0.5 N HCl and compared to uninoculated controls to establish the extent of biological reduction. The resulting solids were characterized by Mössbauer spectroscopy and scanning and transmission electron microscopy (SEM and TEM). The characterization of the starting illite material revealed that it contained a minor component of goethite (α-Fe00H) in addition to fibrous illite. The starting material (both goethite and illite) contained 6% (w/ w) total Fe, and 82% of the total Fe was Fe(lll). Approximately 30% of total Fe was associated with goethite. At the end of a 30-day incubation, residual goethite and illite remained. The extent of reduction was much greater in the presence of AQDS (25%) than in its absence (0%). Modeling of Mössbauer spectra of the bioreduced material indicated that both goethite and illite were reduced but to a different extent. Additionally, TEM evidence suggested that there was a dramatic change in illite morphology upon bioreduction from fibrous needles to plates. The ability of bacteria to utilize Fe(lll) in illite has important implications for microbial functions and survival mechanisms, as well as many geological processes, in the subsurface. [ABSTRACT FROM AUTHOR]

Hormone steroids are a group of endocrine disruptors, which are excreted by humans and animals. In this paper, we briefly review the current knowledge on the fate of these steroids in the environment. Natural estrogenic steroids estrone (E1), 17β-estradiol (E2) and estriol (E3) all have a solubility of approximately 13 mg/l, whereas synthetic steroids 17α-ethynylestradiol (EE2) and mestranol (MeEE2) have a solubility of 4.8 and 0.3 mg/l, respectively. These steroids have a moderate binding on sediments and are reported to degrade rapidly in soil and water. Estrogenic steroids have been detected in effluents of sewage treatment plants (STPs) in different countries at concentrations ranging up to 70 ng/l for E1, 64 ng/l for E2, 18 ng/l for E3 and 42 ng/l for EE2. E2 concentrations in river waters from Japan, Germany, Italy and the Netherlands ranged up to 27 ng/l. In addition, E2 concentrations ranging from 6 to 66 ng/l have also been measured in mantled karst aquifers in northwest Arkansas. This contamination of ground water has been associated with poultry litter and cattle manure waste applied on the land. Although hormone steroids have been detected at a number of sources worldwide, currently, there is limited data on the environmental behaviour and fate of these hormone steroids in different environmental media. Consequently, the exposure and risk associated with these chemicals are not adequately understood. [Copyright &y& Elsevier]

Investigates the nature of soil organic matter and relationship with the sorption of carbon in pesticides. Evidence of high concentration of alkyl C and smallest concentration of carbonyl C in soil; Presence of linear sorption coefficients between carbaryl and phosalone compounds.

Urbanisation will be one of the 21st century's most transformative trends. By 2050, it will increase from 55% to 68%, more than doubling the urban population in South Asia and Sub-Saharan Africa. Urbanisation has multifarious (positive as well as negative) impacts on the wellbeing of humans and the environment. The 17 UN Sustainable Development Goals (SDGs) form the blueprint to achieve a sustainable future for all. Clean Water and Sanitation is a specific goal (SDG 6) within the suite of 17 interconnected goals. Here we provide an overview of some of the challenges that urbanisation poses in relation to SDG 6, especially in developing economies. Worldwide, several cities are on the verge of water crisis. Water distribution to informal settlements or slums in megacities (e.g. >50% population in the megacities of India) is essentially non-existent and limits access to adequate safe water supply. Besides due to poor sewer connectivity in the emerging economies, there is a heavy reliance on septic tanks, and other on-site sanitation (OSS) system and by 2030, 4.9 billion people are expected to rely on OSS. About 62–93% of the urban population in Vietnam, Sri Lanka, the Philippines and Indonesia rely on septic tanks, where septage treatment is rare. Globally, over 80% of wastewater is released to the environment without adequate treatment. About 11% of all irrigated croplands is irrigated with such untreated or poorly treated wastewater. In addition to acute and chronic health effects, this also results in significant pollution of often-limited surface and groundwater resources in Sub-Saharan Africa and Asia. Direct and indirect water reuse plays a key role in global water and food security. Here we offer several suggestions to mitigate water and food insecurity in emerging economies. Unlabelled Image • Urbanisation will be one of the 21st century's most transformative trends. • Worldwide several cities are on the verge of water crisis. • Over 80% of wastewater is poorly treated and is used to irrigate 11% of all croplands. • About 60–90% of the urban population in many emerging economies relies on septic tanks. • We offer several suggestions to mitigate water and food insecurity in emerging economies. [ABSTRACT FROM AUTHOR]

This article focuses on the invitation of papers for the Ecological Risk Assessment for Terrestrial Ecosystems Workshop that was held in Adelaide, South Australia in April 2004. The workshop was fortunate in attracting international experts from the U.S., Europe and New Zealand, plus about 100 Australian delegates. Glenn Suter from the U.S. Environmental Protection Agency, provided a U.S. perspective and Jack Faber from Wageningen University and Research Centre, the Netherlands, provided a European viewpoint on site-specific ecological risk assessments. A feature of the workshop was that the afternoons were devoted completely to workshop discussions, following thought provoking introductions from the invited experts. The topics of discussions at the workshop included contaminant sources, bioavailability and toxicity to receptor organisms, exposure pathways, databases, data deficiency randomness, data quality, mistakes in assessment, sampling strategies, analytical and modeling tools as well as stakeholder involvement and risk communication.

Due to reduced tillage practices, glyphosate is widely used as a herbicide in grain farming systems of Australia. Residual glyphosate when mixed with water bodies can be a health concern. Updated information concerning the fate of glyphosate in soil systems with biochar amendment is lacking. For this experiment, different biochars were weighed and premixed in 2 ml Eppendorf tubes. A solution (Mixture of mercuric chloride and radiolabeled C14 glyphosate) having different concentrations provided by the commonwealth scientific and industrial research organization was used. Tubes having solutions were shaken on end over end shaker for 24 h. Tubes were removed from the shaker and centrifuged for 5 min. at 13000 revolutions per minute. Digested, labeled samples after counting disintegration per minute on Tricarb 4810 were used as sorption data. Results showed significant adsorption of glyphosate in the Entisol soil systems in the presence of char. The results have been published, however, the author wants to communicate in detail the role of liquid scintillation counting as a future research method for radiolabeled herbicides to understand the adsorption behavior of herbicides like glyphosate in different soil systems. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Irrigated crops showed varied impact on the hydraulic and solute exchange to the river. • Annual flow to the river under almond was 2.1 times higher than wine grapes. • 20, 60, and 40 m buffers needed for grapes, almond, and annual horticulture, respectively, to control solutes to the river. • Solute residence time was twice long for grapes compared to almonds and annual horticulture. Abstract Riparian zones are essential to preserve water quality of rivers adjacent to large areas of irrigated agriculture. We used HYDRUS (2D/3D) to quantify the long-term (8 years) influence of crops (almonds, wine grapes and potato-carrot) irrigated with recycled water on water and solute exchange at the Gawler River interface in relation to vegetation buffer widths from 10 to 110 m. We found that under almond and annual horticulture the likely average annual water flow from the irrigated area to the river was nearly twice as much (2.1 and 1.8, respectively) that under wine grapes. The hydraulic exchange at river interface for different irrigated crops was found to be sensitive to the buffer widths. For wine grapes, almonds and annual horticulture, the average annual hydraulic balance reached an equilibrium at 20, 65 and 55 m buffer widths, respectively. Furthermore, for wine grapes, with a 20 m buffer width, the average annual load of salts became negligible. This study shows that buffer widths of 20, 60, and 40 m for irrigated wine grapes, almond, and annual horticulture, respectively, are needed to restrict the migration of salts to the river. Further refinements are possible by incorporating the influence of preferential flow paths, improved water stress response functions, and addressing the data limitations for calibration of the model for solute dynamics. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Chlorine has a higher reactivity with oxazepam than with diazepam. • pH affects the kinetic rate constants by impacting the reactant species of reactants. • The C-3 of 1,4-benzodiazepine structure is the main site of attack. • Transformation products will be comparatively stable during chlorination process. Abstract The pharmaceutical benzodiazepine diazepam and its metabolite oxazepam have been detected in wastewater treatment plants effluents, surface water and treated drinking water, but their transformation during chlorination process is not well understood. We investigated the reactions of diazepam and oxazepam with free available chlorine using a high-resolution mass analyzer and theoretical calculation to elucidate the fate of benzodiazepines during water chlorination process. The obtained apparent second-order rate constants (k app) for chlorine reaction with diazepam and oxazepam varied from 0.01 to 1.7 M−1 s−1 and 0.7 to 31.6 M−1 s−1 in the pH range of 5.5–10.0, respectively. Under typical wastewater disinfection conditions of neutral pH values, free chlorine concentrations of 5 mg L−1 and contact times of up to 2 h, the corresponding half-lives for diazepam (∼180 min) and oxazepam (∼61 min) suggest that diazepam will be partly transformed during disinfection. Conversely, oxazepam will be considerably transformed during wastewater disinfection. The pH-dependency of k app for diazepam could be explained by the reactions between neutral diazepam and HClO species. The kinetic pattern for oxazepam can be well described by species-specific reactions involving oxazepam or Cl 2 and Cl 2 O species. In total, fifteen and eight transformation products were identified for chlorination of diazepam and oxazepam, respectively. The C-3 of 1,4-benzodiazepine structure was the main site of attack, leading predominantly to the oxidation and then cleavage of the C(3)-N(4) bond, as well as diazepine ring contractions. Based on mass balance estimation, the main chlorination product for diazepam and oxazepam are 7-chloro-1-methyl-5-phenyl-1,3-dihydro-2H-1,4-benzodiazepin-2,3-dione and 6-chloro-4-phenyl-2(1H)-quinazolinone, respectively. [ABSTRACT FROM AUTHOR]

We are racing to manage a phenomenally increasing volume of organic wastes from urban, industrial and agricultural entities. Composting is one of the preferred ways to convert biodegradable wastes into nutrient-rich soil conditioners. The age-old technique of composting process is being improved with innovative scientific means. Biochar, a widely studied soil amendment, is a carbonaceous material that can hold nutrients from endogenic/exogenic sources. Biochar-compost, a biochar-complemented compost, may provide a wide range of benefits expected from both materials. Compost and biochar can improve physicochemical and microbiological attributes of soils by supplying labile and stable carbons, and nutrients. Compost may also supply beneficial microbes. This means biochar-compost is a synergic soil amendment that can improve soil quality, increase crop production, and remediate contaminated soils. Having stable carbon, large reactive surface with nutrient loads, biochar can interact widely with organic biomass and modify physicochemical and-microbial states during a composting process while making biochar-compost. Production and application methods of biochar, compost and biochar-compost are covered for agricultural and contaminated soils. Metal and organic contaminations are also discussed. A case study on making and field-testing a mineral-enhanced biochar and a biochar-compost to improve rice yield, is presented at the end. [ABSTRACT FROM AUTHOR]

Widespread usage of per- and polyfluoroalkyl substances (PFASs) has caused major environmental contamination globally. The hydrophilic and hydrophobic properties of PFASs affect the sorption behaviour and suggest organic carbon may not be the only factor affecting sorption. We reviewed the quality of all data published in peer-reviewed literature on sorption of PFASs to critically evaluate the role organic carbon (OC) and other properties have in sorption of PFASs in soils or sediments. The largest data sets available were for perfluorooctanoic acid (PFOA, n = 147) and perfluorooctane sulfonic acid (PFOS, n = 178), and these analyses showed very weak correlations between sorption coefficient (K d ) and OC alone (R 2  = 0.05–0.07). When only laboratory-derived K d values of PFASs and OC were analysed, the R 2 values increased for PFOA (R 2  = 0.24, n = 42), PFOS (R 2  = 0.38, n = 69), perfluorononanoic acid (PFNA, R 2  = 0.77 n = 12), and perfluorodecanoic acid (PFDA, R 2  = 0.78, n = 13). However, the relationships were heavily skewed by one or two high OC values. Similarly there was no significant relationship between K d values and pH for PFOS (R 2  = 0.06) and PFOA (R 2  = 0.07), across a range of environmental pH values. Our analyses showed sorption behaviour of a range of PFASs could not be explained by a single soil or sediment property. Multiple regression models better explained the sorption behaviour of a number of PFASs. Regressions of OC and pH together explained a significant proportion of the variation in K d values for 9 out of 14 PFASs and 8 of these regressions had ≥10 data points. This review highlighted that at least OC, pH and clay content are properties having significant effect on sorption. There is a clear need for more data and studies with thorough characterisation of soils or sediments to better understand their role in PFASs sorption. Current assessments based on OC alone are likely to be erroneous. [ABSTRACT FROM AUTHOR]

• Overlooked contribution of PBMs towards the DBP formation was critically reviewed. • Elastomers, tire waste, polyelectrolytes, and MPs serve as potent DBP precursors. • Leached DOC and dissolved nitrogen from PBMs play a key role in DBP formation. • DBPs formation potential of polyelectrolytes was found as high as ∼2 mg/L. • DBPs formation potential of different microplastics ranged from 1.9 to 15,990 µg/L. Disinfection by-products (DBPs) are formed through the disinfection of water containing precursors such as natural organic matter or anthropogenic compounds (e.g., pharmaceuticals and pesticides). Due to the ever increasing use of plastics, elastomers, and other polymers in our daily lives, polymer-based materials (PBMs) are detected more frequently and at higher concentrations in water and wastewater. The present review provides a comprehensive and systematic analysis of the contribution of PBMs - including elastomers, tire waste, polyelectrolytes, and microplastics - as precursors of DBPs in water and wastewater. Literature shows that the presence of PBMs can lead to the leaching of dissolved organic matter (DOM) and subsequent formation of DBPs upon disinfection in aqueous media. The quantity and type of DBPs formed strongly depends on the type of polymer, its concentration, its age, water salinity, and disinfection conditions such as oxidant dosage, pH, temperature, and contact time. DOM leaching from elastomers and tire waste was shown to form N -nitrosodimethylamine up to concerning levels of 930 ng/L and 466,715 ng/L, respectively upon chemical disinfection under laboratory conditions. Polyelectrolytes can also react with chemical disinfectants to form toxic DBPs. Recent findings indicate trihalomethanes formation potential of plastics can be as high as 15,990 µg/L based on the maximum formation potential under extreme conditions. Our analysis highlights an overlooked contribution of DOM leaching from PBMs as DBP precursors during disinfection of water and wastewater. Further studies need to be conducted to ascertain the extent of this contribution in real water and wastewater treatment plants. [Display omitted] [ABSTRACT FROM AUTHOR]

Studies were undertaken to assess sorption of seven endocrine-disrupting chemicals (EDCs), namely, estrone (E1), 17β-estradiol (E2), estriol (E3), 17α-ethynylestradiol (EE2), bisphenol A (BPA), 4-tert-octyl phenol (4-t-OP), and 4-n-nonyl phenol (4-n-NP) on four soils (from sandy to clay soil) with different physicochemical properties and biodegradation of five EDCs (BPA, E2, EE2, 4-t-OP, and 4-n-NP) in a loam soil associated with wastewater reuse. We also characterized the biotransformation of E2 to E1 in the loam soil under aerobic and anaerobic conditions. Sorption test using a batch equilibrium method demonstrated that alkylphenols (4-t-OP and 4-n-NP) had the strongest sorption onto soils, followed by estrogens (EE2, E2, E1, E3) and BPA. This laboratory study showed that all five EDCs, including the degradation product E1, were degraded rapidly in the soil within 7 d under aerobic conditions. However, under anaerobic conditions in the soil, little or no degradation of the five EDCs was noted except for E2, which showed slow degradation during the 70-d study. The calculated half-lives for E2 under anaerobic conditions were 24 d in the soil. Estradiol was found to be biotransformed to E1 under both aerobic and anaerobic conditions. The study suggested that the five EDCs as well as E1, which may be present in reclaimed wastewater, would not persist in well-aerated soil. But these EDCs persisting in anaerobic soil may affect soil and groundwater quality and ecosystem. [ABSTRACT FROM AUTHOR]

Background and aims: Plant uptake of active pharmaceutical ingredients (APIs) is increasingly leading to concerns about their potential exposure to humans and wildlife via dietary intake. Due to the extraordinary ability of biochars to bind organic compounds, plant uptake experiments were conducted to assess the effect of soil-amendment of three different biochars on the uptake of APIs from spiked soil. Methods: Pot experiments were undertaken to assess the extent of sorption and corresponding bioaccessibility of two APIs (carbamazepine - CBZ and propranolol -PRL) to ryegrass ( Lolium perenne) grown in an API-spiked loamy sand, with and without biochar amendment (5 t/ha equivalent). The soil was amended with three different biochars produced from eucalyptus wood and wheat residues. Results: Both APIs were taken up by ryegrass, with CBZ preferentially accumulated (14.3 mg/kg CBZ, 3.8 mg/kg PRL in unamended soil) due to its comparatively high concentration in porewater. Soil amendment with biochars increased partitioning of the two APIs by up to three- fold, with corresponding decreases in porewater (34-72 % of unamended soil) and plant tissue (17-64 %) concentrations. Conclusions: Biochars were effective in reducing the uptake of APIs into plant tissues from a contaminated soil and may be effective in the management of API residues in contaminated soils. [ABSTRACT FROM AUTHOR]

Indaziflam is a relatively new herbicide for which sorption–desorption information is lacking, and nothing is available on its metabolites. Information is needed on the multiple soil and pesticide characteristics known to influence these processes. For four soils, the order of sorption was indaziflam (N-[1R,2S)-2,3-dihydro-2,6-dimethyl-1H-inden-1-yl]-6-[(1R)-1-fluoroethyl]-1,3,5-triazine-2,4-diamine) (sandy clay loam:Kf= 5.9, 1/nf= 0.7,Kfoc= 447; sandy loam:Kf= 3.9, 1/nf= 0.9,Kfoc= 276) > triazine indanone metabolite (N-[(1R,2S)-2,3-dihydro-2,6-dimethyl-3-oxo-1H-inden-1-yl]-6-[(1R)-1-fluoroethyl]-1,3,5-triazine-2,4-diamine) (sandy clay loam:Kf= 2.1, 1/nf= 0.8,Kfoc= 177; sandy loam:Kf= 1.7, 1/nf= 0.9,Kfoc= 118) > fluoroethyldiaminotriazine metabolite (6-[(1R-1-Fluoroethyl]-1,3,5-triazine-2,4-diamine) (sandy clay loam:Kf= 0.3, 1/nf= 0.9,Kfoc= 28; sandy loam:Kf= 0.3, 1/nf= 0.9,Kfoc= 22) = indaziflam carboxylic acid metabolite (2S,3R)-3-[[4-amino-6-[(1R)-1-fluoroethyl]-1,3,5-triazin-2-yl]amino]-2,3-dihydro-2-methyl-1H-indene-5-carboxylic acid) (sandy clay loam:Kf= 0.3, 1/nf= 0.9,Kfoc= 22; sandy loam:Kf= 0.5, 1/nf= 0.8,Kfoc= 32). The metabolites being more polar than the parent compound showed lower sorption. Desorption was hysteretic for indaziflam and triazine indanone metabolite, but not for the other two metabolites. Unsaturated transient flowKd's were lower than batchKd's for indaziflam, but similar for fluoroethyldiaminotriazine metabolite. BatchKd's would overpredict potential offsite transport if desorption hysteresis is not taken into account. [ABSTRACT FROM AUTHOR]

Batch experiments were conducted to evaluate the sorption-desorption behaviour of 14C-labelled carboxylic acids (citric and oxalic) and amino acids (glutamic, alanine, phenylalanine and lysine) on pure minerals (kaolinite, illite, montmorillonite, ferrihydrite and goethite). The sorption experiments were complemented by ATR-FTIR spectroscopy to gain possible mechanistic insight into the organic acids-mineral interactions. In terms of charge, the organic solutes ranged from strongly negative (i.e., citric) to positively charged solutes (i.e., lysine); similarly the mineral phases also ranged from positively to negatively charged surfaces. In general, sorption of anionic carboxylic and glutamic acids was higher compared to the other compounds (except lysine). Cationic lysine showed a stronger affinity to permanently charged phyllosilicates than Fe oxides. The sorption of alanine and phenylalanine was consistently low for all minerals, with relatively higher sorption and lower desorption of phenylalanine than alanine. Overall, the role of carboxylic functional groups for the sorption and retention of these carboxylic and amino acids on Fe oxides (and kaolinite) and of amino group on 2:1 phyllosilicates was noticeable. Mineral properties (surface chemistry, specific surface area), chemistry of the organic compounds (pKa value, functional groups) and the equilibrium pH of the system together controlled the differences in sorption-desorption patterns. The results of this study aid to understand the effects of mineralogical and chemical factors that affect naturally occurring low molecular weight organic compounds sorption under field conditions. [ABSTRACT FROM AUTHOR]

Biochar is produced by thermal decomposition of biomass under oxygen-limited conditions (pyrolysis), and it has received attention in soil remediation and waste disposal in recent years. The characteristics of biochar are influenced mainly by the preparation temperature and biomass. Higher pyrolysis temperature often results in the increased surface area and carbonized fraction of biochar leading to high sorption capability for pollutants. Biochars derived from various source materials show different properties of surface area, porosity and the amount of functional groups which are important concerning on the effect of biochar. Biochar has been proved to be effective in improving soil properties and increasing crop biomass. It has also been suggested that it can even enhance crop resistance to disease. Biochar has recently been used to remediate soil with both heavy metal and organic pollutants. The mechanism is electrostatic interaction and precipitation in the case of heavy metal, and the surface adsorption, partition and sequestration in the case of organic contaminants. However, application of biochar in soil has been shown to result in decreased efficacy of pesticides, which indicates a trade-off between the potentially promising effect of biochar on pesticide remediation and its negative effect on pesticide efficacy. While arguments on the effectiveness of biochar appear sound, further research is needed prior to widespread application of biochar in soil remediation. [ABSTRACT FROM AUTHOR]

Abstract: Imidazolinones are chiral herbicides, comprised of two enantiomers with differential herbicidal activity. In this study, the selective degradation of enantiomers of the three imidazolinone herbicides, imazapyr, imazethapyr and imazaquin, was determined in a variety of soils selected to cover a broad range of physico-chemical characteristics. The R(+) enantiomer of all three herbicides, which has greater herbicidal activity (up to eight times), was found to degrade faster than the less active S(−) enantiomer. The enantiomer fraction (EF) was used as a descriptor of enantio-selectivity of the imidazolinone herbicides. The EF values increased with increasing incubation time for imidazolinones with a fast initial phase followed by a slower phase. While the enantio-selectivity was not significant in acidic soils (pHw 5.02 and 5.20), it was highly significant (P <0.001) in alkaline soils (pHw 7.6, 8.2 and 8.7). Significant positive correlations of EF values of imazapyr (P <0.001, R 2 =0.41), imazethapyr (P <0.002, R 2 =0.47) and imazaquin (P <0.001, R 2 =0.54) were found with the soil pHw ranging from 5.02 to 8.7. However, no correlation of EF was found with other soil properties. In addition to showing enantioselective degradation of the three herbicides in the soils studied, the study highlighted that for imidazolinones the herbicidally more active enantiomer can be preferably degraded by microorganisms. [Copyright &y& Elsevier]

Abstract: We have investigated the effect of antimicrobials triclosan (TCS) and triclocarban (TCC) on biodegradation of 17β-Estradiol (E2) and 17α-Ethynylestradiol (EE2) in a sandy soil from South Australia. Two separate batch studies were conducted. In the first, the rates of loss of E2 and EE2 were determined at time intervals of 0, 3, 7, 14, 21, 28 and 56 d after initial spiking of soil with each estrogen at 1mgkg−1 and the antimicrobials at 10 and 100mgkg−1. Little loss of E2 and EE2 (<15%) under sterile conditions was noted compared to rapid loss in non-sterile soil (>60% in 24h). There were no measurable effects on estrogen degradation by the two antimicrobials at spiked concentrations up to 100mgkg−1. The experiments were repeated to study degradation rates of the estrogens within the first 24h (0, 3, 8, 24h), 3 d and then weekly to 56 d. Again, E2 and EE2 degradation was not significantly affected by the presence of TCS up to 100mgkg−1 (p >0.05). However TCS did significantly affect biodegradation of the estrogens when the soils were spiked with 1000mgkg−1 of TCS (p <0.0005). In contrast, presence of TCC in soil showed no significant effect on biodegradation of the two compounds up to 1000mgkg−1 (p >0.05). Considering environmental concentrations of the antimicrobials reported in the literature, it is highly unlikely these biocides would have any adverse impact on biodegradation of E2 or EE2 in soils. [Copyright &y& Elsevier]

The present study assessed contamination and toxicity of sediments from seven remediated and remnant wetland sites within Sydney Olympic Park, Australia, and four unremediated Sites adjacent to its boundary using chemical analysis and a luminescent bacterial biosensor assay (Escherichia coli). Concentrations of metals (Pb, Cr, Cu, Ni, Zn, Cd, and As) and persistent organic chemicals (DDT and its metabolites, dichlorodiphenyldichloroethane and dichlorodiphenyldichloroethylene; polycyclic aromatic hydrocarbons; polychlorinated biphenyls; and polychlorinated dibenzo-p-dioxins and dibenzofurans) in sediments and their pore-water samples were determined. Zinc concentrations were the highest of the metals in the sediments (84-618 mg/kg), and at eight sites, metal concentrations in sediments exceeded the Australian ecological trigger values for Pb, Zn, and Ni. Concentrations of organic contaminants in the sediments exceeded the trigger values at all 11 sites for DDTs, at 6 sites for polycyclic aromatic hydrocarbons, and 5 sites for polychlorinated biphenyls. Sediment samples from the four unremediated sites outside the Sydney Olympic Park had dioxin concentrations greater than 200 pg (toxic equivalency per gram). The same four sites were identified as contaminated in pore-water toxicity tests with the luminescent biosensor, generally consistent with the bioavailable fractions of the contaminants (pore-water and Tenax® extraction data), as well as dioxin levels, in the sediments. Preliminary toxicity identification and evaluation tests of the pore water from the four sites outside the park demonstrated that organic contaminants were the main cause of toxicity to E. coli, with no evidence that metals contributed to the toxicity of the pore water. [ABSTRACT FROM AUTHOR]

Abstract: The effect of solvent-conditioning on the sorption of diuron and phenanthrene was investigated. The organic carbon-normalized sorption coefficients (K OC) for diuron and phenanthrene (determined from single initial concentrations of 0.8mgL−1 and 1.5mgL−1, respectively) were consistently higher following solvent-conditioning of a whole soil with five organic solvents (acetonitrile, acetone, methanol, chloroform and dichloromethane). The relative increase in K OC was inversely related to the polarity of the conditioning solvent (i.e. greater increases in K OC were observed for the least polar solvents: chloroform and dichloromethane). The effect of solvent-conditioning on the sorption properties of the same soil that had been lipid-extracted using accelerated solvent extraction (ASE) was also investigated. Since lipid extraction involves treatment with a non-polar solvent (95:5 dichloromethane:methanol) one may have expected no further increase in K OC on solvent-conditioning. On the contrary, the lipid-extracted soil exhibited very similar increases in K OC as the whole soil. This demonstrated that lipid removal and solvent-conditioning, which both increased K OC for this soil, are quite separate phenomena. [Copyright &y& Elsevier]