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Per- and poly-fluoroalkyl substances (PFASs) are contaminants of emerging concern, yet the understanding of factors that control their leaching and release from contaminated soils remains limited. This study aimed to investigate the impact of dissolved organic carbon (DOC) on the release of PFASs—specifically, perfluorohexane sulfonate (PFHxS), perfluorooctane sulfonate (PFOS), and perfluorooctanoic acid (PFOA)from soils contaminated by aqueous film forming foam (AFFF). Batch aqueous leaching experiments were conducted on AFFF-contaminated soils under alkaline solution conditions (pH 9.5, 10.5, and 12) as it enhances leaching of both PFAS and DOC. Leaching of PFOS was significantly increased under alkaline conditions. Although the leaching of PFAS generally increased with pH, PFOS appeared to be more retained under the very alkaline pH conditions used in this study. At the same solution pH, leaching of PFOS and DOC was less in Ca(OH) 2 than in NaOH. The retention of PFOS under these conditions may be attributable to the shielding of the negative charge of the soil components and colloids (e.g., DOC and clay minerals) in the leachates and/or the screening of negative charges on head groups of PFOS due to the high concentration of divalent cations. Solution chemistry affected desorption of PFOS more than PFHxS and PFOA. The study highlights that the influence of DOC on PFAS leaching and transport can be very complex, and depends on leachate chemistry (e.g., pH and cation type), PFAS chemistry, the magnitude of PFAS contamination and factors that influence the solid:liquid partitioning of organic carbon in soil. [Display omitted] • DOC affects PFAS leaching; impact varies with PFAS concentration & leachate chemistry. • Effect of DOC and solution chemistry on PFAS leaching is more pronounced for PFOS. • Increasing cation concentrations reduces PFAS mobility in environments at high pH. • Cations can decrease the leaching of PFAS at high pH via charge screening. • DOC has a small effect on PFOS desorption from highly contaminated soils. [ABSTRACT FROM AUTHOR]

Immobilisation/stabilisation is one of the most developed and studied approaches for treating soils contaminated with per- and poly-fluoroalkyl substances (PFAS). However, its application has been inhibited by insufficient understanding of the effectiveness of added soil sorbents over time. Herein, we present results on the effectiveness of select carbon-based sorbents, over 4 years (longevity) and multiple laboratory leaching conditions (durability). Standard batch leaching tests simulating aggressive, worst-case scenario conditions for leaching (i.e., shaking for 24–48 h at high liquid/solid ratios) were employed to test longevity and durability of stabilisation in clay-loam and sandy-loam soils historically contaminated with PFAS (2 and 14 mg/kg ∑ 28 PFAS). The different sorbents, which were applied at 1–6% (w/w), reduced leaching of PFAS from the soils to varying degrees. Among the 5 sorbents tested, initial assessments completed 1 week after treatment revealed that 2 powdered activated carbon (PAC) sorbents and 1 biochar were able to reduce leaching of PFAS in the soil by at least 95%. Four years after treatment, the performance of the PAC sorbents did not significantly change, whilst colloidal AC improved and was able to reduce leaching of PFAS by at least 94%. The AC-treated soils also appeared to be durable and achieved at least 95% reduction in PFAS leaching under repetitive leaching events (5 times extraction) and with minimal effect of pH (pH 4–10.5). In contrast, the biochars were affected by aging and were at least 22% less effective in reducing PFAS leaching across a range of leaching conditions. Sorbent performance was generally consistent with the sorbent's physical and chemical characteristics. Overall, the AC sorbents used in this study appeared to be better than the biochars in stabilising PFAS in the long term. [Display omitted] • Efficacy of soil stabilisation treatments may change over time. • Activated carbon can reduce leaching of PFAS in both short and long term. • Biochars in this study were only effective in the short term. • Sorption of PFAS onto AC is predominately driven by hydrophobic interactions. • Sorbent performance was consistent with the sorbent's physico-chemical properties. [ABSTRACT FROM AUTHOR]

Fullerenes (e.g. C 60 , C 70 , etc.) present in soil may undergo changes in its retention with aging. In this study, the partitioning behavior of ( 14 C)-C 60 aged up to 12 weeks was investigated in biosolids-amended soil. Spiked samples were subjected to sequential partitioning using water, methanol, and toluene followed by total combustion of solids; the distribution of 14 C across solvents and matrices were used to provide insights on C 60 behavior. In most samples, 14 C only partitioned in toluene with the remaining (non-extractable) activity detected in the solid phase. In all biosolids-amended soil samples, an increase in non-extractable 14 C were observed for those exposed to light (vs dark) with the greatest difference observed in biosolids + sand samples. Possible processes that contribute to the observed 14 C distribution, i.e. retention and potential transformation of C 60, were discussed. Over-all, results suggest that environmental exposure to C 60 and potentially transformed C 60 species, as a result of their release from soils, is likely to be low. [ABSTRACT FROM AUTHOR]

Char as a carbon-rich material, can be produced under pyrolytic conditions, wildfires or prescribed burn offs for fire management. The objective of this study was to elucidate mechanistic interactions of copper (Cu 2+ ) and nickel (Ni 2+ ) with different chars produced by pyrolysis (green waste, GW; blue-Mallee, BM) and forest fires (fresh-burnt by prescribed fire, FC; aged char produced by wild fire, AC). The pyrolytic chars were more effective sorbents of Cu 2+ (∼11 times) and Ni 2+ (∼5 times) compared with the forest fire chars. Both cross-polarization (CPMAS-NMR) and Bloch decay (BDMAS-NMR) 13 C NMR spectroscopies showed that forest fire chars have higher woody components (aromatic functional groups) and lower polar groups (e.g. O -alkyl C) compared with the pyrolytic chars. The polarity index was greater in the pyrolytic chars (0.99–1.34) than in the fire-generated chars (0.98–1.15), while aromaticity was lower in the former than in the latter. Fourier transform infrared (FTIR) and Raman spectroscopies indicated the binding of carbonate and phosphate with both Cu 2+ and Ni 2+ in all chars, but with a greater extent in pyrolytic than forest fire-generated chars. These findings have demonstrated the key role of char's oxygen-containing functional groups in determining their sorption capacity for the Cu 2+ and Ni 2+ in contaminated lands. [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]

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]

Spills of hydraulic fracturing (HF) fluids and of produced water during unconventional gas extraction operations may cause soil contamination. We studied the degradation and microbial toxicity of selected HF chemical components including two biocides (methylisothiozolinone- MIT, chloromethylisothiozolinone- CMIT), a gel-breaker aid (triethanolamine -TEA), and three geogenic chemicals (phenol, m- cresol and p- cresol) in ultrapure water, HF fluid and produced water in five different soil types (surface and subsurface soils). The degradation of the two biocides (in soils treated with HF fluid or ultrapure water) and of the three geogenic chemicals (in soils treated with produced water) was rapid (in all cases DT 50 values < 2 days in surface soils). In contrast, the loss of TEA was much slower in soils, especially in those treated with HF fluid (DT 50 > 30 days). Sorption coefficients (K oc in L/Kg) in these soils ranged from 71 to 733 for TEA, 64–408 for MIT and 11–72 for CMIT. In terms of soil microbial toxicity, exposure to HF fluid and produced water reduced microbial respiration, albeit temporarily. The overall microbial activities in surface soils contaminated with produced water had fully recovered in most soils. In contrast, the HF fluid addition to soils completely inhibited the nitrification in all soils, with little recovery over the 60 day experimental period. In the case of produced water exposure, three out of five surface soils showed complete recovery in nitrification during the study period. The functional genes for nitrogen fixation (nifH) and carbon cycling (GA1) and microbial community composition (16 S rRNA) were significantly affected by HF fluid in some soils. Overall, the study shows that the HF fluid can have significant detrimental impact on soil microbial functions, especially on nitrogen cycling. More work is needed to identify the exact cause of microbial toxicity in soils contaminated with HF fluid. [Display omitted] • Hydraulic fracturing (HF) fluid inhibited soil nitrification and altered the microbial community. • Substrate induced nitrification did not recover 60 days after HF fluid addition. • Triethanolamine degradation was markedly reduced in HF fluid treated soils. • Biocides and target geogenic organic chemicals disappeared from soils within two days. • Biocides showed little sorption to soils and were considered to be mobile. [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]

Manufactured nanoparticles (NPs) present in consumer products could enter soils through re-use of biosolids. Among these NPs are those based on silver (Ag), which are found sulphidised (e.g. silver sulphide, Ag2S) in biosolids. Herein, our aim was to examine the release of retained Ag(0) and Ag2S NPs in soils and biosolids as facilitated by environmentally and agriculturally relevant ligands. Under natural soil conditions, exemplified by potassium nitrate and humic acid experiments, release of Ag retained in soil was limited. The highest total Ag release was facilitated by ligands that simulated root exudates (citrate) or fertilisers (thiosulphate). Released Ag was predominantly present in the colloidal phase (>3 kDa–< 0.45 μm); intact NPs only identified in Ag2S-NP extracts. For biosolids containing nanoparticulate-Ag-S, release was also enhanced by thiosulphate, though mostly as colloidal-Ag–not intact NPs. These results suggest that exposure to NPs as a result of its release from soils or biosolids will be low. [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]

Highlights: [•] We assessed the bioaccumulation of triclosan and methyl triclosan by mussels. [•] The log bioconcentration factor for triclosan from seawater was 4.13 (lipid based). [•] Field deployed mussels (70days) showed detectable residues (up to 10μgkg−1). [•] Mussels can help monitor pollution of triclosan and methyl triclosan in seawater. [ABSTRACT FROM AUTHOR]

We investigated the occurrence and removal of four benzotriazoles (BTs) (benzotriazole: BT; 5-methyl-benzotriazole: 5-TTri; 5-chloro-benzotriazole: CBT; 5,6-dimethyl-benzotriazole: XTri) and six UV filters (benzophenone-3: BP-3; 3-(4-methylbenzylidene)camphor: 4-MBC; octyl 4-methoxycinnamate: OMC; 2-(3-t-butyl-2-hydroxy-5-methylphenyl)-5-chloro benzotriazole: UV-326; 2-(2′-Hydroxy-5′-octylphenyl)-benzotriazole: UV-329; octocrylene: OC) in a full scale municipal wastewater treatment in South Australia. BT, 5-TTri and BP-3 were found as the dominant compounds detected in the wastewater samples with average concentrations up to 5706 ± 928 ng/L, 6758 ± 1438 ng/L and 2086 ± 1027 ng/L in influent, and up to 2439 ± 233 ng/L, 610 ± 237 ng/L and 153 ± 121 ng/L in effluent, respectively. In the biosolid, 4-MBC and OC were found with the highest concentrations of 962 ± 135 ng/g and 465 ± 65 ng/g, respectively. Sorption onto sludge played a dominant role in the removal for UV filters, especially for 4-MBC, UV-326 and OC, which accounted for 54%–92% of influent loads, while biological degradation played a significant role for the other compounds. [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 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]

Triclocarban and triclosan are two antimicrobial agents widely used in many personal care products. Their biodegradation behaviour in soil was investigated by laboratory degradation experiments and environmental fate modelling. Quantitative structure–activity relationship (QSAR) analyses showed that triclocarban and triclosan had a tendency to partition into soil or sediment in the environment. Fate modelling suggests that either triclocarban or triclosan “does not degrade fast” with its primary biodegradation half-life of “weeks” and ultimate biodegradation half-life of “months”. Laboratory experiments showed that triclocarban and triclosan were degraded in the aerobic soil with half-life of 108 days and 18 days, respectively. No negative effect of these two antimicrobial agents on soil microbial activity was observed in the aerobic soil samples during the experiments. But these two compounds persisted in the anaerobic soil within 70 days of the experimental period. [Copyright &y& Elsevier]

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]

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]

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]

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]

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]

The sorption behaviour of three perfluoroalkyl substances (PFASs), namely perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA) and perfluorohexane sulfonic acid (PFHxS), was determined on 28 tropical soils. Tropical soils are often highly weathered, richer in sesquioxides than temperate soils and may contain variable charge minerals. There are little data on sorption of PFASs in tropical soils. The highest K d values were found for PFOS with mean values ranging from 0 to 31.6 L/kg. The K d values for PFOA and PFHxS ranged from 0 to 4.9 L/kg and from 0 to 5.6 L/kg, respectively. While these values are in the range of literature sorption data, the average K d values for PFOS and PFOA from the literature were 3.7 times and 3.6 times higher, respectively, than those measured in this study. Stepwise regression analysis did explain some of the variance, but with different explanatory variables for the different PFASs. The main soil properties explaining sorption for PFOS and PFOA were oxalate-extractable Al and pH, and for PFHxS was pH. Image 1 • Sorption values for PFOS, PFOA and PFHxS were determined for 28 tropical soils. • PFOS sorption values were approximately 3.7 times lower than mean literature values. • PFOA sorption values were approximately 3.6 times lower than mean literature values. • Sorption of PFOA and PFOS was explained by pH and oxalate-extractable Al. [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]

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: 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]

Abstract: We investigated the effectiveness of two types of biochars in reducing the bioavailability of two soil-applied insecticides (chlorpyrifos and carbofuran) to Spring onion (Allium cepa). The biochars prepared from the pyrolysis of Eucalyptus spp. wood chips at 450 and 850°C (BC850) were thoroughly mixed into the soil to achieve 0%, 0.1%, 0.5% and 1% by soil weight. A spring onion crop was grown for 5 wk in the biochar-amended soils spiked with 50mgkg−1 of each pesticide. The loss of both pesticides due to degradation and or sequestration in soils decreased significantly with increasing amounts of biochars in soil. Over 35 d, 86–88% of the pesticides were lost from the control soil, whereas it was only 51% of carbofuran and 44% of chlorpyrifos from the soil amended with 1.0% BC850. Despite greater persistence of the pesticide residues in biochar-amended soils, the plant uptake of pesticides decreased markedly with increasing biochar content of the soil. With 1% of BC850 soil amendment, the total plant residues for chlorpyrifos and carbofuran decreased to 10% and 25% of that in the control treatment, respectively. The BC850 was particularly effective in reducing phytoavailability of both pesticides from soil, due to its high affinity for and ability to sequester pesticide residues. [Copyright &y& Elsevier]

The influence of lipids on the sorption of diuron and phenanthrene to soils was investigated. Accelerated solvent extraction (ASE) was used to extract lipids from twelve soil horizons. Extractable lipids accounted for 3–13% of organic C. The organic carbon-normalized sorption coefficients (K OC) for diuron and phenanthrene were consistently higher for the lipid-extracted soils than for the whole soils (average of 31% for diuron and 29% for phenanthrene), indicating that lipids compete for or block sorption sites on the organic matter. Sorption experiments on one pair of HF-treated soils indicated that the blocking effects of minerals and lipids are independent, since lipid extraction and HF-treatment combined increased K OC by more than either treatment alone. Lipids extracted from whole and HF-treated soils were very similar in composition, consisting predominantly of long-chain polymethylene structures. K OC of the lipid itself was lower than for any of the whole soils and soil fractions (lipid extracted and HF-treated) for diuron, but higher for phenanthrene. Solid-state 13C NMR spectra of the HF-treated soils before and after lipid extraction indicated that 15–20% of alkyl C was removed by ASE and that no other structures were affected. [Copyright &y& Elsevier]

Even though it is well established that soil C content is the primary determinant of the sorption affinity of soils for non-ionic compounds, it is also clear that organic carbon-normalized sorption coefficients (K OC) vary considerably between soils. Two factors that may contribute to K OC variability are variations in organic matter chemistry between soils and interactions between organic matter and soil minerals. Here, we quantify these effects for two non-ionic sorbates—diuron and phenanthrene. The effect of organic matter–mineral interactions were evaluated by comparing K OC for demineralized (HF-treated) soils, with K OC for the corresponding whole soils. For diuron and phenanthrene, average ratios of K OC of the HF-treated soils to K OC of the whole soils were 2.5 and 2.3, respectively, indicating a substantial depression of K OC due to the presence of minerals in the whole soils. The effect of organic matter chemistry was determined by correlating K OC against distributions of C types determined using solid-state 13C NMR spectroscopy. For diuron, K OC was positively correlated with aryl C and negatively correlated with O-alkyl C, for both whole and HF-treated soils, whereas for phenanthrene, these correlations were only present for the HF-treated soils. We suggest that the lack of a clear effect of organic matter chemistry on whole soil K OC for phenanthrene is due to an over-riding influence of organic matter–mineral interactions in this case. This hypothesis is supported by a correlation between the increase in K OC on HF-treatment and the soil clay content for phenanthrene, but not for diuron. [Copyright &y& Elsevier]