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The accumulation of microplastics (MPs) and nanoplastics (NPs) in terrestrial and aquatic ecosystems has raised concerns because of their adverse effects on ecosystem functions and human health. Plastic waste management has become a universal problem in recent years. Hence, sustainable plastic waste management techniques are vital for achieving the United Nations Sustainable Development Goals. Although many reviews have focused on the occurrence and impact of micro- and nanoplastics (MNPs), there has been limited focus on the management of MNPs. This review first summarizes the ecotoxicological impacts of plastic waste sources and issues related to the sustainable management of MNPs in the environment. This paper then critically evaluates possible approaches for incorporating plastics into the circular economy in order to cope with the problem of plastics. Pollution associated with MNPs can be tackled through source reduction, incorporation of plastics into the circular economy, and suitable waste management. Appropriate infrastructure development, waste valorization, and economically sound plastic waste management techniques and viable alternatives are essential for reducing MNPs in the environment. Policymakers must pay more attention to this critical issue and implement appropriate environmental regulations to achieve environmental sustainability.

This study assessed the ability of phosphorus (P) fertilizer to remediate the rhizosphere of three wild plant species (Banksia seminuda, a tree; Chloris truncata, a grass; and Hakea prostrata, a shrub) growing in a soil contaminated with total (aliphatic) petroleum hydrocarbon (TPH). Plant growth, photosynthesis (via chlorophyll fluorescence), soil microbial activity, alkane hydroxylase AlkB (aliphatic hydrocarbon-degrading) gene abundance, and TPH removal were evaluated 120 days after planting. Overall, although TPH served as an additional carbon source for soil microorganisms, the presence of TPH in soil resulted in decreased plant growth and photosynthesis. However, growth, photosynthesis, microbial activities, and AlkB gene abundance were enhanced by the application of P fertilizer, thereby increasing TPH removal rates, although the extent and optimum P dosage varied among the plant species. The highest TPH removal (64.66%) was observed in soil planted with the Poaceae species, C. truncata, and amended with 100 mg P kg−1 soil, while H. prostrata showed higher TPH removal compared to the plant belonging to the same Proteaceae family, B. seminuda. The presence of plants resulted in higher AlkB gene abundance and TPH removal relative to the unplanted control. The removal of TPH was associated directly with AlkB gene abundance (R2 > 0.9, p < 0.001), which was affected by plant identity and P levels. The results indicated that an integrated approach involving wild plant species and optimum P amendment, which was determined through experimentation using different plant species, was an efficient way to remediate soil contaminated with TPH.

Antimony (Sb) is introduced into soils, sediments, and aquatic environments from various sources such as weathering of sulfide ores, leaching of mining wastes, and anthropogenic activities. High Sb concentrations are toxic to ecosystems and potentially to public health via the accumulation in food chain. Although Sb is poisonous and carcinogenic to humans, the exact mechanisms causing toxicity still remain unclear. Most studies concerning the remediation of soils and aquatic environments contaminated with Sb have evaluated various amendments that reduce Sb bioavailability and toxicity. However, there is no comprehensive review on the biogeochemistry and transformation of Sb related to its remediation. Therefore, the present review summarizes: (1) the sources of Sb and its geochemical distribution and speciation in soils and aquatic environments, (2) the biogeochemical processes that govern Sb mobilization, bioavailability, toxicity in soils and aquatic environments, and possible threats to human and ecosystem health, and (3) the approaches used to remediate Sb-contaminated soils and water and mitigate potential environmental and health risks. Knowledge gaps and future research needs also are discussed. The review presents up-to-date knowledge about the fate of Sb in soils and aquatic environments and contributes to an important insight into the environmental hazards of Sb. The findings from the review should help to develop innovative and appropriate technologies for controlling Sb bioavailability and toxicity and sustainably managing Sb-polluted soils and water, subsequently minimizing its environmental and human health risks.

QC 20230515

Poly- and perfluoroalkyl substances (PFAS) are synthetic chemicals, which reach terrestrial and aquatic environments through anthropogenic activities. Major sources of PFAS in the environment include fire-fighting foams (aqueous film forming foam (AFFF)), wastewater sources, biosolids, and composts. Limited information is available about PFAS in wastewater, which is the focus of this review. PFAS wastewater sources include domestic effluents, industrial effluents, landfill leachates, stormwater, and agricultural effluents through their use in various applications. Land application of PFAS-contaminated wastewater can lead to the contamination of soil and groundwater, thereby reaching the food chain through plant uptake and consumption of potable water. Landfill leachates and industrial effluents contain the highest concentrations of PFAS, posing serious risks to surrounding waterways. Transformation of PFAS precursors can occur through abiotic and biotic processes within the treatment of wastewater, resulting in the formation of harmful PFAS compounds. Currently, there is limited data reported on novel short-chain and ultra-short chain PFAS and PFAS precursors. The strong thermal and chemical stability of PFAS and the complex nature of PFAS mixtures makes the remediation of PFAS in wastewater challenging. However, the review examines and compares current technologies which can treat and remove PFAS from wastewaters. In this review, the distribution, transformation, and remediation of PFAS and their substitutes in wastewater sources are covered.

Poly- and perfluoroalkyl substances (PFASs) are synthetic chemicals, which are introduced to the environment through anthropogenic activities. Aqueous film forming foam used in firefighting, wastewater effluent, landfill leachate, and biosolids are major sources of PFAS input to soil and groundwater. Remediation of PFAS contaminated solid and aqueous media is challenging, which is attributed to the chemical and thermal stability of PFAS and the complexity of PFAS mixtures. In this review, remediation of PFAS contaminated soils through manipulation of their bioavailability and destruction is presented. While the mobilizing amendments (e.g., surfactants) enhance the mobility and bioavailability of PFAS, the immobilizing amendments (e.g., activated carbon) decrease their bioavailability and mobility. Mobilizing amendments can be applied to facilitate the removal of PFAS though soil washing, phytoremediation, and complete destruction through thermal and chemical redox reactions. Immobilizing amendments are likely to reduce the transfer of PFAS to food chain through plant and biota (e.g., earthworm) uptake, and leaching to potable water sources. Future studies should focus on quantifying the potential leaching of the mobilized PFAS in the absence of removal by plant and biota uptake or soil washing, and regular monitoring of the long-term stability of the immobilized PFAS. © 2020 Elsevier B.V.

With the ever-increasing demand for lithium (Li) for portable energy storage devices, there is a global concern associated with environmental contamination of Li, via the production, use, and disposal of Li-containing products, including mobile phones and mood-stabilizing drugs. While geogenic Li is sparingly soluble, Li added to soil is one of the most mobile cations in soil, which can leach to groundwater and reach surface water through runoff. Lithium is readily taken up by plants and has relatively high plant accumulation coefficient, albeit the underlying mechanisms have not been well described. Therefore, soil contamination with Li could reach the food chain due to its mobility in surface- and ground-waters and uptake into plants. High environmental Li levels adversely affect the health of humans, animals, and plants. Lithium toxicity can be considerably managed through various remediation approaches such as immobilization using clay-like amendments and/or chelate-enhanced phytoremediation. This review integrates fundamental aspects of Li distribution and behaviour in terrestrial and aquatic environments in an effort to efficiently remediate Li-contaminated ecosystems. As research to date has not provided a clear picture of how the increased production and disposal of Li-based products adversely impact human and ecosystem health, there is an urgent need for further studies on this field.

Aqueous film-forming foam, used in firefighting, and biowastes, including biosolids, animal and poultry manures, and composts, provide a major source of poly- and perfluoroalkyl substances (PFAS) input to soil. Large amounts of biowastes are added to soil as a source of nutrients and carbon. They also are added as soil amendments to improve soil health and crop productivity. Plant uptake of PFAS through soil application of biowastes is a pathway for animal and human exposure to PFAS. The complexity of PFAS mixtures, and their chemical and thermal stability, make remediation of PFAS in both solid and aqueous matrices challenging. Remediation of PFAS in biowastes, as well as soils treated with these biowastes, can be achieved through preventing and decreasing the concentration of PFAS in biowaste sources (i.e., prevention through source control), mobilization of PFAS in contaminated soil and subsequent removal through leaching (i.e., soil washing) and plant uptake (i.e., phytoremediation), sorption of PFAS, thereby decreasing their mobility and bioavailability (i.e., immobilization), and complete removal through thermal and chemical oxidation (i.e., destruction). In this review, the distribution, bioavailability, and remediation of PFAS in soil receiving solid biowastes, which include biosolids, composts, and manure, are presented.

The term “Total petroleum hydrocarbons” (TPH) is used to describe a complex mixture of petroleum-based hydrocarbons primarily derived from crude oil. Those compounds are considered as persistent organic pollutants in the terrestrial environment. A wide array of organic amendments is increasingly used for the remediation of TPH-contaminated soils. Organic amendments not only supply a source of carbon and nutrients but also add exogenous beneficial microorganisms to enhance the TPH degradation rate, thereby improving the soil health. Two fundamental approaches can be contemplated within the context of remediation of TPH-contaminated soils using organic amendments: (i) enhanced TPH sorption to the exogenous organic matter (immobilization) as it reduces the bioavailability of the contaminants, and (ii) increasing the solubility of the contaminants by supplying desorbing agents (mobilization) for enhancing the subsequent biodegradation. Net immobilization and mobilization of TPH have both been observed following the application of organic amendments to contaminated soils. This review examines the mechanisms for the enhanced remediation of TPH-contaminated soils by organic amendments and discusses the influencing factors in relation to sequestration, bioavailability, and subsequent biodegradation of TPH in soils. The uncertainty of mechanisms for various organic amendments in TPH remediation processes remains a critical area of future research. © 2021 Elsevier B.V.

The aim of this review is to provide insights into the upstream processing of microalgae, and to highlight the advantages of each step. This review discusses the most important steps of the upstream processing in microalgae research such as cultivation modes, photobioreactors design, preparation of culture medium, control of environmental factors, supply of microalgae seeds and monitoring of microalgal growth. An extensive list of bioreactors and their working volumes used, elemental composition of some well-known formulated cultivation media, different types of wastewater used for microalgal cultivation and environmental variables studied in microalgae research has been compiled in this review from the vast literature. This review also highlights existing challenges and knowledge gaps in upstream processing of microalgae and future research needs are suggested.

In this study, typical animal- and plant-derived biochars derived from pig carcass (PB) and green waste (GWB), and their iron-engineered products (Fe-PB and Fe-GWB) were added at the dose of 3% (w/w) to an acidic (pH = 5.8) soil, and incubated to test their efficacy in improving soil quality and immobilizing arsenic (As = 141.3 mg kg−1) and lead (Pb = 736.2 mg kg−1). Soil properties, microbial activities, and the geochemical fractions and potential availabilities of As and Pb were determined in the non-treated (control) and biochar-treated soil. Modification of PB (pH = 10.6) and GWB (pH = 9.3) with Fe caused a decrease in their pH to 4.4 and 3.4, respectively. The application of PB and GWB significantly increased soil pH, while Fe-PB and Fe-GWB decreased soil pH, as compared to the control. Application of Fe-GWB and Fe-PB decreased the NH4H2PO4-extractable As by 32.8 and 35.9%, which was more effective than addition of GWB and PB. However, PB and GWB were more effective than Fe-PB and Fe-GWB in Pb immobilization. Compared to the control, the DTPA-extractable Pb decreased by 20.6 and 21.7%, respectively, following PB and GWB application. Both biochars, particularly PB significantly increased the 16S rRNA bacterial gene copy numbers, indicating that biochar amendments enhanced the bacterial abundance, implying an alleviation of As and Pb bio-toxicity to soil bacteria. The results demonstrated that pristine pig carcass and green waste biochars were more effective in immobilizing Pb, while their Fe-engineered biochars were more effective in As immobilization in co-contaminated soils.

In this review, we present the environmental perspectives of the viruses and antiviral drugs related to SARS-CoV-2. The present review paper discusses occurrence, fate, transport, susceptibility, and inactivation mechanisms of viruses in the environment as well as environmental occurrence and fate of antiviral drugs, and prospects (prevalence and occurrence) of antiviral drug resistance (both antiviral drug resistant viruses and antiviral resistance in the human). During winter, the number of viral disease cases and environmental occurrence of antiviral drug surge due to various biotic and abiotic factors such as transmission pathways, human behaviour, susceptibility, and immunity as well as cold climatic conditions. Adsorption and persistence critically determine the fate and transport of viruses in the environment. Inactivation and disinfection of virus include UV, alcohol, and other chemical-base methods but the susceptibility of virus against these methods varies. Wastewater treatment plants (WWTPs) are major reserviors of antiviral drugs and their metabolites and transformation products. Ecotoxicity of antiviral drug residues against aquatic organisms have been reported, however more threatening is the development of antiviral resistance, both in humans and in wild animal reservoirs. In particular, emergence of antiviral drug-resistant viruses via exposure of wild animals to high loads of antiviral residues during the current pandemic needs further evaluation., QC 20210309

The aim of this review is to provide insights into the upstream processing of microalgae, and to highlight the advantages of each step. This review discusses the most important steps of the upstream processing in microalgae research such as cultivation modes, photobioreactors design, preparation of culture medium, control of environmental factors, supply of microalgae seeds and monitoring of microalgal growth. An extensive list of bioreactors and their working volumes used, elemental composition of some well-known formulated cultivation media, different types of wastewater used for microalgal cultivation and environmental variables studied in microalgae research has been compiled in this review from the vast literature. This review also highlights existing challenges and knowledge gaps in upstream processing of microalgae and future research needs are suggested.

Global development has been heavily reliant on the overexploitation of natural resources since the Industrial Revolution. With the extensive use of fossil fuels, deforestation, and other forms of land-use change, anthropogenic activities have contributed to the ever-increasing concentrations of greenhouse gases (GHGs) in the atmosphere, causing global climate change. In response to the worsening global climate change, achieving carbon neutrality by 2050 is the most pressing task on the planet. To this end, it is of utmost importance and a significant challenge to reform the current production systems to reduce GHG emissions and promote the capture of CO2 from the atmosphere. Herein, we review innovative technologies that offer solutions achieving carbon (C) neutrality and sustainable development, including those for renewable energy production, food system transformation, waste valorization, C sink conservation, and C-negative manufacturing. The wealth of knowledge disseminated in this review could inspire the global community and drive the further development of innovative technologies to mitigate climate change and sustainably support human activities.

Increased concern has recently emerged pertaining to the occurrence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in aquatic environment during the current coronavirus disease 2019 (COVID-19) pandemic. While infectious SARS-CoV-2 has yet to be identified in the aquatic environment, the virus potentially enters the wastewater stream from patient excretions and a precautionary approach dictates evaluating transmission pathways to ensure public health and safety. Although enveloped viruses have presumed low persistence in water and are generally susceptible to inactivation by environmental stressors, previously identified enveloped viruses persist in the aqueous environment from days to several weeks. Our analysis suggests that not only the surface water, but also groundwater, represent SARS-CoV-2 control points through possible leaching and infiltrations of effluents from health care facilities, sewage, and drainage water. Most fecally transmitted viruses are highly persistent in the aquatic environment, and therefore, the persistence of SARS-CoV-2 in water is essential to inform its fate in water, wastewater and groundwater and subsequent human exposure., QC 20220614

Green remediation of soils highly contaminated with potentially toxic elements (PTEs) can be achieved using suitable plants. Such phytoremediation procedure often takes into consideration PTE concentrations in plants only, but not produced biomass. Phytoremediation potential of certain species of wild plants for PTEs in contaminated floodplain soils has not been assessed yet. Therefore, in this work 12 native species were tested, 3 of which (Poa angustifolia, Galium mollugo, and Stellaria holostea) to our knowledge have never been used before, in a two-year pot experiment and assessed their potential as phytoremediation species. The results showed that plant PTE concentrations were dramatically elevated for Cd and Zn in Alopecurus pratensis, Arrhenatherum elatius, Bromus inermis, Artemisia vulgaris, Achillea millefolium, Galium mollugo, Stellaria holostea, and Silene vulgaris. A. vulgaris was by far the most highly PTE absorbing plant among the 12 tested in this work, especially concerning Zn, Cd, and to a lesser degree Cu and Ni. Also, among species non-studied-before, G. mollugo and S. holostea were characterized by high Zn and Cd uptake, while P. angustifolia did not. Assessing the number of harvests necessary to decrease soil PTE to half of the initial concentrations, it was found that for Cd plants would achieve site phytoremediation within 8 (A. vulgaris) to 28 (S. holostea) and 51 (G. mollugo) harvests, while for Zn, harvests ranged from 104 (A. vulgaris) to 209 (S. holostea), and 251 (A. millefolium). A clear grouping of the tested species according to their functional type was evident. Herbaceous species were collectively more efficient than grasses in PTE uptake combined by high biomass accumulation; thus, they may act as key-species in a phytoremediation-related concept. Our approach puts phytoremediation into a practical perspective as to whether the process can be achieved within a measureable amount of time. In conclusion, A. vulgaris behaved as a hype

This book offers various soil and water treatment technologies due to increasing global soil and water pollution. In many countries, the management of contaminated land has matured, and it is developing in many others.

Vanadium (V), although serving as an important component of industrial activities, has bioinorganic implications to pose highly toxic hazards to humans and animals. Soils and sediments throughout the world exhibit wide ranges of vanadium concentrations. Although vanadium toxicity varies between different species, it is mainly controlled by soil redox potential (E H ). Nonetheless, knowledge of the redox geochemistry of vanadium lags in comparison to what is known about other potentially toxic elements (PTEs). In particular, the redox-induced speciation and mobilization of vanadium in soils and sediments and the associated risks to the environment have not been reviewed to date. Therefore, this review aims to address 1) the content and geochemical fate of vanadium in soils and sediments, 2) its redox-induced release dynamics, 3) redox-mediated chemical reactions between vanadium and soil organic and inorganic colloidal materials in soil solution, 4) its speciation in soil solution and soil-sediments, and 5) the use of advanced geochemical and spectroscopic techniques to investigate these complex systems. Vanadium (+5) is the most mobile and toxic form of its species while being the thermodynamically stable valence state in oxic environments, while vanadium (+3) might be expected to be predominant under euxinic (anoxic and sulfidic) conditions. Vanadium can react variably in response to changing soil E H : under anoxic conditions, the mobilization of vanadium can decrease because vanadium (+5) can be reduced to relatively less soluble vanadium (+4) via inorganic reactions such as with H 2 S and organic matter and by metal-reducing microorganisms. On the other hand, dissolved concentrations of vanadium can increase at low E H in many soils to reveal a similar pattern to that of Fe, which may be due to the reductive dissolution of Fe(hydr)oxides and the release of the associated vanadium. Those differences in vanadium release dynamics might occur as a result of the dire, QC 20190220

Mercury and its species are toxic and therefore strategies to immobilize them or to impede the formation of bioaccumulative MeHg are a hot topic of ongoing research. Biochar (BC) and sugar beet factory lime (SBFL) are suggested to have the potential to meet these goals. However, their ability to restrain the mobilization of total Hg (Hgt), methylmercury (MeHg), and ethylmercury (EtHg) or the formation of MeHg and EtHg has not been examined to date. Moreover, the effect of systematically altered redox conditions on the release dynamics of Hgt, MeHg, and EtHg in a contaminated floodplain soil as affected by these soil amendments has not been studied. Therefore, we investigated the impact of pre-defined redox conditions on the release dynamics of Hgt, MeHg, and EtHg in a contaminated floodplain soil (CS) and the soil amended with either BC (CS+BC) or SBFL (CS+SBFL).The mobilization of Hgt, MeHg, and EtHg was generally higher at low redox potential (EH) and decreased with increasing EH, irrespective of soil treatment. Both BC and SBFL diminished the release of Hgt from soil but not the methylation and ethylation of Hg. In CS+SBFL approximately half of Hgt was found in solution compared to CS. However, higher methylation efficiency (MeHg/Hgt ratio) was found in CS+SBFL counterbalancing this benefit. Abundances of specific phospholipid fatty acids suggest the presence of sulfate-reducing bacteria, which are considered as primary Hg methylators. The results indicate that both BC and SBFL have the potential to curtail the release of Hgt from inundated soils, while SBFL was more efficient. However, these amendments had no marked effect on the MeHg and EtHg concentrations. Therefore, further research should be conducted to identify soil additives that are capable to reduce the release and formation of these Hg species.

Hydrothermal carbonization is a promising approach of biosolids management and its utilization as a soil amendment. This study evaluated the physical and chemical properties of hydrothermally converted biosolids (Sewchar) and its effect as a potential soil amendment on the growth of rice, beans, and radish. The germination experiment was conducted in a greenhouse in a randomized design using five Sewchar doses (0, 10, 20, 40 and 60 Mg ha−1). The results showed that hydrothermal carbonization influences the physicochemical properties of the biosolids, such as promoting pore structure and trace elements below the threshold values for use in agriculture. The spectroscopic techniques demonstrated higher presence of oxygen-containing functional groups (e.g., CO/OH) on surfaces of Sewchar than that of biosolids. The Sewchar doses of 10 Mg ha−1 and 60 Mg ha−1 yielded the highest dry biomass for beans and rice respectively. Increasing Sewchar doses negatively correlated with radish dry biomass, as indicated by linear regression equation fitting (p < 0.05). Thus, biomass responses to Sewchar application into the soil varied with Sewchar dose and type of plant. For a proper environmental management, a survey was conducted to assess farmers' perception and acceptance of Sewchar as a soil amendment. The survey revealed that younger farmers who had higher education qualifications were more prone to use Sewchar as soil amendment. Additionally, farmers who would not use Sewchar as soil amendment attributed the highest level of importance to economic criteria, such as fertilizer and freight prices. In the future, studies on a longer term under field conditions should be performed to elucidate the interactions between Sewchar and soil properties on plant growth and to ensure the safe use of Sewchar as a soil amendment.

© 2019, © 2019 Taylor & Francis Group, LLC. Contaminants in water bodies cause potential health risks for humans and great environmental threats. Therefore, the development and exploration of low-cost, promising adsorbents to remove contaminants from water resources as a sustainable option is one focus of the scientific community. Here, we conducted a critical review regarding the application of pristine and modified/treated biosorbents derived from leaves for the removal of various contaminants. These include potentially toxic cationic and oxyanionic metal ions, radioactive metal ions, rare earth elements, organic cationic and anionic dyes, phosphate, ammonium, and fluoride from water media. Similar to lignocellulose-based biosorbents, leaf-based biosorbents exhibit a low specific surface area and total pore volume but have abundant surface functional groups, high concentrations of light metals, and a high net surface charge density. The maximum adsorption capacity of biosorbents strongly depends on the operation conditions, experiment types, and adsorbate nature. The absorption mechanism of contaminants onto biosorbents is complex; therefore, typical experiments used to identify the primary mechanism of the adsorption of contaminants onto biosorbents were thoroughly discussed. It was concluded that byproduct leaves are renewable, biodegradable, and promising biosorbents which have the potential to be used as a low-cost green alternative to commercial activated carbon for effective removal of various contaminants from the water environment in the real-scale plants.

This study compared the effects of sewchar and mineral fertilizer on plant responses in beans (Phaseolus vulgaris, var. “Jalo precoce”) and soil properties in a pot experiment in a completely randomized design with two harvests. The initial treatments consisted of a control, sewchar doses of 4, 8, 16 and 32 Mg ha−1 and mineral fertilizer (30 mg N, 90 mg P2O5 and 60 mg K2O kg−1). The treatments (4 replications each) were fertilized with 135 mg P2O5 kg−1 at the second harvest. The sewchar application rates correlated positively with the CEC, the water holding capacity, the availability of Zn, Ca, Fe, Cu, and P, and the concentrations of nitrate, ammonium, total N, total organic carbon and hot water extractable carbon. They correlated negatively with the Mg availability and the soil C: N ratio. Additionally, they correlated positively with the P, Zn and Ca uptake from the soil. For both harvests, the 16 Mg ha−1 sewchar treatment had a total dry matter equivalent to that of the mineral fertilizer. After the second harvest, the 16 Mg ha−1 sewchar treatment revealed 96% higher plant biomass than the control and 79% higher biomass than it did during the first period. The positive effect of sewchar in addition to phosphorous on the plant response and soil properties suggests that the residual effect of sewchar could be a promising alternative as a soil amendment for partly replacing mineral fertilizers. In future, further studies are necessary to evaluate long-term residual effects of sewchar in soil.

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The hydrothermal carbonization of sewage sludge has been studied as an alternative technique for the conversion of sewage sludge into value-added products, such as soil amendments. We tested the toxicity of biosolid hydrochar (Sewchar) to earthworms. Additionally, the toxicity of Sewchar process water filtrate with and without pH adjustment was assessed, using brine shrimps as a model organism. For a Sewchar application of 40 Mg ha−1, the earthworms significantly preferred the side of the vessel with the reference soil (control) over side of the vessel with the Sewchar treatments. There was no acute toxicity of Sewchar to earthworms within the studied concentration range (up to 80 Mg ha−1). Regarding the Sewchar process water filtrate, the median lethal concentration (LC50) to the shrimps was 8.1% for the treatments in which the pH was not adjusted and 54.8% for the treatments in which the pH was adjusted to 8.5. The lethality to the shrimps significantly increased as the amount of Sewchar process water filtrate increased. In the future, specific toxic substances in Sewchar and its process water filtrate, as well as their interactions with soil properties and their impacts on organisms, should be elucidated. Additionally, it should be identified whether the amount of the toxic compounds satisfies the corresponding legal requirements for the safe application of Sewchar and its process water filtrate.

From 1954 to 1963, approximately 42 million ha of the Southern Russian steppe, of which 6.2 million ha are located in Western Siberia, were converted into large-scale intensive agricultural area. The affected areas are highly vulnerable to wind erosion and the presently ongoing climate change effect. The establishment of sustainable land management practices is essential to secure agricultural production and the further economic development of the region. The assessment and management of the soil water is of great importance for crop yield potentials and protection against wind erosion. The paper presents a meteorological and soil hydrological measuring network. The results showed that the No-Tillage technology gradually formed soil conditions close to the natural dry steppe background. Furthermore, the installed techniques can be used to measure the parameter “actual evapotranspiration” which is a key factor to evaluate climate change impacts.

For the first time, the impact of pre-definite redox conditions on the release dynamics of rare earth elements (REEs) and the determining factors pH, iron (Fe), manganese (Mn), aluminum (Al), dissolved organic carbon (DOC), dissolved inorganic carbon (DIC), and sulfate (SO42−) in a floodplain soil was elucidated using an advanced, highly sophisticated automatic biogeochemical microcosm apparatus. The redox potential (EH) ranged between +82 and + 498 mV during the experiment. The systematic increase of EH caused a decreasing pH from 6.6 to 4.6 which resulted in an enhanced mobilization and release of REEs along with Fe, Al, and Mn under oxic and acidic conditions. Also, organic matter seems to contribute to the mobilization of REEs under changing redox conditions. A factor analysis identified that the REEs form one group with EH, Fe, Al, and Mn what indicates that REEs and sesquioxides have a similar geochemical behavior. The pH, DOC, and DIC are together in another cluster which demonstrates that their behavior substantially differs from the other group. The sequential extraction procedure revealed that the majority of the REEs were bound in the residual fraction, followed by the reducible, the oxidisable and the water soluble/exchangeable/carbonate bound fraction. Future studies should further elucidate the specific release kinetics of REEs, the controlling factors on the release dynamics and the underlying mobilization processes in highly dynamic wetland soils around the globe.

The study examined the impact of raking and fish bioturbation on modulating phosphorus (P) concentrations in the water and sediment under different trophic conditions. An outdoor experiment was set to monitor physicochemical and microbiological parameters of water and sediment influencing P diagenesis. A pilot study with radioactive 32P was also performed under the agency of raking and bacteria (Bacillus sp.). Raking was more effective in release of P under unfertilized conditions by significantly enhancing orthophosphate (35%) and soluble reactive phosphate (31.8%) over respective controls. Bioturbation increased total and available P in sediments significantly as compared to control. The rates of increase were higher in the unfertilized conditions (17.6–28.4% for total P and 12.2 to 23.2% for available P) than the fertilized ones (6.5–12.4% for total P and 9.1 to 15% for available P). The combined effects of raking and bioturbation on orthophosphate and soluble reactive phosphate were also stronger under unfertilized state (54.5 and 81.8%) than fertilized ones (50 and 70%). The tracer signature showed that coupled action of introduced bacteria and repeated raking resulted in 59.2, 23 and 16% higher counts of radioactive P than the treatments receiving raking once, repeated raking and bacteria inoculation, respectively. Raking alone or in sync with bioturbation exerted pronounced impact on P diagenesis through induction of coupled mineralization and nutrient release. It has significant implication for performing regular raking of fish-farm sediments and manipulation of bottom-grazing fish to regulate mineralization of organic matter and release of obnoxious gases from the system. Further, they synergistically can enhance the buffering capacity against organic overload and help to maintain aquatic ecosystem health.

Rare earth elements (REE) are of increasing interest in many industrial key technologies and in animal/plant production. Their environmental impacts cannot be forecasted because of knowledge gaps concerning the presence and the mobility of REE in soils and critical concentrations with respect to health effects on humans and other biota. In this study, the soil's chemical and physical characteristics were compared to REE concentrations and REE mobilities, as determined by ammonium nitrate/aqua regia ratio, in Luvisols developed from loess under arable and forest land according to genetic horizons in complete soil profiles in Germany. Single REE concentrations varied from 0.17 mg kg−1 (Lu) to 77.3 mg kg−1 (Ce). We detected the highest REE concentrations in illuvial B-horizons and found a significant correlation between REE and clay content/Fe-Mn oxides. This is probably because REE adsorb onto clay minerals and Fe-Mn oxides (found as coatings on clay minerals) and migrate with the colloids. Aqua regia–extractable REE concentrations ranged from 166 to 211 mg kg−1 in the soil profile under forest land and from 176 to 230 mg kg−1 under arable land. Stocks of REE in the top 100 cm are significantly higher under arable land use (277 g m−2) than under forest land use (252 g m−2), which might be caused by phosphorous fertilization and a significantly higher bulk density of the arable topsoil. The higher pH of the arable land leads to a lower potential mobility of REE in comparison with the soil under forest land.

Seasonal dynamics of microbial community under frequently fluctuating oxidized and reduced conditions in floodplain soils are poorly understood, but are considered to be important for understanding microbial community and carbon cycling dynamics in these ecosystems. We determined the microbial community structure using phospholipid fatty acid analysis (PLFA) of three different floodplain soils (Eutric Gleysol = GLe, Eutric Fluvisol = FLe, and Mollic Fluvisol = FLm) at the Elbe River, Germany, for 17 months. Flood duration, soil moisture, soil temperature were also monitored, and hot and cold water extractable carbon (CHWE, CCWE) were determined. Flood duration seems to have a negative impact on total PLFA biomass which increased in the order GLe < FLe << FLm. All PLFA profiles were dominated by Gram-positive bacteria (GPB) and actinomycetes, respectively, and a low content of fungi and arbuscular mycorrhizal fungi (AMF). In the briefly flooded relatively quickly drained soils (FLe and FLm) Gram-negative bacteria (GNB) were abundant compared to the longer flooded, relatively slow drained soil (GLe). This was also obvious in the significant lowest fungi-bacteria ratio and aerobe-anaerobe ratio of GLe. Non-metric dimensional scaling (NMDS) and canonical discriminant analysis (CDA) as multivariate statistical procedures reveal that FLm could be separated from GLe and FLe probably due to aerobic conditions and available soil organic carbon. The GLe can be discriminated from FLe and FLm mainly due to different flooding durations. The GNB, fungi and AMF were more affected by changes of soil moisture and extractable carbon than the GPB, actinomycetes and anaerobes. We conclude that more stable properties of bulk soil such as the magnitude of soil organic carbon, soil texture, and associated flood duration had a stronger impact on soil microbial community than month

River-floodplain ecosystems are long-term sinks for certain contaminants. Fluctuations between flooding and drying are major drivers of spatial and temporal changing biogeochemical processes within floodplain soils. Even small changes of the frequency, magnitude, and timing of drying and rewetting can episodically turn those ecosystems into a source for matter.To understand such changes we investigated the effects on top soils of three hydro-geomorphological units that are typical for floodplains: depression, levee, and plateau. They show distinct characteristics regarding soil type, trace element (TE) pollution level and hydrology. In the laboratory we used an automated biogeochemical microcosm set up to simulate oxidized–reduced cycles to monitor the effects of strong fluctuating redox potential (EH), on pH, iron (Fe), manganese (Mn), sulfur (S), nitrate (NO3), dissolved organic carbon (DOC) and dissolved concentrations of arsenic (As), cadmium (Cd), copper (Cu), chromium (Cr), nickel (Ni), and zinc (Zn) in the soil solution.The results indicated different responses regarding the course of EH/pH and different release patterns of TEs for each hydro-geomorphological unit separately. Both could be mainly allocated to their explicit spatial characteristics; due to differences in its buffer capacities and to the interaction between pH-value and microbial activity. In particular, we could demonstrate that a combination of several biogeochemical factors may influence TE release or retention in floodplain soils by means of generalized additive models (GAMs). Using those, Fe and S were identified as most important factors that determined the dynamics of TEs in all three studied soils; concentrations of As, Cu, Cr, Ni, and Zn increased with increasing Fe-concentrations whereas Cd, Cu, Cr, Ni, and Zn seem correspondingly to be dependent on S that went along with the course of the oxidized–reduced cycle.Still, several uncertainties between environmental changes and TE release

We aimed to investigate the distribution coefficients (Kd) of Cd and Zn in different soils in mono-metal (MS) and competitive sorption (CS) systems. Eleven surface soil samples varying widely in their origin and properties were collected in Egypt and Greece. Sorption isotherms were determined and Kd derived. Clayey Entisols showed a higher affinity for Zn, while a Histosol showed a higher affinity for Cd. In MS the Kd of Zn was higher than the Kd of Cd in the studied soils, except for an Aridisol and acidic Alfisols. In case of CS the Kd of Zn was higher than the Kd of Cd in the soils. The Kd of Cd decreased in CS compared to MS. The decreasing percentage of Kd-Cd ranged from 6.5% in the Histosol to 81.8% in the sandy Entisols. Kd-Zn in CS decreased in the Entisols, Alfisols, and Histosol, but increased in the Aridisol, Vertisol, and Mollisol compared to MS. This suggests that upon co-addition of the two metals to the soil Zn became preferentially sorbed at the expense of Cd. Permanent charge clayey soils with relatively low Fe-, Al- and Mn-oxides content sorbed more Cd and Zn than the variable charge red soils with a higher content of these oxides. Cation exchange capacity (CEC), soil organic matter, Ald, Fed, Feo, Alo and total carbonates are important for the sorption of Cd, whereas clay, CEC, Sid, Sio and Alo content determine the sorption of Zn.

We aimed to determine the concentrations and geochemical fractions of rare earth elements (REEs) according to the genetic soil horizons of two soil profiles (Eutric Fluvisols) at the Wupper River, Germany. The concentrations were determined using aqua regia extraction and the geochemical fractions were assessed using a sequential extraction procedure developed by the Commission of the European Communities Bureau of Reference. Single REE concentrations varied from 0.09 mg kg− 1 (Lu) to 40 mg kg− 1 (Ce). We have detected small differences of the REE concentrations between the horizons that seem to be due to flooding and the linked homogenisation processes. Rare earth elements dominate in the residual fraction (73.5%), followed by reducible (19.6%), oxidisable (6.6%), and water soluble, exchangeable (0.4%) fraction (calculated from the sum of the fractions and mean of both soil profiles). The proportion of the residual fraction tends to decrease with increasing atomic number, whereas the proportions of the other three fractions increase. Rare earth elements with higher atomic number seem to take earlier the bonding-places in the first three fractions than REEs with lower atomic number and therefore, rather the latter are bound to residual fraction or occur as free species. Important factors that affect the geochemical fractions and mobility of REEs are the adsorption of REEs onto clay and amorphous Fe–Mn oxides as well as formation of phosphate or organic complexes with REEs. A low pH favours the releases of REEs from the soil. In future, the impact of flooding regime and physico-chemical soil properties on the concentrations, geochemical fractions, and release kinetics of REEs should be determined in frequently flooded soils around the globe to improve our understanding of the geochemical behaviour of REEs.