The current study focused on the Bortala River – a typical inland river located in an oasis of arid area in northwestern China. The sediment and soil samples were collected from the river and ...drainage basin. Results showed that: (1) the particle size of the sand fraction of the sediments was 78–697µm, accounting for 78.82% of the total samples; the average concentrations of eight heavy metals fell within the concentration ranges recommended by the Secondary National Standard of China, while the maximum concentrations of Pb, Cd, and Hg exceeded these standards; (2) results from multivariate statistical analysis indicated that Cu, Ni, As, and Zn originated primarily from natural geological background, while Cd, Pb, Hg and Cr in the sediments originated from human activities; (3) results of the enrichment factor analysis and the geo-accumulation index evaluation showed that Cd, Hg, and Pb were present in the surface sediments of the river at low or partial serious pollution levels, while Zn, Cr, As, Ni, and Cu existed at zero or low pollution levels; (4) calculation of the potential ecological hazards index showed that among the eight tested heavy metals, Cd, Pb, Hg, and Cr were the main potential ecological risk factors, with relative contributions of 25.43%, 22.23%, 21.16%, and 14.87%, respectively; (5) the spatial distribution of the enrichment factors (EFS), the Geo-accumulation index (Igeo), and the potential ecological risk coefficient (Eri) for eight heavy metals showed that there was a greater accumulation of heavy metals Pb, Cd, and Hg in the sediments of the central and eastern parts of the river. Results of this research can be a reference for the heavy metals pollution prevention, the harmony development of the ecology protection and the economy development of the oases of inland river basin of arid regions of China, Central Asia and also other parts of the world.
•The maximum values of Pb, Cd, and Hg of the sediment exceeded the standards values of China (II).•Cu, Ni, As, and Zn originated primarily from natural geological background.•Cd, Pb, Hg and Cr in the sediments originated primarily from human activities.•Cd, Pb, Hg, and Cr were the main potential ecological risk factors of eight heavy metals.
Biosolids are extensively used in agriculture as fertilizers while offering a practical solution for waste disposal. Many pharmaceutical and personal care products (PPCPs), such as triclosan and ...triclocarban, are enriched in biosolids. Biosolid amendment changes soil physicochemical properties, which may in turn alter the persistence of PPCPs and hence the risk for secondary contamination such as plant uptake. To delineate the effect of biosolids on PPCPs persistence, triclosan and triclocarban were used as model compounds in this study and their sorption (Kd) and persistence (t1/2) were determined in different soils before and after biosolid amendment. Biosolids consistently increased sorption of triclosan and triclocarban in soil. The Kd of triclosan increased by 3.9–21 times following amendment of a sandy loam soil with biosolids at 2–10%. The persistence of both compounds was prolonged, with t1/2 of triclosan increasing from 10 d in the unamended soil to 63 d after biosolid amendment at 10%. The relationship between t1/2 and Kd was further examined through a meta-analysis using data from this study and all relevant published studies. A significant linear relationship between t1/2 and Kd was observed for triclosan (r2 = 0.69, p < 0.01) and triclocarban (r2 = 0.38, p < 0.05) in biosolid-amended soils. On the average, when biosolid amendment increased by 1%, t1/2 of triclosan was prolonged by 7.5 d, while t1/2 of triclocarban was extended by 4.7 d. Therefore, biosolid amendment greatly enhances persistence of triclosan and triclocarban, likely due to enhanced sorption or decreased chemical bioavailability. This finding highlights the importance to consider the effect of biosolids when evaluating the environmental risks of these and other biosolid-borne PPCPs.
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•Kd and t1/2 of triclosan and triclocarban were determined in soil with or without biosolid amendment.•Correlation of Kd and t1/2 was tested using values from this study and all available literature.•Negative relationships were observed between Kd and t1/2 for both compounds.•Biosolid amendment significantly prolonged persistence of triclosan in soil.
Amendment of biosolids significantly inhibited degradation and increased persistence of triclosan and triclocarban, likely due to decreased bioavailability.
Acetaminophen is the most widely used human medicine. Trace levels of acetaminophen are frequently detected in treated wastewater and the impacted surface or groundwater resources. However, even ...though soil is a primary receiving compartment, the fate of acetaminophen in soil is poorly known, including in particular the potential for the formation of incomplete degradation products that may have altered biological activity and mobility. In this study, using both (14)C-labeling and LC-MS/MS techniques, we evaluated the dissipation routes and transformation pathways of acetaminophen in soils under a range of conditions. Throughout 120-d aerobic incubation, up to 17.0 ± 0.8% of (14)C-acetaminophen was mineralized, but mineralization was greatly inhibited after sterilization or amendment of biosolids. Immediately after treatment, the majority of (14)C-residue became non-extractable or bound, with the level accounting for 73.4-93.3% of the applied amount at the end of incubation. A total of 8 intermediates were identified, including 3-hydroxyacetaminophen, hydroquinone, 1, 4-benzoquinone, N-acetyl-p-benzoquinone imine, p-acetanisidide, 4-methoxyphenol, 2-hexenoic acid, and 1, 4-dimethoxybenzene. Mineralization and rapid conversion to bound residues suggest that acetaminophen is quickly detoxified in soil, decreasing the potential for off-site transport such as leaching or runoff. On the other hand, the formation of a large number of degradation intermediates, and their potential biological activity, may pose unknown risks, such as accumulation into edible plants. This risk warrants further investigation.
The antiepileptic drug carbamazepine (CBZ) is one of the most frequently detected human pharmaceuticals in wastewater effluents and biosolids. Soil is a primary environmental compartment receiving ...CBZ through wastewater irrigation and biosolid application. In this study, we explored the transformation of CBZ to biologically active intermediates in soil. Both (14)C labeling and liquid chromatography-tandem mass spectrometry (LC-MS/MS) were used to track transformation kinetics and identify major degradation intermediates. Through 120 days of incubation under aerobic conditions, mineralization of CBZ did not exceed 2% of the spiked rate in different soils. Amendment of biosolids further suppressed mineralization. The fraction of non-extractable (i.e., bound) residue also remained negligible (<5%). On the other hand, CBZ was transformed to a range of degradation intermediates, including 10,11-dihydro-10-hydroxycarbamazepine, carbamazepine-10,11-epoxide, acridone-N-carbaldehyde, 4-aldehyde-9-acridone, and acridine, of which acridone-N-carbaldehyde was formed in a large fraction and appeared to be recalcitrant to further degradation. Electrocyclization, ring cleavage, hydrogen shift, carbonylation, and decarbonylation contributed to CBZ transformative reactions in soil, producing biologically active products. The persistence of the parent compound and formation of incomplete intermediates suggest that CBZ has a high risk for off-site transport from soil, such as accumulation into plants and contamination of groundwater.
Biosolids from wastewater treatment are primarily disposed of via land applications, where numerous pharmaceuticals and personal care products (PPCPs) may contaminate food crops and pose a human ...exposure risk. Biosolids are rich in organic carbon and addition of biosolids can increase the sorption of certain PPCPs in soil, decreasing their bioavailability. This study tested the hypothesis that the relative plant uptake of PPCPs decreases with increasing biosolids amendment. Accumulation of triclosan and triclocarban was measured in roots of radish and carrot grown in soils with or without biosolids. Addition of biosolids significantly prolonged the persistence of triclosan in soil. When expressed in bioaccumulation factor (BCF), accumulation of triclosan drastically decreased in biosolids-amended soils, while the effect was limited for triclocarban. Compared to the unamended soil, amending biosolids at 2% (w/w) decreased BCF of triclosan in the edible tissues of radish and carrot by 85.4 and 89.3%, respectively. Measurement using a thin-film passive sampler provided direct evidence showing that the availability of triclosan greatly decreased in biosolids-amended soils. Partial correlation analysis using data from this and published studies validated that biosolids decreased plant uptake primarily by increasing soil organic carbon content and subsequently sorption. Therefore, contamination of food crops by biosolids-borne contaminants does not linearly depend on biosolids use rates. This finding bears significant implications in the overall risk evaluation of biosolids-borne contaminants.
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•Systematic experiments to evaluate plant uptake of triclosan and triclocarban before and after biosolid amendment.•Comprehensive statistical analysis of results from this study and all relevant literature to discern biosolids effects.•Use of a thin-film passive sampler to provide direct evidence on reduced bioavailability from biosolids amendment.•Establishment of inhibition in plant uptake of triclosan and triclocarban by biosolids.
Land application of biosolids or compost constitutes an important route of soil contamination by emerging contaminants such as acetaminophen and sulfamethoxazole. Using 14C labeling, we evaluated the ...influence of biosolids and compost on individual fate processes of acetaminophen and sulfamethoxazole in soil. The amendment of biosolids or compost consistently inhibited the mineralization of both compounds but simultaneously enhanced the dissipation of their extractable residues or parent form. Immediately after treatment, the majority of 14C-residue became non-extractable, reaching 80.3–92.3% of the applied amount at the end of 84-d incubation. Addition of biosolids or compost appreciably accelerated the formation of bound residue, likely due to the fact that the organic material provided additional sites for binding interactions or introduced exogenous microorganisms facilitating chemical transformations. This effect of biosolids or compost should be considered in risk assessment of these and other emerging contaminants.
•14C Labeling was used to understand the fate processes of acetaminophen and sulfamethoxazole in aerobic soil.•Majority of acetaminophen and sulfamethoxazole quickly became non-extractable or mineralized.•Biosolids or compost amendment inhibited mineralization.•Biosolids or compost appreciably enhanced the formation of bound residue.
Biosolids or compost amendment inhibited mineralization of acetaminophen and sulfamethoxazole and appreciably enhanced the formation of bound residue.
Pharmaceutical and personal care products (PPCPs) are continuously introduced into the soil-plant system, through practices such as agronomic use of reclaimed water and biosolids containing these ...trace contaminants. Plants may accumulate PPCPs from soil, serving as a conduit for human exposure. Metabolism likely controls the final accumulation of PPCPs in plants, but is in general poorly understood for emerging contaminants. In this study, we used diclofenac as a model compound, and employed 14C tracing, and time-of-flight (TOF) and triple quadruple (QqQ) mass spectrometers to unravel its metabolism pathways in Arabidopsis thaliana cells. We further validated the primary metabolites in Arabidopsis seedlings. Diclofenac was quickly taken up into A. thaliana cells. Phase I metabolism involved hydroxylation and successive oxidation and cyclization reactions. However, Phase I metabolites did not accumulate appreciably; they were instead rapidly conjugated with sulfate, glucose, and glutamic acid through Phase II metabolism. In particular, diclofenac parent was directly conjugated with glutamic acid, with acyl-glutamatyl-diclofenac accounting for >70% of the extractable metabolites after 120-h incubation. In addition, at the end of incubation, >40% of the spiked diclofenac was in the non-extractable form, suggesting extensive sequestration into cell matter. The rapid formation of non-extractable residue and dominance of diclofenac-glutamate conjugate uncover previously unknown metabolism pathways for diclofenac. In particular, the rapid conjugation of parent highlights the need to consider conjugates of emerging contaminants in higher plants, and their biological activity and human health implications.
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•A tiered approach involving 14C trace technique and liquid chromatography-high resolution mass spectrometry (LC-HRMS) was used to obtain a comprehensive fate of diclofenac in Arabidopsis (i.e. phase I, phase II, and phase III).•Target, suspect, and non-target analysis was multi-applied to identify the metabolites.•Eleven phase I and phase II metabolites were identified in Arabidopsis cells and validated in seedlings.•>40% non-extractable residue was observed in cells after 120-h incubation with diclofenac.•Acyl-glutamatyl-diclofenac was newly found phyto-transformation product of diclofenac.
Diclofenac was quickly metabolized by A. thaliana cells, resulting in a number of Phase I metabolites and Phase II conjugates, as well as Phase III non-extractable residue.
Chlorpyrifos (CPF), as an organophosphate insecticide extensively used in the modern agricultural system, has been gradually banned in many countries due to its reported health risks to organisms, ...including humans. This study used simulated paddy field experiments and carbon-14 tracing to explore the possibility of reducing environmental risks of chlorpyrifos application through appropriate agronomic practice. Results showed 14C-CPF concentration in rice plants planted in the red soil (RS) was significantly higher than that in black soil (BS) and fluvo-aquic soil (FS). The application of biochar and chicken manure in RS reduced 14C-CPF accumulation in rice plants, and the content of 14C-CPF in rice grains decreased by 25% and 50%, respectively. Adding biochar to all three soils reduced the migration of 14C-CPF, especially in FS with the highest risk of 14C-CPF migration. The addition of chicken manure in FS reduced the migration of 14C-CPF and the total residual amount of 14C-CPF in the soil. In addition, chicken manure treatment increased the formation of 14C-bound residues (BRs) in soils and changed the distribution 14C-BRs in humus. The results indicated that the degree of environmental risks associated with the CPF application varies with soil types and could be reduced by introducing suitable exogenous organic matter into different soils, which is of great significance for guiding the scientific application of chlorpyrifos in agronomic practices.
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•The environmental risks of chlorpyrifos application vary with soil types.•Adding organic matter to red soils decreased chlorpyrifos accumulation in plants.•The addition of biochar in soils decreased the risk of chlorpyrifos leaching.•Chicken manure treatment promoted the formation of 14C-bound residues.•Environmental risk of CPF can be reduced by appropriate agricultural management.
•The addition of the specific rice starch showed superior gelation than control.•Addition of the specific rice starch showed no adverse influence on gel proteins.•Pre-incubation temperatures ...significantly affected the gel properties.•The addition of 4% specific rice starch at 25°C pre-incubation is the optimum.•SRS showed a positive influence on the freeze–thaw stability of the surimi gels.
The effects of a specific rice starch (SRS), containing highly resistant starch (RSIII), on gel properties of grass carp (Ctenopharyngodon idella) and the influence of five levels of SRS (0%, 2%, 4%, 6%, and 8%w/w) on gel physicochemical properties at three different pre-incubation temperatures (4°C, 25°C, and 40°C) were investigated. Gels with increasing amounts of SRS addition showed lower expressible water contents and cooking loss values than did control gels. SDS gel electrophoresis revealed no changes in protein patterns, regardless of different SRS-added levels at the same pre-incubation temperature, but an evident decrease in the MHC when the pre-incubation temperature increased. The texture properties, colour attributes, SEM were optimal in the treatments containing 4%w/w SRS at the pre-incubation temperature 25°C. Thus, the optimum SRS addition level and pre-incubation temperature are proposed to be 4%w/w and 25°C, respectively.
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•IVIS was first used to track the uptake and distribution of MPs/NPs in jellyfish.•MPs/NPs primarily accumulated on the umbrella edge and mouthlets of jellyfish.•PCB28 induced ...apoptosis, tissue injury, and physiological alteration in jellyfish.•MPs/NPs co-exposure reduced PCB28′s bio-accumulation and toxicity to jellyfish.•Jellyfish consumption posed a limited exposure risk of MPs/NPs to the public.
Due to their ubiquity and potential risks, microplastics (MPs) and nanoplastics (NPs) are concerning environmental issues. Yet there are still significant knowledge gaps in understanding the tissue-specific accumulation and dynamic change of MPs and NPs in the aquatic organism and how these micro/nano-scale emerging contaminants interact with other environmental pollutants such as persistent organic pollutants (POPs). Here, in vivo imaging systems (IVIS), radioisotope tracing, and histological staining were innovatively used to reveal the fate and toxicity of fluorescently-labeled MPs/NPs and 14C-labeled 2,4,4′-trichlorobiphenyl (PCB28) in edible jellyfish Rhopilema esculentum. These contaminants' ingestion, biological effects, and interactions were visualized at cellular, tissue, and whole-body multidimensional levels. Both MPs and NPs were shown to be preferentially accumulated in the mouthlets of oral arms, and most ingested MPs/NPs were present in the extracellular environment instead of being internalized into the mesoglea. Moreover, the presence of MPs or NPs in the seawater significantly inhibited the bioaccumulation of PCB28 in the jellyfish tissue, thus alleviating physiological alteration, gastric damage, and apoptosis caused by PCB28. This study provides a multi-dimensional visualization strategy to display the distribution and biological effects of typical pollutants in marine organisms and offers new insights for understanding the impacts of MPs/NPs and POPs on marine ecosystems.
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