National-scale monitoring of historic used organochlorine pesticides (OCPs) and current used pesticides (CUPs) in Chinese surface soil: Old topic and new story

Mapping pesticide residues in soil for China: Characteristics and risks

The widespread application of pesticides in China has led to the accumulation of residues in soil. However, few regional studies have fully elucidated the characteristics of pesticide residues in soil (PRS) and the associated risks to the ecosystem and human health on a national level. Therefore, this study aims to compile a dataset on PRS in China from 2006 to 2020 and analyze the interactions and impacts between PRS and the environment. The average concentration of PRS in China was 243.96 μg/kg which was lower than the levels reported in Euro-Americans and other nations. This study revealed PRS in China predominantly originates from organochlorine pesticide residues, with DDTs and HCHs being significant contributors. Despite the high intensity of pesticide application in the Southeast China, PRS concentrations were comparable to those in the Northeast, due to environmental factors that favor pesticide degradation in the Southeast. Both legacy and in-use pesticides were transported by surface runoff or air current, resulting in their accumulation in soil of the lower Yangtze River basin or the piedmont soil of Qinling Mountains, respectively. The average soil environment carrying capacity of PRS in China was -69.5 kg. The ecological risk contributed by PRS in China was mainly at a negligible level. Carcinogenic risks of PRS to adults (4.6 ×10-4) and children (6 ×10-4) exceeded the tolerable thresholds (10-5) by a small margin.

Environmental exposure patterns to 94 current-use pesticides in women of reproductive age who are preparing for pregnancy

Current-use pesticides (CUPs), including insecticides, fungicides, and herbicides, are extensively employed in agriculture to manage pests, diseases, and weeds. Nonetheless, their widespread application raises significant concerns regarding potential impacts on human health, particularly with reproductive health. This study focuses on exploring the landscape of CUP exposure among pre-pregnancy women. Based on a cohort study comprising 354 pre-pregnancy women of reproductive age in Beijing, China, we measured the concentrations of 94 CUPs in serum and conducted an in-depth analysis of exposure profiles, health risks, and contributing factors. The results revealed that the serum of pre-pregnancy women was contaminated with CUPs, of which the median concentrations ranged from 0.114 (fenamiphos-sulfone) to 61.2 ng/L (mefenacet). Among the 94 CUPs, 54 exhibited detection rates higher than 50 %, including 26 insecticides, 14 fungicides, and 14 herbicides. The exposure concentration profile highlighted that the insecticides contributed 56 % to the total CUP concentration percentages, with organophosphate insecticides being the primary contributors within this category (63.0 %). The average daily intake (ADI) of CUPs ranged from 2.23 to 16,432.28 ng/kg, while diflubenzuron had the highest ADI. Health risk assessments showed that exposure to a combination of total insecticides or herbicides poses a moderate risk for 15.8 % and 30.2 % of women, with mefenacet being the most significant, which showed moderate hazard in 29.4 % of participants. The overlap analysis showed that methiocarb-sulfone, diflubenzuron, and mefenacet were the dominant pesticides. In addition, maternal age, annual income level, smoking, and vitamin B12 supplementation were associated with serum CUP concentrations. Our study contributes a novel and comprehensive exposure profile of CUPs in pre-pregnancy women in northern China, providing valuable insights for evaluating the potential consequences of pre-pregnancy exposure on reproductive health. SYNOPSIS: We provided a comprehensive exposure landscape, health effects, and influential factors of 94 current-use pesticides among pre-pregnancy women in China.

Radiometric approaches with carbon-14-labeled molecules for determining herbicide fate in plant systems

Weeds cause economic losses in cropping systems, leading to the use of 1.7 million tons of herbicides worldwide for weed control annually. Once in the environment, herbicides can reach non-target organisms, causing negative impacts on the ecosystem. Herbicide retention, transport, and degradation processes determine their environmental fate and are essential to assure the safety of these molecules. Radiometric strategies using carbon-14 herbicides (14C) are suitable approaches for determining herbicide absorption, translocation, degradation, retention, and transport in soil, plants, and water. In this work, we demonstrate how 14C-herbicides can be used from different perspectives. Our work focused on herbicide-plant-environment interactions when the herbicide is applied (a) through the leaf, (b) in the soil, and (c) in the water. We also quantified the mass balance in each experiment. 14C-mesotrione foliar absorption increased with oil and adjuvant addition (5-6 % to 25-46 %), and translocation increased only with adjuvant. More than 80 % of 14C-quinclorac and 14C-indaziflam remained in the soil and cover crops species absorbed less than 20 % of the total herbicides applied. In water systems, Salvinia spp. plants removed 10-18 % of atrazine from the water. Atrazine metabolism was not influenced by the presence of the plants. The radiometric strategies used were able to quantify the fate of the herbicide in different plant systems and the mass balance varied from 70 % to 130 %. Importantly, we highlight a critical and practical view of tracking herbicides in different matrices. This technique can aid scientists to explore other pesticides as environmental contaminants.

Occurrence and fate of current-use pesticides in Chinese forest soils

Pesticides play a crucial role in securing global food production to meet increasing demands. However, because of their pervasive use, they are now ubiquitous environmental pollutants that have adverse effects on both ecosystems and human health. In this study, the environmental occurrence and fate of 16 current-use pesticides (CUPs) were investigated in 93 forest soil samples obtained from 11 distinct mountains in China. The concentrations of the target pesticides ranged from 0.36 to 55 ng/g dry weight. Cypermethrin, dicofol, chlorpyrifos, chlorothalonil, and trifluralin were the most frequently detected CUPs. The CUP concentrations were generally higher in the O-horizon than in the A-horizon. Chlorpyrifos, chlorothalonil, and dicofol were detected in most deep layers in soil profiles from three mountains selected to represent distinct climate zones. No clear altitudinal trend in organic carbon-normalized concentrations of CUPs was observed in the O- or A-horizons within individual mountains. A negative correlation was noted between the CUP concentrations and the altitudes across all sampling sites. This indicated that proximity to emission sources was a key factor affecting the spatial distribution of CUPs in mountain forest soil on a national scale. The ecological risk assessment showed that dicofol and cypermethrin pose potential risks to earthworms. This study emphasizes the importance of source control when setting management strategies for CUPs.

Construction of biochar-based organohalide-respiring bacterial agent for remediation of 2,4,6-trichlorophenol contaminated soil

Construction of an efficient bio-reductive dechlorination system remains challenging due to the narrow ecological niche and low-growth rate of organohalide-respiring bacteria during field remediation. In this study, a biochar-based organohalide-respiring bacterial agent was obtained, and its performance and effects on indigenous microbial composition, diversity, and inter-relationship in soil were investigated. A well-performing material, Triton X-100 modified biochar (BC600-TX100), was found to have the superior average pore size, specific surface area and hydrophicity, compared to other materials. Interestingly, Pseudomonas aeruginosa CP-1, which is capable of 2,4,6-TCP dechlorination, showed a 348 times higher colonization cell number on BC600-TX100 than that of BC600 after 7 d. Meanwhile, the dechlorination rate in soil showed the highest (0.732 d-1) in the BC600-TX100 bacterial agent than in the other agents. The long-term performance of the BC600-TX100 OHRB agent was also verified, with a stable dechlorination activity over six cycles. Soil microbial community analysis found the addition of the BC600-TX100 OHRB agent significantly increased the relative abundance of genus Pseudomonas from 1.53 % to 11.2 %, and Pseudomonas formed a close interaction relationship with indigenous microorganisms, creating a micro-ecological environment conducive to reductive dechlorination. This study provides a feasible bacterial agent for the in-situ bioremediation of soil contaminated organohalides. ENVIRONMENTAL IMPLICATION: Halogenated organic compounds are a type of toxic, refractory, and bio-accumulative persistent compounds widely existed in environment, widely detected in the air, water, and soil. In this study, we provide a feasible bacterial agent for the in-situ bioremediation of soil contaminated halogenated organic compounds. The application of biochar provides new insights for "Turning waste into treasure", which meets with the concept of green chemistry.

Analysis of nationwide soil pesticide pollution: Insights from China

China is a typical agricultural country that heavily relies on pesticides. Some pesticides can remain in the soil after application and thus pose a significant threat to human health. In order to characterize the status and hazards of nationwide soil contamination, this study extracted concentration data from published literature and analyzed them by a scoring approach, standard comparison and health risk assessment. For the soil pollution score, northern regions got the highest values, such as Henan (0.63), Liaoning (0.55), Heilongjiang (0.54) and Jilin (0.53), which implies high soil pesticide residues in these provinces. In contrast, Qinghai (-0.77), Guizhou (-0.64) and Tibet (-0.63) had lower scores. China's soil pesticide standards cover only 16 pesticides, and these pesticide concentrations were all below the corresponding standards. Direct exposure to soil pesticides in this study generally posed a negligible risk to children. Furthermore, pesticide dissipation and usage intensity in each province were analyzed as they were possible influences on pollution. The result showed that soil in the northern regions could accumulate more pesticides than those in the southern regions, and this geographic pattern was basically consistent with the distribution of soil pollution. However, the relationship between agricultural activities and soil pollution was less well characterized. It is recommended to establish a long-term monitoring database for pesticides and include more pesticides in regulatory frameworks. Additionally, efforts to accelerate pesticide degradation and shift the planting structure to reduce pesticide usage can help alleviate the pressure on soil from pesticides. This study can serve as a critical reference for policymakers and stakeholders in the field of agriculture.

Evaluation of the Effectiveness of Innovative Sorbents in Restoring Enzymatic Activity of Soil Contaminated with Bisphenol A (BPA)

As part of the multifaceted strategies developed to shape the common environmental policy, considerable attention is now being paid to assessing the degree of environmental degradation in soil under xenobiotic pressure. Bisphenol A (BPA) has only been marginally investigated in this ecosystem context. Therefore, research was carried out to determine the biochemical properties of soils contaminated with BPA at two levels of contamination: 500 mg and 1000 mg BPA kg-1 d.m. of soil. Reliable biochemical indicators of soil changes, whose activity was determined in the pot experiment conducted, were used: dehydrogenases, catalase, urease, acid phosphatase, alkaline phosphatase, arylsulfatase, and β-glucosidase. Using the definition of soil health as the ability to promote plant growth, the influence of BPA on the growth and development of Zea mays, a plant used for energy production, was also tested. As well as the biomass of aerial parts and roots, the leaf greenness index (SPAD) of Zea mays was also assessed. A key aspect of the research was to identify those of the six remediating substances-molecular sieve, zeolite, sepiolite, starch, grass compost, and fermented bark-whose use could become common practice in both environmental protection and agriculture. Exposure to BPA revealed the highest sensitivity of dehydrogenases, urease, and acid phosphatase and the lowest sensitivity of alkaline phosphatase and catalase to this phenolic compound. The enzyme response generated a reduction in the biochemical fertility index (BA21) of 64% (500 mg BPA) and 70% (1000 mg BPA kg-1 d.m. of soil). The toxicity of BPA led to a drastic reduction in root biomass and consequently in the aerial parts of Zea mays. Compost and molecular sieve proved to be the most effective in mitigating the negative effect of the xenobiotic on the parameters discussed. The results obtained are the first research step in the search for further substances with bioremediation potential against both soil and plants under BPA pressure.

Determination of pesticide residues in urine by chromatography-mass spectrometry: methods and applications

Introduction

Pollution has emerged as a significant threat to humanity, necessitating a thorough evaluation of its impacts. As a result, various methods for human biomonitoring have been proposed as vital tools for assessing, managing, and mitigating exposure risks. Among these methods, urine stands out as the most commonly analyzed biological sample and the primary matrix for biomonitoring studies.

Objectives

This review concentrates on exploring the literature concerning residual pesticide determination in urine, utilizing liquid and gas chromatography coupled with mass spectrometry, and its practical applications.

Method

The examination focused on methods developed since 2010. Additionally, applications reported between 2015 and 2022 were thoroughly reviewed, utilizing Web of Science as a primary resource.

Synthesis

Recent advancements in chromatography-mass spectrometry technology have significantly enhanced the development of multi-residue methods. These determinations are now capable of simultaneously detecting numerous pesticide residues from various chemical and use classes. Furthermore, these methods encompass analytes from a variety of environmental contaminants, offering a comprehensive approach to biomonitoring. These methodologies have been employed across diverse perspectives, including toxicological studies, assessing pesticide exposure in the general population, occupational exposure among farmers, pest control workers, horticulturists, and florists, as well as investigating consequences during pregnancy and childhood, neurodevelopmental impacts, and reproductive disorders.

Future directions

Such strategies were essential in examining the health risks associated with exposure to complex mixtures, including pesticides and other relevant compounds, thereby painting a broader and more accurate picture of human exposure. Moreover, the implementation of integrated strategies, involving international research initiatives and biomonitoring programs, is crucial to optimize resource utilization, enhancing efficiency in health risk assessment.

The combined effects of azoxystrobin and different aged polyethylene microplastics on earthworms (Eisenia fetida): A systematic evaluation based on oxidative damage and intestinal function

Pesticides and microplastics are common pollutants in soil environments, adversely affecting soil organisms. However, the combined toxicological effects of aged microplastics and pesticides on soil organisms are still unclear. In this study, we systematically studied the toxicological effects of azoxystrobin and four different aged polyethylene (PE) microplastics on earthworms (Eisenia fetida). The purpose was to evaluate the effects of aging microplastics on the toxicity of microplastics-pesticides combinations on earthworms. The results showed that different-aged PE microplastics promoted azoxystrobin accumulation in earthworms. Meanwhile, combined exposure to azoxystrobin and aged PE microplastics decreased the body weight of earthworms. Besides, both single and combined exposure to azoxystrobin and aged PE microplastics could lead to oxidative damage in earthworms. Further studies revealed that azoxystrobin and aged PE microplastics damage the intestinal structure and function of earthworms. Additionally, the combination of different aged PE microplastics and azoxystrobin was more toxic on earthworms than single exposures. The PE microplastics subjected to mechanical wear, ultraviolet radiation, and acid aging exhibited the strongest toxicity enhancement effects on earthworms. This high toxicity may be related to the modification of PE microplastics caused by aging. In summary, these results demonstrated the enhancing effects of aged PE microplastics on the toxicity of pesticides to earthworms. More importantly, aged PE microplastics exhibited stronger toxicity-enhancing effects in the early exposure stages. This study provides important data supporting the impact of different aged PE microplastics on the environmental risks of pesticides.

Current-use pesticides monitoring and ecological risk assessment in vegetable soils at the provincial scale

Pesticides represent one of the largest intentional inputs of potentially hazardous compounds into agricultural soils. However, as an important vegetable producing country, surveys on pesticide residues in soils of vegetable production areas are scarce in China. This study presented the occurrence, spatial distribution, correlation between vegetable types and pesticides, and ecological risk evaluation of 94 current-use pesticides in 184 soil samples from vegetable production areas of Zhejiang province (China). The ecological risks of pesticides to soil biota were evaluated with toxicity exposure ratios (TERs) and risk quotient (RQ). The pesticide concentrations varied largely from below the limit of quantification to 20703.06 μg/kg (chlorpyrifos). The situation of pesticide residues in Jiaxing is more serious than in other cities. Soils in the vegetable areas are highly diverse in pesticide combinations. Eisenia fetida suffered exposure risk from multiple pesticides. The risk posed by chlorpyrifos, which exhibited the highest RQs at all scenarios, was worrisome. Only a few pesticides accounted for the overall risk of a city, while the other pesticides make little or zero contribution. This work will guide the appropriate use of pesticides and manage soil ecological risks, achieving green agricultural production.

Occurrence, distribution and ecological risk assessment of herbicide residues in cropland soils from the Mollisols region of Northeast China

The first systematic and comprehensive investigation of herbicide residues was conducted by identifying their spatial distribution, influencing factors and ecological risk in cropland soils from the Mollisols region covering 109 million hm2 in Northeast China. Fifty-six herbicides were detected with total herbicide concentrations ranging from 1.01 to 1558.13 μg/kg (mean: 227.45). Atrazine, its degradates deethyl atrazine (DEA) and deisopropyl atrazine (DIA), trifluralin and butachlor were the most frequently detected herbicides, while DEA, clomazone, nicosulfuron, fomesafen, and mefenacet exhibited the highest concentrations. Despite being less frequently reported in Chinese soils, fomesafen, nicosulfuron, clomazone, and mefenacet were found widely present. Although most of the compounds posed a minimal or low ecological risk, atrazine, nicosulfuron and DEA exhibited medium to high potential risks. The key factors identified to regulate the fate of herbicides were soil chemical properties, amount of herbicides application, and the crop type. The soybean soils showed highest herbicide residues, while the soil mineral contents likely adsorbed more herbicides. This study provides a valuable large-scale dataset of herbicide residues across the entire Mollisols region of China along with fine-scale characterization of the ecological risks. Mitigation and management measures are needed to reduce the herbicide inputs and residues in the region.

Pesticide contamination pattern from Morocco, insights into the surveillance situation and health risk assessment: a review

The widespread application of pesticides in Morocco's agriculture renders their monitoring in food and environmental samples very necessary. Recent years have witnessed a growing interest in reporting studies related to the monitoring of pesticide residues in food, water, groundwater, and soil as well as their quantitative health risk assessment. Most published studies have been done by university researchers. However, the lack of research reproducibility remains a problem that considerably limits the possibility of exploiting data from the literature. Our study involves an extensive literature review utilizing search engines with keywords like "pesticide residues," "monitoring," "vegetables and fruits," "water and soil," "risk assessment," and "Morocco" from 2009 to 2023. Analysis of pesticide residues in foodstuffs and environmental samples highlights concerns over compliance with EU regulations, the health risks associated with pesticide exposure, and the necessity for comprehensive monitoring and risk assessment strategies. This paper could help influence policies to develop a strategy and action plan for the sound management of pesticides, including measures to reduce their use, raise awareness, and monitor compliance. Also, this paper could be useful for scientists interested in understanding the current situation and challenges regarding pesticide residues in Morocco, as well as countries with which commercial links exist.

Occurrence, seasonal variation and gas/particle partitioning of current used pesticides (CUPs) across 60 °C temperature and 30° latitudes in China

Gas and particle phases samples were collected at three sites in China in 2019-2020, with 60 °C temperature span and 30° latitude range. Totally, among 76 target current used pesticides (CUPs) with four types, 51 were quantified in at least one sample. The concentrations of individual CUPs ranged from 8 orders of magnitude, indicating different pollution levels. Herbicides were the dominated CUPs in Northeast China, while higher concentrations of fungicides were found in Southeast China. The highest concentrations of CUPs were observed in Southeast China in spring and winter, while in summer and autumn in Northeast China, caused by local climates and crop cultivation patterns. The gas/particle (G/P) partitioning of CUPs was mainly influenced by their physicochemical properties and ambient temperature. The G/P partitioning study indicated that the L-M-Y model was the optimum prediction model for herbicides, fungicides and pyrethroids. The L-M-Y model and the H-B model presented equal performance for organophosphate insecticides. To our knowledge, the L-M-Y model was firstly applied for the study of the G/P partitioning of CUPs, which provided new insights into the related fields of new emergency contaminates.

A critical review of sustainable pesticide remediation in contaminated sites: Research challenges and mechanistic insights

Incidental pesticide application on farmlands can result in contamination of off-target biota, soil, groundwater, and surrounding ecosystems. To manage these pesticide contaminations sustainably, it is important to utilize advanced approaches to pesticide decontamination. This review assesses various innovative strategies applied for remediating pesticide-contaminated sites, including physical, chemical, biological, and nanoremediation. Integrated remediation approaches appear to be more effective than singular technologies. Bioremediation and chemical remediation are considered suitable and sustainable strategies for decontaminating contaminated soils. Furthermore, this study highlights key mechanisms underlying advanced pesticide remediation that have not been systematically studied. The transformation of applied pesticides into metabolites through various biotic and chemical triggering factors is well documented. Ex-situ and in-situ technologies are the two main categories employed for pesticide remediation. However, when selecting a remediation technique, it is important to consider factors such as application sites, cost-effectiveness, and specific purpose. In this review, the sustainability of existing pesticide remediation strategies is thoroughly analyzed as a pioneering effort. Additionally, the study summarizes research uncertainties and technical challenges associated with different remediation approaches. Lastly, specific recommendations and policy advocacy are suggested to enhance contemporary remediation approaches for cleaning up pesticide-contaminated sites.

Cross-regional scale studies of organochlorine pesticides in air in China: Pollution characteristic, seasonal variation, and gas/particle partitioning

Few simultaneous studies of organochlorine pesticides (OCPs) in the atmosphere have been conducted across Southeast and Northeast China, and no data on the gas/particle (G/P) partitioning behaviors of several current-use OCPs are available. In this study, a one-year synchronous monitoring program was conducted for OCPs in Chinese atmosphere spanning 30° latitude and 60 °C temperature. A total of 111 pairs of gas and particle samples were collected from Mohe and Harbin in Northeast China and from Shenzhen in Southeast China. The detection frequency for 66.7 % of the OCPs exceeded 80 %, indicating their prevalence in the atmosphere. The concentrations of individual OCPs spanned six orders of magnitude, indicating different pollution levels. Highest levels of hexachlorobenzene were observed at all sites. Banned OCPs were found predominantly in secondary distribution patterns, whereas current-use OCPs were dominated by primary distribution patterns. In Harbin and Mohe, the concentrations of OCPs were highest in summer, followed by autumn and winter. No obvious seasonal variation was observed in Shenzhen associated with different cultivation types. At all three sites, OCPs were predominantly found in the gas phase, and higher percentages of particle-phase OCPs were observed in Harbin and Mohe than in Shenzhen. In this study, G/P partitioning models were used to study the G/P partitioning mechanism of OCPs. The Li-Ma-Yang model provided the most accurate prediction of the G/P partitioning behavior of OCPs with high molecular weights and low vapor pressures, particularly at low temperatures. However, OCPs with lower molecular weights and higher vapor pressures were predominantly in the equilibrium state, for which the Junge-Pankow model was suitable. This systematic cross-scale study provides new insights into pollution, G/P partitioning, and the environmental behavior of OCPs in the atmosphere.

First surveillance of pesticides in soils of the perimeter of Tadla, a Moroccan sugar beet intensive area

With the long-term application of pesticides on sugar beet farms in the irrigated perimeter of Tadla in Morocco for over 50 years, pesticide monitoring is necessary to assess soil health. The objective of our study was to monitor multiple pesticide residues in topsoil samples collected from post-harvest sugar beet fields and verify their migration to deep soil layers. Topsoil and deep soil samples were collected from arbitrarily selected sugar beet fields in the IPT. In this study, a target-screening method was applied. All target pesticides were detected in soil samples, with tefluthrin being the most frequently detected pesticide. The residue with the highest concentration in soil samples was DDE. All the soil samples contained a mixture of pesticide residues, with a maximum of 13 residues per sample. The total pesticide content decreased toward more profound layers of soil, except in one field where it reached a concentration of 348 µg/kg at the deeper soil layer. For pesticides detected at the three soil depths, only tefluthrin concentration increased in the deep soil layer. The results provide comprehensive and precise information on the pesticide residue status in sugar beet soils warning against the multiple risks that this contamination can cause. This study indicates the need of regular monitoring of pesticides over a large area of the perimeter to enable decision-makers to pronounce the impacts of the extension and intensification of sugar beet cultivation at the irrigated perimeter of Tadla.

Reduced attention on restricted organochlorine pesticides, whereas still noteworthy of the impact on the deep soil and groundwater: a historical site study in southern China

The use of hexachlorocyclohexanes (HCHs) in pesticides has been prohibited for decades in China. Since then, there have been urbanization and transformation of the functional areas of many sites, which were formerly involved in the HCH industry. However, it is possible that, unless properly managed, these sites may still contain HCH residues in the soil and thus pose a threat to the surrounding environment and the quality of groundwater. This study aimed to characterize soil residues in a typical site that was historically involved in HCH production in southern China, by analyzing the α-HCH, β-HCH, and γ-HCH contents of the soil. The results suggested that HCHs persist in the environment and can have long-term effects. It was found that α-HCH and β-HCH were present in many samples in concentrations that were comparable or higher than those specified by China's Class 1 screening values. The distribution of residues was significantly correlated with the historical HCH production activities in the areas. The characteristic ratios of α-HCH/γ-HCH and β-HCH/(α + γ)-HCH at different soil depths were 1.4-3.7 and 0.21-1.04, respectively, which indicated the presence of significant localized residues of HCHs. The presence of HCHs in the soil suggested a downward migration, with concentrations rapidly decreasing in the upper layer soil (0-5 m), but a gradual increase in the deeper soil (5-14 m). HCHs were detected at depths exceeding 24 m, indicating heavy penetration. The proportions of γ-HCH and β-HCH changed with increasing soil depth, which was related to their relatively volatile and stable molecular structures, respectively. The results strongly suggested that there is widespread contamination of both soil and groundwater by HCHs even after decades. The likelihood of residual HCHs in the soil should therefore be taken into full consideration during urban planning to limit risks to human and environmental health.

Review of scientific literature on available methods of assessing organochlorine pesticides in the environment

Organochlorine pesticides (OCPs) are persistent organic pollutants (POPs) widely used in agriculture and industry, causing serious health and ecological consequences upon exposure. This review offers a thorough overview of OCPs analysis emphasizing the necessity of ongoing work to enhance the identification and monitoring of these POPs in environmental and human samples. The benefits and drawbacks of the various OCPs analysis techniques including gas chromatography-mass spectrometry (GC-MS), gas chromatography-electron capture detector (GC-ECD), and liquid chromatography-mass spectrometry (LC-MS) are discussed. Challenges associated with validation and optimization criteria, including accuracy, precision, limit of detection (LOD), and limit of quantitation (LOQ), must be met for a method to be regarded as accurate and reliable. Suitable quality control measures, such as method blanks and procedural blanks, are emphasized. The LOD and LOQ are critical quality control measure for efficient quantification of these compounds, and researchers have explored various techniques for their calculation. Matrix interference, solubility, volatility, and partition coefficient influence OCPs occurrences and are discussed in this review. Validation experiments, as stated by European Commission in document SANTE/11813/2017, showed that the acceptance criteria for method validation of OCP analytes include ≤20 % for high precision, and 70-120 % for recovery. This may ultimately be vital for determining the human health risk effects of exposure to OCP and for formulating sensible environmental and public health regulations.

Integrating environmental carry capacity based on pesticide risk assessment in soil management: A case study for China

Pesticides are widely used in agriculture and can pose risks to soil health and environmental quality. This study assessed the occurrence, distribution, ecological risk, and environmental carrying capacity of 56 currently used pesticides and three metabolites in agricultural soils of Horqin Left Middle Banner, a typical Northeast China agricultural area. 29 pesticides were detected, with atrazine, clothianidin, and propiconazole the most common. Clothianidin and difenoconazole were high-risk to non-target organisms according to risk-toxicity exposure ratio and risk quotient approaches. This study provides a comprehensive and improvement framework for pesticide soil environmental carrying capacity (SECC) assessment and soil quality protection early warning. The SECC model showed no pesticides surpassed the soil carrying capacity threshold under the current application pattern. Five pesticides (clothianidin, difenoconazole, propiconazole, atrazine, and imidacloprid) may reach the threshold within 10 years, requiring pesticide reduction and soil quality monitoring. An early warning system based on SECC values and cumulative amounts of pesticides predicted that clothianidin may exceed the threshold within 0.1 years. These pesticides should be prioritized for management and regulation to prevent soil environmental degradation. The findings can help inform policymakers and stakeholders on pesticide management and sustainable agricultural development in Horqin Left Middle Banner and similar regions.

Spatial redistribution and enantiomeric signatures of hexachlorocyclohexanes in Chinese forest soils: Implications to environmental behavior and influencing factors

Hexachlorocyclohexanes (HCHs) are a group of highly persistent pesticides. The concentrations of HCHs and the enantiomeric fractions of α-HCH in the O- and A-horizons from 30 mountains across China were analyzed in this study. The concentrations of total HCHs ranged from 0.061 to 46.9 ng/g (mean 2.12 ng/g) and 0.046 to 16.1 ng/g (mean 0.792 ng/g) in the O- and A-horizons, respectively. The HCH residues were mainly derived from the historical applications of technical HCH and lindane. Higher concentrations of HCHs were typically found in northern China, and no significant correlations were found between historical technical HCH usage and HCH isomer concentrations in either the O- or A-horizons (p > 0.05). Conversely, the concentrations of HCH isomers were significantly correlated with the environmental parameters (temperature and precipitation), thus indicating a typical secondary distribution pattern. Some HCH isomers tended to be transported northward under the long-term effect of monsoon. Chiral α-HCH was non-racemic in soils and showed preferential degradation of (-) α-HCH in both the O- and A-horizons. The transformation from γ-HCH to α-HCH might alter the enantiomeric signatures of α-HCH in soils. Moreover, the deviation from racemic of α-HCH was positively correlated with the C/N ratio in the A-horizon (p < 0.01), thus suggesting that the C/N ratio could alter the microbial activity and significantly affect the enantioselective degradation extent of α-HCH in soils.

Spatio-temporal distribution of organochlorine pesticides in agricultural soils of southeast China during 2014-2019

Organochlorine pesticides (OCPs) are organic pollutants that are persistent and undegradable in the environment. To investigate their residual concentrations, spatial and temporal distributions, and the relationship with the crops planted, 12 individual OCPs in 687 soil samples from Jiangsu, Zhejiang and Jiangxi provinces of southeast China were examined. The detection frequencies of OCPs in the studied areas were 1.89%-64.9%. The concentrations of dichloro-diphenyl-trichloroethanes (DDTs), hexachlorocyclohexanes (HCHs), and endosulfans ranged from 0.01 to 5659 μg/kg, 0.03-3.58 μg/kg, and 0.05-3235 μg/kg, respectively. Jiangsu was mainly contaminated by p,p'-DDT, p,p'-DDD and endosulfan sulfate, Zhejiang was more polluted by OCPs except δ-HCH, and Jiangxi was more vulnerable to the contamination of OCPs except o,p'-DDE. The partial least-squares discrimination analysis (PLS-DA) model with RX2 36.3-36.8% revealed that compounds with similar chemical properties tended to appear in the same year and month. All crop lands were polluted by DDTs and Endosulfans. The highest concentrations of DDTs and Endosulfans were found in citrus and vegetable fields, respectively. This study offers new insight into the layout and partitioning of OCPs in agricultural land and into insecticide management on public health and ecological safety.

Pesticides and Parabens Contaminating Aquatic Environment: Acute and Sub-Chronic Toxicity towards Early-Life Stages of Freshwater Fish and Amphibians

Pesticides and personal care products are two very important groups of contaminants posing a threat to the aquatic environment and the organisms living in it.. Therefore, this study aimed to describe the effects of widely used pesticides and parabens on aquatic non-target biota such as fish (using model organisms Danio rerio and Cyprinus carpio) and amphibians (using model organism Xenopus laevis) using a wide range of endpoints. The first part of the experiment was focused on the embryonal toxicity of three widely used pesticides (metazachlor, prochloraz, and 4-chloro-2-methyl phenoxy acetic acid) and three parabens (methylparaben, propylparaben, and butylparaben) with D. rerio, C. carpio, and X. laevis embryos. An emphasis was placed on using mostly sub-lethal concentrations that are partially relevant to the environmental concentrations of the substances studied. In the second part of the study, an embryo-larval toxicity test with C. carpio was carried out with prochloraz using concentrations 0.1, 1, 10, 100, and 1000 µg/L. The results of both parts of the study show that even the low, environmentally relevant concentrations of the chemicals tested are often able to affect the expression of genes that play either a prominent role in detoxification and sex hormone production or indicate cell stress or, in case of prochloraz, to induce genotoxicity.

Dissecting the Enantioselective Neurotoxicity of Isocarbophos: Chiral Insight from Cellular, Molecular, and Computational Investigations

Chiral organophosphorus pollutants are found abundantly in the environment, but the neurotoxicity risks of these asymmetric chemicals to human health have not been fully assessed. Using cellular, molecular, and computational toxicology methods, this story is to explore the static and dynamic toxic actions and its stereoselective differences of chiral isocarbophos toward SH-SY5Y nerve cells mediated by acetylcholinesterase (AChE) and further dissect the microscopic basis of enantioselective neurotoxicity. Cell-based assays indicate that chiral isocarbophos exhibits strong enantioselectivity in the inhibition of the survival rates of SH-SY5Y cells and the intracellular AChE activity, and the cytotoxicity of (S)-isocarbophos is significantly greater than that of (R)-isocarbophos. The inhibitory effects of isocarbophos enantiomers on the intracellular AChE activity are dose-dependent, and the half-maximal inhibitory concentrations (IC₅₀) of (R)-/(S)-isocarbophos are 6.179/1.753 μM, respectively. Molecular experiments explain the results of cellular assays, namely, the stereoselective toxic actions of isocarbophos enantiomers on SH-SY5Y cells are stemmed from the differences in bioaffinities between isocarbophos enantiomers and neuronal AChE. In the meantime, the modes of neurotoxic actions display that the key amino acid residues formed strong noncovalent interactions are obviously different, which are related closely to the molecular structural rigidity of chiral isocarbophos and the conformational dynamics and flexibility of the substrate binding domain in neuronal AChE. Still, we observed that the stable "sandwich-type π-π stacking" fashioned between isocarbophos enantiomers and aromatic Trp-86 and Tyr-337 residues is crucial, which notably reduces the van der Waals' contribution (ΔG_vdW) in the AChE-(S)-isocarbophos complexes and induces the disparities in free energies during the enantioselective neurotoxic conjugations and thus elucidating that (S)-isocarbophos mediated by synaptic AChE has a strong toxic effect on SH-SY5Y neuronal cells. Clearly, this effort can provide experimental insights for evaluating the neurotoxicity risks of human exposure to chiral organophosphates from macroscopic to microscopic levels.