Residue levels and risk assessment of pesticides in nuts of China

Pesticide residues and risk assessment of trunk-injected pesticides in pine nut (Pinus koraiensis) seeds

Pine nuts, the edible seeds of pines (Family: Pinaceae, Pinus spp.), are popular worldwide, particularly those from the Korean pine tree (Pinus koraiensis), which is economically significant and widely exported. The spread of pine wilt disease (PWD) caused by pinewood nematodes (PWNs) has necessitated the use of trunk injections of pesticides in Korea, raising concerns about pesticide residues in edible pine nuts. This study investigated the concentration of pesticide residues in pine nuts from trunk-injected trees and assessed their potential health risks to consumers. After Korean pine tree was trunk-injected with pesticide, the pine nuts were subsequently harvested and analyzed for pesticide residues using LC‒MS/MS. Short- and long-term risk assessments of trunk-injected pesticides in pine nuts were conducted. Abamectin and emamectin benzoate were not detected, while acetamiprid and sulfoxaflor were detected, but their levels were below the maximum residue limits (MRLs) set by Korea, the EU, and the US. The short-term and long-term risk assessments indicated negligible health risks for consumers from these residues. Despite the low risk, we recommend continued monitoring of pesticide residues in pine nuts intended for sale to ensure consumer safety.

Effects of organochlorine pesticides on human and rat 17β-hydroxysteroid dehydrogenase 1 activity: Structure-activity relationship and in silico docking analysis

The objective of this study was to examine the effect of 11 organochlorine pesticides on human and rat 17β-Hydroxysteroid dehydrogenase 1 (17β-HSD1) in human placental and rat ovarian microsome and on estradiol production in BeWo cells. The results showed that the IC50 values for endosulfan, fenhexamid, chlordecone, and rhothane on human 17β-HSD1 were 21.37, 73.25, 92.80, and 117.69 μM. Kinetic analysis revealed that endosulfan acts as a competitive inhibitor, fenhexamid as a mixed/competitive inhibitor, chlordecone and rhothane as a mixed/uncompetitive inhibitor. In BeWo cells, all insecticides except endosulfan significantly decreased estradiol production at 100 μM. For rats, the IC50 values for dimethomorph, fenhexamid, and chlordecone were 11.98, 36.92, and 109.14 μM. Dimethomorph acts as a mixed inhibitor, while fenhexamid acts as a mixed/competitive inhibitor. Docking analysis revealed that endosulfan and fenhexamid bind to the steroid-binding site of human 17β-HSD1. On the other hand, chlordecone and rhothane binds to a different site other than the steroid and NADPH-binding site. Dimethomorph binds to the steroid/NADPH binding site, and fenhexamid binds to the steroid binding site of rat 17β-HSD1. Bivariate correlation analysis showed a positive correlation between IC50 values and LogP for human 17β-HSD1, while a slight negative correlation was observed between IC50 values and the number of HBA. ADMET analysis provided insights into the toxicokinetics and toxicity of organochlorine pesticides. In conclusion, this study identified the inhibitory effects of 3-4 organochlorine pesticides and binding mechanisms on human and rat 17β-HSD1, as well as their impact on hormone production.

Determination, temporal variation and potential health risk assessment of pesticide residues in grapes from South and Southwest China

Pesticide residues in grapes from South and Southwest China were determined using the QuEChERS procedure and UHPLC-MS/MS and GC-MS/MS methods. The 4-year monitoring and survey showed 94.6% of the 1341 samples of grapes collected from eight main production areas contained one or multiple pesticide residues (above the respective LOQs). Overall, 40 pesticides were detected, including 24 fungicides, 12 insecticides, 2 acaricides and 2 plant growth modulators, of which one pesticide was unauthorised for use in treating grapes. Two or more pesticide residues were discovered in 87.4% of the samples (above the respective LOQs), and pesticide residues in 5.7% of the samples exceeded the MRLs, such as difenoconazole, cyhalothrin, propiconazole, etc. The main risk factors affecting the safety of grape before 2019 were difenoconazole, cyhalothrin and cyazofamid. After 2019, however, the frequency of occurrence of the above pesticides significantly declined, and the banned or restricted pesticides including omethoate were not found, which was credited to the stricter supervision and management policies by local governments. Despite the high detection rates and multi-residue occurrence of pesticides in grapes, about 84% of the samples were compliant with regulatory standards. Moreover, the accumulative chronic diet risk determined from ADI is very low. This study and timely monitoring can ensure that grape growers comply with GAP and minimise the occurrence of residues.

Review of the Terminology, Approaches, and Formulations Used in the Guidelines on Quantitative Risk Assessment of Chemical Hazards in Food

This paper reviews the published terminology, mathematical models, and the possible approaches used to characterise the risk of foodborne chemical hazards, particularly pesticides, metals, mycotoxins, acrylamide, and polycyclic aromatic hydrocarbons (PAHs). The results confirmed the wide variability of the nomenclature used, e.g., 28 different ways of referencing exposure, 13 of cancer risk, or 9 of slope factor. On the other hand, a total of 16 equations were identified to formulate all the risk characterisation parameters of interest. Therefore, the present study proposes a terminology and formulation for some risk characterisation parameters based on the guidelines of international organisations and the literature review. The mathematical model used for non-genotoxic hazards is a ratio in all cases. However, the authors used the probability of cancer or different ratios, such as the margin of exposure (MOE) for genotoxic hazards. For each effect studied per hazard, the non-genotoxic effect was mostly studied in pesticides (79.73%), the genotoxic effect was mostly studied in PAHs (71.15%), and both effects were mainly studied in metals (59.4%). The authors of the works reviewed generally opted for a deterministic approach, although most of those who assessed the risk for mycotoxins or the ratio and risk for acrylamide used the probabilistic approach.

Current-use pesticide exposure pathways in Czech adults and children from the CELSPAC-SPECIMEn cohort

INTRODUCTION

In this study, we aimed to characterise exposure to pyrethroids, organophosphates, and tebuconazole through multiple pathways in 110 parent-child pairs participating in the CELSPAC-SPECIMEn study.

METHODS

First, we estimated the daily intake (EDI) of pesticides based on measured urinary metabolites. Second, we compared EDI with estimated pesticide intake from food. We used multiple linear regression to identify the main predictors of urinary pesticide concentrations. We also assessed the relationship between urinary pesticide concentrations and organic and non-organic food consumption while controlling for a range of factors. Finally, we employed a model to estimate inhalation and dermal exposure due to spray drift and volatilization after assuming pesticide application in crop fields.

RESULTS

EDI was often higher in children in comparison to adults, especially in the winter season. A comparison of food intake estimates and EDI suggested diet as a critical pathway of tebuconazole exposure, less so in the case of organophosphates. Regression models showed that consumption per g of peaches/apricots was associated with an increase of 0.37% CI [0.23% to 0.51%] in urinary tebuconazole metabolite concentrations. Consumption of white bread was associated with an increase of 0.21% CI [0.08% to 0.35%], and consumption of organic strawberries was inversely associated (-61.52% CI [-79.34% to -28.32%]), with urinary pyrethroid metabolite concentrations. Inhalation and dermal exposure seemed to represent a relatively small contribution to pesticide exposure as compared to dietary intake.

CONCLUSION

In our study population, findings indicate diet plays a significant role in exposure to the analysed pesticides. We found an influence of potential exposure due to spray drift and volatilization among the subpopulation residing near presumably sprayed crop fields to be minimal in comparison. However, the lack of data indicating actual spraying occurred during the critical 24-hour period prior to urine sample collection could be a significant contributing factor.

Pollution characteristics, ecological and health risks of herbicides in a drinking water source and its inflowing rivers in North China

This study measured the pollution characteristics and ecological and health risks of 19 herbicides found in drinking water sources and their inflowing rivers. The targeted herbicides were prevalent in the study area, but most concentrations were well below 10 ng L-1. Acetochlor and atrazine were the dominant herbicides, although their levels were much lower than previously reported. Total herbicide residual levels were greater in April than in December and increased from upstream to downstream, resulting in the highest pollution levels found in the reservoirs, likely due to herbicides delivered from upstream and dense agricultural planting in the surrounding areas. Only atrazine and ametryn presented moderate ecological risks, while the summed risk quotients (ΣRQs) of each sample were >0.1, indicated that the total herbicide levels represented a moderate risk in all samples. For the human health risks, the risk quotients (RQ) of all target herbicides, the total RQs of each sample, and estimated life-stage RQs were far smaller than the 0.2 threshold, indicating the absence of human health risks when the water was consumed at any stage of life. However, early life stages exhibited 3-6 times higher RQ values than adulthood and should not be overlooked. And crucially, the synergistic or antagonistic effects of mixed herbicides are not well understood, and further research is needed to understand the impact of these herbicides on the ecosystem and human health, particularly possible affects in early life stages, such as infants and children.

Determination, Quality, and Health Assessment of Pesticide Residues in Kumquat in China

Pesticide residues in kumquat fruits from China, and the quality and chronic/acute intake risks in Chinese consumers, were assessed using the QuEChERS procedure and UHPLC-MS/MS and GC-MS/MS methods. Our 5-year monitoring and survey showed 90% of the 573 samples of kumquat fruits collected from two main production areas contained one or multiple residual pesticides. Overall, 30 pesticides were detected, including 16 insecticides, 7 fungicides, 5 acaricides, and 2 plant growth modulators, of which 2 pesticides were already banned. Two or more residual pesticides were discovered in 81% of the samples, and pesticide residues in 9.4% of the samples surpassed the MRLs, such as profenofos, bifenthrin, triazophos, avermectin, spirodiclofen, difenoconazole, and methidathion. The major risk factors on the safety of kumquat fruits before 2019 were profenofos, bifenthrin, and triazophos, but their over-standard frequencies significantly declined after 2019, which was credited to the stricter supervision and management policies by local governments. Despite the high detection rates and multi-residue occurrence of pesticides in kumquat fruits, about 81% of the samples were assessed as qualified. Moreover, the accumulative chronic diet risk determined from ADI is very low. To better protect the health of customers, we shall formulate stricter organic phosphorus pesticide control measures and stricter use guidelines, especially for methidathion, triazophos, chlorpyrifos, and profenofos. This study provides potential data for the design of kumquat fruit quality and safety control guidelines and for the reduction in health risks to humans.

Pyrethroid residues in Indonesian river Citarum: A simple analytical method applied for an ecological and human health risk assessment

Pyrethroid residues in the Citarum River, Indonesia, was first investigated based on their occurrences, water assimilative capacity, and risk assessment. In this paper, first, a relatively simple and efficient method was built and validated for analysis of seven pyrethroids in river water matrix: bifenthrin, fenpropathrin, permethrin, β-cyfluthrin, cypermethrin, fenvalerate, and deltamethrin. Next, the validated method was used to analyze pyrethroids in the Citarum River. Three pyrethroids, β-cyfluthrin, cypermethrin, and deltamethrin, were detected in some sampling points with concentration up to 0.01 mg/L. Water assimilative capacity evaluation shows that β-cyfluthrin and deltamethrin pollution exceed the Citarum river water capacity. However, due to hydrophobicity properties of pyrethroids, removal through binding to sediments are expected. Ecotoxicity risk assessment shows that β-cyfluthrin, cypermethrin and deltamethrin pose risks to the aquatic organisms in the Citarum River and its tributaries through bioaccumulation in food chain. Based on bioconcentration factors of the detected pyrethroids, β-cyfluthrin poses the highest adverse effect to humans while cypermethrin is the safest. Human risk assessment based on hazard index suggests that acute non-carcinogenic risk associated to consuming fish from the study location polluted with β-cyfluthrin, cypermethrin and deltamethrin is unlikely. However, hazard quotient shows that chronic non-carcinogenic risk associated to consuming fish from the study location polluted with β-cyfluthrin is likely. However, since the risk assessment was performed separately for each pyrethroid, further assessment on the impact of mixture pyrethroid to aquatic organisms and humans should be performed to explore the real impact of pyrethroids to the river system.

Potassium bromate in bread, health risks to bread consumers and toxicity symptoms amongst bakers in Bamenda, North West Region of Cameroon

This study evaluated the occurrence of potassium bromate in bread, its overall health risks to bread consumers, and its toxicity symptoms amongst bakers in Bamenda. Thirteen bakeries were included in a cross-sectional survey to gather information about the quantities of bread produced and the symptoms of potassium-bromated toxicity experienced by bakers during baking. The concentration of potassium bromate in the most consumed bread types was determined using a spectrophotometric method. The hazard quotient and hazard ratio were computed for each bread type to determine its chemical and carcinogenic risks. Results showed that all bakers had experienced symptoms of potassium bromate toxicity, and painful eyes, cough, diarrhea, and sore throat were the most recurrent symptoms of toxicity. The concentration of potassium bromate in all bread samples (100%) ranged from 48.50 mg/kg to 10148.50 mg/kg, exceeding the maximum acceptable limits by 9-203 times the dose (50 mg/kg) recommended by Food and Drug Administration. There was no significant difference (p = 0.109) in potassium bromate concentration between bread types, and simple bread, milk bread, and French bread had the highest concentration of potassium bromate. The chronic hazard quotient ranged from 277.93 to 2459.36, and the hazard ratio ranged from 251434.30 to 32862.86, indicative of possible chemical and carcinogenic risks after prolonged regular consumption. From the hazard ratios, the chances of having cancer from an average daily consumption of either simple bread or milk bread, or French bread are approximately 290,000 in 1,000,000 or 220,000 in 1,000,000 or 190,000 in 1,000,000. Thus regulatory authorities need to monitor, control or prohibit the use of potassium bromate as a flour additive.

Level and risk assessment of selected polychlorinated biphenyls, polycyclic aromatic hydrocarbons, and organochlorine pesticides in walnut and soil

It is unknown how hydrophobic organic contaminants (HOCs) are distributed and how they affect the environment in high-fat nuts and their planted soil. The profile of HOCs in walnut/soil system was investigated in this study. Polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), and organochlorine pesticides (OCPs) were found in walnuts at concentrations of 0.67, 127, and 116 μg/kg, respectively. The target hazard quotients (THQ) of 17 PCBs, 16 PAHs, and 21 OCPs from walnut consumption by human were 0.06, 0.01, and 0.11, respectively. The highest concentrations of HOC in the soil were found in Nap and toxaphene, with concentrations of 2580 and 902 μg/kg, respectively. Bioaccumulation factors (BAF) and biota-sediment accumulation factors (BSAF) in walnuts were ranged from <0.01 to 7.04 and <0.01 to 3.83, respectively. Concentrations of most individual HOCs in soil samples were significantly correlated with soil organic matter (SOM) (p < 0.01) and minerals (p < 0.01), with maximum correlation coefficients of 0.70 (OM-PCB81) and -0.84 (P-BaP). According to this study, high-fat walnuts do not have a high bioaccumulation of HOCs from soil, and the risk of consumption is within the safe range.

Organophosphate Pesticides and Pyrethroids in Farmland of the Pearl River Delta, China: Regional Residue, Distributions and Risks

A regional-scale survey was conducted to assess the occurrence, distribution, and risk of two extensively used pesticides (organophosphate pesticides and pyrethroids) in agricultural soils from the Pearl River Delta (PRD), South China. All target organophosphate pesticides (OPPs) and pyrethroids (PYs) were detected in the soil samples and both with a detection rate of 100%. The residues of the sum of six OPPs and the sum of four PYs were in the range of LOD-991 ng/g and 8.76-2810 ng/g, respectively. Dimethoate was the dominant OPPs, and fenpropathrin was the predominant PYs in the soils of the PRD region. With intensive agricultural activities, higher residues of OPPs and PYs in soils were detected closer to the seaside, among which Zhuhai city and Huizhou city suffered more serious combined pesticide pollution. The vertical compositional profiles showed that dimethoate could be detected through each soil layer in the PRD region's nine cities. The human exposure estimation of OPPs showed insignificant risks to the local population. In contrast, cypermethrin and fenpropathrin showed a potential ecological risk of 2.5% and 3.75% of the sampling sites, respectively. These results can facilitate those commonly used pesticide controls and promote sustainable soil management.

Occurrence, distribution, and driving factors of current-use pesticides in commonly cultivated crops and their potential risks to non-target organisms: A case study in Hainan, China

Multiple pesticides are heavily applied in crops grown in China's tropics due to the prevalence of diseases and pests, thus posing potential risks to nontarget organisms (e.g., honeybees, lacewings, ladybugs, and humans). However, there is little information on this topic. This study is the first assessment of the occurrence, driving factors, and ecological/human health risks of 32 current-use pesticides (CUPs) in 10 frequently-planted crops collected from practicing rice-vegetable rotation systems in Hainan, China. Of the 132 whole crop samples, 44 (33.3 %) residues from ≥8 pesticides were detected in 9.09 % of crop samples with concentrations ≥0.5 mg kg-1. Six pesticide residues, namely carbendazim, pyraclostrobin, acetamiprid, thiophanate methyl, phoxim, and imidacloprid, were detected in 72.7 % of samples, with concentrations ranging from 0.0021 to 13.5 (median = 0.032) mg kg-1. Among them, carbendazim, pyraclostrobin, and acetamiprid were the most common, contributions from 10.2 to 25.5 % and a detection frequency ranging from 25.6 to 56.1 %. The order of total concentration of 32 CUPs (∑32 CUP) concentrations during the year was January > May > November > August and vegetables > rice, being highly related with pesticides usage pattern, crop type, plant accumulation/dissipation and plant lipid contents. The ecological risk quotients (RQs) to four beneficial terrestrial organisms showed that 9.6-39.1 % of samples posed a potential medium or high ecological risk, with 13.6-65.9 % of samples at ∑RQ > 1 being highly affected by the residues of neonicotinoids and emamectin benzoate. Emamectin benzoate (8.9 %) and acetamiprid (5.6 %) exceeded the individual Maximum Residue Levels based on Chinese legislation (GB2763-2021). Moreover, cumulative dietary exposure presented a higher risk to humans in 11.0 and 22.0 % of the cases for acute and chronic, mainly originating from the higher concentration contributors of systemic pesticides in edible crops. Therefore, the regulation and monitoring of CUP residues is imperative for rice-vegetable rotation systems in tropical China to avoid negative effects on nontarget organisms.

Human health risk assessment of pesticide residues in vegetable and fruit samples in Gujarat State, India

The present study was initiated with the purpose to evaluate possible health risks associated with pesticide residues through consumption of vegetables and fruits by general population of Gujarat, India. A total of 1075 samples comprising of twelve different varieties of commonly consumed food commodities were collected from twenty-five divergent locations in Gujarat. The collected samples were extracted using QuEChERS method and analyzed for the presence of organophosphorus (OPs), organochlorine (OCs) and synthetic pyrethroids (SPs) pesticides using UHPLC-HR/MS, GC-μECD and GC-MS/SIM. The results indicated that 2.3% of vegetable and fruit samples showed the presence of pesticide residues exceeding maximum residue limits (MRLs). The results suggested that, detected residue levels in samples were within safe limits and their consumption will not pose any significant health risk to human. The outcomes present significant information regarding the status of vegetable and fruit contamination and pointed out the prerequisite for further studies with reference to monitoring of pesticides and other toxic contaminants in different samples for assessing cumulative health risk.

Analysis of dietary exposure and risk assessment of pesticide residues in roots and rhizomes of Chinese herbs

Medicine food homologous (MFH) plants provide therapeutic and health care effects through diet. Thus, a risk assessment system for hazardous ingredient residues is urgently required to ensure their safe use. In this study, the pesticide contamination of six root and rhizome Chinese herbs, Ginseng Radix et Rhizoma, Panacis Quinquefolii Radix, Pseudostellariae Radix, Salviae Miltiorrhizae Radix et Rhizoma, Codonopsis Radix, and Glehniae Radix, and the risks associated with their intake were investigated. A total of 420 MFH plant samples collected from 22 provinces in China were tested, and 61 pesticides were detected in 413 samples. Multiple pesticide residues were detected in each MFH sample, with contents ranging from 0.0002 to 3.010 mg/kg dry weight. Carbendazim (≥47.14%) and propham (≥40%) were the most frequently detected pesticides. Risk assessment determined by hazard quotients indicated that the risks were acceptable, with no short- or long-term adverse health effects. However, considering the high incidence of residues and the detection of unregistered or even prohibited pesticides, strict supervision of soil quality and pesticide application (particularly cadusafos) in MFH plant cultivation are recommended to aid in monitoring MFH plant quality and ensuring diet and drug safety. PRACTICAL APPLICATION: Ensure the diet and drug safety of Chinese herbs.

Plants exert beneficial influence on soil microbiome in a HCH contaminated soil revealing advantage of microbe-assisted plant-based HCH remediation of a dumpsite

Persistence of hexachlorocyclohexane (HCH) pesticide is a major problem for its disposal. Soil microflora plays an important role in remediating contaminated sites. Keeping concepts of microbial- and phyto-remediation together, the difference between soil microflora with and without association of HCH accumulating plant species was studied. Metagenomic analysis among the non-plant soil (BS) (∑HCH 434.19 mg/g), rhizospheric soil of shrubs (RSS) (∑HCH 157.31 mg/g), and rhizospheric soil of trees (RSD) (∑HCH 105.39 mg/g) revealed significant differences in microbial communities. Shrubs and trees occurred at a long-term dumpsite accumulated α- and β- HCH residues. Plant rhizospheric soils exhibited high richness and evenness with higher diversity indices compared to the non-plant soil. Order Rhizobiales was most abundant in all soils and Streptomycetales was absent in the BS soil. Proteobacteria and Ascomycota were highest in BS soil, while Actinobacteria was enriched in both the plant rhizospheric soil samples. In BS soil, Pseudomonas, Sordaria, Caulobacter, Magnetospirillum, Rhodospirillum were abundant. While, genera Actinoplanes, Streptomyces, Bradyrhizobium, Rhizobium, Azospirillum, Agrobacterium are abundant in RSD soil. Selected plants have accumulated HCH residues from soil and exerted positive impacts on soil microbial communities in HCH contaminated site. This study advocates microbe-assisted plant-based bioremediation strategy to remediate HCH contamination.

Health risk assessment of hexachlorocyclohexane in soil, water and plants in the agricultural area of Potohar region, Punjab, Pakistan

In this study analysis of soil, water and plant residue samples is presented to evaluate the contamination levels and possible health risks. Hexachlorocyclohexane (HCH) is a persistent organic pollutant used as a pesticide in agricultural sector for pest control in order to obtain higher productivity. For analysis soil, water and crop residue samples were collected from different agricultural areas of the northern Punjab region of Pakistan. The investigation of the samples shows significant levels of HCH residues in all types of samples. Gas chromatography-mass spectrometry analysis was used to assess the higher residue levels of HCH in the samples. The concentration of HCH residues detected in samples ranged from 2.43 to 8.88 µg/g in soil, nd -5.87 µg/l in water and nd - 4.87 µg/g in plants. The presence of HCH residues in soil, water and plant samples was beyond the recommended quality guidelines. Human health risk was evaluated for cancer and non-cancer risks through dietary and non-dietary exposure routes. The hazard index was HI > 1 in children and HI < 1 in adults, while the non-dietary incremental lifetime cancer risks (ILCR) were beyond the internationally acceptable limit of 1 × 10^-5. Hence, results of the present investigation concluded the presence of high levels of HCH residues in samples and pose high health risk to the inhabitants. These findings are alarming and apprise the concerned departments for the remediation of contamination and proper implementation of environmental laws in the area.

Contamination of Foods from Cameroon with Residues of 20 Halogenated Pesticides, and Health Risk of Adult Human Dietary Exposure

(1) Background: Halogenated pesticides are abundantly used in Cameroon, but there is no information on the health risk of consumers from exposure to their residues in foods. (2) Methods: Residues of 20 halogenated pesticides were determined in 11 agricultural products collected in the 3 largest cities of Cameroon using QuEChERS extraction and gas chromatography with electron capture detector (GC-ECD), and health risk from dietary exposure was assessed. (3) Results: Organochlorines pesticides aldrin, p,p'-dichlorodiphenyl-trichloroethane (DDT) and β-hexachlorocyclohexane (β-HCH) found in 85.0%, 81.9% and 72.5% of samples, respectively, were the most frequently detected. The highest average concentrations of residues were 1.12, 0.74 and 0.39 mg/kg for methoxychlor, alachlor and β-HCH, respectively, found in chilli pepper. Chili pepper (58.9%), cowpea (56.8%), black beans (56.5%) and kidney beans (54.0%) exhibited the highest residue occurrences. Levels above the European Union maximum residue limits (MRLs) were found for all the 20 pesticides, in 40.1% of the positive analyses, and the food samples contained 14 pesticides banned in Cameroon. Chronic, acute, cumulative and carcinogenic risk assessments revealed that lifetime consumption of maize, black beans, kidney beans, groundnuts and chili pepper contaminated with aldrin, dieldrin, endrin, HCB, heptachlor, o,p'-DDT, p,p'-DDD, p,p'-DDT, p,p'-DDE and β-HCH, could pose health risks. (4) Conclusion: These results show that there is an urgent need of pesticide usage regulation, effective application of pesticide bans and management of obsolete pesticide stocks in Cameroon.

Pesticide Residue Analysis of Khat Leaves and Health Risks among Khat Chewers in the Amhara Region, Northwestern Ethiopia

Introduction

Farmers use a large number of pesticides to increase the productivity of Khat cultivation. Since Khat is consumed by many Ethiopians as a habit, there may be a significant concentration of pesticide residues in Khat leaves which result in adverse effects among the exposed population. Excess use of pesticides in Khat causes cancer, genotoxicity, and endocrine disturbances. The current study aimed to determine the concentration of selected pesticide residues on Khat leaves samples and to estimate the possible health risk on consumers.

Methods

Thirty Khat samples were collected from Khat cultivators in the Amhara region, Ethiopia. Pesticide residue extraction and cleanup of Khat samples were performed using the QuEChERS method. Data were also collected about personal variables and Khat consumption habits. The pesticide concentrations were determined and the health risks were estimated.

Results

Profenofos, dimethoate, and chlorpyrifos were detected in 6 (20%), 24 (80%), and 28 (93.3%) Khat samples, respectively. However, diazinon was detected in two samples and endosulfan I was not detected. The average concentration of chlorpyrifos, dimethoate, profenofos, and diazinon in Khat samples was 75.39 ± 20.26, 130 ± 48.94, 242.45 ± 119.79, and 81.5 ± 21.0 μg/kg, respectively. The HQ for diazinon was greater than 1 which shows the chronic health risks associated with intake of diazinon among Khat chewers. The acute health risks associated with intake of profenofos and diazinon were minimal. Discussion. Pesticide residue exposure is a risk factor for cardiac complications, reduction in antioxidant defense system, and developing neurological symptoms. All the pesticides were higher than the European Union Maximum Residue Levels (EU-MRL). Diazinon has the potential to cause higher chronic health risks. Chronic Khat chewers in the region may face potential health risks from pesticide residues. Awareness creation among people in the study area is necessary to avoid the adverse health effects of pesticide residues.

Simultaneous multi-determination of pesticide residues in black tea leaves and infusion: a risk assessment study

This study aimed to investigate the concentration of 33 pesticide residues in 60 black tea samples collected from Iran, determine their transfer rate, and assess their health risk during brewing. Pesticide extraction and analysis were performed by using a quick, easy, cheap, effective, rugged, and safe (QuEChERS) method and gas chromatography/tandem mass spectrometry (GC-MS/MS), respectively. The limits of detection (LOD) and the limits of quantification (LOQ) of pesticides were ranged 0.1-7.26 and 0.8-24 μg/kg for dried tea leaves and 0.03-3.1 and 0.09-10 μg/L for the tea infusion, respectively. The levels of pesticide residue in 52 (86.67%) out of 60 tea samples were above the LOD (0.1-7.26 μg/kg). Twenty four (40%) of the samples contained pesticides in a concentration higher than the maximum residue limit (MRL) set by the European Commission (EC). Seven out of 33 validated pesticides were detected in dried tea leaf samples that only four of seven, including buprofezin, chlorpyrifos, hexaconazole, and triflumizole, were transferred into tea infusion, demonstrating that the concentrations of pesticides in infusion were raised during brewing. The risk assessment study for detected pesticides in the tea infusion samples indicated that this beverage consumption was safe for consumers, while the mean residue of some pesticides in positive samples was higher than the MRL; therefore, periodic control of these pesticides should be regularly implemented.

Levels and health risk assessment of organochlorine pesticide residues in vegetables from Yamaltu area in Gombe, Nigeria

The study determined the levels of organochlorine pesticides (OCPs) residues and assesses health risks linked with the consumption of vegetables cultivated in the Yamaltu area in Gombe, Nigeria. OCPs residues were solvent extracted and analyzed with a high performance liquid chromatography equipped with UV/VIS Detector. The mean concentrations of ten detected OCPs residues were almost all above the set limit of EU/WHOMRL. The estimated daily intake of OCPs from samples was below the acceptable daily intake, hazard index estimated were <1, indicated no probable non-carcinogenic health effect, while the carcinogenic health effect showed that children were more vulnerable for the consumption of the contaminated vegetables.

Study on the dissipation pattern and risk assessment of metalaxyl-M in rice grains and paddy soil and water by liquid chromatography-tandem mass spectrometry

Herein, field experiment trials were conducted at two different sites (Heilongjiang and Hubei Province) in China to determine the residual levels and dissipation kinetics of metalaxyl-M in rice grains, and paddy soil and water. A modified quick, easy, cheap, effective, rugged, and safe "QuEChES" method coupled with liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed for determination of metalaxyl-M residual levels in different matrices. The method showed an excellent linear response (R² > 0.99) over the concentration range of 0.01-0.50 mg kg^-1 with satisfactory recovery rates in between 76.00 and 111.36%. The limits of quantification (LOQ) were estimated to be 0.010 mg kg^-1 for all matrices. Half-lives of 0.27 to 10.83 days in rice plant, paddy soil, and water indicate that the analyte is easily degraded in the environment within a relatively short time. The terminal residues of metalaxyl-M in rice husks and rice grains were less than 0.05 mg kg^-1. Dietary risk assessment showed that harvested rice treated with metalaxyl-M would not pose unreasonable risk to humans or the environment.

Pesticide residue monitoring and risk assessment in the herbal fruits Schisandra chinensis, Lycium chinense, and Cornus officinalis in Korea

Schisandra chinensis, Lycium chinense, and Cornus officinalis are cultivated in South Korea, China and Japan. Because of their beneficial biological effectiveness, the consumption of these herbs is increasing. The objective of this study was to analyze the pesticide residue levels on these herbal fruits produced in Korea. A short- and long-term risk assessment of the pesticides in herbal fruits was conducted. Pesticides were detected in most samples, and all samples with multiple residues were also noted. The average numbers of pesticides detected in the S. chinensis, L. chinense, and C. officinalis samples were 1.84, 10.28, and 5.87, respectively. The short-term and highest long-term risks, and the cumulative risk (cHI) were 0.633%, 1.14%, and 7.56% (S. chinensis), 1.0 × 10-1%, 1.1 × 10-5%, and 4.0 × 10-5% (L. chinense), and 2.2 × 10-5%, 1.6 × 10-5%, and 8.9 × 10-5% (C. officinalis). No significant health risk for consumers via herbal fruit consumption was detected.

Pesticides in human milk collected from Jinhua, China: Levels, influencing factors and health risk assessment

In China, many studies have been carried out on pesticide residues in human milk, yet all of them are on organochlorine pesticides (OCPs) and mostly focused on large, economically developed cities. In this study, 27 pesticides including OCPs, pyrethroid pesticides (PYRs) and organophosphate pesticides (OPPs) in human milk were investigated in Jinhua, an inland and medium sized city in China. Method based on QuEChERS extraction and gas chromatography-mass spectrometer (GC-MS) determination was adopted to analyze the above pesticide residues. The influencing factors as well as the health risks were also evaluated. Results show that PYRs and OPPs in human milk samples were both undetectable. Regarding OCPs, the detection rate of hexachlorobenzene (HCB), β-hexachlorocyclohexane (β-HCH) and p,p'-dichlorodiphenyl-dichloroethylene (p,p'-DDE) were 83.6%, 36.4% and 58.2%, respectively, and their mean value were 29.4, 32.0 and 85.2 ng/g lipid, respectively. p,p'-DDE levels in human milk was significantly (p < 0.05) related to maternal age, but no association was detected between OCPs residues and other factors (living environment, dietary habit, living style, etc.), suggesting that OCPs in human milk in Jinhua were originated from nonspecific source. All estimated daily intake of pesticides (EDI_pesticides) by infants were under the guideline suggested by Food and Agriculture Organization (FAO) and China Ministry of Health (CMH). Yet 9% of EDIs_HCB and 16% of EDIs_HCHs exceeded the guideline recommended by Health Canada. The associations between DDE residues and the delivery way as well as HCBs residues and the birth weight were seemly significant, yet the significance disappeared when consider age or gestational age as a cofounder, indicating that OCPs residue in mother's body in Jinhua has no obvious influence on fetus development and the delivery way.

Occurrence, temporal variation, quality and safety assessment of pesticide residues on citrus fruits in China

Citrus is highly consumed in China and considered a major source of pesticide carrier in human diet. In this paper, pesticide residues in mandarins, tangerines and oranges from China were evaluated, as well as the quality and long-term dietary risks for the Chinese consumers. Temporal variations for eight MRL non-compliant pesticides were also investigated. 106 pesticides were analyzed using QuEChERS procedure and UPLC-MS/MS, GC-MS and GC methods. Forty different pesticides were detected in 86% of the 2922 samples from 2013 to 2018. Chlorpyrifos was the most frequently detected pesticide with a detection rate of 40%. Residues of eight pesticides in 3.8% of the total samples exceeded their MRLs. The most severely excessive pesticide was bifenthrin with 283% MRL. The occurrences and exceeding rates of eight pesticides presented clear temporal variations during the six harvesting years. Isocarbophos, carbofuran and triazophos were the main risk factors threatening the citrus safety pre-2015, whereas profenofos and bifenthrin gradually became dominant after 2016, coinciding with government control measures. The index of quality for residues (IqR) levels of 88% of the samples were below 1.0, which indicated a satisfactory quality of citrus fruits in China, although 70% of the samples contained two or more residues. The cumulative chronic dietary risks were acceptable for both the Chinese general population and children and would not pose health risks. However, more strictly enforced control measures for methidathion and isocarbophos, and reduced usage of triazophos, quinalphos, profenofos and bifenthrin should be pursued to further improve the safety of citrus fruits.

Pesticide residues in soils planted with Panax notoginseng in south China, and their relationships in Panax notoginseng and soil

In this study, 73 samples from soils planted with Panax notoginseng and six P. notoginseng samples were collected in Yunnan Province to investigate the residual levels of six pesticides and their relationships with P. notoginseng and soil. All six pesticides were detected in the soils planted with P. notoginseng located in three regions of Shilin, Kaiyuan, and Yanshan. The detection frequencies of the pesticides in the soils followed the order: quintozene (100%) > iprodione (96%) > procymidone (69%) > chlorothalonil (51%) > pyrimethanil (49%) > pyraclostrobin (29%). The median concentrations of iprodione, pyraclostrobin, pyrimethanil, quintozene, procymidone, and chlorothalonil were 46.40, 6.4, 3.1, 2.86, 2.69, and 0.24 μg/kg, respectively. The mean concentrations of pesticides in the three regions followed the order: Kaiyuan > Shilin > Yanshan, except for iprodione. Furthermore, the concentrations of pesticide residues in soils in each region followed the order: soils never planted with P. notoginseng < soils previously planted with P. notoginseng < soils currently planted with P. notoginseng. The concentration of chlorothalonil in P. notoginseng followed the order: root > stem > leaf, whereas those of the other five pesticides followed the opposite order: root < stem < leaf. There were significant positive correlations between the mean concentrations of pesticides in P. notoginseng and those in the corresponding soils. These results indicate that the rational application of pesticides in P. notoginseng cultivation would be effective for reducing the accumulation of pesticides in P. notoginseng to protect people from the harmful effects of residual pesticides.

Dissipation and dietary risk assessment of tristyrylphenol ethoxylate homologues in cucumber after field application

The potential for tristyrylphenol ethoxylates (TSPEOs) residues to contaminate crops or be released into the environment is of increasing concern, as they are toxic to living organisms. This study determined the dissipation of TSPEO homologues in cucumber under field conditions. TSPEOn (n = 6-29) dissipated more rapidly in cucumber than in soil samples, with half-lives of 1.80-4.30 d and 3.73-6.52 d, respectively. Short-chain TSPEOn (n = 6-11) persisted for longer than other oligomers in soil. Concentrations of the final residues (∑TSPEOs) in cucumber and soil were 24.3-1349 μg/kg and 47.3-1337 μg/kg, respectively. TSP15EO or TSP16EO was the dominant oligomer, with concentrations of 2.30-150 μg/kg. The risk assessment showed that the acute and chronic dietary exposure risks of ∑TSPEOs in cucumber were 0.03-0.57% and 0.05-0.39%, respectively, suggesting little or no health risk to Chinese consumers.

Modulation of steroid metabolism and xenobiotic biotransformation responses in zebrafish (Danio rerio) exposed to triadimefon

The widely used fungicide triadimefon (TDF) has been detected in aquatic environments, and appears to disrupt steroid homeostasis; however, the toxic effects on fish reproduction triggered by TDF via the key receptor signaling pathways remain largely unknown. The present study showed that TDF (0.069, 0.138, 0.690 mg/L) exposure not only caused disordered germ cell maturation, but also decreased spawned egg production. In order to better understand this reproductive inhibition, we investigated the effects of TDF based on quantitative PCR, Western blot and mass spectrometry methodology in zebrafish. Due to the preferential accumulation of TDF in the liver, a general pattern of up-regulation of genes involved in biotransformation pathway was observed. A significant increase in abcb4 expression appeared to be responsible for TDF excretion. TDF-induced receptors (AhR2 and PXR) changed many genes involved in steroid metabolism, and subsequent disruptions in steroid homeostasis, which might be the key biological pathway in TDF reproductive toxicity. However, due to the different metabolic demands, the transcript profiles involved in steroid metabolism in zebrafish exhibited a sex-specific expression pattern. For example, the increase in gene expression of ahr2 was accompanied by a reduction in the rate of E2 biosynthesis resulting from the diminished cyp19a1a expression, and in turn led to down-regulation of esr1 and vtg1 in the liver, supporting the anti-estrogenic effect of TDF in male fish. In contrast, the increase in E2 production was accompanied by an increase in Esr1 protein expression caused by TDF and paralleled the increase in ahrr1 expression, suggesting that TDF may induce estrogenic activity through AhR-ER interactions in females. In addition, over-induction of cyp3a65 activity mediated through pxr, which helped to accelerate the transformation from TDF to triadimenol in the liver, appeared to elevate T metabolite rate in females. The down-regulation of fshβ transcript in males further suggested that TDF might adversely affect normal gametogenesis and induce reproductive toxicity.

Bifenthrin Induces Fat Deposition by Improving Fatty Acid Uptake and Inhibiting Lipolysis in Mice

Chemical residues in the environment are considered to be important factors that cause obesity. Bifenthrin is one of the pyrethroid pesticides and is widely used worldwide. However, its effect on adipose tissue is ill-defined. Here, we administered bifenthrin/corn oil to adult C57BL/6 mice by gavage. After 6 weeks, the bifenthrin treatment significantly increased their body weight (P = 0.015) and fat mass (P < 0.001). Then we identified 246 differently expressed proteins by proteomic analysis, and they were highly involved in fatty acid uptake and lipid metabolism processes. Interestingly, protein hormone-sensitive lipase and adipose triacylglyceride lipase were downregulated while lipoprotein lipase is upregulated after bifenthrin treatment. Similar effects in 3T3-L1 cells treated with bifenthrin validated the in vivo results. Thus, this study suggests that long-term exposure to low-dose bifenthrin induces fat deposition in mice by improving fatty acid uptake and inhibiting lipolysis, and it may cause obesity in humans.

Comparative analysis of freshwater species sensitivity distributions and ecotoxicity for priority pesticides: Implications for water quality criteria

Organochlorine pesticides (OCPs) and organophosphate pesticides (OPPs) posed severe threats to the aquatic environment in China. The toxicity data of 18 priority OCPs and OPPs for Chinese and American species were collected, and their species sensitivity distributions (SSDs) and ecotoxicity were compared. Physicochemical characteristics and chemical structures were used to analyze the difference in the pesticide toxicity. Results suggested that there is no significant difference between the HC₅ values (hazardous concentration protecting 95% of species) of China and America as a whole. However, the HC₅ values of nearly half of these pesticides (8/18) differ dramatically between Chinese and American due to the different resident species distribution. It indicated that it is necessary to develop local water quality criteria in China. The regression analysis of pesticides toxicity differences indicated a decrease in LC₅₀/EC₅₀ values (for Oncorhynchus mykiss and Carassius auratu) with the increase in molecular weights of pesticides. Pesticides with larger MWs might be more toxic to aquatic species. Similar trend was also observed in the regression analysis of a decrease in both American and Chinese HC₅ values for with increase of the number of containing halogen atoms. It indicated the potency of these parameters to be used to predict the ecotoxicity of pesticide.

Activation of manganese dioxide with bisulfite for enhanced abiotic degradation of typical organophosphorus pesticides: Kinetics and transformation pathway

Organophosphorus pesticides (OPPs), a kind of effective insecticide, have attracted extensive attention of researchers because of the high toxicity and refractory character of their degradation products. Given the ubiquity of manganese dioxide (MnO₂) and bisulfite (HSO₃^-) in environmental media, the abiotic degradation of several typical OPPs by the MnO₂-HSO₃^- reaction system was investigated in batch experiments. As a representative OPP, methyl parathion (MP) was chosen to be the focus of the study. The removal rate of MP was remarkably improved by adding bisulfite (HSO₃^-) to the MnO₂ single-reaction system, and the oxidation product methyl paraoxon was below the detection limit. The primary active substances generated from the reaction system were determined to be Mn(III) species by adding excess radical scavengers or complexants (methanol and pyrophosphate) to the reaction system. On the basis of the metabolic products of MP identified by liquid chromatography-high-resolution mass spectrometry (LC/HRMS) and gas chromatography-mass spectrometry (GC/MS), the transformation pathway of MP in the MnO₂-HSO₃^- reaction system was elicited, which included the predominant processes of hydrolysis and oxidation. Furthermore, the typical OPPs with different structures were also degraded efficiently by the reaction system because of the oxidative degradation of Mn(III). This study offers significative information related to the abiotic oxidation of manganese minerals and the fate and dissipation of OPPs in the actual environment.

Risk assessment and prediction for toxic heavy metals in chestnut and growth soil from China

BACKGROUND

Toxic heavy metals (THMs) cause severe environmental hazards and threaten human health through various consumption of food stuff. However, little is known of THMs in chestnuts. In this study, the risk assessment and prediction of THMs [lead (Pb), arsenic (As), chromium (Cr), cadmium (Cd) and mercury (Hg)] in chestnuts and growth soils from China were investigated.

RESULTS

The main detected THMs in chestnuts and growth soils were As and Cd. The total pollution levels of the five THMs (Nemerow pollution indexes, NPIs) were 0.062 and 1.06, respectively. The dietary risks for children were higher than those of adults, especially short-term non-carcinogenic risk. The main combined risks from the relationships between THMs were Pb-Cr (r = 0.85, P < 0.01) in chestnuts and Pb-As (r = 0.59, P < 0.01) in growth soils. The risk source was found to be the uptake effect of THMs from soil to chestnut, with the highest bioaccumulation factors (BCFs) of Cd (0.254). Several comprehensive risk models were established with the highest coefficient of determination (R² ) of 0.79. In addition, the main contribution rates of different soil parameters to comprehensive risk of THMs uptake were 49.8% (Cd), 23.4% (pH), 13.8% (Cr) and 13.0% (organic carbon).

CONCLUSION

The total pollution levels of THMs fell outside of the safety domain in growth soils. Furthermore, more attention needs to be paid to Cd pollution owing to its low environment background value and high accumulation ability. Three main soil parameters (Cr content, pH, organic carbon) played important roles in the formations and accumulations of THMs in chestnuts. © 2019 Society of Chemical Industry.

Molecularly imprinted polymers' application in pesticide residue detection

Molecularly imprinted polymers (MIPs) are produced using molecular imprinting technology (MIT) and have specific analyte-binding abilities and unique properties, including chemical and thermal stability, reusability, high selectivity, and high sensitivity. The application of MIPs in the detection of pesticides represents an advance and a superior scientific approach owing to their detection and characterization of trace levels in comparison with other methods. In this review, we have summarized the pre-treatment extraction of pesticides with different types of molecularly imprinted polymer for the detection of single and multiple pesticides by elaborating upon their specific extraction efficiency. The importance of different polymerization methods, functional monomers and cross-linkers is highlighted. The aim of this study is to investigate the importance of the application of MIPs in the detection of pesticides and recent advances in the last few years to overcome the limitations of previously developed methods. Existing restrictions and required future aspects are discussed.

Occurrences of the Typical Agricultural Non-ionic Surfactants Tristyrylphenol Ethoxylates in Cherries ( Cerasus pseudocerasus), Peaches ( Amygdalus persica), and Kiwifruit ( Actinidia chinensis) and the Implications of Human Exposure in China

Tristyrylphenol ethoxylates (TSP nEOs) are widely used as non-ionic surfactants in pesticide formulations in China. However, limited information is available regarding the occurrences of TSP nEOs in fruits. In this study, 361 fruit samples were collected from the main growing areas in China from 2016 to 2017 and analyzed for TSP nEO contamination using gel permeation chromatography-high-performance liquid chromatography-tandem mass spectrometry. TSP nEOs were detected in all samples, with a total concentration range of 0.5-14786.0 μg/kg (median of 85.0 μg/kg). The total concentrations were significantly but weakly correlated with the residues of acetamiprid ( r = 0.119; p < 0.05) and carbendazim ( r = -0.170; p < 0.01), suggesting that the TSP nEO residues are probably associated with the use of these pesticides during fruit growth. A risk assessment showed that there were little or no risks to human health. However, the risks to health associated with exposure to TSP nEOs should not be ignored because of their ubiquitousness in fruit samples.

Assessing residual status and spatial variation of current-use pesticides under the influence of environmental factors in major cash crop growing areas of Pakistan

The status of seven currently used pesticides were assessed under the influence of soil parameters in surface soils of cash crop growing areas of Pakistan. Chlorpyrifos occurred in highest mean concentration (1.18 mg kg^-1). Selected pesticides exhibited higher affinity towards both organic carbon and black carbon fractions. The δ¹³C stable carbon isotopic fraction of inorganic carbon was also used as a tracer and disclosed high retention of total organic carbon in Swat and Swabi sites. Statistical analysis revealed that carbon storage was primarily influenced by altitude and temperature. Soil clay mineral oxides of aluminum and iron positively correlated with organic carbon and selected pesticides (chlorpyrifos and cyprodinil). Soil to plant bio-concentration ratios predicted heightened uptake of azinfos and diazinon in major cash crop bio mass. Occupational risk via soil ingestion expressed no significant threat to the farmer community.

Residue behavior and risk assessment of thifluzamide in the maize field ecosystem

In the present work, the dissipation kinetics and final residue levels of thifluzamide in the maize field ecosystem were investigated. Using a modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) extraction combined with liquid chromatography-tandem mass spectrometric detection (LC-MS/MS), a rapid, sensitive, efficient, and reliable method for extraction and quantitative analysis of thifluzamide residues in maize grain, maize plant, and soil was developed. Satisfactory recoveries of 78.7-97.0% were achieved with relative standard deviations (RSDs) in the range of 1.6 to 8.2%. The limits of detection (LODs) and the limit of quantification (LOQ) were 0.002-0.005 and 0.010 mg kg^-1, respectively. The dissipation kinetics of thifluzamide in maize plant was well fitted by the first-order kinetic model with short half-lives of 0.19-0.22 days, while thifluzamide degraded slowly in soil with half-lives of 4.56-15.85 days. The final residues in maize grain, maize plant, and soil samples collected at the milk stage and the physiological maturity stage were no more than 0.010, 0.807, and 0.278 mg kg^-1, respectively. Given that no maximum residue limit (MRL) for thifluzamide in maize has been established, the safety of this fungicide application was estimated by a dietary risk assessment. The hazard quotient was 0.03%, which was substantially less than 1, indicating that the long-term risk induced by the thifluzamide application on maize at the recommended dose is negligible. These results help governments to develop regulations for the safe use of thifluzamide.

Distribution, relationship, and risk assessment of toxic heavy metals in walnuts and growth soil

Walnut is one of the most popular nuts worldwide and contains various mineral nutrients. Little is known, however, about the relationship between toxic heavy metals in walnuts and growth soil. In this study, we investigated the distribution, relationship, and risk assessment of five toxic heavy metals-lead (Pb), arsenic (As), chromium (Cr), cadmium (Cd), and mercury (Hg)-in walnuts and growth soil in the main production areas of China. The results showed that the main heavy metal pollution in walnut and soil was Pb and Cd. Regionally, positive relationships existed between heavy metals and the pH and organic matter of soil. In addition, we observed a notable uptake effect between walnut and growth soil. In this study, we found a significant correlation (r = 0.786, P < 0.05) between the bioconcentration factors and the longitude of the sampling areas. The risks (total hazard quotients) of five heavy metals toward children and adults by dietary walnut consumption were 46.8 and 56.2%, respectively. The ability to identify toxic heavy metal pollution in walnuts and growth soil could be helpful to screen suitable planting sites to prevent and control heavy metal pollution and improve the quality and safety of walnut.

Dietary exposure to HCH and DDT congeners and their associated cancer risk based on Pakistani food consumption

Dietary exposure to organochlorine pesticides such as hexachlorocyclohexane (HCH) and dichlorodiphenyltrichloroethane (DDT) congeners was assessed using diet study approach, and for this purpose, different food items were collected in August 2014. The levels of ∑(HCHs + DDTs) in different food groups were ranged from 2.57 to 206 ng g^-1, ww, with contamination order of fish > poultry > milk > vegetables > cereals > flour > fruits. In the present study, the ratios of β-HCH/∑HCH (0.19-0.40) were < 0.5, where the ratios of (DDE + DDD)/∑DDT (0.48-6.70 with mean value of 0.61) were > 0.5 demonstrated the recent and past inputs of HCH and DDT, respectively. The major contributing groups (6.3-70.3%) to total dietary intake of HCHs and DDTs were animal origin (fish, poultry, and milk), while the less contributing food groups (2-4.5%) were vegetarian origin (vegetables, cereals, flour, and fruits). Cancer risk was estimated for HCHs and DDTs ingested via local foodstuffs. On the basis of both average and high end (95th percentile) exposure levels, the HRs for HCHs and DDTs were found greater than one (safety limit), indicating a potential cancer risk for Pakistani people from life-time consumption of contaminated food items selected in this study. The congener-specific cancer risk was found in order of α-HCH > β-HCH > ∑DDT > γ-HCH > p,p'-DDE > p,p'-DDT. Graphical abstract ᅟ.

Human health risk assessment on the consumption of fruits and vegetables containing residual pesticides: A cancer and non-cancer risk/benefit perspective

Pesticide residues in food is a public health concern. This study aimed to evaluate health risk and benefit associated with chronic consumption of fruits and vegetables (F&V) containing residual pesticides in the province of Quebec, Canada. Based on a representative sample of Quebecers (n=4727, aged 1-79) enrolled in the Canadian nutrition survey, population's mean chronic dietary exposure through consumption of F&V was evaluated for 169 different pesticide active ingredients (PAI), including 135 for which toxicological reference values (TRV) were available in the literature. Total lifetime cancer risk was estimated to be 3.3×10^-4 considering the 28 substances for which an oral slope factor was also available. Non-cancer risk quotients greater than 1 were obtained at the 95th percentile of children's exposure for 10 of the 135 PAIs, and considering the most severe pesticide-specific TRV. Dithiocarbamates and imazalil are the authorized PAI that contribute the most to cancer and non cancer risk; they are therefore identified as "priority" PAI. For each estimated case of cancer triggered by PAI exposure, at least 88 cases were deemed prevented by the consumed F&V, based on the population's etiological fraction of the cancer risk that F&V prevent. Concluding, chronic health risks investigated are low and health benefits of F&V consumption by far outweigh the PAI-related risk. However, risk estimates are not negligeable and uncertainties remain. Thus, reducing PAI exposure through F&V consumption with a particular focus on "priority" PAI mentionned above, while maintaining an abundant and varied F&V diet, is desirable.

Pesticide residues in nut-planted soils of China and their relationship between nut/soil

Twenty-nine pesticide residues in nut-planted soils from China were investigated. One organophosphate (chlorpyrifos) was detected in 5.3% soils, and the residue levels of 7.2 μg/kg to 77.2 μg/kg. The concentrations of six organochlorines (DDT, HCH, endosulfan, quintozene, aldrin and dieldrin) detected in 78.9% soils were 0.6 μg/kg to 90.1 μg/kg. The residue levels of six pyrethroids (bifenthrin, fenpropathrin, cyhalothrin, cypermethrin, fenvalerate and deltamethrin) detected in 65.8% soils were 1.5 μg/kg to 884.3 μg/kg. Triadimefon and buprofezin were found in 71.1% and 52.6% samples, respectively, with the corresponding concentrations of 9.8 μg/kg to 193.7 μg/kg and 87.9 μg/kg to 807.4 μg/kg. The multiple residues were found in 76.3% soils. A significant correlation between pesticide residues in nuts and soils was observed, with the correlation coefficient (r) 0.83 (P < 0.001). In addition, the bioconcentration factor (BCF) values for the explanation of pesticides from soils into nuts were ranged from 0.8 to 16.5. The results showed that some pesticides could accumulate in nut by the uptake effect from soil.

Novel Biomimic Crystalline Colloidal Array for Fast Detection of Trace Parathion

A novel gold doped inverse opal photonic crystal (IO PC) was successfully fabricated with combination of molecularly imprinted technical for the fast determination of parathion. First, a closest silica array arrangement behaved as the 3D photonic crystal precursors to build the opal photonic crystal (O PC). Second, the parathion-containing polymeric solution with gold nanoparticles was drawn into the 3D array cracks. After polymerization, the well-designed O PC was treated with HF solution for the etching of the silica skeleton. Finally, the template parathion was removed and the Au-MIP IO PCs were obtained. The morphology of SiO₂ and Au NPs was characterized by transmission electron microscopy (TEM), and the eluted influence of the IO PCs was monitored by scanning electron microscopy (SEM). The cross-linking effect was well optimized according to the best spectrum signal of parathion. The as-synthesized Au-MIP IO PCs displayed the specificity toward parathion and the selectivity to other competitive pesticide molecules. The response time was only 5 min, and the parathion could be well detected from real water samples. The recoveries were between 95.5% and 101.5%.

Effects of Fungicides on Rat's Neurosteroid Synthetic Enzymes

Exposure to environmental endocrine disruptors may interfere with nervous system's activity. Fungicides such as tebuconazole, triadimefon, and vinclozolin have antifungal activities and are used to prevent fungal infections in agricultural plants. In the present study, we studied effects of tebuconazole, triadimefon, and vinclozolin on rat's neurosteroidogenic 5α-reductase 1 (5α-Red1), 3α-hydroxysteroid dehydrogenase (3α-HSD), and retinol dehydrogenase 2 (RDH2). Rat's 5α-Red1, 3α-HSD, and RDH2 were cloned and expressed in COS-1 cells, and effects of these fungicides on them were measured. Tebuconazole and triadimefon competitively inhibited 5α-Red1, with IC50 values of 8.670 ± 0.771 × 10-6 M and 17.390 ± 0.079 × 10-6 M, respectively, while vinclozolin did not inhibit the enzyme at 100 × 10-6 M. Triadimefon competitively inhibited 3α-HSD, with IC50 value of 26.493 ± 0.076 × 10-6 M. Tebuconazole and vinclozolin weakly inhibited 3α-HSD, with IC50 values about 100 × 10-6 M, while vinclozolin did not inhibit the enzyme even at 100 × 10-6 M. Tebuconazole and triadimefon weakly inhibited RDH2 with IC50 values over 100 × 10-6 M and vinclozolin did not inhibit this enzyme at 100 × 10-6 M. Docking study showed that tebuconazole, triadimefon, and vinclozolin bound to the steroid-binding pocket of 3α-HSD. In conclusion, triadimefon potently inhibited rat's neurosteroidogenic enzymes, 5α-Red1 and 3α-HSD.

Cis-bifenthrin induces immunotoxicity in adolescent male C57BL/6 mice

Bifenthrin (BF) is an important synthetic pyrethroid. Previous studies have demonstrated that cis-BF exhibits toxic effects on development, the neurological, reproductive and endocrine system. In this study, we evaluated the immunotoxicity caused by cis-BF in adolescent male C57BL/6 mice. Mice were exposed orally to 0, 5, 10, and 20 mg/kg/d for 3 weeks. The results showed that body weight, spleen weight, and splenic cellularity decreased in mice exposed to 20 mg/kg/d cis-BF. Additionally, we found that the mRNA levels of the pro-inflammatory factors IL-1β, IL-6, CXCL-1, and TNF-α, in peritoneal macrophages, the spleen, and the thymus were inhibited in the cis-BF-treated groups. Moreover, MTT assays demonstrated that cis-BF inhibited splenocyte proliferation stimulated by LPS or Con A, as well as the secretion of IFN-γ on Con A stimulation. Collectively, the results of this study suggest that exposure to cis-BF has the potential to induce immunotoxicity in adolescent male C57BL/6 mice.

Tebuconazole and Azoxystrobin Residue Behaviors and Distribution in Field and Cooked Peanut

Residue behaviors of tebuconazole and azoxystrobin in field condition and the variation of their residue levels during the boiling process were evaluated. The terminal residues of peanut kernels were determined by using a modified QuEChERS method (quick, easy, cheap, effective, rugged, and safe) by means of the optimization of the novel purification procedure with multiwalled carbon nanotubes (MWCNTs) and Fe₃O₄-magnetic nanoparticle (Fe₃O₄-MNP) in the presence of an external magnetic field, and the terminal residues were all at trace level at harvest time. The residues in shells were detected as well to investigate the distribution in peanuts. Tebuconazole and azoxystrobin residue levels varied before/after boiling in kernels and shells to different degrees due to various factors, such as the modes of action and physicochemical properties of pesticides. The residues have been transferred from peanut into the infusion during boiling with the higher percentage of azoxystrobin as its lower logK_ow. The processing factors (PFs) for tebuconazole and azoxystrobin after processing were <1, indicating that home cooking in this study could reduce the residue levels in peanut. Risk assessment showed there was no health risk for consumers.