Lindane is a broad-spectrum insecticide widely used on fruits, vegetables, crops, livestock and on animal premises to control the insects and pests. The extensive use of pesticides and their residues in the soil and water typically join the food chain and thus accumulate in the body tissues of human and animals causing severe health effects. The study was designed to determine the toxicity effects of sub-lethal concentrations of lindane on hemato-biochemical profile and histo-pathological changes in Rohu (Labeo rohita). A significant increase in the absolute (p<0.05) and relative (p<0.05) weights was observed along with severe histo-pathological alterations in liver, kidneys, gills, heart and brain at 30μg/L and 45μg/L concentration of lindane. A significant (p<0.05) decrease in RBCs count, PCV and Hb concentration while a significant (p<0.05) increased leukocytes were observed by 30μg/L and 45μg/L concentrations of lindane at 45 and 60 days of the experiment. Serum total protein and albumin were significantly (p<0.05) decreased while hepatic and renal enzymes were significantly (p<0.05) increased due to 30μg/L and 45μg/L concentrations of lindane at days-45 and 60 of experiment compared to control group. The observations of thin blood smear indicated significantly increased number of erythrocytes having nuclear abnormalities in the fish exposed at 30μg/L and 45μg/L concentrations of lindane. ROS and TBARS were found to be significantly increased while CAT, SOD, POD and GSH were significantly decreased with an increase in the concentration and exposure time of lindane. The results showed that lindane causes oxidative stress and severe hematological, serum biochemical and histo-pathological alterations in the fish even at sub-lethal concentrations.

Socio-economic activities like food trade can increase the uncertainty of human risk of persistent organic pollutants (POPs). We compared the change in model predicted α-hexachlorocyclohexane (α-HCH) cancer risk (CR) with and without grain trade in mainland China. In scenario without grain logistics, α-HCH moved fast away from southern and southeastern China via northward atmospheric transport. However, the grain logistics from northeastern China delivers the α-HCH previously accumulated in northeastern sink back to densely populated areas in recent years, which enhance CR by >50 % in the southern seaboard of China. The northward movement of grain production center and recent grain deficiency in southern provinces induced by dietary pattern changes is identified as the major driving factors of the reversed transport of α-HCH. The finding highlights the potential of socio-economic activities that can otherwise offset the risk reduction effect of the geochemical cycle of POPs.

Hexachlorocyclohexane (HCH) isomers are persistent organic pollutants (POPs) with high toxicity, lipid solubility, chemical stability. Despite the current ban on usage of Lindane, residual contamination cannot be ignored, and HCH are frequently detected in groundwater and threaten human health. Cultures capable of degrading α-HCH, β-HCH, γ-HCH, and δ-HCH individually have been enriched in anoxic aqueous conditions. Compound-Specific Isotope Analysis (CSIA) was applied to examine the transformation mechanisms of different HCH isomers by the four enrichment cultures. 16S rRNA sequencing techniques were employed to examine the community composition of the enrichment cultures and detect changes in these communities resulting from adding individual HCH isomers. The results indicated that the ability of the enrichment cultures for dichloroelimination of HCH isomers was inconsistent. During dichloroelimination, different bond cleavage mode of β- and δ-HCH led to distinct isotopic effects. HCH isomers had significant impact on the microbial community, while different microbial communities showed comparable isotopic effects during the transformation of a specific HCH isomer. In addition, bacteria in the phyla Proteobacteria and Firmicutes were proposed as the dominant dechlorinators. This study provides a novel perspective on the mode of bond cleavage during HCH dichloroelimination and the effect of HCH on microbial communities, which could potentially support the evaluation of HCH transformation by CSIA and their effects on the microecosystems of groundwater.

Are the residues of organochlorine pesticides (OCPs) in freshwater in China still of concern after prohibition and restriction for decades? The scarcity of monitoring data on OCPs in freshwater in China over the past few years has hampered understanding of this issue. In this study, water and suspended particulate matter (SPM) samples were collected from the middle reach of the Huai River for OCP analyses. Residues of ∑OCPs in water and SPM ranged from ND to 8.6 ng L-1 and 0.50 to 179 ng L-1, with mean concentrations of 1.7 ± 1.3 ng L-1 and 6.1 ± 31 ng L-1, respectively. ∑HCHs (α-, β-, γ-, and δ-HCH) and ∑HEPTs (heptachlor and heptachlor epoxide) were the most predominant pesticides in the dissolved phase and SPM, respectively, accounting for 43 ± 35% and 27 ± 29% of ∑OCPs. HCHs and heptachlor epoxide mainly existed in the dissolved phase, while heptachlor mainly existed in SPM. The isomeric composition pattern of HCHs in water differed from that in SPM. Briefly, β-HCH dominated in water, while δ-HCH dominated in SPM. However, the composition pattern of DDT and its metabolites in water was similar to that in SPM. o,p\'-DDD and p,p\'-DDE dominated in both water and SPM. The ratios of α-/γ-HCH and (DDD + DDE)/DDTs indicated that HCHs and DDTs were mainly derived from historical residues. Risk assessments indicated that OCPs may not pose carcinogenic and non-carcinogenic risks to residents.

Rapid industrial and agricultural developments in China have led to the wide use and discharge of chemical products and pesticides, resulting in extensive residues in environmental media. These residues can enter the human body through various pathways, leading to high exposure risks and health hazards. Because the human body is exposed to a variety of chemical pollutants, accurately quantifying the exposure levels of these pollutants in the human body and evaluating their health risks are of great importance. In this study, the serum concentrations of 97 typical chemical pollutants of 60 adults in central China were simultaneously determined using solid-phase extraction coupled with gas chromatography-tandem mass spectrometry (SPE-GC-MS/MS). In this method, 200 μL of a serum sample was mixed with 10 μL of an isotope-labeled internal standard solution. The sample was vortexed and refrigerated overnight at 4 ℃. Each sample was then deproteinized by the addition of 200 μL of 15% formic acid aqueous solution and vortexed. The serum sample was loaded into a preconditioned Oasis® PRiME HLB SPE cartridge and rinsed with 3 mL of methanol-water (6∶1, v/v). The SPE cartridge was subsequently vacuumed. The analytes were eluted with 3 mL of dichloromethane followed by 3 mL of n-hexane. The eluent was concentrated to near dryness under a gentle nitrogen stream and reconstituted with 100 μL of acetone. The samples were determined by GC-MS/MS and separated on a DB-5MS capillary column (30 m×0.25 mm×0.25 μm) with temperature programming. The column temperature was maintained at 70 ℃ for 2 min, increased at a rate of 25 ℃/min to 150 ℃, increased at a rate of 3 ℃/min to 200 ℃, and then held for 2 min. Finally, the column temperature was increased at a rate of 8 ℃/min to 300 ℃ and maintained at this temperature for 8 min. The samples were detected in multiple-reaction monitoring (MRM) mode and quantitatively analyzed using the internal standard method. Multiple linear regression models were used to analyze the effects of demographic characteristics, lifestyle habits, and diet on the concentrations of the chemical pollutants in the serum samples, and known biomonitoring equivalents (BEs) and human biomonitoring (HBM) values were combined to compute hazard quotients (HQs) and hazard indices (HIs) and evaluate the health risks of single and cumulative exposures to the chemical pollutants. The results showed that the main pollutants detected in human serum were organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), and polycyclic aromatic hydrocarbons (PAHs). The detection rates of eight pollutants, including hexachlorobenzene (HCB) (100%), pentachlorophenol (PCP) (100%), p,p\'-dichlorodiphenylene (p,p\'-DDE) (100%), PCB-138 (100%), PCB-153 (98.3%), β-hexachlorocyclohexane (β-HCH) (91.7%), fluorene (Flu) (85.0%), and anthracene (Ant) (75.0%), were greater than 70%. The serum levels of β-HCH were higher in females than in males, and age was positively correlated with exposure to p,p\'-DDE, PCB-138, PCB-153, and β-HCH. Increased exposure levels to p,p\'-DDE and β-HCH may be associated with a high frequency of meat intake, whereas increased exposure level to PCP may be associated with a high frequency of vegetable intake. The serum HQ of PCP was greater than 1 in 6.7% of the samples, and no risk was observed for HCB and p,p\'-DDE exposure in the study population. Approximately 28.3% of the study subjects had HI values greater than 1. Overall, the general adult population in this region is widely exposed to a wide range of chemical pollutants, and gender, age, and diet are likely to be the main factors influencing the concentration of chemical pollutants. The health risk of single and compound exposures to chemical pollutants should not be ignored.

As long-lived apex predators, marine mammal adults often accumulate alarmingly levels of environmental contaminants. Nevertheless, the accumulation and risks of these contaminants in the critical calf stage of marine mammals remain largely unknown. Here, we investigated the exposure status and health risks of 74 organohalogen contaminants (OHCs) in Indo-Pacific humpback dolphin calves (Sousa chinensis) collected from the Pearl River Estuary (PRE), China, during 2005-2019. Our findings revealed moderate levels of polychlorinated biphenyls (PCBs), medium-high levels of dichlorodiphenyltrichloroethanes (DDTs) and hexachlorocyclohexanes (HCHs), and the highest levels of polybrominated diphenyl ethers (PBDEs) and alternative halogenated flame retardants (AHFRs) compared to those reported for cetaceans elsewhere. Traditional OHCs like DDTs, PCBs, and PBDEs did not exhibit significant decreasing trends in the dolphin calves despite global restrictions on these compounds, and AHFRs as emerging OHCs showed an increasing trend over the study period. Risk quotients of DDTs, HCHs, PBDEs, and PCBs in most of the dolphin samples were > 1, indicating that humpback dolphin calves may have suffered long-term threats from OHC exposure. The significant correlation observed between the traditional OHC levels and the stranding death number of the dolphin calves suggests these OHCs may impact the survival of this endangered species.

Epidemiological studies have related exposure to pesticides to increased risk of diabetes. However, few studies have evaluated the health effects of mixed pesticides exposure, especially in an elderly population. Here, we utilized gas chromatography-tandem mass spectrometry to quantify the levels of 39 pesticides in 4 categories in a Chinese elderly population. Then we used general linear models to explore the association between individual pesticide exposure and type 2 diabetes mellitus (T2DM). Restricted cubic spline (RCS) models were fitted to identify potential non-linearities between those associations. Furthermore, stratified analysis by gender was conducted to explore the gender-specific associations. Finally, we used weighted quantile sum (WQS) regression, quantile-based g computation (qgcomp), and Bayesian kernel machine regression (BKMR) to evaluate the effects of mixed exposure to 39 pesticides. The results showed that exposure to pesticides was associated with high risk of T2DM, with β-Hexachlorocyclohexane (β-BHC) and oxadiazon being the most significant independent contributors, which was pronounced among elderly women. Moreover, the association of β-BHC and oxadiazon with T2DM was linear. These indicated that it is an urgent need to take practical measures to control these harmful pesticides.

There is a lack of studies on the ability of plants to metabolize chlorinated organic pollutants (COPs) and the dynamic expression changes of metabolic molecules during degradation. In this study, hybrid rice Chunyou 927 (CY) and Zhongzheyou 8 (ZZY), traditional rice subsp. Indica Baohan 1 (BH) and Xiangzaoxian 45 (XZX), and subsp. Japonica Yangjing 687 (YJ) and Longjing 31 (LJ) were stressed by a typical COPs of lindane and then transferred to a lindane-free culture to incubate for 9 days. The cumulative concentrations in the roots of BH, XZX, CY, ZZY, YJ and LJ were 71.46, 65.42, 82.06, 80.11, 47.59 and 56.10 mg·kg-1, respectively. And the degradation ratios on day 9 were 87.89 %, 86.92 %, 94.63 %, 95.49 %, 72.04 % and 82.79 %, respectively. On the 0 day after the release of lindane stress, the accumulated lindane inhibited the normal physiological activities of rice by affecting lipid metabolism in subsp. Indica BH, amino acid metabolism and synthesis and nucleotide metabolism in hybrid CY. Carbohydrate metabolism of subsp. Japonica YJ also was inhibited, but with low accumulation of lindane, YJ regulated amino acid metabolism to resist stress. With the degradation of lindane in rice, the amino acid metabolism of BH and CY, which had high degradation ratios on day 9, was activated to compound biomolecules required for the organism to recover from the damage. Amino acid metabolism and carbohydrate metabolism were disturbed and inhibited mainly in YJ with low degradation ratios. This study provides the difference of the metabolic capacity of the metabolic capacity of different rice varieties to lindane, and changes at the molecular level and metabolic response mechanism of rice during the metabolism of lindane.

Large quantities of organochlorine pesticides (OCPs) have been used in tropical regions. The fate processes and risks of these legacy contaminants in the tropics are poorly understood. Herein, we investigated the occurrence of three classes of widely used OCPs and their metabolites in surface and core soil from five cities across Vietnam with a prevalent tropical monsoon climate and a long history of OCP application. We aimed to elucidate migration potentials, degradation conditions, and transformation pathways and assess current health risks of these contaminants. Generally, the concentrations of OCPs and metabolites in the soil core were slightly lower than those in surface soil except for hexachlorocyclohexane (HCH) isomers. 2,2-bis(4-chlorophenyl)-1,1,1-trichloroethane (p,p\'-DDT), 2,2-bis(4-chlorophenyl)-1,1-dichloroethylene (p,p\'-DDE), the sum of dicofol and 4,4\'-dichlorobenzophenone (p,p\'-DBP), and 2,2-bis(4-chlorophenyl)-1,1-dichloroethane (p,p\'-DDD) were the most abundant compounds in both surface and core soils. A uniform distribution of HCHs (the sum of α-, β-, γ-, and δ-HCH) at trace levels was found in almost all soils, serving as evidence of the lack of recent use of HCH pesticides. Higher concentrations of DDTs (the sum of DDT, DDD, and DDE) were observed in north-central Vietnamese soil, whereas appreciable concentrations of ENDs (the sum of α- and β-endosulfan and endosulfan sulfate) were only found in southern Vietnamese soils. Empirical diagnostic ratios indicated residuals of DDTs were mainly from technical DDT rather than dicofol, whereas aged HCHs could be explained by the mixture of lindane and technical HCH. Both historical applications and recent input explain DDTs and ENDs in Vietnamese soil. Total organic carbon performs well in preventing vertical migration of more hydrophobic DDTs and ENDs. The dominant transformation pathway of DDT in surface soil followed p,p\'-DDE→2,2-bis(4-chlorophenyl)-1-chloroethylene or p,p\'-DDMU→1,1-bis(4-chlorophenyl)ethylene or p,p\'-DDNU→p,p\'-DBP, whereas the amount of p,p\'-DDMU converted from p,p\'-DDD and p,p\'-DDE is similar in soil core. Non-cancer risks of OCPs and metabolites in all soils and cancer risks of those chemicals in core soils were below the safety threshold, whereas a small proportion of surface soil exhibited potential cancer risk after considering the exposure pathway of vegetable intake. This study implied that organic matter in non-rainforest tropical deep soils still could hinder the leaching of hydrophobic organic contaminants as in subtropical and temperate soils. When lands with a history of OCP application are used for agricultural purposes, dietary-related risks need to be carefully assessed.