Linking pesticide exposure to neurodegenerative diseases: An in vitro investigation with human neuroblastoma cells

Although many organochlorine pesticides (OCPs) have been banned or restricted because of their persistence and linkage to neurodegenerative diseases, there is evidence of continued human exposure. In contrast, registered herbicides are reported to have a moderate to low level of toxicity; however, there is little information regarding their toxicity to humans or their combined effects with OCPs. This study aimed to characterize the mechanism of toxicity of banned OCP insecticides (aldrin, dieldrin, heptachlor, and lindane) and registered herbicides (trifluralin, triallate, and clopyralid) detected at a legacy contaminated pesticide manufacturing and packing site using SH-SY5Y cells. Cell viability, LDH release, production of reactive oxygen species (ROS), and caspase 3/7 activity were evaluated following 24 h of exposure to the biocides. In addition, RNASeq was conducted at sublethal concentrations to investigate potential mechanisms involved in cellular toxicity. Our findings suggested that aldrin and heptachlor were the most toxic, while dieldrin, lindane, trifluralin, and triallate exhibited moderate toxicity, and clopyralid was not toxic to SH-SY5Y cells. While aldrin and heptachlor induced their toxicity through damage to the cell membrane, the toxicity of dieldrin was partially attributed to necrosis and apoptosis. Moreover, toxic effects of lindane, trifluralin, and triallate, at least partially, were associated with ROS generation. Gene expression profiles suggested that decreased cell viability induced by most of the tested biocides was related to inhibited cell proliferation. The dysregulation of genes encoding for proteins with anti-apoptotic properties also supported the absence of caspase activation. Identified enriched terms showed that OCP toxicity in SH-SY5Y cells was mediated through pathways associated with the pathogenesis of neurodegenerative diseases. In conclusion, this study provides a basis for elucidating the molecular mechanisms of pesticide-induced neurotoxicity. Moreover, it introduced SH-SY5Y cells as a relevant in vitro model for investigating the neurotoxicity of pesticides in humans.

Accumulation of persistent organic pollutants in the kidneys of pet cats (Felis silvestris catus) and the potential implications for their health

Persistent organic pollutants (POPs), such as polychlorinated diphenyls (PCBs) and brominated diphenyl ethers (PBDEs), are ubiquitous in the pet cat's living environment and are ingested through dietary intake and environmental exposure such as house dust. Cats are known to be susceptible to chronic kidney disease (CKD) and exposure to POPs may be associated with CKD. However, no studies have been conducted on the renal accumulation and health effects of POPs in cats. The objective of this study was to elucidate the accumulation of PCBs, PBDEs, and organochlorine pesticides (OCPs) in the kidneys of domestic cats and discuss their potential impact on feline health. We report here that cats specifically accumulate POPs in their kidneys. Tissue samples were collected from the kidneys, livers, and muscles of cats and the concentrations of POPs in these tissues were analyzed in this study. The results showed that these compounds accumulated significantly higher in the kidney compared to other tissues. In addition, the ability to accumulate in the kidney was higher in cats than in other animals, suggesting that cats have a unique pattern of POPs accumulation in their kidneys, which is thought to occur because cats store a significant number of lipid droplets in the proximal tubules of the kidneys. This unique feature suggests that lipophilic POPs may accumulate in these lipid droplets during the excretory process. Accumulation of certain POPs in the kidneys causes necrosis and sloughing of renal tubular epithelial cells, which may be associated with CKD, a common disease in cats. This study provides valuable insight into understanding the renal accumulation and risk of POPs in cats and provides essential knowledge for developing strategies to protect the health and welfare of domestic cats.

Differentiated cognition of the effects of human activities on typical persistent organic pollutants and bacterioplankton community in drinking water source

Accelerated urbanization in developing countries led to a typical gradient of human activities (low, moderate and high human activities), which affected the pollution characteristics and ecological functions of aquatic environment. However, the occurrence characteristics of typical persistent organic pollutants, including organochlorine pesticides (OCPs) and polycyclic aromatic hydrocarbons (PAHs), and bacterioplankton associated with the gradient of human activities in drinking water sources is still lacking. Our study focused on a representative case - the upper reaches of the Dongjiang River (Pearl River Basin, China), a drinking water source characterized by a gradient of human activities. A comprehensive analysis of PAHs, OCPs and bacterioplankton in the water phase was performed using gas chromatography-mass spectrometry (GC-MS) and the Illumina platform. Moderate human activity could increase the pollution of OCPs and PAHs due to local agricultural activities. The gradient of human activities obviously influenced the bacterioplankton community composition and interaction dynamics, and low human activity resulted in low bacterioplankton diversity. Co-occurrence network analysis indicated that moderate human activity could promote a more modular organization of the bacterioplankton community. Structural equation models showed that nutrients could exert a negative influence on the composition of bacterioplankton, and this phenomenon did not change with the gradient of human activities. OCPs played a negative role in shaping bacterioplankton composition under the low and high human activities, but had a positive effect under the moderate human activity. In contrast, PAHs showed a strong positive effect on bacterioplankton composition under low and high human activities and a weak negative effect under moderate human activity. Overall, these results shed light on the occurrence characteristics of OCPs, PAHs and their ecological effects on bacterioplankton in drinking water sources along the gradient of human activities.

Transgenic Arabidopsis thaliana plants expressing bacterial γ-hexachlorocyclohexane dehydrochlorinase LinA

BACKGROUND

γ-Hexachlorocyclohexane (γ-HCH), an organochlorine insecticide of anthropogenic origin, is a persistent organic pollutant (POP) that causes environmental pollution concerns worldwide. Although many γ-HCH-degrading bacterial strains are available, inoculating them directly into γ-HCH-contaminated soil is ineffective because of the low survival rate of the exogenous bacteria. Another strategy for the bioremediation of γ-HCH involves the use of transgenic plants expressing bacterial enzyme for γ-HCH degradation through phytoremediation.

RESULTS

We generated transgenic Arabidopsis thaliana expressing γ-HCH dehydrochlroninase LinA from bacterium Sphingobium japonicum strain UT26. Among the transgenic Arabidopsis T2 lines, we obtained one line (A5) that expressed and accumulated LinA well. The A5-derived T3 plants showed higher tolerance to γ-HCH than the non-transformant control plants, indicating that γ-HCH is toxic for Arabidopsis thaliana and that this effect is relieved by LinA expression. The crude extract of the A5 plants showed γ-HCH degradation activity, and metabolites of γ-HCH produced by the LinA reaction were detected in the assay solution, indicating that the A5 plants accumulated the active LinA protein. In some A5 lines, the whole plant absorbed and degraded more than 99% of γ-HCH (10 ppm) in the liquid medium within 36 h.

CONCLUSION

The transgenic Arabidopsis expressing active LinA absorbed and degraded γ-HCH in the liquid medium, indicating the high potential of LinA-expressing transgenic plants for the phytoremediation of environmental γ-HCH. This study marks a crucial step toward the practical use of transgenic plants for the phytoremediation of POPs.

Incorporation of Cu-TATAB metal-organic framework within polyurethane nanocomposite for enhanced thin film microextraction of some chlorinated pesticides

In this research, electrospun nanofibers based on copper-based metal organic framework (MOF)/polyurethane (PU) were prepared in order to achieve an applicable and superior extractive phase. The incorporation of MOF, in the synthesized nanocomposite contributed to the enhanced sorption efficiency. The prepared sorbent was implemented for the thin film microextraction (TFME) of target compounds with subsequent quantification using gas chromatography-mass spectrometry (GC-MS). To obtain the maximum efficiency of the synthesized sorbent, the influential parameters on extraction and desorption steps, including the MOF percentage in nanocomposite, desorption solvent type and its volume, desorption time, solution ionic strength and extraction time were optimized. After method development, the linear dynamic range (0.02-700 μg L-1), limits of detection (LODs) (0.005-0.1 μg L-1) and limits of quantification (LOQs))0.02-0.33 μg L-1(were calculated. The relative standard deviations values for intra-day and inter-day analysis were found to be in the range of 4.3-5.3 % and 6.2-8.1 %, respectively. The developed method was validated for the TFME of model organochlorine (OC) pesticide residues in fish, soil and water samples. the recovery values for the spiked samples at two concentration levels of 5 and 100 µg l-1 were found in the range of 72-110 %.

Diabetes mellitus and serum organochlorine pesticides mixtures in Mexican women

BACKGROUND

Very recently, it has been reported that exposure to different mixtures of organochlorine pesticides (OCP) is associated with the development of diabetes mellitus (DM). In Mexico, DM is a public health problem that might be related to the historical intense use of OCP. We aimed to evaluate, the association between DM and serum concentrations of OCP mixtures, and identify the main contributors within them.

METHODS

We conducted a secondary cross-sectional analysis on the control group from a breast cancer population-based case-control study conducted from 2007 to 2011 in Northern Mexico. We identified 214 self-reported diabetic women and 694 non-diabetics. We obtained direct information about sociodemographic, lifestyle and reproductive characteristics. We determined 24 OCP and metabolites in serum by gas chromatography using an electron capture micro detector. We used Weighted Quantile Sum regression to assess the association of DM and exposure to multiple OCP, and the contribution of each compound within the mixture.

RESULTS

We found a positive adjusted association between DM and an OCP mixture (OR: 2.63, 95%CI: 1.85, 3.74), whose primary contribution arose from p, p'-DDE (mean weight 23.3%), HCB (mean weight 17.3%), trans nonachlor (mean weight 15.4%), o, p'-DDE (mean weight 7.3%), heptachlor epoxide (mean weight 5.9%), oxychlordane (mean weight 4.7%), and heptachlor (mean weight 4.5%). In addition, these OCP along with p, p'-DDT and cis chlordane, were of concern and remained associated when excluding hypertensive women from the analysis (OR 2.55; 95% CI 1.56, 4.18).

CONCLUSIONS

Our results indicate, for the first time in a Latin-American population, that the concomitant exposure to multiple OCP is associated with DM. Further research is needed since the composition of OCP mixtures may vary according to regional pesticides use patterns.

Occurrence and health risk estimate of organochlorine pesticides in fruits and vegetables matrices

Occurrence of 20 organochlorine pesticides (OCPs) in 60 organic and non-organic fruits and vegetables matrices was undertaken using QuEChERS Method EN 15662 for sample preparation analyzed by gas chromatography-mass spectrometry (GC-MS/MS). The procedural method was validated by spiking the OCP standard solutions at three fortified levels at 10, 50, and 100 µg/kg wet weight (ww) to the real matrix of fruit and vegetable with good recovery ranging from 75 to 108% with relative standard deviation (RSD) ≤ 11%, and the limits of detection and quantification (LODs and LOQs) were 0.002-0.02 μg/kg and 0.004-0.1 μg/kg ww, respectively. The assessment of health risks associated with pesticide residues through consumption of vegetables and fruits and the effect of washing and peeling on concentration of various pesticides were also studied. The results showed that the concentration levels of 60% of samples were lower than the LOQs, while the rest was contaminated by OCP residues. Organic fruits and vegetables showed the absence of OCPs, while several of the studied compounds were detected from conventional agriculture. Skin removal (peeling) was the most effective strategy to eliminate or decrease pesticide residues, and should be one of the solutions to reduce the health impact of pesticides in fruits and vegetables. The analysis of health risk assessment was based on the use of the estimated average daily intake (EDI), hazard index (HI), and hazard ratio (HR) for individuals in two weight categories: children (weighing 16.7 kg) and adults (weighing 60 kg). The HI values were less than 1 suggesting that there was no probable non-carcinogenic health effect, except for heptachlor for children (HI of 1.285). However, the values of HR revealed that children were more susceptible to the carcinogenic health effect associated with consuming contaminated vegetables.

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.

Potential lethality of organochlorine pesticides: Inducing fatality through inflammatory responses in the organism

BACKGROUND

Organochlorine pesticides, with their environmental persistence and bioaccumulation potential, have gained significant attention. This study explores the impact of organochlorine pesticides on mortality and chronic diseases, investigates their link to inflammatory states, and examines the role of anti-inflammatory diets in mitigating adverse reactions to these pesticides.

METHODS

This study, with 2,847 participants, used gas chromatography and mass spectrometry to measure organochlorine pesticide exposure in NHANES data. Conventional statistical methodologies, encompassing survival curves, Cox proportional hazards regression, regression analysis, and restricted quadratic spline analysis, were employed to investigate the association between pesticides and mortality, chronic ailments, and inflammation. Furthermore, machine learning techniques, comprising RF, AdaBoost, Extra-Trees, LightGBM, and BPNN, were leveraged to evaluate the impact of pesticides on chronic disease and mortality prognostication.

RESULTS

Organochlorine pesticides were significantly and positively correlated with increased mortality (p<0.05). Additionally, these pollutants were linked to the incidence of chronic diseases such as chronic kidney disease, diabetes, and hypertension (p< 0.05). Our study, utilizing various machine learning models, also showed a notable increase in the Area Under the Curve when incorporating organochlorine pesticide indicators into the model as opposed to excluding them. Furthermore, strong correlations were observed between serum c-reactive protein (CRP) and CRP to serum albumin ratio (CAR) concentrations with these substances, demonstrating their pro-inflammatory effects at specific concentrations. Interestingly, cutting down on dietary inflammation through changes in diet effectively reduced the risk of death at high organochlorine pesticide exposure levels, but the effect was less noticeable at low to moderate exposure levels.

CONCLUSIONS

Exposure to organochlorine pesticides was linked to a higher risk of mortality, likely due to an increased prevalence of chronic diseases. In this context, inflammation played a crucial role, and adopting an anti-inflammatory diet significantly reduced the mortality risk associated with these pesticides.

Centurial deposition records of polychlorinated biphenyls and organochlorine pesticides in sediment cores from a plateau deep-water lake of China: Significance of anthropogenic impacts, transformation signals and ecological risks revealed by full congener analysis

Lake Fuxian, the largest deep freshwater lake in China, has been suffering from increasing ecological and environmental issues along with the rapid urbanization and industrialization in the past 40 years. To better understand the historical pollution of persistent organic pollutants (POPs) in Lake Fuxian, comprehensive analyses of 209 polychlorinated biphenyl (PCB) congeners and 20 organochlorine pesticides (OCPs) were conducted in two intact sediment cores (Core V1 and Core V2). The total mass concentrations of PCBs ranged from 7.60 to 31.47 ng/g (dry weight basis) and 5.55 to 28.90 ng/g during the period of 1908-2019 in Core V1 and 1924-2019 in Core V2, respectively. PCBs exhibited a consecutive increasing trend from 1940s to 2019 in Core V1. The temporal trend of PCBs in Core V2 basically matched to the history of PCB usage and prohibition in China (increasing from 1940s to mid-1960s, a remarkable drop in mid-1970s, and then increasing until 2019). Moreover, low-chlorinated PCBs were dominant among PCB homologues. Mono-CBs, di-CBs, tri-CBs and tetra-CBs accounted for 86.71 %-98.57 % in sediment segments. The PCB sources included unintentional emission and atmospheric deposition, as well as biological transformation. The total mass concentrations of OCPs ranged from 0.74 to 3.82 ng/g in Core V1 and 0.35 to 2.23 ng/g in Core V2, respectively. Similar trend was observed in the two sediment cores with peaks in the early 1990s. The predominant OCPs were γ-hexachlorohexane (γ-HCHs), dieldrin and p,p'-DDD. The ecological risks posed by PCBs and p-p'-DDD in Lake Fuxian were relatively low. In contrast, dieldrin might pose a potential threat to exposed organisms and apparently adverse ecological effects were caused by γ-HCH. This study will provide important baseline information on historical POPs contamination of Lake Fuxian.

Post-synthetic modification of covalent organic framework for efficient adsorption of organochlorine pesticides from cattle's milk

Analysis of organochlorine pesticides (OCPs) residues in milk faces a significant challenge. Herein, a sea urchin structured covalent organic framework bearing boric acid groups named COF-B(OH)2 was synthesized and applied as a coating material for solid-phase microextraction (SPME) of the OCPs in cattle's milk. Its performance was superior to that of three commonly used commercial SPME fibers, which could be due to the coexistence of hydrogen bonding, halogen bonding, π-stacking and electrostatic interactions. Besides, the fiber coating displayed good stability and reusability. After optimization, a COF-B(OH)2 based SPME coupled with gas chromatography-electron capture detection was established for the sensitive detection of the OCPs from milk samples. The limits of detection (S/N = 3) were between 0.04 and 1.00 μg kg-1. Satisfactory accuracy was achieved with the method recoveries in the range of 87.5 % to 112.5 %. These results manifest the feasibility of the COF-B(OH)2 coated fiber for the enrichment of the trace OCPs from milk samples.

Polyaniline-coated kapok fibers for convenient in-syringe solid-phase microextraction and determination of organochlorine and pyrethroid pesticide residues in aqueous samples

Pesticides used in agriculture have low polarity and a tendency to accumulate in fatty tissues, posing potential risks to human health. Effective pre-treatment is crucial due to complex sample matrices and low concentrations of pesticide residues typically encountered in instrument analysis. In this study, polyaniline-coated kapok fiber (PANI-KF) was synthesized successfully using in-situ oxidative polymerization for use as sorbents in in-syringe SPME of pyrethroid pesticides (PYRs) and organochlorine pesticides (OCPs) from aqueous samples. Coating the natural KF with PANI maintained the hollow microtubular structure and fiber morphology while significantly enhancing the extraction efficiency. The extraction process was easily conducted by simply pulling and pushing the syringe plunger. The entire extraction process, utilizing 3 mg of PANI-KF, could be completed in approximately 3 min. Density functional theory results indicated that the adsorption mechanism of PANI-KF towards OCPs and PYRs mainly involved van der Waals interactions, π-π interactions, and weak hydrogen bonding interactions. With the coupling of gas chromatography-mass spectrometry, a quantification method was established that exhibited good linearities (R2 > 0.990), and relative recoveries (87.2-108.5 %). The limits of detection ranged from 0.4 to 2.0 ng mL-1 and the matrix effects were negligible (-12.3-16.4 %). The validated in-syringe SPME-GC-MS method was successfully applied to determine pesticide residues in fruit juices, oral liquids and herbal extract granules with satisfactory accuracy and precision. PANI-KF exhibits remarkable promise as a sorbent for the extraction and enrichment of pesticide residues in aqueous samples, thereby contributing to the advancement of pesticide residue determination methodologies.

In situ formation of natural deep eutectic solvent on membrane after fat hydrolysis for lindane isomers determination in peanut paste

In this work a sample pretreatment approach assumed liquid-liquid microextraction based on the in situ formation of a hydrophobic natural deep eutectic solvent on a hydrophobic membrane impregnated with natural terpenoid was developed. The procedure included alkaline hydrolysis of a food sample containing fat to form fatty acids, which acted as precursors for the in situ formation of the deep eutectic solvent with natural terpenoid. Two processes were observed on the membrane surface: in situ formation of the hydrophobic deep eutectic solvent and liquid-liquid microextraction of the target analytes. After microextraction, the membrane containing the analytes was easily removed from the sample solution. The developed approach was applied to the separation and preconcentration of hydrophobic organochlorine pesticides (ɑ-hexachlorocyclohexane and γ-hexachlorocyclohexane) from a hydrophobic sample matrix (peanut paste), followed by their determination by gas chromatography with electron capture detection. Under optimal conditions, the limits of detection and quantification for both analytes were 0.3 and 1.0 μg kg-1, respectively. The procedure allowed the separation of fat-soluble analytes from a complex sample matrix with a high content of fat. The extraction recoveries were in the range of 93-95 %.

Porous covalent organic framework nanofibrous membrane for excellent enrichment and ultra-high sensitivity detection of trace organochlorine pesticides in water

Developing adsorbents with high performance and long service life for effective extracting the trace organochlorine pesticides (OCPs) from real water is attracting numerous attentions. Herein, a self-standing covalent organic framework (COF-TpPa) membrane with fiber morphology was successfully synthesized by using electrospun nanofiber membranes as template and employed as solid-phase microextraction (SPME) coating for ultra-high sensitivity extraction and analysis of trace OCPs in water. The as-synthesized COF-TpPa membrane exhibited a high specific surface area (800.83 m2 g-1), stable nanofibrous structure, and excellent chemical and thermal stability. Based on the COF-TpPa membrane, a new SPME analytical method in conjunction with gas chromatography-mass spectrometry (GC-MS) was established. This proposed method possessed favorable linearity in concentration of 0.05-2000 ng L-1, high sensitivity with enrichment factors ranging from 2175 to 5846, low limits of detection (0.001-0.150 ng L-1), satisfactory precision (RSD < 10 %), and excellent repeatability (>150 cycles), which was better than most of the reported works. Additionally, the density functional theory (DFT) calculations and XPS results demonstrated that the outstanding enrichment performance of the COF-TpPa membrane was owing to synergistic effect of π-π stacking effects, high specific surface area and hydrogen bonding. This work will expect to extend the applications of COF membrane to captures trace organic pollutants in complex environmental water, as well as offer a multiscale interpretation for the design of effective adsorbents.

Carcinogenic, non-carcinogenic risk, and attributable cases to organochlorine pesticide exposure in women from Northern Mexico

This study aimed to estimate the carcinogenic and non-carcinogenic risk as well as the attributable cases due to exposure to organochlorine pesticides (OCPs): hexachlorobenzene (HCB), dichlorophenyltrichloroethane (DDT), hexachlorocyclohexane (HCH), heptachlor, and chlordane. From serum concentrations of pesticides of interest in a sample of 908 women from Northern Mexico, the risk for both cancer and non-cancer health effects was evaluated. The population attributable fraction (PAF) was also calculated based on summary association estimates between exposure to OCPs and different health events. Findings revealed that due to their OCP exposure slightly less than half of the women in the sample were at increased risk of developing non-cancerous diseases. Moreover, approximately 25% and 75% of participants were at risk of develop some type of cancer associated with their HCB and DDE concentrations, respectively. In addition, it was estimated that 40.5% of type 2 diabetes, 18.7% of endometriosis, and 23.1% of non-Hodgkin's lymphoma cases could have been prevented if women had not been exposed to these OCPs. Results suggest that the use of OCPs may have contributed to the disease burden in the study area and, based on the time required for these substances to be eliminated from the body, there are probably some women who are still at elevated risk of developing diseases associated to OCPs.

Optimization and uncertainty assessment of a gas chromatography coupled to Orbitrap mass spectrometry method to determine organic contaminants in blood: A case study of an endangered seabird

Birds are excellent bioindicators of environmental pollution, and blood provides information on contaminant exposure, although its analysis is challenging because of the low volumes that can be sampled. The objective of the present study was to optimize and validate a miniaturized and functional extraction and analytical method based on gas chromatography coupled to Orbitrap mass spectrometry (GCOrbitrap-MS) for the trace analysis of contaminants in avian blood. Studied compounds included 25 organochlorine pesticides (OCPs), 6 polychlorinated biphenyls (PCBs), 8 polybrominated diphenyl ethers (PBDEs) and 15 polycyclic aromatic hydrocarbons (PAHs). Four extraction and clean-up conditions were optimized and compared in terms of efficiency, accuracy, and uncertainty assessment. Extraction with hexane:dichloromethane and miniaturized Florisil pipette clean-up was the most adequate considering precision and accuracy, time, and costs, and was thereafter used to analyse 20 blood samples of a pelagic seabird, namely the Bermuda petrel (Pterodroma cahow). This species, endemic to the Northwest Atlantic, is among the most endangered seabirds of the region that in the '60 faced a decrease in the breeding success likely linked to a consistent exposure to dichloro-diphenyl-trichloroethane (DDT). Indeed, p,p'-DDE, the main DDT metabolite, was detected in all samples and ranged bewteen 1.13 and 6.87 ng/g wet weight. Other ubiquitous compounds were PCBs (ranging from 0.13 to 6.76 ng/g ww), hexachlorobenzene, and mirex, while PAHs were sporadically detected at low concentrations, and PBDEs were not present. Overall, the extraction method herein proposed allowed analysing very small blood volumes (∼ 100 µL), thus respecting ethical principles prioritising the application of less-invasive sampling protocols, fundamental when studying threatened avian species.

Sediment-water exchange and risk assessment of pesticidal persistent organic pollutants in Bharathappuzha and Periyar Riverine region along the Arabian Sea

Considering the extensive agricultural practices along the perennial rivers, viz. Periyar and Bharathappuzha of Kerala in the southwest coast of India, the first comprehensive surveillance of new and legacy organochlorine pesticides (OCPs) in surface sediment was conducted. Further, the sediment-water exchange fluxes have been elucidated. Mean concentrations of total HCH, DDT and endosulfan were 0.84 ng/g, 0.42 ng/g and 0.30 ng/g for Bharathappuzha Riverine sediment (BRS) and 1.08 ng/g, 0.39 ng/g and 0.35 ng/g for Periyar Riverine sediment (PRS). The dominance α-HCH and β-HCH isomers in PRS and BRS reflect the ongoing use of technical HCH in Kerala. The calculated KSW in both rivers was very low in comparison with other Indian rivers. The average log K'OC for all the detected OCPs in both the rivers was lower than the predicted log KOC in equilibrium indicating the higher adherence of OCPs to sediment. Furthermore, fugacity fraction (fs/fw) was < 1.0 for all OCPs confirming the net deposition of OCPs into the sediment. Sediment concentrations for each of the OCPs in PRS and BRS did not surpass the threshold effect level and probable effect level as stipulated by the Canadian Council of Ministry of the Environment Guidelines. In addition, all the sites of both rivers had sediment quality guideline quotient (SQGQ) values below 0.1 indicating the absence of significant biological and ecological risks.

Organochlorine pesticides and risk of papillary thyroid cancer in U.S. military personnel: a nested case-control study

BACKGROUND

The effects of organochlorine pesticide (OCP) exposure on the development of human papillary thyroid cancer (PTC) are not well understood. A nested case-control study was conducted with data from the U.S. Department of Defense Serum Repository (DoDSR) cohort between 2000 and 2013 to assess associations of individual OCPs serum concentrations with PTC risk.

METHODS

This study included 742 histologically confirmed PTC cases (341 females, 401 males) and 742 individually-matched controls with pre-diagnostic serum samples selected from the DoDSR. Associations between categories of lipid-corrected serum concentrations of seven OCPs and PTC risk were evaluated for classical PTC and follicular PTC using conditional logistic regression, adjusted for body mass index category and military branch to compute odds ratios (OR) and 95% confidence intervals (CIs). Effect modification by sex, birth cohort, and race was examined.

RESULTS

There was no evidence of associations between most of the OCPs and PTC, overall or stratified by histological subtype. Overall, there was no evidence of an association between hexachlorobenzene (HCB) and PTC, but stratified by histological subtype HCB was associated with significantly increased risk of classical PTC (third tertile above the limit of detection (LOD) vs. Collapse

Key Words

• Hexachlorobenzene
• Hexachlorocyclohexane
• Organochlorine pesticides
• Papillary thyroid cancer

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MESH Headings

• Male
• Humans
• Female
• Military Personnel
• Thyroid Cancer, Papillary/epidemiology
• Hexachlorobenzene
• Case-Control Studies
• Pesticides
• Hydrocarbons, Chlorinated
• Thyroid Neoplasms/chemically induced
• Thyroid Neoplasms/epidemiology
• Hexachlorocyclohexane

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Grants

• R01ES020361 NIH HHS
• R01ES020361 NIH HHS
• National Institutes of Health
• Murtha Cancer Center Research Program
• Oak Ridge Associated Universities
• National Cancer Institute Intramural Research Program

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Compatibility of cloud point extraction with gas chromatography: Matrix effects of Triton X-100 on GC-MS and GC-MS/MS analysis of organochlorine and organophosphorus pesticides

Cloud point extraction is an environmentally benign and simple separation/concentration procedure that can be regarded as an alternative to classical liquid-liquid extraction. In the current work, it was studied the compatibility of cloud point extraction followed by back-extraction in low volume of organic solvent with gas chromatography-mass spectrometry (GC-MS and GC-MS/MS). Triton X-100 was preferred than Triton X-114 as a surfactant to produce the clouding phenomenon and hexane or isooctane was found to be appropriate organic solvents which can be used at the back-extraction step. It was observed that ca. 0.09 % w/w Triton X-100 was co-extracted in the organic phase (hexane or isooctane) so further study was carried out to find out its effect on the GC-MS (GC-MS/MS) measurement when liquid samples are injected without any pre-cleaning to remove the surfactant. The chromatographic separation and the mass detection were not deteriorated by the concomitant Triton X-100 for analysis of several Organochlorine and Organophosphorus pesticides (alpha-HCH, beta-HCH, gamma-HCH, Pentachlorobenzene, Hexachlorobenzene, Chlorpyrifos, Chlorpyrifos-methyl, Aldrin, Endrin, Dieldrin, alpha-Endosulfan, Heptachlor, Heptachlor-endo-epoxide-A, o,p-DDD, p,p-DDD, o,p-DDE, p,p-DDE, o,p-DDT and p,p-DDT). The stability of the GC system when introducing surfactant was assessed as acceptable (typically the peak area RSD% for 20 consecutive injections were below 5 %). Under the developed vaporization conditions using PTV or PSS injectors it can be deduced that Triton X-100 is deposited on the inner surface of the liner. This effect is beneficial since the resulting surfactant layer makes a surface which facilitates the pesticides transfer to the GC column. As a consequence, for some analytes, a substantial enhancement (up to 2.3 times) in the sensitivity was observed when the matrix-matched medium (0.09 % w/w Triton X-100 in organic solvent) is used compared to calibration in solely hexane or isooctane. Meanwhile, the measurement precision in the presence of Triton X-100 remains unchanged. The GC-MS/MS analysis was alternatively accomplished by the use of glass or metal liner and it was found that the glass one should be preferable. Finally, it can be concluded that cloud point extraction with Triton X-100 can be combined with GC-MS or GC-MS/MS analysis by applying liquid injection of the target analytes transferred in organic solvents such as hexane or isooctane. We have established a positive effect of Triton X-100 on the instrumental performance which is on opposite to the generally accepted concern of the negative influence of the surfactants on the gas chromatographic analysis.

Persistent organic pollutants and polycyclic aromatic hydrocarbons in livers of stranded Arctocephalus australis in southern Brazilian beaches

23 livers of South American fur seal (Arctocephalus australis) found stranded in southern Brazilian beaches were evaluated for Persistent Organic Pollutants (POPs) and Polycyclic Aromatic Hydrocarbons (PAHs). POPs (DDTs, mirex, eldrin, dieldrin, aldrin, isodrin, HCHs, chlordanes and PCBs) and PAHs in livers were Soxhlet extracted, analyzed and quantified using Gas Chromatography Tandem Mass Spectrometry (GC-TQMS). The main POPs found were PCBs and DDTs, totaling 81 %. Among pesticides, mirex followed DDTs, possibly due to usage in Uruguay, followed by Σdrins, ΣCHLs and ΣHCHs. Naphthalene was the major PAH found, while heavier compounds did not significantly bioaccumulate. Concentrations of POPs resembled previous findings for A. australis. Considering only juveniles, no POPs showed significant differences between sexes. Lipidic content, weight and length did not show any correlation with POP concentration. This was the first record of PAHs and PBDEs in South American fur seals, and the levels of these pollutants were relatively low.

Residual levels, phase distributions, and human health risks of OCPs in the middle reach of the Huai River, China

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.

Organochlorine pesticides disrupt T helper cell regulation and reduce IL-2 and IFN-γ favoring infection and production of autoantibodies among pemphigus patients

The list of environmental factors that trigger autoimmune diseases in genetically susceptible individuals has grown in the recent years and is far from complete. The possible intervention of the environment in triggering these diseases is ever more perceived by the clinicians. This study investigated the effect of environmental factors like organochlorine pesticides (OCPs) on proportions of different T lymphocyte subsets and their cytokine secretion in-vitro among pemphigus patients, before and after specific immunosuppressive therapy. Higher levels of OCPs like β-HCH (isoform of hexachlorohexane), α-endosulfan (a form of endosulfan) and p,p΄-DDE (a metabolite of o,p'-dichlorodiphenyltrichloroethane) were observed in the blood of pemphigus patients as compared to healthy controls. HCH and DDT exposure caused specific reduction in CD8+CD45RA+ and CD4+CD25+ T lymphocyte subpopulations in these patient PBMCs. A strong reduction in Th1 (IL-2 and IFN-γ) cytokines upon exposure to these OCPs in-vitro was also observed. These findings indicate that HCH and DDT have a significant impact on Th1 lymphocytes. Impaired production of these cytokines might favor infections and production of autoantibodies. We therefore speculate that the systemic absorption of the pesticide after the topical contact may be one of the factors triggering the immunological mechanism among pemphigus patients.

Per- and polyfluoroalkyl substances, polychlorinated biphenyls, organochlorine pesticides, and polybrominated diphenyl ethers and dysregulation of MicroRNA expression in humans and animals-A systematic review

BACKGROUND

Persistent organic pollutants (POPs) are chemicals characterized by their environmental persistence. Evidence suggests that exposure to POPs, which is ubiquitous, is associated with microRNA (miRNA) dysregulation. miRNA are key regulators in many physiological processes. It is thus of public health concern to understand the relationships between POPs and miRNA as related to health outcomes.

OBJECTIVES

This systematic review evaluated the relationship between widely recognized, intentionally manufactured, POPs, including per- and polyfluoroalkyl substances (PFAS), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and organochlorine pesticides (dichlorodiphenyltrichloroethane [DDT], dichlorodiphenyldichloroethylene [DDE], hexachlorobenzene [HCB]), with miRNA expression in both human and animal studies.

METHODS

We used PubMed and Embase to systematically search the literature up to September 29th, 2023. Search results for human and animal studies were included if they incorporated at least one POP of interest in relation to at least one miRNA. Data were synthesized to determine the direction and significance of associations between POPs and miRNA. We utilized ingenuity pathway analysis to review disease pathways for miRNA that were associated with POPs.

RESULTS

Our search identified 38 eligible studies: 9 in humans and 29 in model organisms. PFAS were associated with decreased expression of miR-19, miR-193b, and miR-92b, as well as increased expression of miR-128, miR-199a-3p, and miR-26b across species. PCBs were associated with increased expression of miR-15a, miR-1537, miR-21, miR-22-3p, miR-223, miR-30b, and miR-34a, as well as decreased expression of miR-130a and let-7b in both humans and animals. Pathway analysis for POP-associated miRNA identified pathways related to carcinogenesis.

DISCUSSION

This is the first systematic review of the association of POPs with miRNA in humans and model organisms. Large-scale prospective human studies are warranted to examine the role of miRNA as mediators between POPs and health outcomes.

Air monitoring of organochlorine pesticides (OCPs) in Bursa Türkiye: Levels, temporal trends and risk assessment

Monitoring concentration levels of persistent organic pollutants (POPs) is required to evaluate the effectiveness of international regulations to minimize the emissions of persistent organic pollutants (POPs) into the environment. In this manner, we evaluated the spatial and temporal variations of 22 organochlorine pesticides (OCPs) using polyurethane foam passive air samplers at ten stations in Bursa in 2017 and 2018. The highest concentration value for Σ22OCPs was detected in Ağaköy (775 pg/m3) and Demirtaş (678 pg/m3) sampling sites, while the lowest value was observed in Uludağ University Campus (UUC, 284 pg/m3) site. HCB, γ-HCH, Endo I, and Mirex were the most frequently detected OCPs, which shows their persistence. Diagnostic ratios of β-/(α + γ)-HCH have pointed to historical and possible illegal OCP usage in the study area. The seasonality of air concentrations (with spring and summer concentrations higher than winter and autumn concentrations) was well exhibited by α-HCH, β-HCH, ɣ-HCH, HCB, Endo I, and Mirex but not aldrin, dieldrin, and α-chlordane (CC). Levels of OCPs detected in ambient air in the current study were relatively similar to or lower than those reported in previous studies conducted in Türkiye. Back trajectory analysis was applied to identify the possible sources of OCPs detected in the sampling regions. The Clausius-Clapeyron approach was used to investigate the temperature dependence of OCP gas-phase atmospheric concentrations. The data showed that long-range atmospheric transport affects ambient air OCP concentrations in the study area.

Pentachlorophenol affects doxycycline and tetracycline resistance genes in soil by altering microbial structure

Tetracycline antibiotics play a vital role in animal husbandry, primarily employed to uphold the health of livestock and poultry. Consequently, when manure is reintegrated into farmland, tetracycline antibiotics can persist in the soil. Simultaneously, to ensure optimal crop production, organochlorine pesticides (OCPs) are frequently applied to farmland. The coexistence of tetracycline antibiotics and OCPs in soil may lead to an increased risk of transmission of tetracycline resistance genes (TRGs). Nevertheless, the precise mechanism underlying the effects of OCPs on tetracycline antibiotics and TRGs remains elusive. In this study, we aimed to investigate the effects of OCPs on soil tetracycline antibiotics and TRGs using different concentrations of doxycycline (DOX) and pentachlorophenol (PCP). The findings indicate that PCP and DOX mutually impede their degradation in soil. Furthermore, our investigation identifies Sphingomonas and Bacillus as potential pivotal microorganisms influencing the reciprocal inhibition of PCP and DOX. Additionally, it is observed that the concurrent presence of PCP and DOX could impede each other's degradation by elevating soil conductivity. Furthermore, we observed that a high concentration of PCP (10.7 mg/kg) reduced the content of efflux pump tetA, ribosome protective protein tetM, tetQ, and passivating enzyme tetX. In contrast, a low PCP concentration (6.4 mg/kg) only reduced the content of ribosome protective protein tetQ. This suggests that PCP may reduce the relative abundance of TRGs by altering the soil microbial community structure and inhibiting the potential host bacteria of TRGs. These findings have significant implications in understanding the combined pollution of veterinary antibiotics and OCPs. By shedding light on the interactions between these compounds and their impact on microbial communities, this study provides a theoretical basis for developing strategies to manage and mitigate their environmental impact, and may give some information regarding the sustainable use of antibiotics and pesticides to ensure the long-term health and productivity of agricultural systems.