Agrochemical Exposure Research Articles

Safety induction for agricultural workers in particular areas of Gadog Village in handling hazardous agrochemical exposures

Safety induction for agricultural workers in particular areas of Gadog Village in handling hazardous agrochemical exposures

Nutrition, pesticide exposure, and virus infection interact to produce context-dependent effects in honey bees (Apis mellifera)

Declines in pollinator health are frequently hypothesized to be the combined result of multiple interacting biotic and abiotic stressors; namely, nutritional limitations, pesticide exposure, and infection with pathogens and parasites. Despite this hypothesis, most studies examining stressor interactions have been constrained to two concurrent factors, limiting our understanding of multi-stressor dynamics. Using honey bees as a model, we addressed this gap by studying how variable diet, field-realistic levels of multiple pesticides, and virus infection interact to affect survival, infection intensity, and immune and detoxification gene expression. Although we found evidence that agrochemical exposure (a field-derived mixture of chlorpyrifos and two fungicides) can exacerbate infection and increase virus-induced mortality, this result was nutritionally-dependent, only occurring when bees were provided artificial pollen. Provisioning with naturally-collected polyfloral pollen inverted the effect, reducing virus-induced mortality and suggesting a hormetic response. To test if the response was pesticide specific, we repeated our experiment with a pyrethroid (lambda-cyhalothrin) and a neonicotinoid (thiamethoxam), finding variable results. Finally, to understand the underpinnings of these effects, we measured viral load and expression of important immune and detoxification genes. Together, our results show that multi-stressor interactions are complex and highly context-dependent, but have great potential to affect bee health and physiology.

Higher prevalence of sacbrood virus in Apis mellifera (Hymenoptera: Apidae) colonies after pollinating highbush blueberries.

Highbush blueberry pollination depends on managed honey bees (Apis mellifera) L. for adequate fruit sets; however, beekeepers have raised concerns about the poor health of colonies after pollinating this crop. Postulated causes include agrochemical exposure, nutritional deficits, and interactions with parasites and pathogens, particularly Melisococcus plutonius [(ex. White) Bailey and Collins, Lactobacillales: Enterococcaceae], the causal agent of European foulbrood disease, but other pathogens could be involved. To broadly investigate common honey bee pathogens in relation to blueberry pollination, we sampled adult honey bees from colonies at time points corresponding to before (t1), during (t2), at the end (t3), and after (t4) highbush blueberry pollination in British Columbia, Canada, across 2 years (2020 and 2021). Nine viruses, as well as M. plutonius, Vairimorpha ceranae, and V. apis [Tokarev et al., Microsporidia: Nosematidae; formerly Nosema ceranae (Fries et al.) and N. apis (Zander)], were detected by PCR and compared among colonies located near and far from blueberry fields. We found a significant interactive effect of time and blueberry proximity on the multivariate pathogen community, mainly due to differences at t4 (corresponding to ~6 wk after the beginning of the pollination period). Post hoc comparisons of pathogens in near and far groups at t4 showed that detections of sacbrood virus (SBV), which was significantly higher in the near group, not M. plutonius, was the primary driver. Further research is needed to determine if the association of SBV with highbush blueberry pollination is contributing to the health decline that beekeepers observe after pollinating this crop.

Field agrochemical exposure impacts locomotor activity in wild bumblebees.

Agricultural intensification has been identified as one of the key causes of global insect biodiversity losses. These losses have been further linked to the widespread use of agrochemicals associated with modern agricultural practices. Many of these chemicals are known to have negative sublethal effects on commercial pollinators, such as managed honeybees and bumblebees, but less is known about the impacts on wild bees. Laboratory-based studies with commercial pollinators have consistently shown that pesticide exposure can impact bee behavior, with cascading effects on foraging performance, reproductive success, and pollination services. However, these studies typically assess only one chemical, neglecting the complexity of real-world exposure to multiple agrochemicals and other stressors. In the summer of 2020, we collected wild-foraging workers of the common eastern bumblebee, Bombus impatiens, from five squash (Cucurbita) agricultural sites (organic and conventional farms), selected to represent a range of agrochemical, including neonicotinoid insecticide, use. For each bee, we measured two behaviors relevant to foraging success and previously shown to be impacted by pesticide exposure: sucrose responsiveness and locomotor activity. Following behavioral testing, we used liquid chromatography-tandem mass spectrometry (LC-MS/MS) chemical analysis to detect and quantify the presence of 92 agrochemicals in each bumblebee. Bees collected from our sites did not vary in pesticide exposure as expected. While we found a limited occurrence of neonicotinoids, two fungicides (azoxystrobin and difenoconazole) were detected at all sites, and the pesticide synergist piperonyl butoxide (PBO) was present in all 123 bees. We found that bumblebees that contained higher levels of PBO were less active, and this effect was stronger for larger bumblebee workers. While PBO is unlikely to be the direct cause of the reduction in bee activity, it could be an indicator of exposure to pyrethroids and/or other insecticides that we were unable to directly quantify, but which PBO is frequently tank-mixed with during pesticide applications on crops. We did not find a relationship between agrochemical exposure and bumblebee sucrose responsiveness. To our knowledge, this is the first evidence of a sublethal behavioral impact of agrochemical exposure on wild-foraging bees.

Neonicotinoid exposure increases Varroa destructor (Mesostigmata: Varroidae) mite parasitism severity in honey bee colonies and is not mitigated by increased colony genetic diversity.

Agrochemical exposure is a major contributor to ecological declines worldwide, including the loss of crucial pollinator species. In addition to direct toxicity, field-relevant doses of pesticides can increase species' vulnerabilities to other stressors, including parasites. Experimental field demonstrations of potential interactive effects of pesticides and additional stressors are rare, as are tests of mechanisms via which pollinators tolerate pesticides. Here, we controlled honey bee colony exposure to field-relevant concentrations of 2 neonicotinoid insecticides (clothianidin and thiamethoxam) in pollen and simultaneously manipulated intracolony genetic heterogeneity. We showed that exposure increased rates of Varroa destructor (Anderson and Trueman) parasitism and that while increased genetic heterogeneity overall improved survivability, it did not reduce the negative effect size of neonicotinoid exposure. This study is, to our knowledge, the first experimental field demonstration of how neonicotinoid exposure can increase V. destructor populations in honey bees and also demonstrates that colony genetic diversity cannot mitigate the effects of neonicotinoid pesticides.

Combined effects of polyethylene microplastics and carbendazim on Eisenia fetida: A comprehensive ecotoxicological study

Microplastic (MP) pollution is becoming an emerging environmental concern across aquatic and terrestrial ecosystems. Plastic mulching and the use of pesticides in agriculture can lead to microplastics and agrochemicals in soil, which can result in unintended exposure to non-target organisms. The combined toxicity of multiple stressors represents a significant paradigm shift within the field of ecotoxicology, and its exploration within terrestrial ecosystems involving microplastics is still relatively limited. The present study investigated the combined effects of polyethylene MP (PE-MP) and the agrochemical carbendazim (CBZ) on the earthworm Eisenia fetida at different biological levels of organization. While E. fetida survival and reproduction did not exhibit significant effects following PE-MP treatment, there was a reduction in cocoon and hatchling numbers. Notably, prolonged exposure revealed delayed toxicity, leading to substantial growth impairment. Exposure to CBZ led to significant alterations in the endpoints mentioned above. While there was a decrease in cocoon and hatchling numbers, the combined treatment did not yield significant effects on earthworm reproduction except at higher concentrations. However, lower concentrations of PE-MP alongside CBZ induced a noteworthy decline in biomass content, signifying a form of potentiation interaction. In addition, concurrent exposure led to synergistic effects, from oxidative stress to modifications in vital organs such as the body wall, intestines, and reproductive structures (spermathecae, seminal vesicles, and ovarian follicles). The comparison of multiple endpoints revealed that seminal vesicles and ovarian follicles were the primary targets during the combined exposure. The research findings suggest that there are variable and complex responses to microplastic toxicity in terrestrial ecosystems, especially when combined with other chemical stressors like agrochemicals. Despite these difficulties, the study implies that microplastics can alter earthworms' responses to agrochemical exposure, posing potential ecotoxicological risks to soil fauna.

Architecture and potential roles of a delta-class glutathione S-transferase in protecting honey bee from agrochemicals

The European honey bee, Apis mellifera, serves as the principle managed pollinator species globally. In recent decades, honey bee populations have been facing serious health threats from combined biotic and abiotic stressors, including diseases, limited nutrition, and agrochemical exposure. Understanding the molecular mechanisms underlying xenobiotic adaptation of A. mellifera is critical, considering its extensive exposure to phytochemicals and agrochemicals present in the environment. In this study, we conducted a comprehensive structural and functional characterization of AmGSTD1, a delta class glutathione S-transferase (GST), to unravel its roles in agrochemical detoxification and antioxidative stress responses. We determined the 3-dimensional (3D) structure of a honey bee GST using protein crystallography for the first time, providing new insights into its molecular structure. Our investigations revealed that AmGSTD1 metabolizes model substrates, including 1-chloro-2,4-dinitrobenzene (CDNB), p-nitrophenyl acetate (PNA), phenylethyl isothiocyanate (PEITC), propyl isothiocyanate (PITC), and the oxidation byproduct 4-hydroxynonenal (HNE). Moreover, we discovered that AmGSTD1 exhibits binding affinity with the fluorophore 8-Anilinonaphthalene-1-sulfonic acid (ANS), which can be inhibited with various herbicides, fungicides, insecticides, and their metabolites. These findings highlight the potential contribution of AmGSTD1 in safeguarding honey bee health against various agrochemicals, while also mitigating oxidative stress resulting from exposure to these substances.

Indiscriminate use and inappropriate application of agrochemicals by smallholder farmers in Amhara Region, Ethiopia: Implications for sustainable beekeeping, crop and livestock production

This study was conducted to investigate the knowledge gaps regarding the use of agrochemicals by the farming communities in the Amhara Region, Ethiopia and its impact on beekeeping, crop and livestock production. The primary data were collected through household surveys, key informant interviews, focus group discussions and researchers’ observations. A total of 540 farmers (270 beekeepers and 270 non-beekeepers) were interviewed using a semi-structured questionnaire. The survey data was analyzed using SPSS software version 21, while the qualitative data was analyzed using content analysis. The results revealed that beekeeping contributes significantly to the livelihoods of smallholder farmers in the Amhara Region, mainly through the provision of hive products for home consumption and income but also for pollination services. The trends in the past decade showed that honeybee colony holdings and hive productivity had decreased due to indiscriminate use of agrochemicals, among others. Both beekeeper and non-beekeeper farmers in the study areas have been using different types of agrochemicals to control crop pests, diseases and weeds, and in some areas farmers used herbicides to clear weeds from pastureland. Farmers also stated that they are already aware of the negative effects of agrochemicals on honeybees. Nevertheless, the applications of agrochemicals are continuing without attitudinal changes. The results also showed that farmers purchase agrochemicals from legal as well as illegal vendors without proper understanding of their safe use and the expiry dates. Farmers’ use of agrochemicals in violation of the technical recommendations on their proper applications; they ignore risks and safety instructions, use unsafe storage facilities, do not use protective devices when applying agrochemicals, and dispose of agrochemical containers unsafely. The findings demonstrated that apart from the direct effects on honeybees, indiscriminate and inappropriate application of agrochemicals even poses risks to the lives of farmers. Beekeepers, non-beekeepers and both crop and livestock experts revealed that nowadays IPM has not been used by farmers as an alternative to synthetic agrochemicals. Farmers are also unaware of the legal frameworks available to protect honeybees from the negative effects of agrochemicals, and they have not developed local bylaws that can be used by farming communities to protect honeybees from the negative effects of agrochemicals. The results also showed that the direct economic losses incurred due to the loss of honey bee colonies from the indiscriminate application of agrochemicals run into ETB 11,520,000.00 /USD422,133.00/. Thus, the indiscriminate use of agrochemicals has become one of the major threats to the development of beekeeping, crop and livestock production. Therefore, very strong actions are needed by concerned and responsible stakeholders to save the lives of honeybees. The interventions to reduce agrochemical exposure should be implemented through context-specific and integrated approaches.

Colouration matters in dull toads: ultraviolet adornment for ladies and agrochemicals fading effects.

Integument colouration can influence many aspects of fitness, and is under strong sexual selection. Amphibians often express sexual dichromatism, and ultra-violet (UV) colouration is usually biased toward males as a sexual signal. As an honest signal, colouration is related to several individual traits, but can also be related to environmental factors such as anthropogenic pollutants, to which amphibians are highly sensitive. In this study, we investigated sexual dichromatism and UV reflectance covering a large visual spectrum (wavelength ranging from 300 to 700nm) on different body areas (throat, ventral and dorsal areas), in a widespread amphibian species, the spiny toad (Bufo spinosus). Then, we tested the impact of chronic exposure to two widespread herbicides (glyphosate's primary metabolite [AMPA] and Nicosulfuron) on their colouration. We found a strong but unexpected sexual dichromatism with females reflecting more in the UV spectrum (throat and ventral area) than males, suggesting these body parts might be critical in intra-specific signalling. Females with higher ventral UV reflectance were in better body condition, suggesting an honest signal role of UV reflectance which could influence male choice. Throat colouration was further differentially influenced by agrochemicals according to sexes. In AMPA-exposed males, throat was more saturated in yellow-orange than in control males, and Nicosulfuron exposure decreased the throat's reflectance hue in females, which can bear consequences on mate attractiveness. Future studies need to investigate the underlying mechanisms that are altered by agrochemical exposure.

Laboratory Determination of Particulate-Matter-Bound Agrochemical Toxicity among Honeybees, Mason Bees, and Painted Lady Butterflies.

Pollinator population declines are global phenomena with severe consequences for native flora and agriculture. Many factors have contributed to pollinator declines including habitat loss, climate change, disease and parasitism, reductions in abundance and diversity of foraging resources, and agrochemical exposure. Particulate matter (PM) serves as a carrier of toxic agrochemicals, and pollinator mortality can occur following exposure to agrochemical-contaminated PM. Therefore, laboratory-controlled experiments were conducted to evaluate impacts of individual PM-bound agrochemicals. Honeybees (Apis mellifera), blue orchard mason bees (Osmia lignaria), and painted lady butterfly (Vanessa cardui) larvae were exposed to bifenthrin, permethrin, clothianidin, imidacloprid, abamectin, and ivermectin via suspended, airborne PM. Agrochemical concentrations in PM to which pollinators were exposed were based on concentrations observed in fugitive beef cattle feedyard PM including a "mean" treatment and a "max" treatment reflective of reported mean and maximum PM-bound agrochemical concentrations, respectively. In general, pollinators in the mean and max treatments experienced significantly higher mortality compared with controls. Honeybees were most sensitive to pyrethroids, mason bees were most sensitive to neonicotinoids, and painted lady butterfly larvae were most sensitive to macrocyclic lactones. Overall, pollinator mortality was quite low relative to established toxic effect levels derived from traditional pollinator contact toxicity tests. Furthermore, pollinator mortality resulting from exposure to individual agrochemicals via PM was less than that reported to occur at beef cattle feedyards, highlighting the importance of mixture toxicity to native and managed pollinator survival and conservation. Environ Toxicol Chem 2023;42:2642-2650. © 2023 SETAC.

Toxic freedom: how middle-class seasonal fruit pickers perceive and manage agrochemical exposures

ABSTRACT In a global agricultural context that is more chemically dependent than ever, occupational exposure to pesticides typically maps onto entrenched inequalities. Existing research has documented the health hazards of agrochemical exposure facing predominantly low-income, racialized farmworkers. Yet some young middle-class people in wealthy countries are intentionally pursuing informal seasonal farm jobs. How do workers in social positions that typically protect against workplace vulnerability manage the uncertainty of toxic exposures? This study draws on ethnographic observations and in-depth interviews with French, English and Spanish-speaking domestic and international farmworkers in British Columbia, Canada. I identify three pathways by which farmworkers perceive and manage agrochemical exposure: informal bodily evidence, individually managing risks and rationalizing exposure. This article introduces the concept of ‘toxic freedom’ to show how workers may downplay workplace risks by framing pesticide exposure as a reasonable trade-off for personal autonomy, countercultural idealism and temporary youthful adventure. This research underscores why individual-level agricultural health and safety interventions may be limited in protecting workers from harmful agrochemical exposures. Rather, it signals the opportunity for policy interventions such as stronger pesticide regulation, proactive spot inspections, higher penalties for non-compliance, and clearer channels for farmworkers to have a collective democratic voice in the workplace.

A neonicotinoid pesticide alters Drosophila olfactory processing

Neonicotinoid pesticides are well-known for their sublethal effects on insect behavior and physiology. Recent work suggests neonicotinoids can impair insect olfactory processing, with potential downstream effects on behavior and possibly survival. However, it is unclear whether impairment occurs during peripheral olfactory detection, during information processing in central brain regions, or in both contexts. We used Drosophila melanogaster to explore the potential for neonicotinoids to disrupt olfaction by conducting electrophysiological analyses of single neurons and whole antennae of flies exposed to varying concentrations of the neonicotinoid imidacloprid (IMD) that were shown to cause relative differences in fly survival. Our results demonstrated that IMD exposure significantly reduced the activity of a single focal olfactory neuron and delayed the return to baseline activity of the whole antenna. To determine if IMD also impacts olfactory-guided behavior, we compared flies’ relative preference for odor sources varying in ethanol content. Flies exposed to IMD had a greater relative preference for ethanol-laced pineapple juice than control flies, demonstrating that neuronal shifts induced by IMD that we observed are associated with changes in relative preference. Given the interest in the sensory impacts of agrochemical exposure on wild insect behavior and physiology, we highlight the potential of Drosophila as a tractable model for investigating the effects of pesticides at scales ranging from single-neuron physiology to olfactory-guided behavior.

Fertilizer and herbicide alter nectar and pollen quality with consequences for pollinator floral choices.

Pollinating insects provide economically and ecologically valuable services, but are threatened by a variety of anthropogenic changes. The availability and quality of floral resources may be affected by anthropogenic land use. For example, flower-visiting insects in agroecosystems rely on weeds on field edges for foraging resources, but these weeds are often exposed to agrochemicals that may compromise the quality of their floral resources. We conducted complementary field and greenhouse experiments to evaluate the: (1) effect of low concentrations of agrochemical exposure on nectar and pollen quality and (2) relationship between floral resource quality and insect visitation. We applied the same agrochemcial treatments (low concentrations of fertilizer, low concentrations of herbicide, a combination of both, and a control of just water) to seven plant species in the field and greenhouse. We collected data on floral visitation by insects in the field experiment for two field seasons and collected pollen and nectar from focal plants in the greenhouse to avoid interfering with insect visitation in the field. We found pollen amino acid concentrations were lower in plants exposed to low concentrations of herbicide, and pollen fatty acid concentrations were lower in plants exposed to low concentrations of fertilizer, while nectar amino acids were higher in plants exposed to low concentrations of either fertilizer or herbicide. Exposure to low fertilizer concentrations also increased the quantity of pollen and nectar produced per flower. The responses of plants exposed to the experimental treatments in the greenhouse helped explain insect visitation in the field study. The insect visitation rate correlated with nectar amino acids, pollen amino acids, and pollen fatty acids. An interaction between pollen protein and floral display suggested pollen amino acid concentrations drove insect preference among plant species when floral display sizes were large. We show that floral resource quality is sensitive to agrochemical exposure and that flower-visiting insects are sensitive to variation in floral resource quality.

Management practices and seasonality affect stingless bee colony growth, foraging activity, and pollen diet in coffee agroecosystems

Stingless bees are essential pollinators in tropical ecosystems. Yet compared to their temperate zone counterparts, we know very little about how they respond to agriculture-associated land use, or how this effect is modulated by seasonal variation. Coffee, a dominant crop across the tropics, is grown under diverse management practices, making coffee agroecosystems an important context in which to investigate effects of agricultural management on stingless bees. We evaluated the performance and pollen diet of replicated experimental colonies of the stingless bee Scaptotrigona mexicana in three habitats in a coffee-dominated landscape in southern Chiapas, Mexico: a conventional sun coffee farm, a shaded organic coffee farm, and a forest fragment. We asked how habitat and seasonality influenced colony weight, forager activity, and pollen diet over one year. We placed eight experimental colonies in three habitats (three each in coffee farms; two in forest) and monitored them monthly for colony weight and forager activity. We collected corbicular pollen loads from returning foragers and identified pollen morphospecies. We compared performance and diet metrics across habitats and between wet and dry seasons. Colony performance was dramatically worse in the sun coffee farm; all sun coffee colonies died during the study. Colony performance did not differ between shade coffee and forest. Pollen diet richness was lower in the sun coffee colonies, but all habitats shared the same core pollen morphospecies. Across habitats, colony weight and activity and pollen diet richness decreased during the wet season. Our study suggests that conventional sun coffee cannot support stingless bee colonies, likely because of combined effects of agrochemical exposure and floral resource scarcity. By contrast, shade coffee is equivalent to forests in supporting stingless bee colonies.

Prevalence of Chronic Kidney Disease of Uncertain Etiology Within Selected Farming Communities in Rural Sri Lanka.

Chronic kidney disease of uncertain etiology (CKDu) is an emergent health concern, particularly in tropical farming communities in several global hotspots, including Sri Lanka. This particular nephropathy is characterized by a progressive decline in kidney function in the absence of conventional chronic kidney disease (CKD) risk factors such as diabetes mellitus, hypertension, and other identifiable kidney disorders. As it is almost asymptomatic at early stages, CKDu is mostly diagnosed at late stages with significant kidney damage. Hence, the identification of disease susceptibility and vulnerable communities at the earliest possible instances is highly important for the management of the disease. We aimed to compare kidney health across three different farming communities in Sri Lanka to identify CKDu susceptibilities. A cross-sectional study was performed with three selected farming communities: paddy farmers (PF; N = 581), sugarcane farmers (SF; N = 550), and vegetable farmers (VF; N = 244) in comparison with an age-matched control group of nonfarming (NF; N = 225) individuals. A medical examination was performed to investigate health status and medical history, whereas a urinalysis was performed to determine creatinine and albumin contents. Estimated glomerular filtration rate (eGFR) and urinary albumin-creatinine ratio (ACR) were used for assessment of kidney function. CKDu susceptibility was determined based on eGFR, and urinary ACR adhering to the clinical practice guidelines in Sri Lanka. The median (interquartile range [IQR]) eGFR levels of PF (85 mL/min/1.73 m2 [72-97]) and SF (93 mL/min/1.73 m2 [73-112]) were significantly lower than that of the NF group (103 mL/min/1.73 m2 [87-125]) (P < .0001), whereas eGFR of VF (100 mL/min/1.73 m2 [80-111]) was not significantly different compared with NF. The median (IQR) urinary ACR levels of the study groups, PF, SF, VF, and NF, were 0.59 (0.26-1.45), 0.46 (0.28-0.88), 0.45 (0.34-0.90), and 0.44 (0.34-1.02) mg/mmol, respectively. However, urinary ACR did not differ significantly across the study groups (P > .05). The prevalence of CKDu within PF (13.60%), SF (12.54%), and VF (6.67%) communities was significantly higher (P < .05) compared with the NF (2.67%). Of the total CKD cases, CKDu susceptible cases represented 73%, 69%, 50%, and 25% in PF, SF, VF, and NF, respectively, indicating a high risk of CKDu susceptibility among farming communities. Moreover, a noteworthy association of CKDu was observed with agrochemical exposure (odds ratio [OR] = 3.11, 95% confidence interval [CI] = 1.36-7.09). Concerning the farming practices, sugarcane farming showed the highest association with CKDu prevalence (OR = 3.40, 95% CI = 1.49-7.78). Compared with the nonfarming group, a significant risk of CKDu was observed in the three farming communities, particularly among paddy and sugarcane farmers. Longitudinal epidemiological studies to identify vulnerable farming communities and associated risk factors are critically needed to develop effective management strategies against CKDu within farming communities.

Weakly supervised anomaly detection coupled with Fourier transform infrared (FT-IR) spectroscopy for the identification of non-normal tissue.

The detection and classification of histopathological abnormal tissue constituents using machine learning (ML) techniques generally requires example data for each tissue or cell type of interest. This creates problems for studies on tissue that will have few regions of interest, or for those looking to identify and classify diseases of rarity, resulting in inadequate sample sizes from which to build multivariate and ML models. Regarding the impact on vibrational spectroscopy, specifically infrared (IR) spectroscopy, low numbers of samples may result in ineffective modelling of the chemical composition of sample groups, resulting in detection and classification errors. Anomaly detection may be a solution to this problem, enabling users to effectively model tissue constituents considered to represent normal tissue to capture any abnormal tissue and identify instances of non-normal tissue, be it disease or spectral artefacts. This work illustrates how a novel approach using a weakly supervised anomaly detection algorithm paired with IR microscopy can detect non-normal tissue spectra. In addition to incidental interferents such as hair, dust, and tissue scratches, the algorithm can also detect regions of diseased tissue. The model is never introduced to instances of these groups, training solely on healthy control data using only the IR spectral fingerprint region. This approach is demonstrated using liver tissue data from an agrochemical exposure mouse study.

The quest for metabolic biomarkers of agrochemicals exposure via in vitro studies and suspect screening

Numerous agrochemicals, including pesticides and herbicides, are applied in modern agriculture, resulting in concerns for the ecosystem and human safety as humans are easily exposed to these compounds. Many agrochemicals, and their transformation products or metabolites, have shown toxicity in in vitro and in vivo studies. However, given the rapid development of novel agrochemicals, for many there is no information about their effects nor about metabolic transformations when ingested by humans. Tracing biomarkers may be the best method for assessing the impacts of agrochemicals. A combination of in vitro metabolism study and suspect screening of human samples (e.g., urine, blood) can be utilized to efficiently find biomarkers for agrochemical exposure. In the work reported here, we determined the in vitro metabolic profiling of six prioritized pesticides and synergists, namely boscalid, carbendazim, piperonyl butoxide, spiroxamine, dimethomorph and fludioxonil, in human liver microsomes. 17 major metabolites were structurally elucidated by high resolution mass spectrometry (HRMS). Major metabolic transformation processes (e.g., hydroxylation, demethylation and oxidation) were proposed for each pesticide. Individual in silico toxicity assessments showed that some metabolites had the same or even enhanced toxicity compared to parent compounds. Information about these metabolites obtained from HRMS was used for suspect screening in human activities related samples. Carbendazim and a metabolite of fludioxonil were identified in wastewater and laboratory urine samples, respectively. Our findings provide concrete evidence for the use of in vitro metabolites as biomarkers in biomonitoring studies of potential exposure to toxic chemicals.

Reference genes selection for expression studies in Maconellicoccus hirsutus (Green) (Pseudococcidae: Hemiptera) under specific experimental conditions.

Maconellicoccus hirsutus is a destructive pest which causes severe losses of agricultural and horticultural crops. For the management of M. hirsutus, many insecticides have been used and it has been exposed to insufficient dosage or uneven spray coverage which resulted in the development of insecticide resistance. Xenobiotic metabolism can be better understood with the help of gene expression studies by unveiling the underlying molecular mechanisms. The qRT-PCR is the simplest method to analyse gene expression, however, it highly relies on suitable reference genes concerning the different experimental conditions. We evaluated the stability of five reference genes in two sets of experimental conditions viz. developmental stages (nymphs and adults) and agrochemical stress (GA3 and Buprofezin sprayed) against M. hirsutus, using different softwares-NormFinder, geNorm, BestKeeper, and RefFinder. The study revealed that ATP51a and GAPDH can be used as reference genes for gene expression studies when exposed to Gibberellic acid. Additionally, the study revealed that the ideal pair of reference genes for data validation in M. hirsutus treated with Buprofezin was GAPDH and β-tubulin. The ideal reference gene combination for various developmental stages was found to be 28S and Actin. According to the study, GAPDH can be utilized as a reliable reference gene in the agrochemical (GA3 and Buprofezin) exposure set. The genes can be utilized as a suitable reference for qRT-PCR gene expression studies of xenobiotic metabolism to understand the underlying molecular mechanism, which will help further to design suitable management strategies.

Occupational heat exposure alone does not explain chronic kidney disease of uncertain aetiology (CKDu) in Sri Lanka

• The association of occupational heat exposure with CKDu remains debated. • kidney function of individuals in three occupational groups, farmers, fisherfolk and plantation workers in Sri Lanka was assessed. • CKDu risk was lowest in occupational group with highest heat exposure. • CKDu risk was higher among farmers and workers with low to moderate heat exposure. • Heat stress does not appear to be the main driver of CKDu. Chronic kidney disease of uncertain aetiology (CKDu) is an emerging health concern in tropical farming communities. The role ofoccupational heat exposure as a potential driver of CKDu remains debated. Our study examines occupational heat exposure kidney health in three occupational groups in Sri Lanka. We recruited participants from three occupational groups from three climatic zones; fisherfolk from the dry and intermediate zones (N=225), paddy farmers from the intermediate zone (N=180) and tea plantation workers from the wet zone (N=70). Serum creatinine, cystatin-C, urea and uric acid, estimated glomerular filtration rate and urinary albumin-creatinine ratio were used as diagnostic criteria of renal impairment. CKDu susceptibility was at the highest among farmers (13.33%), with a significant differentce compared to the fisherfolk (5.36%; p=0.0003). Among the plantation workers, CKDu susceptibility was 5.71%, and it was not significantly different compared to the farmers (p=0.087) and the fisherfolk (p=0.427). Despite higher exposure to heat stress and dehydration, as indicated by the highest simplified wet bulb globe temperature (sWBGT) in the work environments, fisherfolk reported the lowest CKDu susceptibility, while farmers and workers with low to moderate heat exposure showed an increased incidence of abnormal renal function. Further, a multivariable regression analysis identified a significant effect of occupation (p=0.005), agrochemical exposure (p=0.001) and age (p=0.001) on the likelihood of CKDu susceptibility while the sWBGT in the working environments showed no significant effect (p=0.227). With the evidence from our findings, heat exposure alone does not appear to be the leading driver of CKDu in Sri Lanka, suggesting that the nephropathy is more likely to be associated with occupational risks such as agrochemical exposures.

Health and agrochemical use experiences of agricultural workers with high serum cholinesterase levels in Northeastern Thailand

In developing countries, agrochemicals are frequently used, resulting in direct and indirect chemical exposure as well as a variety of health concerns. Although agrochemical safety education is essential to promoting protective behavior among agricultural workers, there is a gap in the body of evidence concerning experience with agrochemical use and practice, which is critical for developing and improving educational interventions, so they are more effective and acceptable to the workers' culture and lifestyle. This phenomenology study included twenty agricultural workers with high serum cholinesterase levels in two Thai rural communities. Data from semi-structured interviews were transcribed verbatim and analyzed by using Colaizzi's 7-step data analysis, which is mentioned in the data analysis part. Five themes and three subthemes emerged in relation to agrochemical use and health: (i) long-term chemical exposure; (ii) no need to be concerned about health after chemical exposure; (iii) insufficient chemical protection knowledge and practices; (iv) difficulties in adhering to the agrochemical exposure prevention regimen; and (v) government policy and the growth of the organic products market are important components of chemical use reduction. Based on the findings, the workers lacked awareness regarding protective behaviors, because they did not notice any abnormal changes in their health. We, therefore, recommend that they undergo annual checkups for monitoring their SChE levels, which should be provided by the local government. In addition, agrochemical use is influenced by socioeconomic and political factors. Thus, a health education program for agricultural workers should involve a multidimensional and community-engaged training program that would promote the safe handling of chemicals through contextually appropriate interventions.