Hematological, Biochemical Effects, and Self-reported Symptoms in Pesticide Retailers

Biomarkers of oral subacute toxicity of deltamethrin in exposed male Albino rats

Deltamethrin is one of the most effective pyrethroid compounds, widely employed in veterinary medicine, public health, and farming. Deltamethrin-triggered oxidative stress largely causes serious harm to an organism. Acute toxicity of this compound was extensively investigated, while less information is available on its oral sub-acute effects. This study assessed, in the male Albino rats, the effects of oral gavage of either 0.874 mg/kg (0.01 LD50) or 8.740 mg/kg (0.10 LD50) of deltamethrin for successive 14 days to investigate its effects on biomarkers and to detect the tissue injury in rats following subacute deltamethrin treatment. It was found that levels of glutathione peroxidase, superoxide dismutase, and catalase in the brain, kidney, and liver, alkaline phosphatase (ALP), and uric acid in serum, hematocrit, mean corpuscular volume (MCV), white blood cells (WBC)s, eosinophils, and basophils were significantly reduced compared with untreated rats. However, when rats were treated with deltamethrin for successive 14 days, alanine aminotransferase (ALT) and lactate dehydrogenase (LDH) activities in serum and the levels of thiobarbituric acid reactive substances (TBARs) in brain, kidney, and liver, red blood cell distribution width (RDW-CV), total protein, monocytes, and basophils and the ratios of neutrophils to lymphocytes, an aggregated marker of systemic inflammation and systemic immune inflammation indexes, significantly increased compared with the control group. Histologic lesions were observed in the liver, kidney, brain, testis, and epidemies in rats exposed to subacute deltamethrin for 14 days, and most tissues of rats treated with 0.10 LD50 of deltamethrin were more affected than those treated with 0.01 LD50. These findings strongly suggest that subacute exposure to deltamethrin caused significant systemic toxicity through oxidative stress resulting in biochemical and histological changes in the studied tissues. These findings highlight the potential harmful effects of deltamethrin and emphasize the importance of understanding the subacute effects of this compound, particularly in the context of veterinary medicine, public health, and farming.

The situation of chlorpyrifos in Mexico: a case study in environmental samples and aquatic organisms

Chlorpyrifos (CPF) is one of the most commonly used organophosphate pesticides. Because CPF was described as a toxic compound without safe levels of exposure for children, certain countries in Latin America and the European Union have banned or restricted its use; however, in Mexico it is used very frequently. The aim of this study was to describe the current situation of CPF in Mexico, as well as its use, commercialization, and presence in soil, water, and aquatic organisms in an agricultural region of Mexico. Structured questionnaires were applied to pesticide retailers to determine the sales pattern of CPF (ethyl and methyl); in addition, monthly censuses were conducted with empty pesticide containers to assess the CPF pattern of use. Furthermore, samples of soil (48 samples), water (51 samples), and fish (31 samples) were collected, which were analyzed chromatographically. Descriptive statistics were performed. The results indicate that CPF was one of the most sold (3.82%) and employed OP (14.74%) during 2021. Only one soil sample was found above the CPF limit of quantification (LOQ); in contrast, all water samples had CPF levels above the LOQ (x̄ = 4614.2 ng/L of CPF). In the case of fish samples, 6.45% demonstrated the presence of methyl-CPF. In conclusion, the information obtained in this study indicates the need for constant monitoring in the area, since the presence of CPF in soil, water, and fish constitutes a threat to the health of wildlife and humans. Therefore, CPF should be banned in Mexico to avoid a serious neurocognitive health problem.

The impact of the use of personal-protective-equipment on the minimization of effects of exposure to pesticides among farm-workers in India

Introduction

Although excessive use of pesticides and unsafe agricultural practices may contribute to numerous intoxications, the role of PPE (personal-protective-equipment) in the minimization of toxicological effects due to pesticide exposure has not been addressed so far. The present study aimed to assess the impact of the use of PPE on the minimization of effects of exposure to pesticides among farm-workers.

Methods

A community-based follow-up study with questionnaire-based survey and field observations was undertaken among farm-workers (n = 180) of Rangareddy district, Telangana, India. Biomarkers of exposure such as cholinesterase activity, inflammatory markers (TNF-α, IL-1β, IL-6, cortisol, and hs-C reactive protein), nutrients (vitamins A, E), liver function (total protein and A/G ratio, AST and ALT levels) were investigated in the laboratory by following the standard protocols.

Results

Farm-workers who had a mean farming exposure of 18 years of and who neither followed safe pesticide handling practices nor used PPE and also showed reluctance to obey good agricultural practices (GAPs). Inhibition of AChE (acetylcholine esterase) with increased inflammation was found among farm-workers as compared to their respective normal values when they have not used PPE. Linear regression statistical analysis revealed a profound effect on inhibition in the AChE activity and various inflammatory markers with the increase in the duration of pesticide exposure. Further, there was no effect of the duration of pesticide exposure on the levels of vitamins A, E, ALT, AST, total protein, and A/G ratio. Further, intervention studies carried out on the use of PPE provided (commercially available and cost-effective) for 90 days showed a significant reduction in the biomarker levels (p < 0.01).

Conclusion

This study demonstrated the importance of the use of PPE during pesticide applications and other agricultural tasks to minimize pesticide-associated adverse health effects.

Evaluation of hematological indices among insecticides factory workers

Insecticides are commonly used pesticides in the world. Chronic exposure to insecticides has adverse effects on various human body organs. In this study, hematological findings were assessed in workers in an insecticide manufacturing plant. Hematological parameters and clinical symptoms were recorded in 99 workers exposed to insecticides and 107 workers not exposed to them in a cross-sectional study. Assessment of the hematological results showed a higher prevalence of thrombocytosis in the exposed group than the non-exposed group (P < 0.05). Mean white blood cell (WBC) and platelet counts, anisocytosis of red blood cells (RBCs), and neutrophils to lymphocytes ratio (NLR) were significantly higher in the exposed group compared to the non-exposed group (P < 0.05). Prevalence rates of headache, itchy skin, cough, and sleep disorders were higher in the exposed group than in the non-exposed group (P < 0.05). Chronic exposure to insecticides can alter hematological parameters in the normal range. Occupational exposure to insecticides may increase WBCs, platelet count, NLR, and red cell distribution width (RDW). It can also cause thrombocytosis. Complete blood count (CBC), as an inexpensive and accessible tool, can help monitor workers' health status exposed to insecticides properly.

Evaluation of conventional and non-conventional biomarkers of liver toxicity in greenhouse workers occupationally exposed to pesticides

The liver plays a prominent role in maintenance of homeostasis and is the major organ for xenobiotic metabolism, including pesticides. Conventional liver function tests are widely used to assess hepatocellular and biliary system dysfunction by measuring serum levels of aminotransferases (ALT, AST) and cholestasis enzymes (alkaline phosphatase -ALP- and γ-glutamyl transferase -GGT-), respectively. Although these tests are not entirely specific for liver damage, their specificity increases when measured concurrently, but still have limited usefulness to predict early liver dysfunction. Hence, non-conventional biomarkers may have a better performance for the early detection of biochemical hepatotoxicity with a greater specificity and sensitivity. A cross-sectional study with a follow-up component was conducted on 175 greenhouse workers regularly exposed to pesticides under integrated production system, and 91 controls living in the same geographical area. All individuals were evaluated for conventional (ALT, AST, ALP, GGT) and non-conventional biomarkers of hepatotoxicity (ornithine transcarbamylase (-OTC-), Arginase-1 -ARG1- and glutathione S-transferase alpha -GSTα-) over two periods of the same crop season, one of high pesticide exposure and other of low exposure. A slight increase in AST was observed in greenhouse workers relative to controls, suggestive of subtle hepatocellular toxicity. Although ALP, ARG1 and GST-α levels were decreased in greenhouse workers, this might be related to a potential homeostatic mechanism that regulates their expression. Altogether, these findings do not represent unambiguous evidence of liver dysfunction (e.g., hepatocellular or biliary system impairment) but may be the result of the low-toxicity pesticides used by greenhouse workers.

Biochemical and genotoxic effects in women exposed to pesticides in Southern Ecuador

Toxicity refers to the potential of a substance such as a pesticide to cause damage to the structure or functions of an exposed organism. Pesticides can lead to harmful biological effects in exposed animals and their offspring over the medium and long term. They can affect the immunological, nervous, endocrine, and reproductive systems. DNA damage has also been linked to exposure to pesticides, and this damage can cause abortions, degenerative diseases, and cancer. The aim of this work was to establish whether women who are indirectly exposed to pesticides exhibit a compromised health status, including genotoxic effect. Women exposed indirectly to pesticides in Chimchanga and Colaisaca in the south of Ecuador underwent hematological and biochemical tests and micronucleus assay in buccal cells. The subjects were also genotyped for GSTM1, GSTT1, GSTP1, and PON1 polymorphisms, which can modify an individual's capacity to metabolize pesticides and relation with damage of DNA. The study revealed hepatic toxicity in Colaisaca women (AST and ALT) and an increase in the rate of micronucleus (MN) in Colaisaca individuals. In addition, genetic polymorphisms in PON1 and GSTP1 showed effects of modulating the frequency of karyolytic cells, karyorrhectic cells, and condensed chromatin cells.

Neuropsychiatric Disorders in Farmers Associated with Organophosphorus Pesticide Exposure in a Rural Village of Northwest México

This study aims to determine the degree of acetylcholinesterase inhibition and neurological symptoms for each of the psychiatric disorders diagnosed in the farm workers of a rural population in the state of Baja California, Mexico. We conducted a cross-sectional study on 140 agricultural workers (exposed participants). The study was run using the Mini International Neuropsychiatric Interview Diagnostic Test (MINI), a pre-established questionnaire to diagnose the mental state of each agricultural worker. Analysis of enzymatic activity was carried out using the modified Ellman method. The results showed that, among agricultural workers with slightly inhibited enzymatic activity, 25% met the criteria for the diagnosis of major depression with suicidal attitudes, 23.9% with inhibited enzymatic activity showed generalized anxiety, 23.5% showed combined depression⁻anxiety, and 22% met the criteria for major depression and no psychiatric diagnosis disorder. These results suggest the need for the development of effective public-health strategies to inform farm workers about integrated pesticide management in order to prevent serious health complications.

Respiratory and Dermal Symptoms and Raised Serum Concentrations of Biomarkers of Oxidative Stress among Pesticide Retailers

BACKGROUND

Recently concern has been raised regarding possible health effects resulting from exposure of a group of pesticide retailers to chemicals they handle.

OBJECTIVE

To investigate the prevalence of respiratory and dermal symptoms, as well as biomarkers of oxidative stress, among pesticide retailers and to compare them with those of an unexposed comparison group.

METHODS

70 male pesticide retailers and 64 male construction workers (served as the comparison group) were investigated. Blood samples were taken from all participants to assess the biomarkers of oxidative stress. A data sheet and the European Community Respiratory Health Survey II questionnaire were used to determine the prevalence of dermal and respiratory disorders, respectively.

RESULTS

After adjusting for age, weight, height, education level, job tenure, average daily work, presence of family history of respiratory diseases, marital status, smoking status, and number of cigarettes smoked per day, we found that wheezing (OR 4.07, 95% CI 1.17 to 14.17), cough (OR 3.38, 95% CI 1.15 to 9.98), and mucus hypersecretion (OR 3.66, 95% CI 1.45 to 9.05) were significantly more prevalent among pesticide retailers compared with the comparison group. The prevalence of tingling and dryness of skin exposed individuals was significantly higher than unexposed participants. The mean serum concentrations of glutathione and malondialdehyde in the exposed group were significantly higher than those in the comparison group.

CONCLUSION

Occupational exposure to low doses of a mixture of pesticides by retailers was associated with increased prevalence of dermal and respiratory symptoms as well as raised concentrations of biomarkers of oxidative stress.

Evaluation of hematological and biochemical parameters of pesticide retailers following occupational exposure to a mixture of pesticides

AIMS

This study was undertaken to ascertain whether light occupational exposure to pesticides by retailers might be associated with any liver, kidney, nervous system dysfunction or hematological abnormalities.

MAIN METHODS

In this cross-sectional study, 70 male pesticide retailers (cases) and 64 male subjects, randomly selected from the constructions workers of city council contractors, as the referent group, were investigated. Urine and blood samples were taken from all subjects for urine analysis, hematological and biochemical parameters. Data analysis was conducted through SPSS v.19 using t-test and chi-square test.

KEY FINDINGS

The results of urine analysis showed that the frequency of abnormal urine tests was significantly higher in cases than in referent individuals. Similarly, the results of CBC showed that the mean values of monocyte, hemoglobin, hematocrit, mean corpuscular volume, mean corpuscular hemoglobin and platelet distribution width were significantly lower, and mean corpuscular hemoglobin concentration and red blood cell distribution width were significantly higher in retailers. No significant differences were found for other parameters.

SIGNIFICANCE

These findings indicate that an association exists between exposure to pesticides by retailers and early subtle and sub-clinical changes in the urine tests and hematological parameters. Engineering measures are recommended to eliminate exposure to pesticides and to prevent its associated outcomes.

Influence of non-pathological factors on ALT measurements

Alanine transaminase (ALT) is still the most sensitive marker for evaluating the damage of liver cells. ALT measurements may be affected by common non-pathological factors such as gender, age, pregnancy, different physiological conditions, circadian rhythm, diet, drinking, smoking, strenuous exercise, metabolic factors, drugs, blood collection methods, and specimen collection, transmission, and preservation. It is important to emphasize the definition of limits of normal ALT and the influence of the above-mentioned non-pathological factors on its test results.

Oxidative stress and genetic damage among workers exposed primarily to organophosphate and pyrethroid pesticides

The indiscriminate use of pesticides in agriculture and public health campaigns has been associated with an increase of oxidative stress and DNA damage, resulting in health outcomes. Some defense mechanisms against free radical-induced oxidative damage include the antioxidant enzyme systems. The aim of this study was to determine the levels of malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), and the relationship of antioxidant enzyme levels with DNA damage among sprayers (workers) occupationally exposed to pesticides. The determinations of MDA and antioxidant enzymes were performed spectrophotometrically. The genotoxic effects were evaluated using the comet assay. The results showed a marginally significant decrease in SOD and CAT activities in the high exposure group compared to the control group. For MDA, statistically significant differences were found among people working long term vs. those working temporarily (P = 0.02) as sprayers. In the moderate exposure group, a positive correlation was observed between MDA levels and GPx activity. In the high exposure group, a negative correlation was observed between GR and CAT activities, and between MDA levels and GPx activities. Furthermore, in the high exposure group, a positive correlation between DNA damage parameters and MDA levels was observed. The results suggest an important role of antioxidant enzymes for the protection of DNA damage caused by occupational exposure to pesticides.

Methamidophos induces cytotoxicity and oxidative stress in human peripheral blood mononuclear cells

Previous studies have shown that organophosphate pesticide (OP) exposure is associated with oxidative stress. Methamidophos (MET) is an OP widely used in agriculture, which is regarded as a highly toxic pesticide and it is a potent inhibitor of acetylcholinesterase. The aim of this study was to evaluate whether MET can induce oxidative stress at low concentrations in primary cultures of human peripheral blood mononuclear cells (PBMCs). PBMCs from healthy individuals were exposed to MET (0-80 mg/L) for 0-72 h. We performed the MTT and neutral-red assays to assess the cytotoxicity. As indicators of oxidative stress, the levels of reactive oxygen species (ROS) were assessed using flow cytometry, and the malondialdehyde (MDA) and reduced glutathione (GSH) levels were determined. MET decreased the viability of PBMCs in a dose-dependent manner. At concentrations of 3, 10, or 20 mg/L for 24 h, MET increased the ROS production significantly compared with the vehicle control. Similarly, MET increased the levels of MDA at the same concentrations that increased ROS (10 and 20 mg/L); however, no changes in GSH levels were observed. These results suggest that MET increased the generation of oxidative stress in PBMCs. © 2015 Wiley Periodicals, Inc. Environ Toxicol 32: 147-155, 2017.

Changes in Perceptions and Practices of Farmers and Pesticide Retailers on Safer Pesticide Use and Alternatives: Impacts of a Community Intervention in Chitwan, Nepal

Unsafe use of hazardous pesticides is a neglected public health problem in developing countries. This survey evaluates the effects of a training program to increase awareness on harmful effects of pesticides and to enhance capacity for safe handling involving 57 trained farmers, 98 neighboring farmers, 94 control farmers, and 23 pesticide retailers from villages in Chitwan, Nepal. Knowledge and attitude-related variables improved in all 3 farmer groups, with a significant trend of better knowledge and attitude from trained to neighboring to control farmers (in 14/16 [87.5%] variables). In practice, there were significant differences among the groups with a trend from trained to neighboring to control farmers (in 10/26 [38.5%] variables).The pesticide retailers also improved on knowledge and practice. In conclusion, training farmers and pesticide retailers improved their knowledge and practice, with possible positive effect on neighboring farmers and control villages as well. An improved extension service to farmers is recommended.

Developmental Neurotoxicity of Methamidophos in the Embryo-Larval Stages of Zebrafish

Methamidophos is a representative organophosphate insecticide. The knowledge of its developmental neurotoxicity is limited, especially for zebrafish in the early stages of their life. Four hour post-fertilization (hpf) zebrafish embryos were exposed to several environmentally relevant concentrations of methamidophos (0, 25, and 500 μg/L) for up to 72 hpf. Locomotor behavior was then studied in the zebrafish larvae at this timepoint. Acridine orange (AO) staining was carried out in the zebrafish larvae, and the mRNA levels of genes associated with neural development (mbp and syn2a) were analyzed by reverse transcription-polymerase chain reaction (RT-PCR). The number of escape responders for mechanical stimulation was significantly decreased in exposed groups. AO staining showed noticeable signs of apoptosis mainly in the brain. In addition, the mRNA levels of mbp and syn2a were both significantly down-regulated in exposed groups. Our study provides the first evidence that methamidophos exposure can cause developmental neurotoxicity in the early stages of zebrafish life, which may be caused by the effect of methamidophos on neurodevelopmental genes and the activation of cell apoptosis in the brain.

Paraoxonase 1 and its relationship with pesticide biomarkers in indigenous Mexican farmworkers

OBJECTIVE

Biomarkers of pesticide toxicity and paraoxonase 1 (PON1) phenotype and genotypes were evaluated in indigenous Mexican farmworkers exposed mainly to organophosphate (OP) pesticides.

METHODS

Acetylcholinesterase, butyrylcholinesterase, and PON1 activities--arylesterase and CMPAase activities--were evaluated spectrophotometrically. PON1 55 and 192 polymorphisms were determined by real-time polymerase chain reaction. Hematological parameters were evaluated using a cytometer.

RESULTS

Butyrylcholinesterase and arylesterase activities were lower in farmworkers, who also showed lower levels of leukocytes but higher percentages of lymphocytes when compared with the nonexposed group. Our results showed a high frequency of OP, high hydrolysis-related PON1 alleles (LL/QR and LL/RR) in the study population. An association was observed between CMPAase activity and PON1Q192R polymorphism.

CONCLUSIONS

Our results suggest that pesticide exposure modifies biochemical and hematological biomarkers in the study population, and that the phenotype of PON1 (CMPAase) is a sensible susceptibility biomarker of OP pesticide toxicity.

Effects of lead exposure on the status of platelet indices in workers involved in a lead-acid battery manufacturing plant

This study was carried out to determine the effect of Pb exposure on the status of platelet indices in workers exposed to Pb during lead-acid battery plant process. Platelet indices and blood lead levels (BLLs) were determined in 429 male workers. BLLs were determined by using an atomic absorption spectrophotometer. Platelet indices in the samples were quantified by using the Sysmex KX-21 hematology analyzer. The levels of platelet count (PLT), plateletcrit (PCT) and mean platelet mass (MPM) were significantly decreased and platelet distribution width (PDW), platelet large cell ratio (P-LCR) and mean platelet volume were increased with an increase in BLLs. The results of linear multiple regression analysis showed that the platelet count (β -0.143, P=0.005), PCT (β -0.115, P=0.023) and MPM (β -0.110, P=0.030) were negatively associated with BLLs and P-LCR (β 0.122, P=0.016) was positively associated with BLLs. The variable of body mass index showed a positive association with PCT (β 0.105, P=0.032) and MPM (β 0.101, P=0.039). The results of the study may indicate that lead exposure may impair coagulation function through endothelial tissue injury and reduction of nitric oxide.

Pesticide retailers' knowledge and handling practices in selected towns of Tanzania

BACKGROUND

Approximately 300 pesticide retailers are currently registered in Tanzania. Inadequate knowledge and unsafe handling practices among retailers may contribute to human pesticide exposure and environmental contamination. This study investigated pesticide retailers' qualifications, work experience, safety practices and the products distributed so as to identify opportunities for preventing Acute Pesticide Poisoning (APP).

METHODOLOGY

In 2005, employees of pesticide retail firms in six Tanzanian towns were surveyed using a semi-structured questionnaire and physical inspection of premises. In addition, information on products distributed in 2004 and 2005 was collected from Arusha and Arumeru firms to assess potential risk posed for end-users.

RESULTS

More than half of the participating firms (58.6%) were not registered. Most agents on sale in Arusha and Arumeru were hazardous products including WHO Class I and II products (61.7%) and the mean number of cholinesterase inhibiting agents was 5.8 (range 2-8). Major deficiencies found included semi-trained staff (52%), lack of first-aid kits (38.6%), repacking and decanting of pesticides into smaller unlabelled containers (25.3%), lack of fire-fighting equipment (22.6%) and distribution of unregistered products (9.3%). Compared to unregistered companies, those companies that were registered were more likely to report practicing safe container disposal (40% versus 19%; p = 0.06) and to have an absence of leaking containers (36% versus 15%; p = 0.04).

CONCLUSION

Pesticide distribution in Tanzania was accompanied by many unsafe practices that may contribute to the burden from APP, not only affecting the distributors but also farmers who buy and use these products. Market pressures appear to be encouraging decanting of pesticides to enable retailers to make profits. Registration of firms appears to be associated with safer practices. Comprehensive interventions to strengthen enforcement mechanisms by increasing the number of pesticide inspectors, ensuring adequate financial support for enforcement activities and providing training opportunities for pesticide retailers and the end users are strongly recommended.

Comparative effect of technical and commercial formulations of methamidophos on sperm quality and DNA integrity in mice

Methamidophos (MET), widely used in developing countries, is a highly neurotoxic organophosphate pesticide that has been associated with male reproductive alterations. Commercial formulations of pesticides used by agricultural workers and urban sprayers are responsible for thousands of intoxications in developing countries and may not have the same effects as active pure ingredients. Therefore, we compared effects of MET technical (METt) and commercial (METc) grades on sperm quality and DNA integrity. Male mice were injected (intraperitoneal, i.p.) with METt or METc (3.75, 5, and 7 mg/kg bw/day/4 days) and sacrificed 24 h post-treatment. Sperm cells collected from epididymis-vas deferens were evaluated for quality parameters, DNA damage by the comet assay, and lipoperoxidation by malondialdehyde (MDA) production. Erythrocyte acetylcholinesterase (AChE) activity was evaluated by acetylthiocholine inhibition as an index of overall toxicity. A dose-dependent AChE inhibition was observed with both formulations. Sperm quality was decreased after treatment with both MET compounds, but the commercial formulation showed stronger effects; a similar profile was observed with the DNA damage, being METc more genotoxic. None MET formulation increased MDA, suggesting no peroxidative damage involved. In summary, the commercial formulation of MET was more reprotoxic and genotoxic than the active pure ingredient, highlighting that commercial formulations must be considered for more appropriate risk assessment of pesticide exposures.

Pesticide exposure and genetic variation in xenobiotic-metabolizing enzymes interact to induce biochemical liver damage

Metabolic activation of pesticides in the liver may result in highly reactive intermediates capable of impairing various cellular functions. Nevertheless, the knowledge about the effect of pesticide exposure on liver function is still limited. This study assessed whether exposure to pesticides elicits early biochemical changes in biomarkers of liver function and looked for potential gene-environmental interactions between pesticide exposure and polymorphisms of pesticide-metabolizing genes. A longitudinal study was conducted in farm-workers from Andalusia (South Spain), during two periods of the same crop season with different degree of pesticide exposure. Blood samples were taken for the measurement of serum and erythrocyte cholinesterase activities as well as for determining clinical chemistry parameters as biomarkers of liver function. Serum lipid levels were also measured as they may help to monitor the progress of toxic liver damage. A reduction in serum cholinesterase was associated with decreased levels of all clinical chemistry parameters studied except HDL-cholesterol. Conversely, a decreased erythrocyte cholinesterase (indicating long-term pesticide exposure) was associated with increased levels of aspartate aminotransferase and alkaline phosphatase and increased levels of triglycerides, total cholesterol and LDL-cholesterol, but reduced levels of HDL-cholesterol. Changes in liver biomarkers were particularly associated with the PON155M/192R haplotype. The obtained results therefore support the hypothesis that pesticide exposure results in subtle biochemical liver toxicity and highlight the role of genetic polymorphisms in pesticide-metabolizing enzymes as biomarkers of susceptibility for developing adverse health effects.

Effect of pesticide exposure on platelet indices in farm workers

We aimed to assess the effect of exposure to pesticide on platelet indices including mean platelet volume (MPV) and platelet distribution width (PDW) in farm workers. The study group consisted of 40 farm workers (4 females, 36 males; mean age 42.6 ± 9.8 years). An age-, gender- and body mass index-matched control group was composed of 38 healthy volunteers (8 females, 30 males; mean age 46.1±8.9 years). Platelet indices were assessed in farm workers exposed to pesticides. MPV values were significantly lower in farm workers than in those of controls (6.3 ± 1.1 vs. 7.6 ± 0.7 fL, respectively; p < 0.001). Platelet count was significantly lower in farm workers than those of controls (155.7 ± 35.7 vs. 271.3 ± 96.2 × 10(9)/L, respectively; p < 0.001). PDW was significantly lower in farm workers than in those of controls (8.9% ± 2.0% vs. 15.8% ± 0.8%, respectively; p < 0.001). We have found that MPV and other platelet indices were significantly lower in farm workers exposed to pesticides than those of controls. Our findings suggest that MPV may be a sensitive indicator of a pesticide-exposure effect.

Occupational toxicology in Mexico: current status and the potential use of molecular studies to evaluate chemical exposure

Occupational toxicology is of considerable concern for several world organizations including the International Labour Organization, the World Health Organization and the International Commission for Occupational Health and, in Latin America, the Pan American Health Organization. The countries of this Region, including Mexico, own manufacturing, chemical, and petrochemical industries that employ thousands workers who are continually exposed to hazardous chemicals such as solvents, particles and exhaust fumes, many of which are very complex mixtures. Traditionally, physicians have used biochemical analyses to assess the damage caused by chronic chemical exposure. Presently, recent advances in molecular biology may offer tools to perform more thorough and precise evaluations on worker health damage, risk and current health status. In this review, we present a perspective of occupational toxicology in Mexico, as an example for Latin America and developing countries. Moreover, we summarize current reports about occupational disease associated with chemical exposure, and we present an array of molecular studies proposed for the analysis and diagnosis of workers related with industry and the relevance of including molecular biology testing to complement traditional occupational medical assays in order to improve occupational health. We conclude that developing countries, e.g., Mexico, should improve work environment standards by using new technical approaches that will result in more reliable and precise data to design better health policy strategies.