| Abstract|| |
Background: There are few epidemiological studies regarding the effects of pesticides on enzymes related to liver function or on the hematological and biochemical parameters in occupationally exposed individuals. Aims: The aim was to evaluate biochemical and hematological parameters in pesticide sprayers. Materials and Methods: Medical history, characteristics of pesticide use, and related symptoms were recorded, and blood samples were collected from farmers at Samut Songkhram, Thailand during the period November-December 2014. Samples were divided into the pesticide sprayer group (N = 30) and the organic farmer group (N = 41). The collected blood samples were prepared for the following purposes: 1) to determine cholinesterase (ChE) activity, blood glucose, liver function test, kidney function test, and lipid profiles, which were analyzed by the automatic analyzer cobas C501 (Roche Diagnostics, Switzerland) and 2) to evaluate hematological status using complete blood count (CBC), which was analyzed by Celltac E MEK-7222 (Nihon Kohden, Japan). Results and Discussion: The levels of ChE, blood glucose, aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), bilirubin, total protein, albumin, blood urea nitrogen (BUN), and creatinine between the two groups were also not statistically different and were almost within the reference range. Lipid profiles, including levels of cholesterol, triglyceride, high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C), were significantly different between the two groups at P = 0.035, P = 0.049, P = 0.032, and P = 0.043, respectively. Mean corpuscular hemoglobin concentration (MCHC) values of pesticide sprayers and organic farmers were lower than the reference range (30.6 ± 1.9 g/dL and 29.9 ± 1.7 g/dL) and were interpreted as anemia. Conclusions: Subchronic exposure to pesticides may alter the metabolism, which can cause hyperlipidemia and also anemia, as observed in this study.
Keywords: Biochemical test, cholinesterase (ChE), complete blood count (CBC), pesticide exposure
|How to cite this article:|
Sudjaroen Y. Biochemical and hematological status of pesticide sprayers in Samut Songkhram, Thailand. Ann Trop Med Public Health 2015;8:186-90
|How to cite this URL:|
Sudjaroen Y. Biochemical and hematological status of pesticide sprayers in Samut Songkhram, Thailand. Ann Trop Med Public Health [serial online] 2015 [cited 2021 Apr 14];8:186-90. Available from: https://www.atmph.org/text.asp?2015/8/5/186/159843
| Introduction|| |
Pesticides are widely used in developing countries, their usage in developing countries being about 20% of world pesticide use, and the annual pesticide consumption in Thailand is ranked third among the Asian countries. , The agriculture system in Thailand has shifted from labor- to machine-intensive agricultural practices over the past decades, leading to intensive use of pesticides. The most of imported pesticide was herbicides, followed by insecticides and then fungicides.  The heavy use caused high levels of pesticide residues in the ecosystem (including soil, sediment, water, aquatic life, and agricultural products). Humans occupy the top of the food chain; therefore, pesticides are also in the human body and consequently cause adverse health effects. Acute and chronic health effects have been attributed to exposure to pesticides through drinking water and food. ,, The widespread use of pesticides in public health and agricultural programs has caused severe environmental pollution and potential health hazards. The World Health Organization (WHO) has classified pesticides according to their potential health risks. 
The main groups of compounds associated with pesticide poisoning are pyrethroids, organophosphates (OPs), carbamates (CB), and organochlorines.  OPs and CB insecticides inhibit the activity of the enzyme cholinesterase (ChE), including both serum ChE [butyrylcholinesterase (BuChE), also known as pseudocholinesterase] and erythrocyte ChE (acetylcholinesterase, or true cholinesterase).  Although BuChE inhibition is not directly related with the acute toxicity of OPs and CB, it is widely used as a biomarker of acute or chronic exposure to these pesticides. In addition, it has been reported that serum BuChE activity is a slightly more sensitive indicator of mixed pesticide exposure than red blood cell ChE activity.  Most studies in the literature regarding the chronic effects of pesticides have mainly focused on the development of cancer in workers exposed to pesticides. ,, However, there are other health outcomes related to pesticide exposure, including effects in different systems such as the immune, nervous, endocrine, and reproductive systems. ,,,, There are few epidemiological studies regarding the effects of pesticides on enzymes related to liver function or on hematological and biochemical parameters in individuals occupationally exposed to these compounds. ,,
Samut Songkhram is located 72 km from Bangkok, occupies an area of 416 square km, and is administratively divided into three districts: Muang, Amphawa, and Bang Khonthi. Samut Songkhram is a province of fertile land, with many plants and food grains; it is a production source of vegetables and fruits, as well as a vast variety of seafood products. Farmers traditionally cultivated tropical fruits, such as pomelo, lychee, and coconuts.  Pesticide use were trend to reduce by organic agriculture; however, some farmers still sprayed pesticides for many reasons, insect protection, increased the yield of good product, and protect crop before planting. OPs and CB were the most favored pesticide types and were frequently applied on this area. From this standpoint, the researcher was interested in evaluating biochemical and hematological parameters in pesticide sprayers located in Amphawa district, which is the most-planted area of Samut Songkhram. The results of this study, such as the biochemical and hematological status of pesticide sprayers, may be used as a guideline to increase awareness of the practices that prevent the harmful effects resulting from pesticide exposure, especially the subchronic effects.
| Materials and Methods|| |
Anthropometric data, pesticide use characteristics data, and related pesticide exposure symptoms were recorded, and blood samples were collected from farmers who visited Suan Sunandha Rajabhat University, Amphawa district, Samut Songkhram province for academic health service in the period November-December 2014. Samples were divided into the pesticide sprayer group (N = 30) and the organic farmer group (N = 41), which was the control group, reporting no past history of pesticide exposure. Information gathered from the pesticide sprayer group included anthropometrical characteristics, adverse health symptoms, personal protective equipment used, and exposure to pesticides. The symptom of pesticide sprayers were also interviewed in case of recent occurrence.
Specimen preparation and laboratory assay
Each collected blood sample was prepared for the following:
- Serum to determine ChE activity, liver function test [total protein, albumin, aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), total bilirubin, and direct bilirubin], kidney function test [creatinine and blood urea nitrogen (BUN)], and lipid profile [triglyceride, cholesterol, high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C)];
- Ethylenediaminetetraacetic acid (EDTA)-whole blood to evaluate hematological status by complete blood count (CBC), including red blood cell indices, white blood cell count and differential of white blood cells, and platelet count;
- NaF plasma to determine fasting blood glucose. All biochemical parameters were analyzed by the automatic analyzer cobas c501 (Roche-diagnostics, Rotkreuz, Switzerland), and all hematologic parameters of CBC were analyzed by Celltac E MEK-7222 (Nihon Kohden, Tomioka, Japan).
The repeatability of the analysis was assessed on the basis of triplicate analysis of three blood samples. In each case, the coefficient of variation calculated was 10% or less. All analyses were performed in certified clinical laboratories. The research program had to pass the approval of the hospital directors and the Board of Human Research Ethics Committees, and all subjects gave their written consent. Biochemical and hematological parameters were interpreted against reference values according to the Clinical and Laboratory Standards Institute (CLSI).
The age, body mass index (BMI), and the biochemical and hematological parameters were presented in mean ± standard deviation (SD). Statistical analysis was performed using the SPSS program version 11.0 (SPSS, Chicago, IL, USA). The Kolmogorov-Smirnov test of normal distribution was used and the unpaired t-test tested for differences in the biochemical and hematological parameters between pesticide sprayers and organic farmers. The analysis of differences was judged by using P < 0.05 (two-tailed) as the level of statistical significance.
| Results|| |
The individuals participating in this study were 30 pesticide sprayers and 41 organic farmers (control group). The anthropometric characteristics and working conditions of the participants are shown in [Table 1]. The mean BMIs for both the pesticide sprayer group and control trended toward overweight (BMI = 23-24.9). The age ranges and BMIs of both groups were not statistically significant (P > 0.05). More than 50% of pesticide sprayers had >10 years experience in that area. More than 70% of the sprayers reported that they often used protective equipments. No significant symptoms of pesticide exposure, such as burning sensation in eyes and/or skin, chest lightness, dizziness, headache, and weakness (data not shown), were evident. Both the pesticide sprayer and the control groups showed BuChE activities within the normal range (4.65-10.44 U/mL) with no statistically significant difference from the control group [Table 2]. The other biochemical parameters were evaluated in pesticide sprayers and in the control group and they are shown in [Table 2]. The mean of each parameter, including blood glucose, AST, ALT, ALP, billirubin, total protein, albumin, BUN, and creatinine, between the two groups was also not statistically significantly different and was almost within the reference range (except AST and ALT in organic farmers). Lipid profiles, including levels of cholesterol, triglyceride, HDL-C and LDL-C between the two groups showed statistically significant differences at P = 0.035, P = 0.049, P = 0.032, and P = 0.043, respectively. The mean of lipid profiles in the pesticide sprayer group showed a trend toward higher risk of cardiovascular diseases than the control group, being higher in triglyceride, cholesterol, LDL-C levels and lower in HDL-C levels [Table 3]. Hematological parameters were evaluated in pesticide sprayers and in the control group and they are shown in [Table 4]. Almost all parameters of the CBC in both the pesticide sprayers and the control group were in the reference range except that the mean corpuscular hemoglobin concentration (MCHC) values for pesticide sprayers and controls were lower (30.6 ± 1.9 g/dL and 29.9 ± 1.7 g/dL, respectively) than normal (31-37 g dL). All hematological parameters between both groups were not statistical different at P < 0.05.
|Table 1: Anthropometric characteristics, working conditions, and protective equipment used, for pesticide sprayers|
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|Table 2: BuChE activity in liver and kidney function tests on pesticide sprayers|
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| Discussion|| |
BuChE activity is a reliable and widely used biomarker of exposure to pesticides in occupational and clinical toxicology,  but this enzyme does involve a wide range of inter- and intra-individual variation. , Some studies have found an association between exposure to pesticides and decreased BuChE activity in farm workers. , Experts have recommended the removal of an individual from the workplace when the serum ChE activity falls below 60% of the reference value.  The inhibition of BuChE is related to the type of pesticide exposure; patients with mild-to-moderate poisoning by the OP chlorpyrifos have shown severely inhibited BuChE, while, in contrast, BuChE was not severely inhibited in patients who died of dimethoate (an OP) poisoning.  In this study, mean BuChE activities of both groups were within the normal range and did not exhibit any statistically significant difference. The normal BuChE levels in pesticide sprayers were corresponded to good practice of sprayers by often used protective equipments. The liver function test in pesticide sprayers and controls were not statistically significantly different and were almost within the reference range (except AST and ALT in organic farmers). Our results are in accordance with a study where no significant changes in liver enzymes were observed in subjects exposed to pesticides. , However, the control groups showed increased AST and ALT, which might have been caused by some medication for chronic diseases in the more elderly control farmers, and this was the limitation of our study. The lack of comparability between pesticide sprayers and control subjects in terms of characteristics other than age and BMI may also constitute a limitation of this study. Lipid profiles between the two groups were significantly different, and the mean of lipid profiles in the pesticide sprayer group showed a trend toward higher risk of cardiovascular diseases than those in the control group. Previous studies had reported the relationship between OP exposure and the alteration of biochemical metabolism in animal model and epidemiological studies. Subchronic exposure to chlorphyrifos, an OP used by farmers, caused hyperlipedemia, reduced glycogen storage in the liver, and increased oxidative stress, which is associated with the risk for many chronic diseases, such as cardiovascular diseases, hypertension, and diabetes mellitus. , The effects of subchronic pesticide exposure on hematological parameters have received little attention. In this study, the mean of MCHC was lower in pesticide sprayers than in controls; however, both groups showed low levels of MCHC when interpreted by the reference range. The low MCHC and mild anemia may have been caused by 1) anemia in some elderly farmers arising from a condition such as chronic blood loss and/or malnutrition and 2) the sub-chronic pesticide exposure especially OPs may induced anemia in animal models. ,, In addition, Patil et al. reported 60 pesticide sprayers from grape gardens in India, who had statistically significantly lower levels of hemoglobin (Hb), hematocrit (Hct), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), and MCHC than did controls, and the impairment of liver and kidney functions were still apparent. 
| Conclusion|| |
The anthropometric data of the pesticide sprayers and controls studied in Samut Songkhram, Thailand were similar, including age and BMI. No significant symptoms from pesticide exposure which corresponded to normal levels of cholinesterase. Blood glucose, AST, ALT, ALP, billirubin, total protein, albumin, BUN, and creatinine between pesticide sprayers and controls were not statistically significantly different and were almost within the reference range (except AST and ALT in controls). Lipid profiles between the two groups were statistically significantly different, and the means of lipid profiles in the pesticide sprayer group showed a trend toward higher risk of cardiovascular diseases than the control group. The MCHC values of the pesticide sprayers and the controls were lower than the reference range. In conclusion, even with subchronic pesticide exposure and normal BuChE activity with no related symptom, lipid profiles and MCHC were still affected.
| Acknowledgment|| |
I am grateful to the municipal district of Suan Luang, Amphawa district, for publicizing the study to local farmer groups and supporting meeting place for interviewing and collecting samples. I would also like to thank the Research and Development Institute, Suan Sunandha Rajabhat University for funding support and the Faculty of Science and Technology, Suan Sunandha Rajabhat University for supporting me with some instruments.
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Faculty of Science and Technology, Suan Sunandha Rajabhat University, 1 U-Thong-Nok Rd., Dusit - 10300, Bangkok
Source of Support: None, Conflict of Interest: None
[Table 1], [Table 2], [Table 3], [Table 4]