Pesticide residues in occupationally exposed individuals
Comparisons of serum pesticide residues in the exposed and control groups showed that greenhouse workers had multiple pesticides residues above the NOAEL values. Most of the greenhouse workers had OP residues consisting of diazinon, dichlorvos and chlorpyrifos residues above the NOAEL (Table 2). The frequency and quantity of detected pesticide residues in this study might be related to poor work place conditions. It was observed that all individuals did not use personal protection equipment (PPE) regularly. The use of PPE during pesticide application has not yet been generally accepted in developing countries. The lack of safety plans has also been reported in countries such as the United Arab Emirates (Gomes et al. 1999), Egypt (Stewart 1996), Brazil (Recena et al. 2006), and Ethiopia (Mekonnen &Agonafir 2002). In this study, finding a small number of pesticides in a control sample may be due to food chain exposure. Tariq et al. (2007) (Tariq et al. 2007) collected unique statistics on various pesticide-polluted foodstuffs, such as fruits, veggies and fish, collected over past 20 years, from various parts of Pakistan. These authors additionally determined variations in the data reported, relying on the different climatic prerequisites of the country, depending on the varieties and sorts of fruits and vegetables. After a range of preliminary research by means of Masud and Farhat (1985)(Masud &Farhat 1985), Cheema and Shah (1987) (Cheema 1987) and Masud and Hassan (1995) (Masud 1995), concentrations of OCs, OPs and different pesticides were very excessive.
Determination of hemotoxic effects
In the present study, significantly higher values for some hematological parameters, i.e., monocytes, lymphocytes, PLT, MPV, and PCT, along with lower granulocyte, HGB, MCH, and MCHC values, were observed in exposed workers compared to our reference group (Table 3). Our pesticide hemotoxicity findings are in line with recent reports of changes in CBC parameters linked to pesticide exposure (Fareed et al. 2013). In contrast to our study, Sudjaroen (2015) (Sudjaroen 2017) found no significant differences in hematological parameters, e.g., WBC, MCV, MCHC, RDW, HB, or RBC, between exposed workers and the control group. In a similar study by Hayat et al. (2018) (Hayat et al. 2018) , hemoglobin-HB and MCH concentrations below average values were reported in the control group, in consonance with the results of the present study. In another study by Araoud et al. (2002) (Araoud et al. 2012), lower HCT and higher MCHC values were reported in agricultural workers. The results of a metaanalysis showed that pesticide exposure was associated with hematopoietic cancers, including non-Hodgkin lymphoma (Merhi et al. 2007). In contrast, short-term exposure to pesticides has been associated with changes in hemoglobin, monocyte, and platelet levels, indicating a direct toxic impact on peripheral blood cells (Hu et al. 2015).
From regression analysis of variance ANOVA (Table 4), all hematological parameters had been considerably exclusive except RBC and MCH. WBC, HB, HCT, MCV, MCHC, PLT, MPV, and PCT were also appreciably (P < 0.05; Multivariate regression ANOVA) altered with pesticide concentrations detected in their blood. Bhalliet al. (Bhalli et al. 2006) determined that PCV and Hb concentrations were typically affected by pesticide exposure in exposed individuals, while MCH and MCHC were ineffective in the Multan-Punjab region of Pakistan. Varol et al. (Varol et al. 2014) and Edem et al. (Edem et al. 2012) confirmed a similar trend in blood parameters in response to pesticide exposure by farmers. Edem et al. (Edem et al. 2012) also stated decreased PCV of exposed individuals. Quraishi et al. (2015) (Quraishi et al. 2015) showed an increase in WBC, Hb, PCV and MCV levels of farmers exposed to pesticides compared to the control group, but the platelet count in samples exposed to pesticides decreased compared to the controls. This change may be due to exposure to several different pesticides.
Biochemical parameters
The biochemical markers tested in the two groups are presented in Table 3. As seen in Table 4, regression was significant (F calculated>F significance) for all biochemical parameters including blood glucose, AChE, TG, Total cholesterol, HDL-C, LDL-C, Phosphorus, TPSA, and CEA.
For some time, AChE plasma activity has been used as a biomarker of OP pesticide exposure and toxicity. WHO has recommended AuChE activity lower than 50% of the reference value as the critical value (WHO 1986). We observed that plasma AChE activity was considerably lower in exposed workers than in controls, suggesting the presence of residues in the body of workers exposed to OPs. Similar results were found in agricultural workers in Tunisia (Wafa et al. 2013) and tobacco farmers in Pakistan (Hodgson and Levi 1996). Aside from activity, AChE inhibition can also be used as an indicator of risk in evaluations of OP exposure. However, several studies have shown that cholinesterase inhibition alone is insufficient to explain all the toxicological effects reported after exposure to OP pesticides (Amitai et al. 1998).
Exposure to pesticides, particularly organochlorine and OP classes, has been found to increase the risk of cardiovascular disease. Evidence for this association was reported in work by (Zamzila et al. 2011) and supported by (Lasram et al. 2009), whose animal study confirmed that chronic exposure to OP pesticides can reduce paraoxonase activity. In addition, several studies in humans confirmed the association of exposure to endocrine-disrupting chemicals with diabetes, obesity, and associated metabolic disorders (Alonso-Magdalena et al. 2011). Electrolytes such as inorganic phosphorus, sodium and potassium were also affected by chronic or acute exposure to pesticides (Legler et al. 2015), although the mechanisms underlying these effects and their importance have not yet been studied. According to our literature review, only two studies have investigated electrolyte (phosphorus) changes following pesticide exposure; the results of one of these studies (Hu et al. 2015) differed from the present findings, while the results of the other study were consistent with our data.
With regard to the tumor markers TPSA and CEA, serum levels were normal in all participants except for one exposed worker whose TPSA level was above normal. Some studies have assessed prostate cancer risks in relation to years of farming, types of agriculture, and pesticide application (Fleming et al. 1999). Krstev et al. (1998) (Krstev et al. 1998) studied the correlation of the risk of prostate cancer in African Americans with years of employment in agriculture and forms of farming. African American men were found to have a higher prevalence of prostate cancer than any other racial and ethnic group in the world.
To date, several studies have used CEA and other tumor markers to evaluate the prevalence of cancer in people exposed to chemicals. For example, Pluygers and Gourdin (1978) (Pluygers et al. 1993) evaluated the cancer risk related to pesticide use, and found that CEA levels were associated with a definite increase in risk among all agricultural workers.
Our findings show that long-term exposure to pesticides results in detectable pesticide residues in serum, where their cytotoxic effects contribute to blood and biochemical changes. These results underline the importance of prevention and intervention programs in eliminating pesticide-related alterations among agricultural workers. We recommend the following interventions to improve pesticide use and safety behaviors: (1) increase the use of educational programs such as documentaries and talks as well as dissemination through radio, television, and newspapers to raise awareness about good safety behaviors and the long-term consequences of pesticide use; (2) make protective safety devices more accessible and modify them according to local needs; and (3) strengthen monitoring mechanisms to reduce the illegal import of banned pesticides.