Elsevier

NeuroToxicology

Volume 29, Issue 5, September 2008, Pages 833-838
NeuroToxicology

Effects of occupational pesticide exposure on children applying pesticides

https://doi.org/10.1016/j.neuro.2008.06.009Get rights and content

Abstract

Nearly 40% of the Egyptian workforce is employed in agriculture. The cotton industry relies on children and adolescents, who work seasonally, to apply pesticides to the cotton crops. Although previous research has examined adult pesticide exposures in this workforce in Egypt, no research has examined the health effects in adolescents. This study attempts to systematically replicate findings examining the impact of organophosphate pesticide (OP) exposure in adults on Arabic speaking children working as applicators. The aim of this study was to examine the impact of pesticide exposure on children and adolescents spraying cotton fields. Male children currently applying pesticides between the ages of 9 and 15 (Younger, n = 30) and 16 and 19 (Older, n = 20) were recruited for the study. They completed a neurobehavioral test battery; personality inventory; work, health, and exposure questionnaires; and medical and neurological screening exams. Blood samples were collected to measure acetylcholinesterase. Children not working in agriculture, matched on age and education, served as controls. Both Younger and Older applicator groups, performed significantly worse than the controls on the majority of neurobehavioral tests controlling for age and years of education. The applicators reported significantly more neurological symptoms than the controls and had lower acetylcholinesterase activity. A dose–effect relationship demonstrated that increased years of exposure to organophosphate pesticides is associated with cognitive deficits. This is one of the several studies demonstrating that functional cognitive effects are positively correlated with increased years of exposure to OP pesticides, though primarily in adult populations, building confidence in the association. Since children around the world are exposed to OP pesticides, these studies suggest that the need to evaluate this potential problem is urgent.

Introduction

Agriculture is the largest employer in Egypt, employing nearly 40% of the Egyptian workforce (Andersen, 2003). The cotton crop is the primary agricultural product and is highly regulated by the Egyptian Ministry of Agriculture (Rizk, 1999). Pesticides, including organophosphorus pesticides (OPs), are used in Egypt on the cotton crop with large quantities being applied relative to other crops (Mansour, 2004). Children and adolescents work seasonally in the cotton fields applying pesticides.

Adult pesticide applicators and workers who were poisoned by or had high exposures to OP pesticides have reported a broad range of non-specific and neurological symptoms, demonstrated neuropsychological deficits and personality changes, and had acetylcholinesterase (AChE) inhibition associated with exposure to those pesticides. Non-specific symptoms following high exposures have included headache, dizziness, fatigue, weakness, nausea, chest tightness, and difficulty in breathing (Kamel and Hoppin, 2004).

Workers exposed to OP pesticides also demonstrate neurobehavioral deficits on response speed and coordination, sustained attention, visual perception and memory, and complex functioning (Kamel et al., 2003). These studies found that an increasing degree of neurobehavioral deficits were associated with more years working in agriculture and handling pesticides (Rohlman et al., 2007, Roldan-Tapia et al., 2005). An increase in neurological symptoms and neurobehavioral deficits in verbal abstraction, visuomotor speed, problem solving, attention, and memory was shown in adult pesticide workers in Egypt compared to controls (Farahat et al., 2003).

There has been concern about the impact of pesticides on children and adolescents. Children are considered to be more vulnerable due to the significant anatomical and maturational changes occurring in the brain during developmental periods including adolescence (Andersen, 2003), and also the increasing findings of animal studies indicating neurodevelopment effects of pesticides (Johnson et al., 1998, Moser and Padilla, 1998). Although several studies have examined children who live in agricultural communities or whose parents work in agriculture (Handal et al., 2007, Rohlman et al., 2005), only a few studies have examined adolescents who are currently working in agriculture. Adolescent farm workers in Brazil had motor and attention deficits associated with an exposure index derived by interview (Eckerman et al., 2007). US adolescents working in agriculture had significantly worse performance than adolescents not working in agriculture in attention, memory and visuomotor domains (Rohlman et al., 2001) and increased years working in agriculture and applying pesticides was also associated with neurobehavioral performance deficits in adolescent workers (Rohlman et al., 2007).

This study examined neurobehavioral performance in children seasonally exposed to OP pesticides to test the hypothesis (suggested by Kamel et al., 2003, Rohlman et al., 2007, Roldan-Tapia et al., 2005) that increasing exposure to OP pesticides is associated with progressively larger neurobehavioral deficits, in a population likely to have higher exposure than those previously studied.

Section snippets

Participants

This study was conducted from June to August 2005, during the pesticide application period to the cotton crop. It was carried out at Shebin Elkom District, Menoufia governorate, Egypt. During this time, the local agricultural office hired approximately 10 children from each village to apply pesticides to the cotton crop under the supervision of adult engineers and agricultural employees. Five villages out of 50 from the Shebin Elkom District were randomly chosen to recruit children working as

Demographic characteristics

There were no significant differences on age, years of education or smoking between the applicator and control groups in both the Younger and Older children. However, for the Older children the body mass index of the control children (x¯=26.9; S.D. = 4.1) was significantly higher than that of the applicator children (x¯=23.2±0.6) (t = 3.6; p < 0.05).

Duration of work and AChE

The applicator children reported working as pesticide applicators an average of 5 years (range of 1–9 years). During the current application season they

Discussion

This study reveals significant health effects in children who work as pesticide applicators compared to control children. Children who apply pesticides show impaired neurobehavioral performance, report more symptoms, and have lower AChE activity levels than children from the same communities that do not apply pesticides. This study also shows a correlation between days worked during the current season and total years worked as an applicator and the reporting of symptoms and neurobehavioral

Conclusion

This study showed that children and adolescents who apply pesticides in the cotton fields have significantly lower neurobehavioral performance, report more symptoms and have lower activity levels of serum AChE compared to a control group. The neurobehavioral deficits demonstrated a dose–response relationship between days and years of exposure and NB performance and symptom reporting. Since children around the world are exposed to OP pesticides, these studies suggest the need to evaluate this

Acknowledgments

The study was performed in the Public Health and Community Medicine Department, Faculty of Medicine, Menoufia University, Shebin Elkom, Egypt. We thank the children, adolescents and their parents for their participation in the study. We thank also Dr. Khaled Zyada, the Psychology lecturer, Faculty of Arts, Menoufia University, Egypt, for his help in the selection and administration of the appropriate neurobehavioral tests. We thank also Michael Lasarev, for his help in the statistical analysis.

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