Health impact from pesticide residues in a desert environment.

The amount and frequency of use of pesticides in vegetable farming have been shown to be high in the five farming areas in Al-Ain, UAE. The mean usage of all pesticides was high (6.81 g/m2) while the usage of organophosphorus pesticides (2.11 g/m2) was higher compared to the usage of all the other types of pesticides. A number of pesticides banned from use in the developed countries are still used in vegetable farming. The depletion of erythrocyte acetylcholinesterase (AChE) activity among farmworkers was positively correlated with the length (p<0.01), frequency(p<0.05) and the use of pesticides (p<0.0001) and inversely correlated with the use of personal protective equipment (p<0.05) and personal hygiene practice (p<0.05). The morbidity profile among farmworkers was positively correlated with the use of pesticides on the farms (p<0.0001) and the non-use of personal protection (p<0.05).
The mean concentrations of all pesticide residues (1.19±0.09 mg/kg) and the organophosphorus pesticide residues (1.23±0.22 mg/kg) in the locally grown vegetables exceeded the respective MRLs by 4 and 6 times respectively. The mean concentrations for all pesticides and for organophosphorus pesticide residues in
twelve of the thirteen vegetable commodities also exceeded the corresponding MRLs. The mean dietary intakes of all pesticide residues, as a percentage of ADI, were 14% and 17% respectively for the ethnic and farming populations, while corresponding values for organophosphorus pesticides were 37% and 45%
respectively. However, the dietary intakes of pesticide residues exceeded the ADI for mixtures for the ethnic (137%) and the farming populations (163%). A review of congenital malformations among ethnic and immigrant non-farming populations has suggested an interplay of genetic, dietary and environmental factors. Methods are proposed to reduce the environmental exposure and the dietary intake of pesticide residues and these include the establishment of a pesticide register, the training of the farmworkers in the proper use of pesticides, the use of protective measures, alternate methods of farming, the proper processing of vegetables prior to consumption and a comprehensive risk assessment of reproductive and genetic toxicity of organophosphorus pesticides.

A thesis submitted to Middlesex University in partial fulfilment of the requirements for the degree of Doctor of Philosophy.