Effects of topical exposure to a mixture of chlorpyrifos, cypermethrin and captan on the hematological and immunological systems in male Wistar rats

Most Thai orchid farmers heavily used pesticide mixtures, and were shown to have various hematologic/immunologic alterations. The present study investigated the effect of exposure of male Wistar rats to a mixture of three pesticides (chlorpyrifos, cypermethrin and captan) that are most often used by the farmers. Three groups of 10 rats were dermally exposed to three different doses (high, middle and low) for 28 consecutive days. The rats showed significant changes in body, liver, kidneys and adrenals weights. Significant changes were observed in various biological parameters including hematotoxicity (increased leukocyte and platelet counts, percent neutrophil, decreased RBC count, percent lymphocyte and eosinophil), hepatotoxicity (increased serum AST, decreased serum ALP, cholesterol, triglyceride, serum protein and albumin), and immunotoxicity (decrease in numbers of NK cells, decrease splenic proliferative response to LPS, and increase in serum IgG). These results confirm the potential health danger of exposure to these pesticide mixtures in orchid farmers.