A case-control study of persons with elevated blood levels of dieldrin.

Twenty-seven pesticide workers with elevated blood levels of dieldrin (greater than or equal to 15 ppb) were involved in a case-control study which included history and physical examination, comprehensive neurological evaluation, laboratory tests, and psychological and psychomotor testing. No clinically important differences were found on history, physical, specialized neurological tests, or laboratory examination. The exposed group showed a statistically significant difference in five out of 58 psychological (P) and psychomotor (PM) tests--at least three would be expected by chance (p less than or equal to .05). In only one of these tests was there any significant correlation with dieldrin levels. Even though the exposed group had worse scores than the control group in 47 of 58 P--PM tests, such scores were, with a few exceptions, in the normal range of values. Elevated blood levels of dieldrin encountered in this study do not appear to have any chronic deleterious effects on health, as measured by conventional medical work-up and extensive central nervous system testing.