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POSSIBLE EFFECTS OF CHRONIC EXPOSURE TO ENVIRONMENTAL AIRBORNE MANGANESE ON NEUROLOGICAL FUNCTION IN CHILDREN.
Citation:
Hudnell, H. K. AND R. A. Wittberg. POSSIBLE EFFECTS OF CHRONIC EXPOSURE TO ENVIRONMENTAL AIRBORNE MANGANESE ON NEUROLOGICAL FUNCTION IN CHILDREN. Presented at International Conference on Heavy Metals in the Environment, Ann Arbor, MI, August 6-10, 2000.
Description:
Evidence suggests that the estuarine dinoflagellate, Pfiesteria piscicida, and/or morphologically related organisms (Pf-MRO) may release a toxin(s) which kills fish and adversely affects human health. The North Carolina study investigated the potential for persistent health effects in watermen occupationally exposed to Pf-MRO affected estuaries. The results indicated that visual contrast sensitivity (VCS), an indicator of visual pattern detection ability, was reduced by about 30% in the potentially exposed estuary cohort relative to an unexposed age-, gender- and education-matched cohort of offshore workers. A recent study in Maryland investigated the potential for undiagnosed cases of Possible Estuary Associated Syndrome (PEAS), as termed by the CDC, in people having residential and/or recreational exposure to Pf-MRO affected estuaries. The presence of PEAS-associated symptoms was higher, and age-adjusted VCS was significantly lower, in the estuary cohort (N=77) relative to two combined control cohorts (N=87), one without exposure to bodies of water (N=53) and one with exposure to offshore waters (N=34). In the estuary cohort, 37 individuals met the CDC symptomology criteria for PEAS diagnosis and had lower VCS than other cohort members. VCS recovered and symptomology abated after 2 weeks of treatment with cholestyramine. A double-blind, placebo controlled trial showed a similar cholestyramine effect, but no placebo effect. Cholestyramine, the original drug approved for hypercholesterolemia, has previously been reported to enhance the elimination rates of a variety of toxins, presumably by interruption of enterohepatic recirculation through toxin entrapment in its polymeric structure and an anion-exchange process. Control studies showed that repeated VCS testing alone did not improve VCS scores, and that cholestyramine treatment did not affect VCS in hypercholesterolemia patients. These results suggest that: 1) susceptible individuals may acquire PEAS through residential and/or recreational contact with Pf-MRO affected estuaries; 2) VCS is a useful indicator in PEAS diagnosis and treatment monitoring, and; 3) PEAS can be effectively treated with cholestyramine. Since the Maryland study did not use population sampling techniques, the results do not indicate PEAS prevalence. Furthermore, definitive diagnosis of PEAS and association with Pf-MRO toxin(s) must await identification of, and a blood test for, the toxin(s). This abstract does not necessarily reflect the views of the Agency.