Symptom clusters in a community with chronic exposure to chemicals in two superfund sites

Sikes and French, Ltd., two National Priority List sites that are proximal to one another, are located approximately 20 mi (32 km) east of Houston, Texas. Dumping at Sikes occurred during the early 1960s and continued until 1967. Benzene, 1,2-dichloroethane, toluene, 1,1,2-trichloroethane, naphthalene, lead, fluorene, and pyrene are chemicals that pose a particular public health concern. French, Ltd., commenced operations in 1966, and dumping ceased in 1973. Chemicals of potential public health impact at the French, Ltd., site are benzene, benzo(a)anthracene, benzo(a)pyrene, copper, chrysene, chromium, dichlorodiphenyltrichloroethane, heptachlor, lead, nickel, polychlorinated biphenyls, tetrachloroethylene, trichloroethylene, and zinc. During the 1980s, both sites were placed on the National Priority List. Barrett Station is a stable black community located near the two sites. The question of whether levels of exposure to dumpsite chemicals were related to health complaints in the Barrett Station population was examined. The prevalence of 29 symptoms reported by 321 individuals who had been highly exposed was compared with symptoms reported by a group of 351 persons from the same community who had limited exposure. A meaningful difference between the two groups emerged for some of the symptoms, the most notable of which symptoms were neurologic. Almost twice as many subjects in the high-exposure group reported five or more neurologic symptoms, compared with the low-exposure group. This excess of neurological symptoms is consistent with the known toxic properties of the chemicals at the sites.