Great Lakes Critical Pollutants

Introduction In 1985, the Great Lakes Water Quality Board identified persistent toxic pollutants as the principal issue confronting the Great Lakes, and developed a list of eleven “Critical Pollutants” deserving an early focus by remedial action programs. This newsletter continues the examination of recent medical literature on selected persistent organic pollutants from this list, including DDT, dieldrin, and hexachlorobenzene. Recent literature includes mortality studies for organochlorine manufacturing workers, reports of organochlorine residues in tissues of diseased and healthy persons, and morbidity studies among termiticide-exposed populations. The literature was identified by searching computerized data bases (NIOSHTIC, National Library of Medicine) and is not limited to Great Lakes populations. Literature specifically related to breast cancer and the estrogenic effects of xenobiotics as well as additional literature on mirex and hexachlorobenzene, will be reviewed in a subsequent issue. Organochlorine Residues in Normal and Diseased States Investigators in Germany have carried out a series of studies to measure the levels of organochlorine pesticides (termed chlorinated hydrocarbons by these authors) in normal and diseased bone marrow, and in other tissues in normal and diseased states. All studies were conducted in Germany. In the first, the authors attempt to address the question whether these agents, many of which have mutagenic, carcinogenic or teratogenic effects in animals, contribute to pediatric tumors and malformations. They analyzed fat samples taken from 262 children and adolescents aged zero to 18 years. The samples were collected during operations required for other reasons. The children were divided into three groups: Group A, 183 healthy children (babies and children operated on primarily for inguinal hernia or inguinal testis), including 12 neonates sampled before the first meal; Group B, 46 patients with malignant tumors (neuroblastoma, Wilm’s tumor, soft tissue sarcoma, and others); and Group C, 33 babies and children with congenital malformations or benign tumors (renal and urethral malformation, lipoma, lymphangioma and others). The specimens were analyzed for PCB’s, DDT and metabolites, HCH isomers and cyclodienes. The results showed that alpha-, beta-, and gamma-HCH, dieldrin, p,p’-DDE, total PCB and certain PCB isomers various were detected in either all or most samples. Heptachlor was detected in approximately half of samples. The highest levels were found for total PCB, DDT, HCB and HCH isomers. Of the cyclodienes, only dieldrin was detected at significant levels. The concentrations of PCB, DDT, and HCB were highest in neonates who not yet been fed, were significantly lower in infants six months old, and rose again to neonatal levels at the end of the first year of life. The concentrations changed little in the older childhood age groups. There were no significant differences in CHC concentrations between normal children and either babies with malignant tumors or babies with congenital malformations or benign tumors. The authors interpret the drop in concentrations between birth and six months to CHC distribution in the disproportionately increased body fat relative to nonfat tissue, and the apparent rise in the second half of the first year to the decrease in relative fat mass. The steady concentrations during the rest of childhood are interpreted as intake of CHC’s which corresponds to the increase in fat occurring with age. Noting the small sample size, the authors warn against using these negative results to conclude that there is no association between CHC levels and tumor or malformation in children.