Intrauterine growth retardation in Iowa communities with herbicide-contaminated drinking water supplies.

In a statewide survey of 856 Iowa municipal drinking water supplies in 1986-1987 the Rathbun rural water system was found to contain elevated levels of triazine herbicides. Rates of low birth weight, prematurity, and intrauterine growth retardation (IUGR) in live singleton births during the period 1984-1990 by women living in 13 communities served by the Rathbun water system were compared to other communities of similar size in the same Iowa counties. The Rathbun communities had a greater risk of IUGR than southern Iowa communities with other surface sources of drinking water (relative risk = 1.8; 95% CI = 1.3, 2.7). Multiple linear regression analyses revealed that levels of the herbicides atrazine, metolachlor, and cyanzinc were each significant predictors of community IUGR rates in southern Iowa after controlling for several potentially confounding factors including maternal smoking and socioeconomic variables. The association with IUGR was strongest for atrazine, but all three herbicides were intercorrelated and the independent contributions of each to IUGR risk could not be determined. We conclude that communities in southern Iowa with drinking water supplies contaminated with herbicides have elevated rates of IUGR compared to neighboring communities with different water supplies. Because of the limitations of the ecologic design of this study, including aggregate rather than individual measures of exposure and limited ability to control for confounding factors related to source of drinking water and risk of IUGR, a strong causal relationship between any specific water contaminant and risk of IUGR cannot yet be inferred. The association between the water supplied to the Rathbun communities and the increased risk of IUGR should be considered a preliminary finding that needs to be verified by more detailed epidemiologic studies.

Elevated environmental lead levels in a day care setting.

OBJECTIVE: To determine the risk of lead poisoning among children enrolled in day care centers with elevated environmental lead burdens. DESIGN: Survey. SETTING: Six day care centers on properties owned by a major state-supported university. PATIENTS AND OTHER PARTICIPANTS: One hundred fifty-five of 234 eligible children (mean age, 4.8 years) enrolled in these centers were screened by questionnaire for risk factors of lead exposures. Blood samples for lead levels were also obtained. Observations of day care activities relative to lead exposure risks were recorded. Analyses of lead levels in paint, dust, and/or soil samples at the six centers were obtained. MAIN OUTCOME MEASURES: Prevalence of elevated blood lead levels and associated behavioral risk factors for lead exposure in children attending day care centers. RESULTS: Elevated levels of lead in paint (2.4% to 40% lead) were present in all day care facilities. Three day care centers had elevated lead levels in windowsill dust (62,000 to 180,000 micrograms [corrected] of lead per square meter) or soil (530 to 1100 mg of lead per kilogram): Questionnaires documented low risk for lead exposure to children in the home environments. Direct observations in the day care setting revealed optimal supervision and hygiene of the children. Blood lead levels were less than 0.5 mumol/L (10 micrograms/dL) in all but one of the 155 children screened. CONCLUSIONS: Children attending day care centers with high environmental lead burdens need further documentation of blood lead levels, at-risk behaviors, and lead exposure risks in the home environments as an adjunct to the instigation of lead abatement procedures at the day care centers.

The nitrate contamination of private well water in Iowa.

The State-Wide Rural Well-Water Survey was conducted between April 1988 and June 1989. About 18% of Iowa's private, rural drinking-water wells contain nitrate above the recommended health advisory level (levels of NO3-N greater than 10 mg/L); 37% of the wells have levels greater than 3 mg/L, typically considered indicative of anthropogenic pollution. Thirty-five percent of wells less than 15 m deep exceed the health advisory level, and the mean concentration of nitrate-nitrogen for these wells exceeds 10 mg/L. Depth of well is the best predictor of well-water contamination. Individually, NO3-N levels of more than 10 mg/L occurred alone in about 4% of the private wells statewide; pesticides were present alone in about 5%. Total coliform positives occurred alone at 27% of the sites. In a cumulative sense, these three contaminants were detected in nearly 55% of rural private water supplies.