Assessment of urinary metals following exposure to a large vegetative fire, New Mexico, 2000.

INTRODUCTION: In May 2000, a vegetative fire burned 47,000 acres in northern New Mexico, including 7500 acres of land administered by the Los Alamos National Laboratory. We evaluated potential human exposures from the fire. METHODS: We surveyed two populations (firefighters and the general population) in four cities for urine heavy metal concentrations. Reference concentrations were based on the Third National Health and Nutrition Examination Survey (NHANES III). Multivariate linear regression assessed the association of urinary metal concentrations with smoke exposure. We also performed isotopic analysis of uranium and cesium on a subset of specimens. RESULTS: A total of 92 firefighters and 135 nonfirefighters participated. In both populations, urinary nickel, cesium, chromium, and uranium concentrations were greater than expected compared with NHANES III reference values. No values required immediate medical follow-up. Regression analysis demonstrated that for National Guard members, arsenic and cadmium levels were significantly related to smoke exposure, and for firefighters, cesium and arsenic levels were significantly related to exposure; however, only for cesium in National Guard members was this association in the positive direction. Isotopic analysis demonstrated that the cesium and uranium were naturally occurring. CONCLUSIONS: Some people had spot urine metal concentrations above nationally derived reference values, and values for some metals were associated with smoke exposure. These associations had little public health or clinical importance. Studies of exposures resulting from vegetative fires are difficult, and careful consideration should be given to the technical and communication processes at the outset of a fire exposure investigation. Recommendations for future investigations include testing as soon as possible during or after a fire, and early clinical consultation with a medical toxicologist.

Use of isotope ratios to identify sources contributing to pediatric lead poisoning in Peru.

In 1998, a school-based blood lead level (BLL) survey of 2,510 children, conducted in Lima and Callao, Peru, revealed elevated BLLs in children from 2 Callao schools (mean BLL = 25.6 microg/dl; n = 314) and in children from Callao overall (mean BLL = 15.2 microg/dl; n = 898), compared with children from Lima (mean BLL = 7.1 microg/dl; n = 1,612). Public health officials at Peru's Direccion General de Salud Ambiental (DIGESA) hypothesized that a possible source of the elevated pediatric BLLs observed in Callao was a large depository near the port where mineral concentrates are stored prior to shipment. The U.S. Centers for Disease Control and Prevention worked with DIGESA to identify source(s) that contributed to the pediatric lead poisonings by comparing isotopic profiles of lead in blood, mineral, gasoline, and air filter samples. The lead isotope ratio (IR) observed in mineral samples from the depository in Callao differed from those in gasoline samples from Lima and Callao. The blood lead IRs of children living near the depository were similar to the IRs of the mineral samples and different from the IRs of the gasoline samples, suggesting that lead from the depository-and not gasoline-was the primary source of lead in these children. Lead IR analysis of regional air filter samples supported these findings.