Blood levels of metallic chemical element exposure patterns and associated factors in a population living in an Industrial District in Brazil

Abstract

Aim: to estimate the level of metallic chemical elements in the population living in the Steel company vicinity in Santa Cruz, Rio de Janeiro, Brazil; and estimate the association between exposure to the Steel company and the blood metals concentrations patterns.

Method: A cross-sectional study was carried out on 463 individuals aged 18+ years old residing 1+ years in the Steel company vicinity. Mg, Be, Co, Ba, Ni, Cd, Al, and Pb were assessed in blood by DRC-ICP-MS. Metallic chemical element concentration patterns were obtained by exploratory factor analysis in the studied population. Exposure was set as the distance (Km) from each participant's residence to the Steel company in Santa Cruz, georeferenced by GPS. The outcome was set as the positive factor loadings in the factor analysis, including Mg and Be (Factor-1), Co, Ba, and Ni (Factor-2), Cd, Al, and Pb (Factor-4). Crude and adjusted OR, and their respective 95 %CI, were estimated to explore associations between independent variables and the exposures to metallic elements positively associated with the factors using polychotomous logistic regression.

Results: A reduction of 19 % was found between each km distance from the residence and the Steel company and P₅₀ concentration of Cd, Al, and Pb (OR_P50=0.81; 95 %CI:0.67-0.97), after adjusting by age, sex, and smoking. No statistically significant associations were observed for the distance from residences and the Steel company, after adjusting for age, gender, having a domestic vegetable garden and chewing gum for Mg and Be concentrations (Factor-1) (OR_P50=0.84; 95 %CI:0.70-1.01; OR_P75=1.10; 95 %CI:0.91-1.34); nor for Co, Ba and Ni (Factor-2) blood concentrations(OR_P50=1.10; 95 %CI:0.91-1.33; OR_P75=1.03; 95 %CI:0.84-1.26), in the adjusted analysis.

Conclusions: For each Km distance from residences to the Steel company, a 19 % reduction in the risk of Cd, Al, and Pb blood concentration was observed in the population living in Santa Cruz, Rio de Janeiro, Brazil.

Keywords: Environmental exposure; Factor analysis; Human Biomonitoring; Industrial exposures; Metallic chemical elements.