Evaluation of mercury exposure in populations living near the industrial Augusta Bay. Valutazione dell'esposizione al mercurio nelle popolazioni residenti in prossimità dell'area industriale della Rada di Augusta

OBJECTIVES: to assess and quantify the human exposure to mercury (Hg) and to explore the key factors that influence the distribution and extent of the contamination in individuals living in the proximity of the Augusta Bay (Sicily Region, Southern Italy), a high-risk area because of the effect of the uncontrolled sewages of Hg from one on the largest European chlor-alkali plants. DESIGN: a human biomonitoring study was performed in a group of individuals living in the municipalities of Augusta, Priolo, and Melilli (Eastern Sicily, Southern Italy). Each participant filled a detailed questionnaire, so information about personal details, lifestyle, and diet was collected. The levels of Hg in the blood and hair samples, used as tracer of methylmercury exposure, were linked to the frequency of local fish consumption. The urinary Hg content was used to explore potential exposure to atmospheric inorganic Hg. Multiple regression analysis was performed to investigate the factors affecting the human exposure to Hg. A toxicokinetic approach was applied to calculate the provisional tolerable weekly intake (PTWI) and to predict the expected Hg concentration in the blood of individuals with exclusive local fish-based diet. SETTING AND PARTICIPANTS: 224 individuals from Augusta, Melilli, and Priolo municipalities. RESULTS: excesses of Hg were measured in the blood and hair of the considered sample. The highest levels were measured in Augusta, where also the consumption of local fish is high. The calculated PTWI exceeded, in most cases, the international recommendations, particularly in residents in Augusta. CONCLUSIONS: the levels of Hg in the blood and hair samples derive, in all likelihood, from the consumption of local fish. Compared to Augusta subjects, those from Priolo and Melilli suffer from a more limited effect. The exposure to inorganic mercury can be considered negligible.