METAL POLLUTION AND HEALTH RISKS IN SOILS AND RIVER WATER OF SOUTHERN LOUISIANA

Soils and the Mississippi river waters between Baton Rouge and New Orleans area are prone to chemical contamination. Polluted soils and river water are important risk factors for human health and aquatic life. This study aims to map the distribution of toxic elements in soil and water samples from Baton Rouge to New Orleans area and conduct health risk assessment to their exposure. Concentrations of Pb, As, Cd, and U were measured in 16 river water and 182 soil samples using Inductively Coupled Plasma Mass Spectroscopy (ICP-MS). Water samples showed mean concentrations (μg/L) of 0.01±0.005, 2.07±0.23, 0.03±0.02 and 1.2±0.2 for Pb, As, Cd, and U respectively. These mean concentrations do not exceed the WHO permissible limits in drinking water and the U.S. EPA safety standards for aquatic life. Soil samples showed mean concentrations (mg/kg) of 71±130, 6.4±6.7, 0.69±1.9 and 2.1±5.5 for similar elements, respectively. About 16% of the soils exceeded the EPA definition of hazardous waste level of 100mg/kg for Pb while only 3% exceeded the Louisiana Department of Environmental Quality (LDEQ) soil cleaning level and the U.S EPA Regional Screening Level (RSL) of 400mg/kg Pb in residential areas. Arsenic concentrations in all soil samples exceeded 0.39mg/kg; the EPA health-based soil screening level for residential areas and about 8% of the soils exceeded the LDEQ of 12mg/kg. While toxic metals are low in the Mississippi river waters, soils between Baton Rouge and New Orleans could be a significant source of Pb and As to the local populations. Health risk calculations showed possible carcinogenic risks in children due to As exposure via ingestion. This study contributes to the ongoing pollution assessment studies in soils and waters of Louisiana aimed at improving the quality of local environmental resources and forms a basis for establishing necessary primary interventions.