The partitioning of polycyclic aromatic hydrocarbons in the Mahoning River bottom sediments /

Abstract

Polycyclic Aromatic Hydrocarbons occur naturally in the environment because of synthesis by some plants. The greatest amount of Polycyclic Aromatic Hydrocarbons (PAH) is produced by the combustion of fossil fuels. Several PAH are known carcinogens. The discharge of these substances into the aquatic environment at toxic concentration levels endangers aquatic life, wildlife, and human health. The Mahoning River in Northeast Ohio was heavily loaded with PAH during the industrial era. The intent of this study was to investigate the effect of dredging the Mahoning River, specifically the release of 16 PAH compounds from the sediment into the liquid phase. Experiments were conducted to investigate three aspects of PAH behavior: partitioning; desorption; and the solids concentration effect. Mahoning River water and sediments were analyzed using High Performance Liquid Chromatography (HPLC). The results confirmed that the river sediments are very heavily polluted with PAH. The desorption experiments involved mixing PAH-free river water with river bottom sediment at water:sediment ratios of 4:1 and 12:1. The desorption of Chrysene from the Campbell sediment was 28% in the 4:1 experiment and 59% in the 12:1 experiment. Overall, the desorption of PAH compounds ranged from 5% to 71%. Dredging of river bottom sediments would result in significant desorption of PAH into the liquid phase.