Toxicity of water-soluble fractions derived from whole creosote and creosote-contaminated sediments

Abstract Creosote, a complex mixture of aromatic compounds (ACs), contaminates numerous sites in the USA and elsewhere. In addition to pollution of the water column directly after a creosote spill, contaminated sediments can continue to act as source of pollution for many years, because natural and anthropogenic perturbations may redissolve or resuspend sediment-associated contaminants. A 48-h static renewal assay compared survival of the bay mysid, Mysidopsis bahia, exposed to water-soluble fractions (WSFs) generated from two different sources: whole creosote and creosote-contaminated sediment. Sediment was obtained from a Super Fund site located on the Southern Branch of the Elizabeth River in Virginia, USA. Whole creosote, contaminated sediment, and WSFs derived from these source materials were characterized. Median lethal concentrations of WSFs generated from whole creosote and sediment (expressed as total identified ACs) were 180 μg/L and 700 μg/L, respectively. The creosote-derived WSF consisted of more than 70% low molecular weight nitrogen heterocyclics. These heterocyclics were below detectable limits in the sediment-generated WSF, suggesting that losses of these compounds had occurred via weathering. Nitrogen heterocyclics likely contributed to the acute toxicity of the whole creosote WSF.