An integrated assessment of sediment remediation in a midwestern U.S. stream using sediment chemistry, water quality, bioassessment, and fish biomarkers.

A comprehensive biological, sediment, and water quality study of the lower Little Scioto River near Marion, Ohio, USA, was undertaken to evaluate the changes or improvements in biotic measurements following the removal of creosote-contaminated sediment. The study area covered 7.5 river miles (RMs), including a remediated section between RMs 6.0 and 6.8. Fish and macroinvertebrate assemblages, fish biomarkers (i.e., polycyclic aromatic hydrocarbon [PAH] metabolite levels in white sucker [Castostomus commersoni] and common carp [Cyprinus carpio] bile and DNA damage), sediment chemistry, and water quality were assessed at five locations relative to the primary source of historical PAH contamination-upstream (RM 9.2), adjacent (RM 6.5), and downstream (RMs 5.7, 4.4, and 2.7). Overall, the biomarker results were consistent with the sediment PAH results, showing a pattern of low levels of PAH bile metabolites and DNA damage at the upstream (reference or background location), as well as the remediated section, high levels at the two immediate downstream sites, and somewhat lower levels at the furthest downstream site. Results show that remediation was effective in reducing sediment contaminant concentrations and exposure of fish to PAHs and in improving fish assemblages (60% increase in index of biotic integrity scores) in remediated river sections. Additional remedial investigation and potentially further remediation is needed to improve the downstream benthic fish community, which is still heavily exposed to PAH contaminants.

Alkylphenol and alkylphenol-ethoxylates in carp, water, and sediment from the Cuyahoga River, Ohio.

The occurrence of alkylphenol and alkylphenol ethoxylates (APEs) was determined over a 74-mile length of the Cuyahoga River, Ohio. Measurable levels of both the octyl and nonyl forms of these abundantly used nonionic surfactants were observed with the nonylphenol (NP) plus nonylphenol ethoxylates (NPEs) typically accounting for greater than 90% of the total APEs in each sample. For all media (water, fish, and sediment) the total NPE (NP + NPE) concentrations were higher in the more urbanized downstream section of the river. Maximum water and fish values were observed immediately downstream (2.1 miles) from the discharge of the Akron WWTP located 35.31 miles from the river mouth and the sediment maxima occurred at the most downstream site near Cleveland. The ranges in concentration fortotal NPEs and their ethoxylate (EO) makeup were as follows: 32-920 ug/kg wet wt (NP 0 to 2 EO) for carp; 0.13-1.0 ug/L (NP 0 to 3 EO) for water; and 250-1020 ug/kg dry wt (NP 0 to 5 EO) for sediment. When the higher ethoxymers (NP 6 to 17 EO) were added to these sediment totals, the average total estimated NPE concentrations were 1.3-1.8 times higher.