Contaminants such as polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), chlorinated pesticides, herbicides and heavy metals are hydrophobic, will adsorb onto sediments, and thus are overlooked when water chemistry analysis is performed. However, laboratory costs of sediment analyses can prohibit the number of samples that can be analyzed, limiting the ability to isolate sources. The City of Austin Watershed Protection
Department (WPD) has used enzyme linked immunosorbent assays (ELISA) as a fast, cost effective screening method to perform numerous analyses for polycyclic aromatic hydrocarbons (PAHs) in sediments. This method has been used successfully in identifying several localized sources of sediment contamination on four creeks in the Austin area. The contamination had
previously been attributed to unknown sources due to lack of spatial resolution when laboratory expenses limited sampling.
Using ELISA as a screening tool has increased WPDs ability to identify sources of pollutants and eliminated the need for costly laboratory analyses for screening. The ability to collect up to 21 samples, run the analyses and obtain results immediately has increased the cost and time efficiency of sampling. The results have subsequently been verified using standard methods of sediment analysis. Verification of the ELISA results at contract laboratories have identified other pollutants such as heavy metals and pesticides at sites that are heavily contaminated with PAHs. These sites are under consideration for remediation and construction of stormwater controls under other WPD programsWaller Creek Working Grou
