Legacy and current-use toxic contaminants in Pacific sand lance (Ammodytes personatus) from Puget Sound, Washington, USA.

Forage fish are primary prey for seabirds, fish and marine mammals. Contaminant transfer and biomagnification of the toxic compounds measured in this study likely contribute to elevated levels in Puget Sound, Washington, salmon and killer whale tissues that could be sufficiently high to elicit adverse effects and hamper population recovery efforts. Polychlorinated biphenyls, polybrominated diphenyl ethers, chlorinated pesticides, polycyclic aromatic hydrocarbons, alkylphenols, and chlorinated paraffins were detected in all Pacific sand lance tissue samples generally below available health effect levels. Residual polycyclic aromatic hydrocarbon tissue concentrations near a former creosote site suggest ongoing contaminant exposure. Biomagnification calculations suggest that concentrations of polychlorinated biphenyls in some forage fish could result in predator tissue concentrations exceeding effect levels. The emerging contaminants alkylphenols and chlorinated paraffins are first reported here in Puget Sound forage fish, and their frequent detection, high production volumes and endocrine-disrupting properties highlight the need for further study.

Microbial water quality before and after the repair of a failing onsite wastewater treatment system adjacent to coastal waters.

AIMS: The objective was to assess the impacts of repairing a failing onsite wastewater treatment system (OWTS, i.e., septic system) as related to coastal microbial water quality. METHODS AND RESULTS: Wastewater, groundwater and surface water were monitored for environmental parameters, faecal indicator bacteria (total coliforms, Escherichia coli, enterococci) and the viral tracer MS2 before and after repairing a failing OWTS. MS2 results using plaque enumeration and quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) often agreed, but inhibition limited the qRT-PCR assay sensitivity. Prerepair, MS2 persisted in groundwater and was detected in the nearby creek; postrepair, it was not detected. In groundwater, total coliform concentrations were lower and E. coli was not detected, while enterococci concentrations were similar to prerepair levels. E. coli and enterococci surface water concentrations were elevated both before and after the repair. CONCLUSIONS: Repairing the failing OWTS improved groundwater microbial water quality, although persistence of bacteria in surface water suggests that the OWTS was not the singular faecal contributor to adjacent coastal waters. A suite of tracers is needed to fully assess OWTS performance in treating microbial contaminants and related impacts on receiving waters. Molecular methods like qRT-PCR have potential but require optimization. SIGNIFICANCE AND IMPACT OF STUDY: This is the first before and after study of a failing OWTS and provides guidance on selection of microbial tracers and methods.

Tracking microbial transport through four onsite wastewater treatment systems to receiving waters in eastern North Carolina.

AIMS: To examine microbial transport through properly functioning and failing onsite wastewater treatment systems (OWTS) and its implication in surrounding water quality. METHODS AND RESULTS: Water samples were collected from monitoring wells near leach lines of OWTS and nearby ditches and receiving surface waters to analyse for Escherichia coli and enterococci. Tracer studies with Rhodamine WT (RWT) and coliphage MS2 were also carried out to understand the fate and transport of contaminants through each OWTS. Escherichia coli and enterococci concentrations were higher around failing than properly functioning OWTS by as much as 85-fold. A storm event resulting in 9·5 cm of rainfall increased E. coli and enterococci concentrations by averages of 4·1 × 10³ and 7·9 × 10³ MPN per 100 ml, respectively, in wells close to the OWTS. MS2 persisted in the wastewater distribution boxes of the OWTS for several months and was detected in some outer perimeter wells. CONCLUSIONS: Properly functioning OWTS in eastern North Carolina were effective in treating wastewater, whereas the failing OWTS affected the groundwater quality more adversely, especially after a rain storm, but had minor impact on the nearby coastal surface water. SIGNIFICANCE AND IMPACT OF THE STUDY: The study is the first description of the microbial contaminant signature stemming from properly functioning and failing systems under regular use in a high-priority coastal area.