Integrated coastal effects study: Synthesis of findings

Abstract

Municipal wastewater discharges constitute a major source of contaminants of emerging concern (CECs) to coastal waters, yet uncertainty exists regarding their linkage to adverse biological effects such as endocrine disruption. Limited information is available concerning the types and fate of CECs discharged to the Southern California Bight (SCB) from municipal wastewater and their potential for ecological impacts. The present study investigated the impacts of CECs from ocean wastewater discharges on SCB fish. Concentrations of CECs were measured in effluents from four major municipal wastewater dischargers. Seawater, sediment, and hornyhead turbot (Pleuronichthys verticalis) from the discharge sites and a reference area were collected and analyzed for chemical and biological indicators. Low concentrations of pharmaceuticals, personal care products, and industrial and commercial compounds were measured in effluent. Some CECs were also detected in sediment, seawater, and fish livers near the outfalls, confirming exposure to CECs. Fish plasma hormone analyses suggested the presence of physiological effects, including a reduced stress response, altered estrogen synthesis or estrogenic exposure, and reduced thyroxine. Most fish responses were found at all sites and could not be directly associated with effluent discharges. However, concentrations of thyroxine were lower at all discharge sites relative to the reference, and estradiol concentrations were lower at three of the four outfall sites. The physiological responses found were not associated with adverse impacts on fish reproduction or populations. Interpretation of molecular and physiological measurements in field organisms such as those used in the present study is challenging because of a lack of information on baseline conditions and uncertain linkages to apical endpoints such as survival and reproduction.

Biological responses of marine flatfish exposed to municipal wastewater effluent

“…In the laboratory-acclimatized fish exposed to control seawater, plasma E2 levels were lower, often by an order of magnitude (<20 pg/ml) compared with E2 levels in feral fish (200À800 pg/mL; Supplemental Data, Figure S1). Another response previously observed in feral hornyhead turbot was decreased plasma T4 concentrations in fish collected near POTW effluent discharge zones compared with fish from a reference area [15]. The present study did not show this pattern of response after 2 wk of exposure in the laboratory.…”

“…Initial dilution ratios >100:1 are common. The use of lower effluent exposure concentrations was consistent with our objective to investigate biological responses to realistic environmental concentrations to help in interpreting data obtained in previous field studies [15].…”

Annual and seasonal evaluation of reproductive status in hornyhead turbot at municipal wastewater outfalls in the Southern California Bight

“…However, examination of long-term monitoring data on fish community structure does not show signs of impact due to anthropogenic sources of contaminants [24]. Analysis of historical population data from 1970 to 2007 indicated that populations in the SCB are increasing at all outfall locations relative to the 1990s.…”

Temporal patterns of induction and recovery of biomarker transcriptional responses to 4‐Nonylphenol and 17β‐estradiol in the estuarine arrow goby, Clevelandia ios

“…For example, in coastal southern California, benthic Pleuronectiform fishes including the Dover sole ( Microstomus pacificus ) and hornyhead turbot ( Pleuronichthys verticalis )—species that live in direct physical contact with the ocean floor—have been documented with muscle burdens of total DDTs 3–4 times higher than those observed in white croaker ( Genyonemus lineatus ), a schooling species that swims above the substrate (Gossett et al, ; McDermott‐Ehrlich et al, ; see also Zeng and Tran, ). High burdens of 4‐NP have likewise been detected in hornyhead turbot from these same habitats (Maruya et al, ), and there is evidence that these fish may be experiencing adverse endocrine effects (Bay et al, ). Studies that examine not only the induction—but also the recovery or adaptation—of molecular and physiological responses to chemical exposure will therefore be essential to the use of gene expression patterns in benthic marine fishes as reliable biological indicators for environmental monitoring.…”