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Project: Emerging Contaminant Effects on Coastal Fish

Background and Objectives

Municipal wastewater and other discharges to the coastal environment may contain a variety of contaminants of emerging concern, such as pharmaceuticals, hormones, personal care products, industrial compounds, and current use pesticides. These “emerging” compounds are not routinely monitored and little is known regarding their fate in the marine environment. Some have been shown to cause endocrine disruption after being released to the environment, as they either mimic or interfere with the action of reproductive hormones such as estrogen and testosterone. In southern California, indicators of estrogen exposure such as egg yolk protein production and egg development in male flatfish have been observed, but the cause and significance of these effects is not known. Some coastal areas are contaminated with legacy pollutants that can also cause endocrine disruption (e.g., DDTs and PCBs), so these biological responses may not be caused by current discharges to the Southern California Bight.

The goals of this project were to:

1) Determine the types of emerging contaminants discharged to coastal waters in POTW effluents, and evaluate the potential for fish to be exposed to them;
2) Determine whether coastal fish show evidence of endocrine disruption or other impacts associated with emerging contaminant exposure; and
3) Determine whether effects on fish are associated with POTW discharges.


This study was initiated in 2004 and completed in 2011.


The exposure and potential effects of emerging contaminants were investigated on fish living areas near the four largest ocean POTW discharges in southern California. The study areas included the Los Angeles County Sanitation District (LACSD), City of LA, Orange County Sanitation District (OCSD), and City of San Diego outfalls, which represented range of effluent characteristics and levels of legacy contamination in sediments. A reference area at a similar depth offshore of Dana Point was also sampled.

The study area included four sites near the largest offshore discharges of municipal wastewater and a reference site near Dana Point.

Hornyhead turbot (Pleuronichthys verticalis) were collected at each station during May-June 2006, a time period associated with peak spawning activity. Samples of plasma, liver, and gonads were collected at all stations and analyzed to determine the concentration of a suite of endocrine disruption indicators that included vitellogenin (egg yolk protein, estrogen, testosterone, thyroid hormone (T4), cortisol, gene expression (microarray and qPCR), and gonad histopathology). In addition, composite liver samples, sediment, and quarterly samples of POTW final effluent and water were collected for analysis of a suite of legacy contaminants, industrial compounds, current use pesticides, and pharmaceuticals and personal care products (PPCPs). Quarterly samples of fish were also collected from selected locations in order to compare seasonal reproduction patterns among discharge and reference sites.

Hornyhead turbot (Pleuronichthys verticalis) was selected for study because this species occurs throughout southern California at the same depths as ocean wastewater discharges, and samples of blood, liver, and gonad can be easily obtained for analysis.


This study represents one of the most comprehensive investigations of emerging contaminant exposure and effects in coastal waters. Results showed that many PPCPs and industrial compounds were present in wastewater effluent, generally at concentrations of 1-10 micrograms per liter. The estimated mass emission of some of these chemicals reached 1-5 metric tons per year; similar to that of some priority pollutants such as trace metals. Some PPCPs were also detected in seawater at much lower concentrations. These findings indicate that aquatic life is exposed to a wide variety of emerging contaminants, even after 100- to 1000-fold dilutions of wastewater effluent in the ocean.

A wide variety of pharmaceuticals, personal care products and other chemicals of emerging concern enter coastal waters. The median concentrations of chemicals are shown as detected at a frequency of 75% or greater in final effluent from the four largest southern California ocean discharges of municipal wastewater.

Several indicators of endocrine disruption were detected in fish from the study sites. These included the presence of vitellogenin in up to 90% of the male turbot (depending of site and season), unusually high estrogen concentrations in males, reduced thyroid hormone concentrations, and impaired production of the stress hormone cortisol. The effects were generally widespread and could not be attributed to any specific discharge location. Higher-level effects on gonad condition, reproductive cycle or gender ratio were rarely found, suggesting that these hormone changes had limited impacts on hornyhead turbot populations. However, effects on fish survival and reproduction may have been masked by factors such as fish movement, complex life histories, and competing stressors like legacy pollutants and ocean climate change.

Male hornyhead turbot were found to have similar or higher plasma estradiol concentrations than females at all sites. The cause of this unusual pattern is under investigation.


University of California, San Diego
University of California, Riverside
California State University, Long Beach
Ocean Institute
Orange County Sanitation District
City of San Diego
City of Los Angeles
Los Angeles County Sanitation Districts
City of Oxnard


Endocrine Disruption in Hornyhead Turbot - January 2009 presentation to SCCWRP member agencies. Summarizes initial endocrine disruption experiments with hornyhead turbot.


For more information on Emerging Contaminant Effects on Coastal Fish, contact Steve Bay at (714) 755-3204.
This page was last updated on: 7/1/2014