Impact of Storm-Water Outfalls on Sediment Quality in Corpus Christi Bay, Texas, Usa

Abstract

Abstract-To determine the quality of sediments and extent of contaminant impacts, a Sediment Quality Triad (SQT) study was conducted at 36 sites in the Corpus Christi Bay, Texas, USA, system. Fifteen of the 36 sites were located near storm-water outfalls, but 13 other sites (i.e., industrial and domestic outfalls, oil field-produced water discharges, and dredging activity) and eight reference sites were also evaluated. Sediment samples were collected and analyzed for physical-chemical characteristics, contaminant concentrations (metals, polycyclic aromatic hydrocarbons [PAHs], polychlorinated biphenyls [PCBs], and pesticides), toxicity (amphipod and mysid solid phase and sea urchin pore-water fertilization and embryological development tests), and a benthic index of biotic integrity (BIBI) composed of 10 independent metrics calculated for each site. This large data matrix was reduced using multivariate analysis to create new variables for each component representing overall means and containing most of the variance in the larger data set. The new variables were used to conduct the correlation analysis. Toxicity was significantly correlated with both chemistry and ecological responses, whereas no correlations between the benthic metrics and sediment chemistry were observed. Using the combined information from the SQT, four of the five most degraded sites were storm-water outfall sites. Although estuaries are naturally stressful environments because of salinity and temperature fluctuations, this ecosystem appears to have been compromised by anthropogenic influences similar to what has been observed for other heavily urbanized bay systems along the Texas and Gulf coast.

Potential effects of storm-water run-off on assemblages of mobile invertebrates

“…Overall, as in some previous studies (Maxon et al 1997, Nipper et al 1998, Roberts et al 2007), we did not find evidence to support the model that stormwater run-off has strong, clear negative effects on invertebrate assemblages as suggested by laboratory tests (Skinner et al 1999, Carr et al 2000. Our mensurative sampling using AUHs revealed a pattern of difference in assemblages between locations receiving and those not receiving storm-water run-off.…”

“…A wide range of laboratory tests and a few in situ bioassays have established that exposure to stormwater effluent has lethal or sublethal effects on several species of aquatic organisms (Skinner et al 1999, Carr et al 2000. To date, the ecological effects of storm-water run-off in natural systems remain uncertain.…”

MBACI sampling of an episodic disturbance: Stormwater effects on algal epifauna

“…Contaminants within stormwater may pose a greater threat to marine organisms through their tendency to accumulate over time , Carr, et al, 2000. Experimentally increased copper levels in the tissues of the alga S.…”

“…Laboratory tests have established the toxicity of prolonged exposures to stormwater effluent in a variety of marine and aquatic fish and invertebrates (Carr, et al, 2000, Ellis et al, 1995, Hatch and Burton Jr., 1999, Kszos et al, 2004, Skinner et al, 1999. Fish mortality has also been noted following periods of intense storm runoff (Magaud, et al, 1997).…”

Comparison of porewater and elutriate bivalve larval development toxicity testing in a sediment quality triad framework

“…Chapman et al (1997) suggested that toxicity test selection should account for "differences in routes of exposure and in organism physiology". Although specific guidance requiring porewater toxicity testing was not recommended, it is an obvious choice given the available guidance (Chapman, 1990;Chapman et al, 1997), and has been incorporated into many SQTs published in the peer-reviewed literature (e.g., Long et al 1990;Carr et al, 1996a,b;Carr et al, 2000;Anderson et al, 2001a;Hunt et al, 2001). Porewater toxicity tests have been developed for various organisms and toxicological endpoints, including polychaete reproduction (Carr et al, 1989), sea urchin fertilization and development (Carr and Chapman, 1992), copepod survival (Carr et al, 1996a) and kelp spore germination (Hooten and Carr, 1998).…”