Browsing by Author "Broach, Linda"
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Item Contaminant Assessment of Patrick Bayou(Texas Natural Resource Conservation Commission Field Operations Division, 1996-12) Broach, Linda; Crocker, Philip A.In July 1994, the Texas Natural Resource Conservation Commission (TNRCC) and United States Environmental Protection Agency (EPA) Region 6 conducted an ambient toxicity and water and sediment quality survey of Patrick Bayou, a small tributary of Segment 1006 of the Houston Ship Channel (HSC). Patrick Bayou is bounded by and receives effluent from several industrial dischargers and one municipal wastewater treatment plant. This area was investigated because a recent HSC study found ambient water and sediment toxicity and elevated levels of several priority pollutants in Patrick Bayou. The primary objective of this study was to collect water and sediment samples in Patrick Bayou to provide information on the magnitude and spatial distribution of contamination and toxicity in this small bayou. Ten stations were chosen for priority pollutant analyses and a TNRCC routine monitoring station was also sampled during the survey. Several stations were selected for water and/or sediment toxicity testing. Out of five stations tested, water from four was toxic to Mysidopsis bahia and one of those was also toxic to Menidia beryllina. Significant mortality to Cyprinodon variegatus was observed in two of five sediment elutriate tests. State water quality standards were exceeded in Patrick Bayou for dissolved copper (8 sites), dissolved lead (3 sites), total mercury (1 sites), carbon tetrachloride (1 site), and water temperature (4 sites), although a few of these exceedances were inside mixing zones. Three Patrick Bayou stations has unionized ammonia values that exceeded the EPA chronic criteria for saltwater. More than 40 percent of the sediment samples in Patrick Bayou exceeded TNRCC sediment screening levels (85th percentiles) for Cr, Cu, Pb, Hg, Ni, Se, Zn, hexachlorobenzene, total polychlorinated biphenyls (PCBs), and bis(2-ethylhexyl) phthlate. Very high levels of mercury (8.3 ppm), hexachlorobenzene (83,900 ppb), hexachlorobutadiene (138,000 ppb), PCBs (4,150 ppb), polynuclear aromatic hydrocarbons (total PAHs 233,700 ppb), and lead (269 ppb) were found in Patrick Bayou sediments. State screening levels were not available for the remaining 24 organic compounds found in the sediments. Lead, mercury, PCBs, acenapthene, acenaphthylene, anthracene, fluorene, naphthalene, 2-methylnaphthalene, phenanthrene, benzo(a)anthracene, benzo(a)pyrene, chrysene, fluoranthene, pyrene, and total PAHs all exceeded the effects range median levels developed by the National Oceanic and Atmospheric Administration. Overall, Patrick Bayou showed a significant accumulation of many priority pollutants in sediments, exceedances of several water quality standards, and ambient toxicity in both water and sediment. The specific distribution of the contaminants in the sediments gave some information on their potential sources. The major dischargers along Patrick Bayou have proposed to sample their effluents for the compounds found in the bayou to further pinpoint the sources.Item Preliminary Assessment of Nonpoint Source Related Ambient Toxicity in and around Lower Galveston Bay(Ecosystems Protection Branch, US Environmental Protection Agency, Region 6, August 1995) Crocker, Philip A.; Broach, Linda; Hollister, Terry A.; Stockton, David C.; Lane, WillieIn 1991 aquaculture researchers at the old SeaArama facility in Galveston believed that mortality they were observing in their larval shrimp cultures was a result of toxicity of ambient water in the Gulf of Mexico. The researchers utilized near-shore Gulf of Mexico water for rearing larval shrimp. They hypothesized that 2-butoxyethanol was the toxic agent, originating from Galveston Bay waters flowing into the Gulf following heavy rainfall. However, data were not available to support this hypothesis. The US Environmental Protection Agency (EPA) and the Texas Natural Resource Conservation Commission (TNRCC) in a combined effort decided to conduct a water quality study to investigate these concerns. The purposes of the study were to assess the potential for ambient toxicity in lower Galveston Bay and the Gulf of Mexico following rainfall events, and to determine the need for additional studies for a more complete assessment. A total of five stations were sampled during three sampling events: (I) November 1992, (II) June 1993 and (III) February 1994. Sampling stations included Galveston Bay near Redfish Reef, Galveston Channel, and near-shore Gulf of Mexico off Galveston Island. Two additional industrialized areas were also sampled, Texas City Ship Channel and Chocolate Bay. An attempt was made to sample following significant rainfall in the Galveston Bay watershed to assess the potential impact of nonpoint source pollution on bay water quality. Ambient surface water samples were collected for chemical analysis of conventional parameters, EPA priroity pollutants (heavy metals, VOCs, semi-volatiles, pesticides and PCBS), and chronic toxicity testing with mysids and inland silversides. Overall, chemical water quality was good for all sites. The chemical analysis yielded no violations of state water quality standards. Bis(2-ethylhexyl)phthalate at the Gulf of Mexico station exceeded the EPA criterion for protection of human health in February 1994, although the significance is doubtful as this is a common lab contaminant. In November 1992 dissolved nickel approached the state's chronic water quality standard at Chocolate Bay. Chronic toxicity data for mysids and inland silversides, although limited, did not indicate signifcant chronic effects to either species. Because this was a screening study data should be considered preliminary. Chemical and toxicity data indicate that aquatic life uses in the open bay areas sampled are not impacted by toxic substances originating from non-point sources. The need for future open bay type nonpoint source surface water studies is considered low. Studies to assess localized and/or episodic effects of urban stormwater discharges and industrial and agricultural runoff (e.g., western near-shore areas of Galveston Bay; Chocolate Bayou upstream of the area sampled in this study) would be of greater value.