J. Bruce Moring — Page 2

USGS1997

Occurrence and Distribution of Organochlorine Compounds in Biological Tissue and Bed Sediment From Streams in the Trinity River Basin, Texas, 1992-93

This report describes the occurrence and distribution of organochlorine compounds in biological tissue and bed sediment from the Trinity River Basin study area of the National Water-Quality Assessment Program. Concentrations of organochlorine pesticides, polychlorinated biphenyls (PCBs), and other organochlorine compounds were determined in biological tissue and surficial bed sediment from 16 stream sites in the Trinity River Basin of east-central Texas. Asiatic clams (Corbicula fluminea) were collected at 10 sites, and fish, including blue catfish (Ictalurus furcatus), common carp (Cyprinus carpio), bluegill (Lepomis cyanellus), and yellow bullhead (Ameiurus natalis) were collected at all mainstem and two tributary sites. Thirty of the 36 compounds analyzed in biological tissue or surficial bed sediment were detected in one or both media. Overall, more organochlorine compounds were detected in bed sediment than in biological tissue; however, various chlordane isomers, DDT metabolites, and PCBs were detected more frequently in tissue than in sediment. The chlordane isomers and PCBs that were detected more frequently in biological tissue also were detected more frequently at urban sites than at agricultural sites. Organochlorine compound concentrations generally were highest in fish tissue from Trinity River mainstem sites. Fish tissue from the mainstem sites contained a higher percentage of lipids than did fish- and clam-tissue samples from the tributary sites.

Water-Resources Investigations Report↗

USGS1996

Occurrence of polycyclic aromatic hydrocarbons in urban streams as assessed using semipermeable membrane devices, Dallas-Fort Worth metropolitan area, Texas

One of the primary goals of the U.S. Geological Survey's National Water Quality Assessment (NAWQA) Program is to determine the occurrence and distribution of contaminants in stream sediments and tissues of aquatic organisms (Crawford and Luoma, 1993). Metals and persistent organic contaminants are of principal concern. Polycyclic aromatic hydrocarbons (PAHs) are a group of organic compounds that occur abundantly in the environment, are toxic and often carcinogenic to organisms, and could represent a long-term source of contamination. PAHs are metabolized and excreted by most higher vertebrates, particularly fishes, often making assessment of tissues concentrations impossible. Major sources of PAHs are the incomplete combustion of carbonaceous materials and oil spills. The objectives of this fact sheet are to summarize the occurrence of water-borne PAHs in three urban streams in the Dallas- Fort Worth metropolitan area and to assess the use of semipermeable membrane devices (SPMDs) as PAH samplers. One site on each of three streams was selected for monitoring the occurrence of PAHs (fig. 1). The sites were chosen to reflect varied urban land uses and the influences of point- and nonpointsource pollution. The monitoring was done using SPMDs during a 30-day period in late May and June 1994.

Texas↗