Table 4.4. Number of Wastewater Permittees in Galveston Bay Watershed. 
Area 
Number of Permits 
Trinity Basin 
(above Lake Livingston Dam) 
519 
San Jacinto Basin 
(above Lake Houston Dam) 
262 
Galveston Bay 
(below Livingston and Houston Dams) 
1,151 
Total Galveston Bay Watershed 
1,932 
Total Permittees in Texas 
3,756 
sediments, and lipophilic. Lipophilicity implies that the compound can be stored in fat tissues and 
transferred throughout food chains. 
Galveston Bay receives runoff from large agricultural and municipal areas that may contain 
pesticides. Fields used for rice, soybean and sorghum production regularly are sprayed with 
herbicides and organophosphorus pesticides. Rice farming procedures typically keep the rice 
flooded during the growing season, which enhances runoff during these months. Mosquito abate¬ 
ment programs along the shoreline of Galveston Bay are another source of organophosphorus 
insecticides. These programs are usually implemented during the spring and summer months, 
coinciding with the entrance of juvenile crabs, shrimp and fish into the marshes. Most organo- 
phosphates are extremely toxic to juvenile stages of aquatic organisms. A third source of pesticides 
entering the bay is runoff from urban areas. Tons of these chemicals are applied by professional lawn 
care services, pest control services, and individual landowners. Herbicides and insecticides are 
applied to gardens, flower beds and drainage ditches. Chlordane is used as a termiticide around 
residences. Texas Department of Agriculture data indicate that residential runoff transports more 
pesticides into rivers than farmland. 
There are 3,756 permitted wastewater discharge outfalls in Texas. Fifty-one percent (1,932) of 
them discharge into the Galveston Bay watershed (Table 4.4). Thirty-one percent (1,151) discharge 
in the immediate vicinity of the bay. The chemical and biological oxygen demands of wastewater 
effluents and untreated discharges into tributaries and the Houston Ship Channel can drastically 
lower or eliminate dissolved oxygen concentrations and negatively impact fishes and bottom¬ 
dwelling organisms in particular. In addition to the chronic exposure and the continuous or 
intermittent discharge of contaminants, bay inhabitants are also subjected to episodic petroleum and 
chemical spills. Segments of a number of bay tributary streams have been designated as "unfishable, 
unswimmable." Bacterial contaminants from sewage treatment plants and urban runoff have 
frequently closed down oyster harvesting. Approximately 51 percent of the bay is permanently 
closed to shellfish harvesting. Toxicants and carcinogens potentially can be introduced into human 
food chains. 
Has past development and waste disposal influenced the biota of Galveston Bay? The issue is 
difficult to resolve with certainty. As seen in Table 4.4, the species richness of benthic macroinverte¬ 
brates varies considerably in different segments of the bay. West Bay exhibits the greatest diversity. 
Lower Galveston Bay has a richer biota than upper Galveston Bay. The fauna of East Bay seems 
surprisingly low. Trinity Bay, which experiences the lowest salinity and greatest fluctuations in 
environmental conditions, appears to be a naturally stressed community. One clam, Rangia cuneata, 
was considered to be a dominant species in Trinity Bay in the early 1970s but appears to have 
disappeared from many areas, although dead shells occur in all bays (1). Neither polychaetes nor 
mollusks live in the San Jacinto River or Houston Ship Channel; one crustacean persists in the ship 
channel. 
Information Needs 
There are many unresolved questions regarding biogeochemical cycling in Galveston Bay. What 
are the concentrations and locations of arsenic, cadmium, mercury, selenium and toxic organics that 
have yet to be measured? Does the concentration and distribution of pollutants change over time? 
What is the extent of heavy metal contamination in nursery areas receiving urban runoff, industrial 
71 
