Formations elements undergo as they cycle from air into water and biota; and 

 the availability and toxicity of the trace contaminants that do penetrate to 

 the aquatic system. 



The Field Research Station at Victoria, Texas, in cooperation with the 

 Texas Parks and Wildlife Department, conducted acute toxicity tests of oil- 

 produced brine water to several estuarine fishes. Brine water from oil 

 wells located near coastal areas of Texas are generally discharged into es- 

 tuaries. An increase in the concentration of brine was followed by an in- 

 crease in death rates of test organisms. Organisms tested in synthetic sea 

 salt at the same salinity as the brine concentration showed a much lower 

 death rate. Evidently some toxic component of the oil is dissolved in the 

 brine, or the brine is interacting with the oil to increase toxicity. 

 Further research at Victoria will include testing the effects of oil-pro- 

 duced brine water to standing crops and diversity of stream organisms. In- 

 creased salinity in Oklahoma streams has been traced to improperly capped 

 wells and faulty injection casings; field research is planned to assess the 

 impact of the increased salinity. 



The pressures of oil shortages and deregulation of oil prices will re- 

 sult in additional exploration and development of new oil reserves and in- 

 creased production from existing ones. Public lands in the mountainous 

 areas of the western U.S. have been targeted as sites for new production. 

 In active oil fields, large volumes of water are produced with crude oil. 

 Water is separated from the oil and then reused or discharged. The limit of 

 "oil and grease" discharge allowable is 10 parts per million (ppm) (Figure 

 7). No information has been generated to allow a proper hazard evaluation 

 of these tolerated levels. 



The CNFRL Field Research Laboratory at Jackson, Wyoming, conducted 90- 

 day exposures of cutthroat trout to water soluble components of Wyoming 

 Green, one of the major crude oil types produced in that area. At test 

 concentrations of 0.5 ppm (less than one-tenth the allowable effluent con- 

 centration) trout mortality was 48% and growth was reduced by 88%. Growth 

 of trout treated with as little as 0.1 ppm was reduced by 20%, and extensive 

 fin erosion occurred. Avoidance studies have demonstrated that cutthroat 

 trout are attracted to oil concentrations in water that also result in re- 

 duced growth and survival. 



Numerous other contaminant threats to important aquatic resources have 

 been identified. Some problems are of concern because they are ubiquitous, 

 whereas others may affect specific isolated resources that are highly valued 

 and especially vulnerable to contaminant stresses. 



Millions of acres of riparian habitat have been degraded or destroyed by 

 water resource projects over the past 50 years (Figure 8). Much of the des- 

 truction results from restriction of annual overflows of natural wetland 

 areas. Overflow restriction has encouraged extensive land clearing and dis- 

 rupted the normal hydrologic regime and water fluctuations in headwaters and 

 backwater lakes and swamps. Flood control practices have destroyed hardwood 

 forests and degraded once productive aquatic habitats, allowing these areas 

 to be cleared and used for agriculture. Sediments and associated contami- 



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