3) Studies of effects of petroleum hydrocarbons on organisms 

 in CEPEX experimental enclosures — in cooperation with 

 CEPEX participants. 



4) Studies on the occurrence of benzpyrene in oysters, blue 

 crabs, and marine catfish — in cooperation with the National 

 Cancer Institute. Benzpyrene is a poiycyclic aromatic hydro- 

 carbon in crude oil and petroleum combustion products. 



5 ) Analyses of biogenic hydrocarbon in a variety of organisms. 



Organization: Texas A & M University 



Investigators: J. W. Anderson, J. M. Neff 



Project title: Effects of Pollutants on Gulf of Mexico Organrsms 



Grant Nos.: GX-37344, GX-37347, GX-37349 



E^xtensive research wa^'conducted on the effects of sub- 

 lethal levels of several classes of pollutants — petroleum hydro- 

 carbons, polychlorinated byphenyls, phthalate esters, and heavy 

 metals. In addition, acute toxicity studies were conducted to 

 prepare for the sublethal effects experiments. Examples of this 

 work follow. 



Acute Effects — Toxicity: The 96-hour LC-50 values have 

 been determined to allow a more intelligent selection of con- 

 centrations to be used in sublethal effects work. Since earlier 

 literature references to toxic concentrations varied greatly in 

 methodology, analytical capabilities, and other significant fac- 

 tors it was deemed necessary to perform this basic bioassay work. 

 It has been determined that the heavy metals tested, as well as 

 the PCB Aroclor 1254, are toxic to the primary test species 

 {Palaemonetes pugio and Cyprinodon variegatus) at levels in 

 the low ppm range (1-10 ppm). Whole oils have shown sig- 

 nificantly lower toxicity to these species (50-100 ppm range). 

 Phthalates pose a special physical problems as to solution in 

 test medium and losses. Certain specific petroleum hydrocar- 

 bons are more toxic than whole oils. The naphthalenes, for 

 example, have 96-hour LC-50 values in the high ppb range 

 (0.8 ppm). Benzene and toluene appear to be of relatively low 

 toxicity (20 ppm for Cyprinodon). 



Sublethal Effects. Studies of sublethal effects on selected 

 activities, functions, and life stages of various organisms in- 

 cluded the following. 



a. Oxygen consumption: Experiments were conducted 

 with two species each of fish, crustaceans, and molluscs. Results 

 of these studies have indicated that respiratory response is not 

 consistent under these conditions and, therefore, it was con- 

 cluded that for these particular purposes, measurement of this 

 parameter is less useful than others investigated. 



b. Feeding behavior: No effects of mercury on the rate 

 at which crabs Petrolisthes armatus consumed Artemia nauplii 

 were detected. These results may be due to inadequate sam- 

 pling of Artemia. Aroclor 1254 at a concentration of 1.0 ppm 

 significantly decreased the rate at which the mussel Brachi- 

 donte.i recurvus filtered the green flagellate Platymonas from 

 the medium. 



c. Chloride ion regulation: Levels of blood chloride were 

 determined in experiments in which test animals {Palaemontes 

 pugio) were either exposed to a pollutant in seawater at the 

 acclimation salinity (salinity maintenance) or exposed and 

 then transferred to a range of salinities from l-35'V(.(i (salinity 

 shock). In these experiments it has been determined that: 



1 ) Blood chloride levels of adult P. Pugio acclimated to salini- 

 ties of 1-35"/,,,. and exposed to ppb of Aroclor 1254 were not 

 affected (maintenance). 



2) Exposure of juvenile P. pugio to the same concentration of 

 Aroclor 1254 depressed blood chloride levels in those shrimp 

 acclimated to 1 and 7"/,i,|. This effect was not observed at 

 higher salinities to 31 '^/o,,. 



3) Salinity-shocked juveniles which had been exposed to Aro- 

 clor 1254 were less able to adjust blood chloride ion levels 

 compared with controls. 



4) Mercury at 100 ppb did not affect chloride levels in blood 

 of P. pugio. 



5) Blood chloride regulation by P. pugio was also apparently 

 unaffected by exposure to 50 ppb of cadmium. 



6) Mercury at 50 ppb did not affect the ability of Petrolisthes 

 armatus to maintain or adjust blood chloride levels in these 

 experiments. 



7) Exposure to mercury at a concentration of 500 ppb for 2 

 hours in natural seawater aboard Texas A&M's RV Gyre 

 resulted in a significant difference between blood chloride 

 levels of salinity shock experimental and control animals. 



The importance of internal volume changes in the chloride ion 

 balance is currently being investigated by the '*C-inulin tech- 

 nique. 



d. Larval survival, growth, and development: Studies 

 have been conducted and are in progress as to the effects of 

 pollutants on the survival, growth, and development of larval 

 or juvenile organisms. Among the results obtained are: 



1) Exposure of P. pugio to 10 ppb of Aroclor 1254 signifi- 

 cantly prolongs the amount of time from hatching to the post- 

 larvae stage as compared with controls. No physical abnormal- 

 ities were observed. 



2) Cyprinodon variegatus fry exposed to 1.0 ppb of mercury 

 for 63 days were not significantly different in size compared 

 with unexposed controls. Toxic levels for fry are 3 orders of mag- 

 nitude less than for adults. 



3) The effects of exposure to 0.5 and 1.0 ppb of mercury on 

 penaeid (Penaeus) postlarvae are currently being investigated. 



e. Shipboard experiments: On a recent cruise in the Gulf 

 of Mexico aboard Texas A&M RV Gyre, the following experi- 

 ments were conducted: 



1 ) The uptake and accumulation of mercury from natural 

 seawater by bivalved molluscs and penaeid shrimp. 



2) The effects of mercury on the rate of oxygen consumption 

 of these species. 



3 ) The change in chloride ion levels of penaeids and crabs im- 

 mediately after collection and at time intervals thereafter. 



4) The effect of combined mercury exposure and salinity 

 shock on the chloride ion concentrations of the blood of 

 shrimp. 



Numerous biological samples were also obtained for baseline 



8 



