gills of minnows, silverside, and white perch 

 (Olson, etal., 1941). 



Recommendation: Water quality requirements for 

 specifying the permissible limits of settleable solids and 

 floating materials cannot be expressed quantitatively at 

 present. Since it is known that even minor deposits may 

 reduce productivity and alter the benthic environment, 

 it is recommended that no materials containing settle- 

 able solids or substances that may precipitate out in 

 quantities that adversely affect the biota should be in- 

 troduced into estuarine or coastal waters. It is espe- 

 cially urgent that areas serving as habitat or nursery 

 grounds for commercially important species (scallops, 

 lobsters, oysters, clams, crabs, shrimp, halibut, floun- 

 ders, demersal fish eggs and larvae, and other bottom 

 forms) be protected from any infringement on natural 

 conditions. 



Tainting Substances 



Substances found in industrial wastes are fre- 

 quently responsible for objectionable or offensive 

 tastes, odors, and colors of fish and shellfish. Even 

 slight amounts of oil or petroleum products in 

 bays and estuaries will impart an oil or kerosene 

 flavor to mullet, mackerel, and other fishes and 

 also to oysters, clams, and mussels making them 

 unmarketable. Oysters collected in Louisiana 

 waters polluted by crude oil retained a distinct 

 flavor and odor associated with this type of pollu- 

 tion for several weeks after the escape of crude oil 

 from wells and leaky barges had been stopped 

 (Galtsoff, et al., 1935). 



Anaerobic conditions associated with the de- 

 posit of sewage sludge on the bottom are accom- 

 panied by the production of hydrogen sulfide, a 

 substance that causes black discoloration of bi- 

 valve shells and imparts an offensive flavor and 

 odor to their flesh. In the waters receiving black 

 liquor from Kraft pulp mills in the York River, 

 Va., the gills and mantles of oysters developed a 

 gray color. This condition also is found in oysters 

 grown in waters receiving domestic sewage (Galt- 

 soff, etal., 1957). 



Contamination of water with copper results in 

 the accumulation and storage of this metal far 

 above its normal content in the tissues. The cop- 

 per content of oyster flesh from uncontaminated 

 waters off Cape Cod varied from 0.170 to 0.214 

 mg copper per oyster or from 8.21 to 13.77 mg 

 per 100 g dry weight. In green colored oysters 

 collected from adjacent areas only slightly con- 

 taminated with copper salts, the copper content in 

 the flesh ranged from 1.27 to 2.46 mg per oyster 

 or from 121.71 to 271 mg per 100 g dry weight 

 (Galtsoff and Whipple, 1931; Galtsoff, 1964). 



In a current study conducted at the Northeast 

 Marine Health Sciences Laboratory, at Narragan- 



sett, R.I., Dr. B. H. Pringle (unpublished data) 

 found that the average copper content of oysters 

 collected from unpolluted areas along the east 

 shore ranged from 20 to 80 mg/1, wet weight; 

 oysters from areas known to be polluted contained 

 from 124.5 to 392.0 mg/1 wet weight. The copper 

 content of sea water ranged between 0.0038 to 

 0.005 mg/1 in areas not known to be polluted. In 

 certain polluted places, concentrations as high as 

 0.019 mg/1 were recorded. 



Other metals are easily absorbed, stored, and 

 concentrated by oysters in great excess of their 

 concentration in sea water. Experimentally, it has 

 been shown that iron and iodine can be absorbed 

 within a relatively short time by oysters from water 

 to which these metals have been added in excess. 

 The flavor of so-called superiodized oysters pro- 

 duced before World War II in Arcachon, France, 

 was pronounced because the iodine content of flesh 

 was many times higher than that in vmtreated 

 oysters (Galtsoff, 1964). The color of the oysters 

 was not affected. 



Green color of the gills of the European oyster 

 in France and in the American oyster occasionally 

 found in North Carolina and Chesapeake Bay is 

 due to absorption of the blue-green pigment of the 

 diatom, Navicula, present in large numbers on 

 oyster grounds. The color is not associated with 

 the increased copper content of flesh (Ranson, 

 1927). 



Recommendation: To prevent the tainting of fish and 

 other marine organisms, substances that produce tastes 

 and off-flavors should not be present in concentrations 

 above those shown to be acceptable by means of bio- 

 assays and taste panels. Experience has shown that test 

 organisms should be exposed to the materials under 

 test for 2 weeks at selected concentrations to determine 

 the maximum concentration that does not produce 

 noticeable off-flavors as determined by organoleptic 

 tests. (Cooking should be done by baking the material 

 wrapped in aluminum foil.) 



Plant Nutrients and Nuisance Organisms 



Plant nutrients and nuisance organisms are in- 

 terrelated in many ways. There also are many 

 other factors in the environment, such as tempera- 

 ture and salinity, that are closely correlated and, 

 in many instances, seem to be contributing factors 

 to nuisance organisms. 



Man, through altering the hydrography of his 

 environment by building dams and diverting 

 waterflows from their natural courses, has pro- 

 duced conditions in many areas that have caused 

 nuisance growths and brought about an imbalance 

 of natural conditions. He also has enriched surface 

 waters and created imbalances in dissolved mate- 



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