Showing papers on "Bioaccumulation published in 1975"

Behavior and phytotoxicity of inorganic arsenicals in soils

Abstract: This paper reviewed the relationship between arsenic sorption and soil properties and the possible mechanisms of As sorption in soils; various soil test methods in terms of their ability to predict As uptake and phytotoxicity; relationships between soil As and plant uptake which result in phytotoxicity and potential hazards to humans or animals consuming plants grown on soils containing high levels of As; and methods of ameliorating As toxicity. Reports have indicated that As is more toxic on coarse-textured than on fine texured clay soils. Sorption of As by soils is time dependent. Soil ''unproductiveness'' due to arsenical poisoning results from heavy application of arsenical pesticides. Arsenic is not an essential plant nutrient but occasionally small yield increases have been observed at low levels of As, especially for tolerant crops such as potatoes, corn, rye, and wheat. Plants vary considerably in their tolerance to high levels of soil As. Very tolerant plants included: asparagus, potato, tomato, carrot, tobacco, dewberry, grapes, and red raspberry. Bioaccumulation of As is hazardous to human beings and animals because of toxicity and its possible relationship to cancer, artereosclerosis, and chronic liver diseases. The edible portion of plants seldom accumulates a hazardous level of As, primarilymore » because most plants are sensitive to As toxicity and growth is usually severely reduced before a level of As hazardous to man or animals accumulate in the plant. Several approaches have been tried to restore As-contaminated soils to the optimal level of production. One method involved adding phosphate to the system to depress the uptake of arsenate by the plant. The soil was also amended with Fe or Al salts. Deep Plowing to dilute the As concentration seemed to be the most economical method. Leaching of the soil was a viable approach also. 62 references, 7 tables.« less

Bioaccumulation factors for radionuclides in freshwater biota

Abstract: This report analyzes over 200 carefully selected papers to provide concise data sets and methodology for estimation of bioaccumulation factors for tritium and isotopes of strontium, cesium, iodine, manganese, and cobalt in major biotic components of freshwater environments. Bioaccumulation factors of different tissues are distinguished where significant differences occur. Since conditions in the laboratory are often unnatural in terms of chemical and ecological relationships, this review was restricted as far as possible to bioaccumulation factors determined for natural systems. Because bioaccumulation factors were not available for some shorter-lived radionuclides, a methodology for converting bioaccumulation factors of stable isotopes to those of shorter- lived radionuclides was derived and utilized. The bioaccumulation factor for a radionuclide in a given organism or tissue may exhibit wide variations among bodies of water that are related to differences in ambient concentrations of stable-element and carrier-element analogues. To account for these variations, simple models are presented that relate bioaccumulation factors to stable-element and carrier-element concentrations in water. The effects of physicochemical form and other factors in causing deviations from these models are discussed. Bioaccumulation factor data are examined in the context of these models, and bioaccumulation factor relations for the selected radionuclides are presented. (auth)

Bioaccumulation of arsenicals

Abstract: Arsenic is bioconcentrated by aquatic organisms but not biomagnified. Plants usually accumulate more arsenic than fish, and crustacea accumulate intermediate amounts. Marine organisms normally contain more arsenic than their fresh water counterparts. However, the arsenic contained in the organisms is apparently not toxic to animals or humans, and is readily excreted.

Role of bacteria in bioaccumulation of mercury in the oyster Crassostrea virginica.

Abstract: An investigation of mercury-resistant bacteria was undertaken to determine their role in the accumulation of mercury in a simplified food chain. Oysters (Crassostrea virginica) were maintained in a closed system, sealed aquarium with stirred, aerated water containing 10 μg of 203HgCl2 per liter. Uptake of 203Hg by oysters held under control conditions was compared with that of 203Hg uptake by oysters under similar conditions except that mercury-accumulating and mercury-metabolizing species of Pseudomonas, isolated from Chesapeake Bay, were added to the experimental oysters. After incubation for 4 days, the major portion of the 203Hg in the water column was found to be associated with the microparticulate fraction, corresponding to a rise in total viable count. Mercury accumulation in the oysters was significantly higher in the gill and visceral tissue than other tissues. Mercury concentrations were 200 times greater in tissue fractions of oysters dosed with mercury-metabolizing bacteria compared with the oysters held under control conditions without mercury-metabolizing bacteria.

The bioaccumulation and effects of organochlorine pesticides in marine animals

Abstract: Organochlorine pesticides have been in use now for about 30 years. As a class of compounds they are not in general readily degradable and they can now be detected in a wide range of samples taken anywhere in the world, including the deep oceans. Organochlorine pesticides are highly fat soluble and it was discovered over 15 years ago that they were accumulated by several forms of life, especially the top predators. Since this discovery a great deal of effort has been spent in attempts to establish to what extent they affect organisms other than the target insect pests. This paper reviews the levels of various pesticides in the sea and the concentration found at different trophic levels in the marine food chain. The levels of accumulation relative to sea water are discussed, together with the known and potential effects that the accumulation levels might have on different types of organisms.

Distribution and bioaccumulation of mercury in biotic and abiotic compartments of a contaminated river-reservoir system

Abstract: The distribution and bioaccumulation of mercury in the North Fork of the Holston River--Cherokee Reservoir which receives mercury inputs from an abandoned chlor-alkali plant were studied to determine the behavior and ultimate fate of mercury in this system. Mercury in the dissolved form appears to be leaching from waste disposal ponds at the abandoned plant. Dissolved mercury is rapidly adsorbed onto suspended particulates and the main downstream transport of mercury appears to take place in the particulate phase. Total mercury and methylmercurials in fish and benthic invertebrate taxa are highest immediately below the mercury source then decrease downstream. This pattern is similar to the downstream distribution of mercury in the water and sediments. Total mercury in rockbass (Ambloplites rupestris) 83 miles downstream from mercury inputs exceeds 1.0 ppM. Approximately 80 percent of mercury in fish species in the river is methylmercury and on the order of 50 percent of mercury in benthic invertebrates is methylmercury. We have not detected methylmercury in bed sediments in this system. Dietary uptake of methylmercury by fish species feeding on benthic invertebrates may be a significant route of entry of methylmercury into food webs in this river. Future research necessary to more completely understand themore » biogeochemical cycling of mercury in aquatic ecosystems is suggested. (auth)« less

Availability of sediment-bound cobalt, silver, and zinc to a deposit-feeding clam. [Macoma balthica]

Abstract: The availability to Macoma balthica of sediment-bound metals was dependent upon the physical-chemical nature of the metal-sediment association. Laboratory studies of bioaccumulation from individual sedimentary trace-element sinks labelled with radioactive tracers of Ag, Co and Zn indicated bioavailability varied among metals within a given sink and among sinks for a given metal. Little bioaccumulation was observed from several sinks which may be common in nature, e.g., little Zn or Co uptake was observed when those metals were coprecipitated with amorphic iron oxide or manganese oxide. However, Ag, Co, and Zn were all taken up from detrital organics and Ag was accumulated by the clam from the iron oxide precipitate. Even quantitatively minor sinks within aquatic sediments may be important sources of some metals for M. balthica. Uptake rates of Co and Zn from biogenic carbonates (crushed clam shells) were significantly greater than rates of uptake from other sinks. Likewise, Ag uptake from both biogenic carbonates and synthetic calcites was greater than Ag uptake from iron oxides or detrital organics. Sinks from which bioaccumulation of bound metals was greatest also showed the greatest rate of sediment to water desorption of metals. Where such sinks are abundant in nature, bioavailability of sediment-boundmore » metals may be enhanced both through increased uptake from ingested particulates by deposit feeders, and through increased sedimentary desorption, resulting in higher concentrations of solute metals.« less