Bioaccumulation from plants

Environmental. The high lipophilicity of the cydodienes and the prolonged persistence of dieldrin and heptachlor epoxide (soil half-lives 2—10 yr) have resulted in severe environmental contamination. These compounds are bioaccumulated from water to fish up to 100,000- to 300,000-fold and are ubiquitous in human fat and milk. Oxychlordane [26880-48-8], mirex, and chlordecone are also bioaccumulative. The cydodienes are extremely toxic to fish with LC5Qs (ppm) to trout and bluegill of endrin, 0.001-0.002 endosulfan, 0.001-0.003 diddrin, 0.003-0.015 aldrin, 0.006-0.01 heptachlor, 0.03-0.026 and chlordane, 0.022—0.095. The LD5Qs to pheasant and mallard are aldrin 16.8 and 520, dieldrin 79 and 381, and endrin 1.6 and 5.6 mg/kg. As indicated by their rat oral LD - s, they are also extremdy toxic to small mammals in fact, endrin has been used as a rodenticide (see Pesticides). Compounds, eg, aldrin and heptachlor, which have unsubstituted double bonds, readily add oxygen to form epoxides in plant and animal tissues and are preferentially concentrated and stored in animal fats. Aldrin epoxide (dieldrin) and heptachlor epoxide are more stable (half-lives on alfalfa of seven to eight days) than aldrin and heptachlor (half-lives on alfalfa of less than one day). 

Radium may be transported in the atmosphere in association with particulate matter. It exists primarily as a divalent ion in water, and its concentration is usually controlled by adsorption-desorption mechanisms at solid-liquid interfaces and by the solubility of radium-containing minerals. Radium does not degrade in water other than by radioactive decay at rates that are specific to each isotope. Radium may be readily adsorbed by earth materials consequently, it is usually not a mobile constituent in the environment. It may be bioconcentrated and bioaccumulated by plants and animals, and it is transferred in food chains from lower trophic levels to humans. 

This chapter begins at the bottom of the agricultural food chain, looking at the uptake of PCDD/Fs in plants from soil. The second section deals with the uptake in plants from the atmosphere. The attention then switches to the next link in the food chain, and the transfer from plants and soil to livestock and animal food products is examined. This is followed by a discussion of uptake in humans from food and in infants from mothers milk. The chapter concludes with a short summary, an overall perspective on bioaccumulation in the agricultural food chain, and a brief reference to some consequences of this knowledge for risk assessment. 

Food Chain Bioaccumulation. PAHs can bioaccumulate in plants, aquatic organisms, and animals from intake of contaminated water, soil, and food. Extensive metabolism ofthe compounds by high-trophic-level consumers, including humans, has been demonstrated therefore, food chain biomagnification ofthe compounds does not appear to be significant (Edwards 1983 Eisler 1983 ... 

Naturally occurring F associated with hydrous minerals has low mobility because it is occluded in structures. Airborne fluoride pollutants (from smelters, rock phosphate fertilizer factories, etc.) are, in contrast, easily dissolved on contact with the soil. These forms of fluoride can be bioaccumulated by plants before leaching, sorption, or precipitation processes have a chance to lower solubility. 

Calculated Bioaccumulation Factors (BAFs) from Plant Tests Using... 

The high Kqa values coupled with relatively high log Kqw values put the SCCPs and MCCPs in the class of chemicals that could bioaccumulate in air-breathers in mammalian terrestrial food webs, i.e., from plants to herbivores to top predators such as humans or wolves [72, 73]. The Environmental Bioaccumulation Potential (EBAP) of selected CPs assuming humans exposed via a marine and agricultural diet is shown in Fig. 9. Most SCCPs can be seen to fall into the category of >60% maximum EBAP. The EBAP values generated by the model vary depending on human dietary habits, the structure of the key food chains, and the properties of the environment in which the chemical is distributed. 

Octanol/air partition coefficient (K J has been defined recently as the key parameter for the evaluation of bioaccumulation in plants (Paterson et al, 1991). The octanol/air partition coefficient can be obtained from ... 

The Bickford case in Utah illustrates the dangers of explosive contamination. Four out of seven individuals exposed to RDX and RDX intermediates (nitrosamines) for about six to seven years from contaminated private wells have contracted non-Hodgkin s lymphoma one has already died. The levels of RDX were about 60 parts per billion (ppb) in their wells when it was discovered, and the RDX plume is about three miles long. In addition, they watered their food crops with RDX-contaminated water. RDX tends to show moderate bioaccumulation in plant tissues, particularly in the leaves. Surface water has also been contaminated by explosive residue. Pink lagoons are now infamous around explosive plants. 

Dissolves very slowly in water, does not adsorb strongly to soil and migrates further in contaminant plumes in ground-water. It is not bioaccumulative in plant or animal tissues but can be taken up by plants from contaminated soils, thus small amounts could be transferred up the food chain... 

A number of environmental issues have received widespread publicity (Table 7.1), from major accidents at plants (e.g., Seveso and Bhopal) to the global and regional impacts associated with energy utilization (e.g., carbon dioxide, acid rain, and photochemical oxidants), the improper disposal of chemical waste (e.g., Love Canal and Times Beach), and chemicals that have dispersed and bioaccumulated affecting wildlife (e.g., PCBs and DDT) and human health (e.g., cadmium, mercury, and asbestos). 

Bioaccumulation is the process by which terrestrial organisms such as plants and soil invertebrates accumulate and concentrate pollutants from the soil. Bioaccumula-... 

Baumann, PC. and R.B. Gillespie. 1986. Selenium bioaccumulation in gonads of largemouth bass and bluegill from three power plant cooling reservoirs. Environ. Toxicol. Chem. 5 695-701. 

The food of top predators generally comprises small birds and/or mammals. Bioaccumulation of chemicals from soil to small birds and mammals takes place in at least two steps, namely a BCF from soil to food (plants and/or invertebrates), followed by a BAF to small birds and mammals. 

The first consideration was the speciation and distribution of the metal in the sediment and water. Benthic organisms are exposed to surface water, pore water and sediment via the epidermis and/or the alimentary tract. Common binding sites for the metals in the sediment are iron and manganese oxides, clays, silica often with a coating of organic carbon that usually accounts for ca. 2% w/w. In a reducing environment contaminant metals will be precipitated as their sulfides. There is not necessarily a direct relationship between bioavailability and bioaccumulation, as digestion affects the availability and transport of the metals in animals, in ways that differ from those in plants. 

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