Terrestrial food chains

Serious onsite injuries (Temporary disabling worker injuries), n Property damage 1 to 20 times base level. Moderate environmental impact (Cleanup or remediation in less than one week and no lasting impact on food chain, terrestrial life or aquatic life). Loss of production from 1 to 20 times base level. Minor offsite impact (Public nuisance - noise, smoke, odor, traffic). Potential adverse public reaction. 

Onsite fatality or less than 4 permanent disabling worker injuries. Property damage 50 to 200 times base level. Serious environmental impact (Cleanup or remediation requires three to six months and moderate impact on food chain, terrestrial life and/or aquatic life). Loss of production up from 50 to 200 times base level. Significant offsite impact property damage, short term health effects to the public or temporary disabling injuries. Significant public concern or reaction. 

Moderate environmental impact (cleanup or remediation in less than 1 week and no lasting impact on food chain, terrestrial life, or aquatic life)... 

Exposure. The exposure of humans and animals to mercury from the general environment occurs mainly by inhalation and ingestion of terrestrial and aquatic food chain items. Pish generally rank the highest (10—300 ng/g) in food chain concentrations of mercury. Swordfish and pike may frequently exceed 1 p.g/g (27). Most of the mercury in fish is methyl mercury [593-74-8]. Worldwide, the estimated average intake of total dietary mercury is 5—10 p-g/d in Europe, Russia, and Canada, 20 pg/d in the United States, and 40—80 pg/d in Japan (27). 

Generally, tlie main patliways of exposure considered in tliis step are atmospheric transport, surface and groundwater transport, ingestion of toxic materials tliat liave passed tlnough tlie aquatic and terrestrial food chain, and dermal absorption. Once an exposure assessment determines tlie quantity of a chemical witli which human populations may come in contact, tlie information... 

Endosulfan is released to the environment mainly as the result of its use as an insecticide. Significant contamination is limited to areas where endosulfan is manufactured, formulated, applied, or disposed of. The compound partitions to the atmosphere and to soils and sediments. Endosulfan can be transported over long distances in the atmosphere, but the compound is relatively immobile in soils. It is transformed by hydrolysis to the diol and by microorganisms to a number of different metabolites. It is bioconcentrated only to low levels and does not biomagnify in terrestrial or aquatic food chains. 

Food Chain Bioaccumulation. Endosulfan is bioconcentrated by aquatic organisms (Ernst 1977 Novak and Ahmad 1989 NRCC 1975 Roberts 1972 Schimmel et al. 1977) but not by plants or animals (ERA 1982a). The compound is metabolized by terrestrial (Coleman and Dolinger 1982 El Beit et al. 1981c Martens 1977 NRCC 1975) and aquatic organisms (Cotham and Bidleman 1989), and it does not biomagnify to any great extent in terrestrial or aquatic food chains (HSDB 1999). No additional information on the bioaccumulation of endosulfan is needed at this time. 

Biomagnification along terrestrial food chains is principally due to bioaccumulation from food, the principal source of most pollutants (Walker 1990b). In a few instances, the major route of uptake may be from air, from contact with contaminated surfaces, or from drinking water. The bioaccumulation factor (BAF) of a chemical is given by the following equation ... 

As mentioned earlier (Figure 5.5), aldrin and heptachlor are rapidly metabolized to their respective epoxides (i.e., dieldrin and heptachlor epoxide) by most vertebrate species. These two stable toxic compounds are the most important residues of the three insecticides found in terrestrial or aquatic food chains. In soils and sediments, aldrin and heptachlor are epoxidized relatively slowly and, in contrast to the situation in biota, may reach significant levels (note, however, the difference between aldrin and dieldrin half-lives in soil shown in Table 5.8). The important point is that, after entering the food chain, they are quickly converted to their epoxides, which become the dominant residues. 

Although higher chlorinated PCBs are degraded more rapidly than lower chlorinated ones in anaerobic sediments, the reverse is true in terrestrial and aquatic food chains (see Section 6.2.2). As explained earlier, hydroxylations tend to be very slow... 

Apart from CH3 Hg+, other forms of R-Hg+ have been found in the natural environment, which originate from anthropogenic sources but are not known to be generated from inorganic mercury. These forms have been found in terrestrial and aquatic food chains. A major source has been fungicides, in which the R group is phenyl, alkoxy-alkyl, or higher alkyl (ethyl, propyl, etc.). These forms behave in a similar manner... 

Information on dioxins in the environment was acquired rapidly by using some simple, but safe and reliable techniques developed for chlorinated pesticdes. Based on results of these tests, one should be able to predict whether routes of entry into aquatic and terrestrial food chains are significant, the rate and products of decomposition mechanism, and their general longevity in the environment. 

Food Chain Bioaccumulation. Information is available regarding bioaccumulation potential in aquatic food chains. Studies show that trichloroethylene has a low-to-moderate bioconcentration potential in aquatic organisms (Pearson and McConnell 1975) and some plants (Schroll et al. 1994). Information is needed, however, regarding bioaccumulation potential in terrestrial food chains. 

Food Chain Bioaccumulation. Information about americium the levels of americium in aquatic and terrestrial organisms and its bioaccumulation in these organisms is available (Fresquez et al. 1999 DOE 1996 Suchanek et al. 1996). Data are also available on the uptake of americium in plants (Bennett 1979 Cataldo et al. 1980 EPA 1979 Romney et al. 1981 Schreckhise and Cline 1980 Schulz et al. 1976 Zach 1985) and levels in food (Bennett 1979 Cunningham et al. 1989, 1994 Robison et al. 1997a, 1997b). These data indicate that americium does not biomagnify in the food chain (Bennett 1979 Bulman 1978). 

Throughout their friendship, Patterson and Settle fought and argued tooth and nail. But after Dorothy Settle spent two years measuring the lead in tuna muscle, Patterson made her the first author of their 1980 report. To determine the lead levels in the purest animal tissue on Earth, Patterson had chosen tuna because it is at the top of the marine food chain, which is far less polluted than the terrestrial food chain. Settle s work showed that a gram of fresh tuna contains only 0.3 nanogram of lead... 

Food Chain Bioaccumulation. Lead is bioaccumulated by terrestrial and aquatic plants and animals (Eisler 1988). However, lead is not biomagnified in terrestrial or aquatic food chains (Eisler 1988). No additional information is needed. 

The XtraFOOD model was developed within the framework of a research project initiated by the Flemish Institute for Technological Research (VITO) [69]. The model calculates transfer of contaminants in the primary food chain (Fig. 8). In the project, the transfer model was coupled with historical food consumption data to estimate human exposure to contaminated food products. The model focuses on the terrestrial food chain. The XtraFOOD model consists of three modules, which are inter-linked ... 

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