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101.
102.
Concentrations of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and dioxin-like polychlorinated biphenyls (dl-PCBs) in the southern Baltic herring (Clupea harengus), sprat (Sprattus sprattus), and salmon (Salmo salar) are reported.The significant interspecies and season-specific differences in PCDD/Fs and dl-PCBs concentrations were observed. The contribution of dl-PCBs to the total toxicity equivalents (TEQs) ranged between 50% and 70%, dependently on fish species. In all samples, concentrations of PCDF were higher in comparison with that of PCDD.The permissible limits of the content of PCDD/Fs and dl-PCBs (8 pg g−1 fresh weight for the sum of PCDD/Fs and dl-PCBs, and 4 pg g−1 fresh weight for the PCDD/Fs) were exceeded mainly in salmon samples (in 80% of salmon samples studied). The elevated levels of PCDD/F and dl-PCB were observed only in two of seventy two herring samples, and in ten of 62 sprat samples.The multiple regression analysis revealed that fish lipid content, and concentration of PCB 153, used simultaneously, might be useful in the prediction of TEQ values of fish samples. These two variables explained more than 80% of total variance. For all fish species studied, the correlation coefficients obtained with the multiple regression analysis were higher than that obtained with the regression analysis involving total TEQ values, and only one independent variable: fish lipid content.  相似文献   
103.
Food and Environmental Virology - Norovirus is commonly associated with food and waterborne outbreaks. Genetic susceptibility to norovirus is largely dependent on presence of histo-blood group...  相似文献   
104.
The levels of heavy metals and selenium in the eggs and in breast feathers of adult doublecrested cormorant (Phalacrocorax auritus), black-crowned night heron (Nycticorax nycticorax), and franklin's gull (Larus pipixcan) nesting at Agassiz National Wildlife Refuge in Marshall County, northwestern Minnesota were examined. Also examined were metal levels in the feathers of fledgling night herons and gulls, in the feathers of adult and fledgling American bittern (Botaurus lentiginosus), in eggs of American coot (Fulica americana) and eared grebe (Podiceps caspicus), and in feathers of adult Canada geese (Branta canadensis). These species represent different levels on the food chain from primarily vegetation-eating species (geese, coot) to species that eat primarily fish (cormorant). A clear, positive relationship between level on the food chain and levels of heavy metals occurred only for mercury in feathers and eggs. Otherwise, eared grebes had the highest levels of all other metals in their eggs compared to the other species. No clear food chain pattern existed for feathers for the other metals. For eggs at Agassiz: 1) lead, selenium, and manganese levels were similar to those reported in the literature, 2) mercury levels were slightly higher for cormorants and night herons, 3) all species had higher chromium and cadmium levels than generally reported, and 4) eared grebes had significantly higher levels of cadmium than reported for any species from elsewhere. For adult feathers: 1) gulls had higher levels of lead than the other species, 2) cadmium levels were elevated in gulls and adult herons and cormorants, 3) mercury levels showed an increase with position on the food chain, 4) selenium and chromium levels of all birds at Agassiz were generally low and 5) manganese levels in adults were generally higher than in the literature for other species. Adults had significantly higher mercury levels than fledgling gulls, night herons, and bitterns.  相似文献   
105.
SUMMARY

This paper describes the evolution of an evaluation method developed initially to assess progress towards sustainable development for various land use activities in Costa Rica. Since that time, the method has been expanded to apply to all types of business activities in any location, and refined so that a numerical score can be provided for each attribute. These scores can then be presented graphically in four categories. The method has since been tested on a variety of businesses and is being refined for electronic submission and display of the results. The benefits of this approach, as well as its shortcomings and some of the problems resolved, are presented.  相似文献   
106.
SUMMARY

Efforts towards sustainable development are now being undertaken at all levels and the concept has increasingly entered the consciousness of the average person. For many Costa Ricans however, it is not just an abstract concept but a matter of survival as input costs increase, natural resources diminish and the soil loses fertility or is washed away. This paper reviews three case studies representing different approaches towards achieving sustainable development by different types of organization which are each innovative in preventing further destruction of tropical forest resources.  相似文献   
107.
Following a spill of 567 000 gallons of No. 2 fuel oil into the Arthur Kill in New York and New Jersey in January 1990 we studied the emergence and mortality of fiddler crabs. We (1) compared seven salt marsh creeks immediately adjacent to the oil spill with 23 creeks at varying distances from the spill; (2) examined the temporal pattern of emergence in one creek; and (3) compared mortality rate of crabs that emerged with those we dug up. Twice as many crabs emerged in the adjacent creeks compared to those that were only 4.5km away. There were significant differences in the number of crabs that emerged as a function of distance from the spill. Crabs continued to emerge until mid-March. For all the emerged crabs, the percentage of females ranged from 28 to 80, whereas the percentage of females in intact burrows was 64–65%. For all emerged samples, females died earlier than males. In the laboratory, all emerged crabs died within four weeks whereas over 90% of the controls were still alive eight weeks after the initiation of the experiment.  相似文献   
108.
With the ending of the Cold War, the US and other nations were faced with a legacy of nuclear wastes. For some sites where hazardous nuclear wastes will remain in place, methods must be developed to protect human health and the environment. Biomonitoring is one method of assessing the status and trends of potential radionuclide exposure from nuclear waste sites, and of providing the public with early warning of any potential harmful exposure. Amchitka Island (51 degrees N lat, 179 degrees E long) was the site of three underground nuclear tests from 1965 to 1971. Following a substantive study of radionuclide levels in biota from the marine environment around Amchitka and a reference site, we developed a suite of bioindicators (with suggested isotopes) that can serve as a model for other sites contaminated with radionuclides. Although the species selection was site-specific, the methods can provide a framework for other sites. We selected bioindicators using five criteria: (1) occurrence at all three test shots (and reference site), (2) receptor groups (subsistence foods, commercial species, and food chain nodes), (3) species groups (plants, invertebrates, fish, and birds), (4) trophic levels, and (5) an accumulator of one or several radionuclides. Our major objective was to identify bioindicators that could serve for both human health and the ecosystem, and were abundant enough to collect adjacent to the three test sites and at the reference site. Site-specific information on both biota availability and isotope levels was essential in the final selection of bioindicators. Actinides bioaccumulated in algae and invertebrates, while radiocesium accumulated in higher trophic level birds and fish. Thus, unlike biomonitoring schemes developed for heavy metals or other contaminants, top-level predators are not sufficient to evaluate potential radionuclide exposure at Amchitka. The process described in this paper resulted in the selection of Fucus, Alaria fistulosa, blue mussel (Mytilus trossulus), dolly varden (Salvelinus malma), black rockfish (Sebastes melanops), Pacific cod (Gadus macrocephalus), Pacific halibut (Hippoglossus stenolepis), and glaucous-winged gull (Larus glaucescens) as bioindicators. This combination of species included mainly subsistence foods, commercial fish, and nodes on different food chains.  相似文献   
109.
Risk evaluation and assessment have been used as tools to regulate and manage the risks to consumers of eating self-caught fish that have high levels of contaminants. Armed with these risk assessments, health agencies issue consumption advisories, and in some cases, close some waters to fishing. Recently, regulatory agencies have used contaminant levels in fish as a benchmark for remedial action on contaminated sites, using human health risk assessment as the justification. The US Environmental Protection Agency's new surface water criterion for mercury is based on mercury levels in fish tissue. When multiple regulatory agencies have jurisdiction over the same waters or remediation site there is the potential for differing risk evaluations. Using the Peconic River on Long Island, New York as a case study, the paper examines how and why county, state, and federal health risk evaluations for fish contaminated with mercury differed. While the same risk methodology was applied by all agencies, the assessments were conducted for different purposes, applied different consumption and fish biomass assumptions, and arrived at different conclusions. The risk evaluations invoked to design fish consumption advisories use mercury levels currently in fish, and are designed to prevent current exposure. However, the risk assessments that provide a basis for remediation consider many different pathways of exposure (not just ingestion), and deal with long-term exposure. The risk evaluations, and recommendations promulgated by those agencies, differ because they have different goals, use different assumptions, and often fail to communicate among agencies. It is suggested that it is valuable to have these different levels of risk evaluations to adequately address health issues. However, there are policy implications, which include making the distinctions between the types of risk assessments, their methods and assumptions, and the rationale for these assumptions. Further, assessors and managers should involve all interested stakeholders (including regulators and state health officials) in discussions about the use of risk, the assumptions of risk assessment, and the goals of those evaluations. The difficulties in the case of the Peconic were not due to differences in the original data, but rather in the goals and type of risk assessments performed. If all deliberations had been transparent during all phases of the decision-making and management process, the conflicts within the minds of the public, regulators and other agencies might have been avoided. This case study suggests that more reliability, circumspection and transparency should be built into the process where multiple agencies and multiple objectives are involved.  相似文献   
110.
With the ending of the Cold War, several federal agencies are reclaiming land through remediation and restoration and are considering potential future land uses that are compatible with current uses and local needs. Some sites are sufficiently contaminated that it is likely that the responsible federal agency will retain control over the land for the foreseeable future, providing them with a stewardship mission. This is particularly true of some of the larger Department of Energy (DOE) facilities contaminated during the production of nuclear weapons. The use of the term “restoration” is explored in this paper because the word means different things to the public, ecologists, and environmental managers responsible for contaminated sites, such as Superfund sites and the DOE facilities. While environmental restoration usually refers to remediation and removal of hazardous wastes, ecological restoration refers to the broader process of repairing damaged ecosystems and enhancing their productivity and/or biodiversity. The goals of the two types of restoration can be melded by considering environmental restoration as a special case of ecological restoration, one that involves risk reduction from hazardous wastes, and by broadening environmental restoration to include a more extensive problem-formulation phase (both temporal and spatial), which includes the goal of reestablishing a functioning ecosystem after remediation. Further, evaluating options for the desired post remediation result will inform managers and policy-makers concerning the feasibility and efficacy of environmental restoration itself.  相似文献   
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