Environmental media

Before sample preparation, surrogate compounds must be added to the matrix. These are used to evaluate the efficiency of recovery of sample for any analytical method. Surrogate standards are often brominated, fluorinated, or isotopically labeled compounds that are not expected to be present in environmental media. If the surrogates are detected by GC/MS within the specified range, it is... 

Environmental Standards. Lead in the environment is regulated in the United States because of its potential occupational impact, as well as concern about the impact lead may have on the cognitive and physical development of young children. Standards have been set for lead in air, water, and other environmental media. 

PRESCRIBED SUBSTANCE A substancc Controlled by Section I of the Environmental Protection Act (1990) because of its potential to pollute. Different substances are prescribed for release to different environmental media. 

If the processing or otherwise use of similar articles results in a total release of less than 0.5 pound of a toxic chemical in a calendar year to any environmental media, EPA will allow this release quantity to be rounded to zero and the manufactured items remain exempt as articles. EPA requires facilties to round off and report all estimates to the nearest whole number. The 0.5 pound limit does not apply to each individual article, but applies to the sum of all releases from processing or use of like articles. 

IMES was developed to assist in the selection and evaluation of exposure assessment models and to provide model validation and uncertainty information on various models and their applications. IMES is composed of 3 elements 1) Selection - a query system for selecting models in various environmental media, 2) Validation - a database containing validation and other information on applications of models, and 3) Uncertainty - a database demonstrating apfhieatum nl a mode uncertainty protocol. 

Despite the problems of direct experimental evaluation of plutonium stability constants, they are needed in modeling of the behavior of plutonium in reprocessing systems in waste repositories and in geological and environmental media. Actinide analogs such as Am+3, Th+, NpOj and UOj2 can be used with caution for plutonium in the corresponding oxidation states and values for stability constants of these analogues are to be found also in reference 20. 

Figure 1. Conceptual model illustrating examples of major anthropogenic contaminant sources and contaminants, their distribution within the abiotic environmental media, their movement into biota with potential food chain contamination, and potential effects at the organismal, population, conmiunity and ecosystem level of organization.

Populations residing near hazardous waste disposal sites may be subject to higher levels of methyl parathion in environmental media (i.e., air, groundwater, soil) than those experienced by the general population. Methyl parathion has been identified in at least 16 of the 1,585 hazardous waste sites that have been proposed for inclusion on the EPA National Priorities List (NPL). However, the number of sites evaluated for methyl parathion is not known. As more sites are evaluated, the number of sites where methyl parathion has been detected may increase. 

See Chapter 6 for more detailed information regarding coneentrations of methyl parathion in environmental media. 

Ongoing remedial investigations and feasibility studies conducted at the NPL sites known to be contaminated with methyl parathion will add to the available database on exposure levels in environmental media, exposure levels in humans, and exposure registries. 

No ongoing studies concerning the methods of analysis of methyl parathion in biological samples and environmental media were located. 

Half-life—A measure of rate for the time required to eliminate one half of a quantity of a chemical from the body or environmental media. 

Endosulfan (one or both of its isomers) has been identified in a variety of environmental media (air, surface water, groundwater, soil, and sediment) collected at 164 of the 1,577 NPL hazardous waste sites (HazDat 2000). 

Endosulfan has been identified in 162 soil and 45 sediment samples collected at 131 of the 164 NPL hazardous waste sites where it was detected in some environmental media (HazDat 2000). 

In addition to individuals who are occupationally exposed to endosulfan (see Section 5.5), there are several groups within the general population that have potentially high exposures (higher than background levels) to endosulfan. These populations include individuals living in proximity to sites where endosulfan was produced or sites where endosulfan was disposed of, and individuals living near one of the 162 NPL hazardous waste sites where endosulfan has been detected in some environmental media (HazDat 2000). 

Bioavailability from Environmental Media. Endosulfan can be absorbed following inhalation of contaminated workplace air and ingestion of insecticide-contaminated food (Ely et al. 1967). Dermal contact with or ingestion of endosulfan that is tightly bound to soil particles is an exposure route of... 

An enzyme immunoassay technique has been employed for measuring endosulfan and its degradation products (i.e., endosulfan diol, endosulfan sulfate, endosulfan ether, and endosulfan lactone) in water at 3 ppb (Chau and Terry 1972 Musial et al. 1976). However, this technique is not currently in use in environmental residue analysis. Further research into this technique could produce a rapid, rehable, and sensitive method for identifying contaminated areas posing a risk to human health. No additional methods for detecting endosulfan in environmental media appear to be necessary at this time. However, methods for the determination of endosulfan degradation products are needed. 

Bioavailability from Environmental Media. Trichloroethylene can be absorbed following inhalation (Andersen et al. 1980 Astrand and Ovrum 1976 Bartonicek 1962 Dallas et al. 1991 Fernandez et al. 1977 Monster et al. 1976 Muller et al. 1974 Sato and Nakajima 1978), oral (DeFalque 1961 D Souza et al. 

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