Site-specific conditions modeling

By modeling site-specific conditions Inventories of material having explosion or fire potential that can be released Plant volumes and degree of confinement or obstruction (if Multienergy or similar method is used) if vapor cloud explosion is a concern... 

Consequence Screening by Modeling Site-Specific Conditions 35... 

Perform consequence screening by modeling site-specific conditions. 

Consequence Screening by Qualitatively Modeling Site-Specific Conditions... 

Matrix extrapolation undertaken by this model means that the model calculates the free metal ion concentration as the toxic species, given a total metal concentration and site-specific conditions in terms of water hardness, DOC, salinity, and so on. As an example, according to the MINTEQ model, a type of water with a hardness of 10 mg/L CaC03, a DOC content of 10 mg/L, a total Zn concentration of 10 mg/L, and a variable pH gives a distribution of Zn species as given in Table 2.5. 

It is unnecessary, and in fact impossible, to include all chemical components, all types of chemical reactions, or all chemical reactions in the aquifer system in the model. The configuration of a chemical model, decisions on the chemical components, reaction types, and reactions to be included, should depend on site-specific conditions and what questions we want to ask. 

Level 3a A baseline bioavailability correction (Level 3a) can be conducted if a BLM for algae, fish or invertebrates is available. Such baseline bioavailability correction, consisting of the application of a conservative bioavailability factor (Bio-F), is applicable if no direct evidence is available to support a cross-reading or if mechanisms of toxicity differ across species within a specific trophic level. This method is based on the calculation of reference NOEC/ECio values (i.e. reference NOEC/ECio dissolved) and normalised NOEC/ECio values for the test organisms for which the bioavailabiUty models were developed under typical site-specific conditions (i.e. site-specific NOEC/ECio bioavaUabie, dissolved). Both normalised toxicity values are compared for every species for which the bioavailability models were developed, and the most conservative value (smallest correction for bioavailability, site - specific NOEC/ECjq HoavailaWe, dissolved v... 

Once chemicals are released into the environment, their hazards to human and environmental biota depend on the concentrations of chemicals in the environment (ie, dose). However, quantifying the concentration levels is very complicated, because many processes determine the environmental fate, which are specific both to the chemical and the environment. This has led to the development of mathematical models which are applied to the calculation of the chemical concentrations in the environmental media of concern under generic or site-specific conditions. Mathematical models are also used to assess and understand distribution and persistence of chemicals in the environment. 

In this section, we introduce examples of the application of our multi-media models, MNSEM and MAC for evaluating the environmental fate of organic chemicals under generic and site-specific conditions in Japan. 

Monthly Averaged Concentration Model (MAC) is designed to evaluate the environmental fate and human exposure of chemicals released into the terrestrial environment consisting of air and soil phases under monthly averaged site-specific conditions. 

There are several major limits of the simple regression-type statistical analysis model. One is that PbB outcomes for a specific location depend on the site-specific conditions governing the eventual statistical relationship. A second limit arises from typical absence of any means for evaluating Pb exposure pathways from source(s) to exposed individuals, their relative importance to the outcome measure, and evaluation of any role for host factors affecting the resulting PbB values, e.g., child age or family socioeconomic status. 

SADA provides a full human health risk assessment module and associated databases. The risk models follow the USEPA s Risk Assessment Guidance for Superfund (RAGS) and can be customized to fit site-specific exposure conditions. It calculates risks based on the following exposure pathways ingestion, inhalation, dermal contact, food consumption, and also a combined exposure. 

In order make an effort to bring the polyimide-metal adhesion problem to an even more fundamental level, we have previously proposed that model molecules, chosen as representative of selected parts of the polyimide repeat unit, may be used to predict the chemical and electronic structure of interfaces between polyimides and metals (12). Relatively small model molecules can be vapor deposited in situ under UHV conditions to form monolayer films upon atomically clean metal substrates, and detailed information about chemical bonding, charge transfer and molecular orientation can be determined, and even site-specific interactions may be recognized. The result of such studies can also be expected to be relevant in comparison with the results of studies of metal-polymer interfaces. Another very important advantage with this model molecule approach is the possibility to apply a more reliable theoretical analysis to the data, which is very difficult when studying complex polymers such as polyimide. 

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