FOODCHAIN: A Monte Carlo Model to Estimate Individual Exposure to Airborne Pollutants Via the Foodchain Pathway

摘要

Ingestion of contaminated food due to the airborne release of radionuclides or chemical pollutants is a particularly difficult human exposure pathway to quantify. There are a number of important physical and biological processes such as atmospheric deposition and plant uptake to consider. These processes are approximate by techniques encoded in the computer program TEREX. Once estimates of pollutant concentrations are made, the problem can be reduced to computing exposure from ingestion of the food. Some assessments do not account for where the contaminated food is eaten, while others limit consumption to meat and vegetables produced within the affected area. While those approaches lead to an upper bound of exposure, a more realistic assumption is that if locally produced food is not sufficient to meet the dietary needs of the local populace, then uncontaminated food will be imported. This is the approach taken by the computer model FOODCHAIN. Exposures via ingestion of six basic types of food are modeled: beef, milk, grains, leafy vegetables, exposed produce (edible parts are exposed to atmospheric deposition), and protected produce (edible parts are protected from atmospheric deposition). Intake requirements for these six foods are based on a standard diet. Using TEREX-produced site-specific crop production values and food contamination values, FOODCHAIN randomly samples pollutant concentrations in each of the six foodstuffs in an inerative manner. Consumption of a particular food is weighted by a factor proportional to the total production of that food within the area studied. The exposures due to consumption of each of the six foodstuffs are summed to produce the total exposure for each randomly calculated diet. (ERA citation 09:019068)