Exposure models Sample Clauses

Exposure models. ‌ (i) inhalation (via respiratory tract), (ii) dermal (via skin) and (iii) ingestion (via mouth). The model consists of different compartments through which the pesticide can pass. These compartments can broadly be divided into three steps: • Emission from source (source, local source zone) • Transport between source and operator (air-, surface- and bulk- zone) • Transport at the operator (respiratory protective equipment (RPE), outer clothing contaminant layer, inner clothing contaminant layer, skin contaminant layer, (pre-)oral /mouth) The transport of PPPs occur through 4 mechanisms, (i) separation from gas/vapour or solid particles from parent material (source strength), (ii) transport between compartments, (iii) loss of pesticide from compartments due to sinks, and (iv) uptake by the receptor (▇▇▇▇▇▇▇▇▇ et al, 2008). The latter mechanism (uptake) is only included as an estimate after modeling the different routes of exposure. The inhalation exposure models accounts for the most important determinants that are involved in the airborne transfer of PPPs from the formulation. The dermal exposure is the most complex route of exposure and occurs through three potential pathways, i.e. (i) deposition from the air, (ii) contacts between surfaces and the body, and (iii) bulk transfer through splashes or dripping (from liquids) and impaction (from solids) (▇▇▇▇▇▇▇▇▇ et al, 1999). It should be noted that the three potential dermal pathways of exposure are scenario-specific and not always relevant (and therefore not included in all the models). And lastly, a generic estimate is made of ingestion exposure that considers contamination of the hands or gloves and the probability that it is transferred into the mouth and oral route. Ingestion Inhalation For each scenario and exposure route, the most important determinants that influence the transport of a PPP from the source to the receptor were identified and, where appropriate, included in the models. Their effect sizes and correlations were evaluated and determined by means of data analyses, literature reviews and expert opinion. Subsequently, mechanistic algorithms were developed using the available evidence to underpin the models. In general, the following modeling procedure was followed for each scenario: • Collation of available evidence from the literature • Statistical (regression and correlation) analyses of the available exposure data • Identifying exposure determinants and allocating effect sizes and distri...