RISK ASSESSMENT OF STORMWATER CONTAMINANTS FOLLOWING DISCHARGE TO SOIL, GROUNDWATER OR SURFACE WATER

摘要

The basic challenge for future risk assessment of stormwater contaminants is to ensure that the methodologies used account for information about the local context and produce information that feeds into local decision making proceses. It is essential that sound scientific knowledge about the chemodynamics and toxicity of chemical substances is considered to ensure a minimum level of transparency, and learning from principles developed for risk assessment of chemical substances best ensures this. In the future we will need tools of varying complexity that can be applied on various spatial scales by acknowledging that stormwater projects, are often small, have limited budgets and are dealt with by non-experts in chemical risk assessment. Some useful tools would be as follows: 1. an identification list of those stormwater constituents which can be specifically classified as contaminants following discharge to surface water, groundwater and/or soil; 2. a database of physical/chemical properties of these contaminants, their environmental fate and effects, their predicted no-effect concentrations, when available, and their treatability (possible removal in various BMPs); 3. a tool for estimating concentrations of these stormwater contaminants in a site-specific context; and 4. a screening tool for identifying in a site-specific context which stormwater contaminants are critical (priority pollutants) following discharge to surface waters, groundwater and/or soils.