Persistent, Bioaccumulative and Toxic Pollutants

1. Persistent, Bioaccumulative and Toxic Pollutants Persistent, Bioaccumulative and Toxic PollutantsProgramme (PBT)launched by the EPA in 1998: - Reduce the use and release of the PBT pollutants and make sure they are disposed properly - Some of the pollutants on this list are the “dirty dozen” but it also includes inorganic elements, i.e. mercury or organometallic compounds

2. Goals of PBT Programme • Prevent the introduction of new PBTs • Reduce the risk to human health and the environment from exposure to priority PBTs already in the environment • Halt the transfer of PBTs by air, water and land • Assess long-term effect of PBTs on the environment PBT Profiler • The PBT Profiler is expected to answer 3 questions: • Once released, will a chemical go into the air, water, soil or sediment? • How long will this chemical stay in the media? • Will the chemical present a hazard?

3. Persistence PBT Profiler calculates an atmospheric half-life by determining the importance of a chemical’s reaction with hydroxyl radicals (OH) and ozone (O3) Half-life calculated directly from the gas-phase rate coefficients An estimation programme will provide an indication of a chemical’s environmental biodegradation rate in relative terms such as hours

4. Persistence

5. Bioconcentration Determines a chemical’s potential to bioaccumulate directly from an estimated bioconcentration factor (BCF) PBT Profiler assesses the bioconcentration of the chemical of interest from data stored in its database: • BCF < 1000 – chemical not expected to bioaccumulate • BCF > 1000 – chemical will bioaccumulate • BCF > 5000 – chemical will be highly bioaccumulative Toxicity • PBT Profiler considers only the potential chronic toxicity to fish: • estimates toxicity using the Ecological Structure Activity Relationships (ECOSAR) programme → predicts the toxicity of chemical to aquatic organisms such as fish, invertebrates and algae