1. 1 Persistent, Bioaccumulative and Toxic Pollutants Persistent, Bioaccumulative and Toxic Pollutants Programme (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. 2 Goals of PBT Programme 1.Prevent the introduction of new PBTs 2.Reduce the risk to human health and the environment from exposure to priority PBTs already in the environment 3.Halt the transfer of PBTs by air, water and land 4.Assess long-term effect of PBTs on the environment PBT Profiler The PBT Profiler is expected to answer 3 questions: 1.Once released, will a chemical go into the air, water, soil or sediment? 2.How long will this chemical stay in the media? 3.Will the chemical present a hazard?

3. 3 Persistence PBT Profiler calculates an atmospheric half-life by determining the importance of a chemical’s reaction with hydroxyl radicals (OH) and ozone (O 3 ) 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. 4 Persistence Half-life of Chemical MediaNot persistentPersistentHighly persistent Water< 2 months2-6 months> 6 months Soil< 2 months2-6 months> 6 months Air≤ 2 days> 2 days Sediment< 2 months2-6 months> 6 months

5. 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