PERSISTENT BIOACCUMULATIVE

In terms of environmental metrics to assess processes, it is hopefully clear that a considerable testing burden exists to assess potential environmental hazards that lead to a credible risk assessment. At a first pass, one would typically screen compounds from an environmental hazard perspective to assess their tendency for persistence, bioaccumulation and toxicity. Depending on the final application of the compoimd, one might avoid commercial production of a particular compound, or one might devise processes that would use the... 

Benchmark 2 continues the emphasis on persistence, bioaccumulation, and toxicity, but at lower threshold values. In addition. Benchmark 2 includes flammability and explosiveness. It is anticipated that many chemicals will not move past Benchmark 2 because of the broad scope of hazards and challenging threshold values included in the Green Screen. 

The European Commission (EC) has sponsored four reports that evaluate a set of 553 substances selected by experts and stakeholders for assessment for endocrine disruption. Each report addresses a subset of the total set based on priorities such as whether the chemicals are persistent, bioaccumulating or High Production Volume chemicals and/or whether or not there is already regulatory control of the chemical. 

The Danish List of Undesirable Substances is a list of chemicals of concern that the government believes should be avoided to the extent feasible in commerce. Using a systematic analysis, substances are selected automatically if they meet some clear and defined criteria, for example, problematic classifications, because they are imder suspicion for being PBT/vPvB (Persistent, Bioaccumulative, Toxic/very Persistent, very Bio accumulative) or endocrine-disrupting. 

US EPA (2007) Fact Sheet L Multimedia Strategy for Priority Persistent, Bioaccumulative, and Toxic (PBT) Chemicals. [Online - accessed 1 May 2007] Available from URL http //www.epa.gov/ pbt/pubs/fact.htm... 

Reducing the presence of the most persistent, bioaccumulative, and toxic (PBT) chemicals in hazardous wastes by 50% by the year 2005. 

Amot JA, Mackay D (2008) Policies for chemical hazard and risk priority setting can persistence, bioaccumulation, toxicity, and quantity information be combined Environ Sci Technol 42(13) 4648 1654... 

Besides the main process chemicals, a great variety of chemicals are used for auxiliary process purposes. These auxiliary agents may demand special attention because of the problem of reactivity, toxicity, persistence, bioaccumulation, mobility and the generation of problematic metabolites. It is, therefore, important to know the quantities used and their characteristics. 

USEPA (2008) Persistent bioaccumulative and toxic (PBT) Chemical Program. DDT. United States Environmental Protection Agency. Available from www.epa.gov... 

Persistent, Bioaccumulative and Toxic and Very Persistent and Very Bioaccumulative Substances... 

Authorisation will also be required for persistent, bioaccumulative and toxic (PBT) and very persistent and very bioaccumulative (vPvB) substances. The PBT and vPvB criteria are defined in Annex XII of the Regulation (Table 7). There are subtle differences in the... 

ECR Existing Chemicals Regulation PBT Persistent, bioaccumulative and toxic... 

Commenting ona January 5,1999 proposal, environmental groups in early April called again on EPA to lower its proposed Toxic Release Inventory (TRI) reporting threshold to zero for certain chemicals. The chemicals include mercury, dioxins, and lead. Currently facilities are only required to report chemical releases if they manufacture or process at least 25,000 pounds or otherwise use 10,000 pounds annually of a fisted TRI chemical. The environmental advocates argued that any releases of chemicals considered to be persistent, bioaccumulative and toxic should be reported as a threat to public health. This abstract includes all the information contained in the original article. 

The chlorinated chemicals assessed do not have the same risk profile. For the more volatile chemicals the safety margins between the actual exposure and the level at which no effect on the environment would be expected is quite high. For more persistent chemicals there is a need to look to the environmental compartment where they can be accumulated (mainly in sediments and biota). For some of these chemicals the safety margin is quite low and in worst-case situations serious effects may occur. For the very persistent, bioaccumulative and toxic chemicals (like dioxins, PCBs and DDT), acceptable environmental concentrations are so low and difficult to control that the industry is committed to reducing as far as possible releases to the environment through application of Best Available Techniques (BAT), mainly with respect to dioxins. For other chemicals (PCBs, DDT), production has already been halted for some years. 

The so-called persistent organic pollutants (POPs) are the subject of the Rio Declaration (1994) and the Stockholm Convention (2001) these international agreements (yet to be ratified in all signatory countries, including the United States) call for the elimination from production of 12 persistent chemicals, including the chlorinated pesticides and PCBs mentioned above (all of which have already been eliminated from production in the United States). Current regulatory efforts in the European Union and the United States place emphasis on elimination or restriction of all PBTs (persistent, bioaccumulative, and toxic chemicals). 

Persistent bioaccumulative toxics (PBTs) Pollutants that have slow degradation rates and high bioaccumulahon factors. 

As long as chemical regulation is based on this risk-based philosophy, human and environmental exposure to dangerous chemicals - substances of very high concern - will continue. The disperse and dilute model does not work for persistent bioaccumulative chemicals because Nature quite simply collects and concentrates these materials overtime. 

It is not possible to achieve "adequate control" of the risks of persistent, bioaccumulative chemicals. The fact that traditional risk assessment cannot reasonably be applied to such chemicals, and that a revised PBT (persistent, bioaccumulative, toxic) assessment is necessary, is explicitly recognised in the EU s Technical Guidance Document for risk assessment. Their intrinsic properties mean that there is a high risk of exposure at sometime during the lifecycle of the chemical or the article that contains it. Even small releases, if they are continuous, can result in significant exposures. This is why we see significant and, in some cases, escalating levels of brominated flame retardants, nonylphenols and other persistent chemicals in breast milk, umbilical cord blood and human tissue. 

Another model, used in the USA, is the OASYS Pollution Prevention Optional Analysis System, developed by the Toxic Use Reduction Institute. Technologies are assessed on a variety of hazard criteria, including acute and chronic human toxicity, physical properties, aquatic impacts, persistence/bioaccumulation, atmospheric releases, disposal, chemical properties, energy/resource use, product hazard and exposure potential. Alternatives are rated to... 

The Swedish Classification Scheme initiated in 2005 by the Swedish Association of Pharmacy Industries (LIF), the Swedish Medical Products Agency, Apoteket (National Corporation of Swedish Pharmacies), the Swedish Association of Local Authorities and Regions and the Stockholm County Council, take in account Persistence, Bioaccumulation and Toxicity (PBT) characteristics of pharmaceutical products. This voluntary scheme looks at the environmental hazard and the associated risk of pharmaceutical products. The environmental risk is calculated based on the ratio PEC/PNEC according to the EMEA guideline [17,124, 127]. The obtained information is only available on the website www.fss.se, since due to European restrictions it is not possible to include warning labels on the packaging of medications [17]. 

One of the pollutants known to interfere with cardiovascular development is 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD). TCDD is a persistent, bioaccumulative environmental contaminant, as well as a potent developmental toxicant and human carcinogen [30]. Piscine, avian, and mammalian cardiovascular systems are sensitive to TCDD toxicity, with effects including cardiac enlargement, edema, and several dysfunctions. In zebrafish embryos, these effects include areduction in cardiomyocyte number at 48 hpf, decreased heart size, altered vascular remodeling, pericardial edema, and decreased ventricular contraction culminating in ventricular standstill [31-34]. 

The US EPA lists chlordane as a persistent bioaccumulative toxic chemical. In 1978, the EPA cancelled use of chlordane on food crops and by 1988 all use was banned. 

Name persistent environmental contaminants (have various names depending on agency - i.e. US EPA persistent bioaccumulative and toxic (PBT) or United Nations persistent organic pollutant (POP)... 

Mercury Metal - persistent - bioaccumulates - contaminates many species of fish. Widely used in industrial processes. Causes developmental neurotoxicity -children most susceptible... 

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