Identifying Chemicals of Concern

In addition to regulated chemicals, examples of hazard categories that may be selected for identifying chemicals of concern include but are not limited to Box 8.1. 

Appendix 1 contains a number of references and links to chemical lists and resources to help identify chemicals of concern. In addition, it maybe useful to review the criteria used to classify substances via EU s Dangerous Substance Directive (67/548/EEC), Environment Canada s Ecological Categorization of Substances on the Domestic Substances List, or Health Canada s Categorization of Substances on the Domestic Substances List when establishing your organization s criteria for selecting chemicals of concern. 

Chemicals of concern can also be defined based on hazard criteria that apply to chemicals regardless of whether or not they are on regulatory or policy hsts. Below we describe several tools that can help businesses to identify chemicals of concern through modehing programs and by tracking regulatory hsts around the world. 

A Resources to identify chemicals of concern B Chemical toxicity C Exposure assessment tools D Hazard and risk assessment tools E Safer chemistry design tools... 

Environmental Defence recently released Toxic Nation A Report on Pollution in Canadians (Environmental Defence 2005). Samples were collected from 11 people for the presence of 88 chemicals, including heavy metals, PBDEs, PCBs, perfluorinated chemicals, organochlorine pesticides, organophosphorus-insecticide metabolites, and VOCs. The study objectives included determining whether pollutants were present at measurable concentrations in Canadians, identifying chemicals of concern, and creating public awareness of methods for avoiding exposure. 

Identifying chemicals of concern to public health in drinking-water is based on the hazard to health of those chemicals and the probability of exposure. In many parts of developing countries, and in rural areas of some developed countries, water quality data are limited or nonexistent, making it difficult to determine priorities for risk management based on both criteria. In such cases, the priority for risk management must be determined on the probability of exposure alone,... 

In order to be effective as a test battery, the combination of tests shonld be more effective than the individnal tests for identifying chemicals of concern, and the tests must be complementary. That is, they mnst measnre different effects and not duplicate each other to any large extent. In an ideal test battery, false negatives in one test will be correctly identified by one or more of the other tests. 

Department of the Environment, Food and Rural Affairs, Chemicals Stakeholder Forum, Criteria for Identifying Chemicals of Concern (available at http //www.defra. gov.uk/environment/chemicals/csf/criteria/index.htm). See also The Chemicals Stakeholder Forum, Criteria for Concern of the Chemicals Stakeholder Forum (available at http //www.defragov.uk/environment/ chemicals/csf/criteria.htm). 

Chemicals Stakeholder Forum, Criteria for Identifying Chemicals of Concern (available at http //www.defra. gov.uk/environment/chemicals/csf/papers.htm). 

The chemical risk-assessment process begins by identifying chemicals of concern, potential pathways of exposure, and at-risk populations. Consider, for example, a Superfund hazardous chemical waste site, a pesticide manufacturing facility that operated from 1950 to 1970, when it went out of business, and was subsequently razed. Its 20 years of operation were characterized by sloppy waste disposal practices and numerous complaints from nearby residents to local authorities. The site was reported to the U.S. Environmental Protection Agency (ERA) in 1983, and a preliminary site investigation was conducted pursuant to the federal Comprehensive Environmental Response, Compensation and Liability Act of 1980 (CERCLA, or... 

The four steps of the risk-assessment process are hazard identification, analysis of exposure, analysis of effect, and risk characterization. In the hazard identification step, the risk assessor identifies chemicals of concern, environmental pathways of exposure, and populations and subpopulations at risk. The exposure analysis develops exposure scenarios and estimates the chronic daily intake of each chemical of concern. In the analysis of effect, the risk assessor combines the chronic daily intake calculated in the exposure analysis with toxicity data from animal studies (and/or human epidemiological studies, if available) to estimate the risk of toxic effects in exposed populations, whereby risks to public health are divided into two broad categories noncancer health effects and cancer. The final step of the risk-assessment process, risk characterization, is a narrative that marshals all the evidence of risk to public health, including quantitative risk assessments and qualitative evidence of risk. The risk assessor weighs all the evidence and uses professional judgment to draw conclusions about risks. 

Pesticides used on crops grown on the test site in previous seasons may also have an impact on the outcome of a field residue trial. Carryover of prior pesticide applications could contaminate samples in a new trial, complicate the growth of the crop in a trial, or cause interference with procedures in the analytical laboratory. For this reason, an accurate history of what has transpired at the potential test site must be obtained before the trial is actually installed. The protocol should identify any chemicals of concern. If questions arise when the history is obtained, they should be reviewed with the Study Director prior to proceeding with the test site. In most annual crop trials, this will not be a significant issue owing to crop rotations in the normal production practices, because the use of short residual pesticides and different chemical classes is often required for each respective crop in the rotation. However, in many perennial crops (tree, vines, alfalfa, etc.) and monoculture row crops (cotton, sugarcane, etc.), the crop pesticide history will play a significant role in trial site selection. 

Since the completion of the furniture flame retardancy partnership, which moved the industry towards alternatives for the chemical of concern, pentaBDE, the DfE Program has developed partnerships to evaluate Agency priority chemicals (http // www.epa.gov/dfe/altemative assessments.html). These partnerships will assist product manufacturers as they identify safer chemical alternatives [22]. 

Through its partnerships, the DfE Program has effectively applied informed substitution to search for and identify alternatives to chemicals of concern, to guide the development of more sustainable products and in turn safer chemicals, to understand where to make improvements in industrial processes, and, in the absence of safer chemicals, to develop best practices to reduce exposures to toxic chemicals. 

It is not feasible to study a wide array of tissues in a general population sample, so it is important to identify tissues that most accurately account for the body burden of most of the chemicals of concern. Figure 4-5 shows the main routes of exposure and the matrices available for analysis of biomarkers based on the metabolism and pattern of bioaccumulation and... 

Diagnostic indicators such as indicator species and community metric approaches are useful in extrapolation between smaller test units to landscapes and between landscapes themselves. The use of these indicators in extrapolation can be improved by constructing databases with information on the life-cycle characteristics of species, their occurrence and mobility in the landscape, and their sensitivity to the chemicals of concern. In the extrapolation of site-specific ecological impacts of chemical stressors, it is important to use more than one indicator to increase the discriminatory power of identifying impaired sites and to reduce the possibility of false negatives (type 2 errors, in which responses are present but not observed). 

Further, it identifies risk driver chemicals of concern (e.g., benzene). Figure 2.1 provides an example of a site that needs to be characterized. 

Potential chemicals of concern resulting from incineration operations are identified prior to any trial burns, as part of the permitting process. Typically, a few hundred chemicals of concern are identified, but only a small sampling are actually present in incinerator emissions. Since actual emissions data were not initially available from disposal facility sites in the continental United States, data from JACADS operations were used until site-specific emissions data became available. Also, if a given chemical of concern is not detected in site emissions, then it is assumed to be present at the minimum detection limit concentration, whether or not it is actually there. 

The two main criteria for identifying specific chemicals of concern to public health in any particular setting are ... 

This is a qualitative and quantitative evaluation of the potential adverse effects from the possible exposure of the chemical of concern. It involves a summary of ecotoxicity data for chemicals present in a sensitive ecosystem, identifying relevant indexes of toxicity against which potential exposure concentrations can be compared in the risk characterization. 

Screening analysis was conducted for different exposure pathways and chemicals of concern. Using a screening level cutoff of a one-in-a-million excess risk for a 70-year lifetime exposure for the maximally exposed individual (MEI), a set of carcinogenic chemicals was identified for further analysis. For noncarcinogens, MEI exposure levels were compared to health thresholds. If the MEI exposure exceeded the established health threshold, further analysis was done. 

The ATSDR has established a mixtures program that consists of three components trend analysis to identify combinations of chemicals of concern, experimental studies to identify data that would be useful in the development and implementation of predictive decision, support methodologies, and development of assessment methodologies and guidance to provide health assessors with the tools to incorporate the evaluation of multiple-chemical exposure into site assessments. ATSDR suggests the weight of evidence... 

US EPA s approach is essentially an application of NAS , tailored to provide guidance for assessing risk associated with contamination in environmental media. Adverse health impacts associated with exposure to the chemical of concern are identified through the hazard identification, dose response, and toxicity assessment. Exposure is evaluated during the exposure assessment and data collection and evaluation steps. 

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