Human Health Risk Assessment Overview

Assessing the potential health risks associated with chemical exposure in air, food, water, occupational, domestic, or recreational environments has become an issue of critical importance to the registration, regulation and safe use of commercial chemical products. A thorough understanding of potential health risks is also important in liability determination and in toxic tort litigation.

TSG's outstanding team of fully accredited toxicologists are highly skilled in the four basic components of risk assessment — hazard identification, dose-response determination, exposure assessment and risk characterization — and fully conversant with applicable regulatory guidelines and procedures. TSG specializes in unique, custom-designed assessments employing alternative methodologies most suited to the proper resolution of specific problems.

Hazard Identification

Complete, qualitative understanding of the major types of toxic effects inherent in a given chemical typically requires the identification, careful review, interpretation and evaluation of a large and diverse amount of highly specialized data. TSG has direct access to a wide variety of electronic databases which provide a rapid and effective means of searching peer-reviewed scientific literature and identifying toxicity studies which will support regulatory strategy.

TSG's toxicology staff has many years of experience in the evaluation and interpretation of data from in vivo, in vitro, and mechanistic studies, employing a total-weight-of-evidence approach to develop an overall toxicological profile. While fully adhering to the appropriate evaluation criteria, TSG makes full use of newly emerging information from the scientific community and developing advances in evaluation and assessment methods.

Dose-Response Assessment

TSG's consulting staff has outstanding experience in determining dose-response relationships from animal studies and in extrapolating such data to humans. TSG determines NOEL-based reference doses and uses a number of models to develop cancer potency factors from chronic oncogenicity data. In conducting dose-response assessment, TSG employs scientifically rigorous approaches and state-of-the-art methodologies, including:

▲ Mechanistic information

▲ Pharmacokinetic modeling

▲ Meta analysis.

Exposure Assessment

TSG offers clients extensive experience in multimedia exposure assessment to pesticides and other chemicals and utilizes the most advanced software, databases and methodologies available, including its own DietRisk© software for dietary exposure/risk assessments of pesticide residues in food. Members of TSG's staff were also instrumental in developing the EPA-approved Pesticide Handler's Exposure Database (PHED) and have expertise in using this database to provide information on exposures during mixing/loading and application operations. The range of programs offered by TSG allows selection of the model best suited to the client's needs and, at the same time, increases the accuracy and decreases the uncertainty in the exposure assessment process.

Risk Characterization

Risk characterization conveys the presence or absence of risks, along with information about how the risk was assessed and where uncertainties or assumptions still exist. With extensive experience in all facets of human risk characterization, TSG continuously seeks to develop and use new techniques that improve the level of confidence of the risk assessment. TSG also defines and quantifies uncertainty, including route-specific pharmacokinetic considerations, less-than-lifetime exposure and risk estimations, and distributionally based approaches for exposure/risk analysis and for quantifying uncertainties.