|
Sielken & Associates provides statistical research and consulting in human health, environmental, and ecological risk assessment and related activities (especially dose-response modeling, exposure assessment, and risk characterization). Although we can implement and critique standard/default regulatory methods, we can also utilize more advanced techniques to more fully characterize the dose-response relationships, do probabilistic exposure analyses, and lessen the usual compounding of multiple conservatisms and exaggeration of exposure and risk.
We have over 25 years of experience performing human health risk assessments. Cancer potency and risks have been a major focus. Another focus has been noncancer health effects, the use of both deterministic and probabilistic uncertainty factors, and weight-of-evidence analyses.
Our experience in environmental and ecological risk assessments includes a wide variety of toxicological effects in various plant and animal species, endangered species, bioaccumulation, and ecosystem effects.
Members of Sielken & Associates have been developing dose-response modeling techniques since the early 1970s. GEN.T and other tools allow us to fit experimental and epidemiological data; analyze response-frequency and time-to-response data; evaluate linear and nonlinear models; fit threshold and nonthreshold models; incorporate alternative dose metrics; and evaluate different methods of high-to-low-dose, interspecies, and interindivual extrapolation.
Sielken & Associates helped develop some of the earliest probabilistic exposure assessments (e.g., for the superfund site at the Rocky Mountain Arsenal starting in the earlier 1980's). We have considerable experience developing distributions for the exposure inputs and parameters.
Over the last 25 years, we have determined numerous different types of risk characterizations including extra and added risks, benchmark doses, margins of exposure, hazard indices, and reference doses and concentrations. We have calculated distributions and lower bounds in order to put default upper bounds into perspective. We have also calculated alternative, more realistic upper bounds.
In addition, Sielken & Associates have been active in developing methods for aggregate and cumulative risk assessment. We helped develop the Cumulative and Aggregate Risk Evaluation System (CARES) software in response to the Food Quality Protection Act (FQPA).
>> Dose-Response Modeling
>> Exposure
>> Risk Characterization
>> Statistics |