ELSEVIER Toxicology 173(2002) 123-143 www.elsevier.comf1ocateftoxicol Human health risk assessment:selected internet and world wide web resources* Jacqueline Patterson *, P.J. (Bert) Hakkinen 1, Andrea E. Wullenweber t~xJologyExcelkni:e jorRisk Assessment,1757 Chase Avenue, Cincinnati, OR 45223, ~S'A ,. c,. c Abstract The world wide web (WWW) has become a valuable source of 24 hour-a-day accessto infonnation needed by human health risk assessors.Various web sites and other Internet resourcesprovide infonnation needed for human hazard identification, dose-response evaluation, exposure assessment,risk characterization, and risk management. Information on risk communication is also available. Substantial collections of information on multiple aspects of risk assessmentare found in sites sponsored by RiskWorld, the (US) EPA's National Center for Environmental Assessment(NCEA), the (US) National Library of Medicine's TOXNET, the (US) Agency for Toxic Substancesand Disease Registry (ATSDR), and the International Programme on Chemical Safety (IPCS). Also valuable are various web sites providing information on the physical and chemical properties of chemicals, the environmental fate and transport of chemicals, government regulations, and guidance and training for performing risk assessments.Several professional societies and other organizations have web sites addressing risk assessmentissues and information, and there are Internet mailing lists for online help and for sharing infonnation and perspectives.We classify selectedweb sites according to user needsand provide the reader with a collection of selectedsites that can serve as entry points to risk assessment-relatedweb resources.@ 2002 Published by Elsevier ScienceIreland Ltd. Keywords: Risk. assessment;Exposure assessment;Risk. analysis; Internet resources;Web sites I. Introduction '" The authorsdo not n~sarily endorseany productsor Human health risk assessment involves the services mentioned in this paper, or provided via the Web evaluation and quantification of potential health resources described. The have no editorial control over the hazards to humans from exposure to substances ongoing changes in Web site contents other than for the and agents in their environment. This paper iden- Toxicology Excellence for Risk Asscssment (TERA) site. Readers should use caution and apply expert judgment when tifies selectedworld wide web (WWW) and other considering use of the information from Web sites. Internet resourcesthat can assistthose conducting * Corresponding author. Tel.: + 1-513-521-7426. or interpreting these assessments.It focuses on E-mail addresses: [email protected] (J. Patterson), human health hazards primarily from exposure to [email protected] (P.J.B. Hakkinen), [email protected] substancesin the environment. Government and (A.E. Wullenweber). I Tel.: + l-513-542-7475x24. private web sites from the US and elsewhereare 2 Tel.: + 1-815-577.2626. highlighted. Web resourcesfor evaluating ecologi- 0300-483X/O2/S- ~ front matter C>2002 Published by Elsevier ScienceIreland Ltd. PII: SO300-483X(O2)OOO27-6 124 J. Patterson et aI. / Toxicology 173 (2002) 123-143 cal risks and occupational exposures are covered range from simple screeningexercises to complex, elsewherein this series (Russom, Greenberg) and, multi-year projects that quantify risks for a range therefore, have not been addressed here. The of exposures. reader is also referred to Volume 157, Issue I of The four steps of the NAS paradigm are briefly Toxicology (2001) that also was devoted to Inter- described below. Government agenciesand inter- net resourcesfor toxicology. Some of the subjects national bodies have used the NAS paradigm to covered include toxicology information resources provide a framework for their risk efforts, along from the US EPA (Poore et al., 2001), other US with more specific guidance for evaluating and government agencies (Brinkhuis, 2001), profes- quantifying risk for agents causing specific types sional societies (Kehrer and Mirsalis, 2001), fee of effects. Sources for methodology and guidance and non-fee information resources(Wright, 2001), documents will be noted below. Internet search engines and library catalogs In the Hazard Identification step, one identifies (Wukovitz, 2001), digital education tools (Sharpe the contaminants that are suspected to pose et al., 2001), and online resourcesfor news about health hazards, quantifies the concentrations at toxicology and related topics (South, 2001). which they are present in the environment, and The National ResearchCouncil of the National describesthe specific forms of toxicity (e.g. neuro- Academy of Sciences(NAS) described the process toxicity, liver necrosis, and carcinogenicity) that of human health risk assessmentin 1983 (NAS, can be caused by the contaminants of concern. 1983)and subsequentlyupdated their paradigm in The risk assessorthen evaluates the conditions 1994 (NAS, 1994). NAS identified four steps for under which these forms of toxicity might be risk assessment.This paradigm has been adopted expressedin exposed humans. Much of the data by risk assessmentpractitioners and provides a needed for this step is primary scientific literature framework to evaluate the toxicity database for from the fields of toxicology and epidemiology. chemicals to which humans are or may be ex- Conclusions regarding hazard are frequently ex- posed, and to attempt to identify and quantify pressedas a weight-of-evidenceregarding the sub- potential risks to health from these exposures. stance's potential to elicit a particular type of The risk assessmentprocess is also used to esti- effect in exposed humans. This paper will not mate levels of intake that are expectedto be 'safe'. addressresources for seekingprimary literature to These values are then used in conjunction with conduct this step, but rather will highlight sources exposure information to determine acceptablelev- for existing evaluations conducted by government els for concentrations of hazardous chemicals in agenciesor other parties. The reader is referred to environmental media. Risk assessment,evaluation other papers in this serieson specific toxicological of the scientific data, is frequently distinguished endpoints (e.g. carcinogenesis,developmental and from risk management; decision making based in reproductive toxicology, and genetic toxicology), part on the risk assessmentinformation. In mak- as well as the publication by Wright (2001) on ing risk management decisions, the risk manager searching toxicology databases. may consider other factors such as economics, The second step in the NAS paradigm is the technical feasibility, public policy, and/or stake- Dose- ResponseAssessment, in which the quanti- holder considerations. tative relation between the dose and the response Examples of uses for risk assessmentinforma- is described; this may involve the use of mathe- tion include determining clean-up levels for haz- matical models. Variability in response,including ardous waste sites, estimating consumer exposure individual differences in susceptibility would be to a product ingredient, decisions regarding land considered. The result of the dose-response as- use, and setting drinking water standards for wa- sessmentis an estimate of risk, or sometimes an ter supplies. Risk assessmentis a multi-disciplined estimate of a 'safe' exposure or threshold for the effort involving toxicologists, epidemiologists, effect of interest. Much of the data for risk assess- biostatisticians, mathematical, and biological ment comes from laboratory animal research and modelers, and others. Risk assessmentefforts can in vitro and other alternatives to animal testing, J. Pattersonet at. jToxicofogy 173(2002)123-143 '21 necessitating the use of scientific judgements to those that broadly cover an area of risk assess- extrapolate to human exposure. A number of ment. Many of these sites include links to other government entities (and a few private organiza- sites and pages that the reader may find useful. tions) conduct evaluations of hazard and dose- Our selection of sources relies heavily on govern- response, writing substantial documents that ment sites, and primarily US federal sites. Sev- describe and interpret the available data and esti- eral US federal agencies are at the forefront in mate risks. Many of these documents are now human health risk assessmentand in making available through the web, as well as compila- their information available on the web, in partic- tions of risk estimates and summary information, ular the (US) Environmental Protection Agency which has been extracted from them. (EPA). We also focused primarily on sites with Exposure Assessment involves specifying the information freely available to the public and population that might be exposed to the agent or those that we expect would maintain a presence substance, identifying how exposures can occur, on the web in the future. and estimating the magnitude, duration, and tim- Web resources for risk assessmenthave been ing of the doses to which people might be ex- organized below roughly along the lines of the posed. Exposure assessmentsare primarily site NAS paradigm. We first highlight a handful of and/or situation specific evaluations. They re- sites that contain significant basic information quire data on the specific population of interest, and links to other resources. Sections follow on for example the exposures of the general public hazard and dose-response information, physical to consumer products and occupational