Scientific Trends in Risk Assessment Research

1989 ◽  
Vol 5 (5) ◽  
pp. 777-790 ◽  
Author(s):  
Elizabeth L. Anderson

The use of risk assessment approaches to evaluate the effects of toxic chemicals had its primary origin in 1976 when the U. S. Environmental Protection Agency (EPA) adopted the first federal guidelines to commit a major regulatory agency to risk assessment approaches for the evaluation of suspect carcinogens. The accom panying policy statement also adopted a risk management policy, which acknowledged that the agency would accept risk in making public health policy decisions; in essence, this represented a pri mary departure from the zero-risk goal that had dominated the first half of the environmental movement of the '70s. The approach adopted in 1976 was based on the experience of risk assessment approaches used for assessing low-dose-radiation effects on human health. To be certain that no public health risk be underestimated, particularly in light of the prior zero-risk goal, the practice of risk assessment for the first decade relied heavily on extremely protec tive assumptions in all aspects of the assessment process. For example, these assumptions included ranking the weight-of- evidence according to results in all related studies without regard for distinctions of tumor end point relevance to humans and the possibility that low-dose effects at environmental exposures might not be the same as high-dose effects. For low-dose-response charac terization, the practice has been to characterize a plausible upper bound on risk by the use of a low-dose linear non-threshold dose- response curve. Exposure assessment likewise relied on maximum plausible assumptions to characterize exposure. More recently, more attention is being paid to developing accurate scientific data bases that advance almost every aspect of the risk assessment pro cess in the direction of more accurate risk characterization. This paper will discuss the recent trends in weight-of-evidence characterization, dose-response modeling, and exposure assessment and will compare the outcomes of these refined assessments to those evaluations that have relied on the earlier, conservative approaches. In essence, if the practices of the first decade for estab lishing plausible upper bounds on the risk were accurate, improved scientific data by and large should be expected to lower the overall theoretical risk. Indeed, this is the case when recent risk assessment research is applied but there are examples to the contrary. This paper represents a survey of recent trends and applications.

2010 ◽  
Vol 29 (4) ◽  
pp. 249-261 ◽  
Author(s):  
Edward J Calabrese

This paper summarizes numerous conceptual and experimental advances over the past two decades in the study of hormesis. Hormesis is now generally accepted as a real and reproducible biological phenomenon, being highly generalized and independent of biological model, endpoint measured and chemical class/physical stressor. The quantitative features of the hormetic dose response are generally highly consistent, regardless of the model and mechanism, and represent a quantitative index of biological plasticity at multiple levels of biological organization. The hormetic dose-response model has been demonstrated to make far more accurate predictions of responses in low dose zones than either the threshold or linear at low dose models. Numerous therapeutic agents widely used by humans are based on the hormetic dose response and its low dose stimulatory characteristics. It is expected that as low dose responses come to dominate toxicological research that risk assessment practices will incorporate hormetic concepts in the standard setting process.


2014 ◽  
Vol 32 (No. 2) ◽  
pp. 122-131 ◽  
Author(s):  
P. Ačai ◽  
Ľ. Valík ◽  
D. Liptáková

Quantitative risk assessment of Bacillus cereus using data from pasteurised milk produced in Slovakia was performed. Monte Carlo simulations were used for probability calculation of B. cereus density at the time of pasteurised milk consumption for several different scenarios. The results of the general case exposure assessment indicated that almost 14% of cartons can contain &gt; 10<sup>4</sup> CFU/ml of B. cereus at the time of pasteurised milk consumption. Despite the absence of a generally applicable dose-response relationship that limits a full risk assessment, the probability of intoxication per serving and the estimated number of cases in the population were calculated for the general exposure assessment scenario using an exponential dose-response model based on Slovak data. The mean number of annual cases provided by the risk assessment model for pasteurised milk produced in Slovakia was 0.054/100 000 population. In comparison, the overall reporting rate of the outbreaks in the EU in which B. cereus toxins were the causative agent was 0.02/100 000 population in 2010. Our assessment is in accordance with a generally accepted fact that reporting data for alimentary intoxication are underestimated, mostly due to the short duration of the illness. &nbsp;


1993 ◽  
Vol 9 (4) ◽  
pp. 439-447 ◽  
Author(s):  
Francisco J. R. Paumgartten

Virtually all chemical substances may cause adverse health effects, depending on the dose and conditions under which individuals are exposed to them. Toxicology - the study of harmful effects of chemicals on living organisms - provides the scientific data base on which risk assessment of adverse health effects stands. Risk assessment (RA) is the process of estimating the probability that a chemical compound will produce adverse effects on a given population, under particular conditions of exposure. Risk assessment process consists of four stages: Hazard Identification (HI), Exposure Assessment (EA), Dose-Response Assessment (DRA), and Risk Characterization (RC). The risk assessment process as a whole makes it possible to carry out cost(risk)/benefit analysis, and thus risk management, on a rational basis. A capacity to undertake risk assessment is thus sine qua non for making decisions that are concerned with achieving a balance between economic development and adequate protection of public health and the environment.


1995 ◽  
Vol 58 (3) ◽  
pp. 289-295 ◽  
Author(s):  
SHEILA A. MARTIN ◽  
THOMAS S. WALLSTEN ◽  
NANCY DEAN BEAULIEU

This paper reports the results of a risk assessment of the adverse health effects from ingesting foods contaminated with certain microbial pathogens. The risk assessment was performed as part of a larger project to develop a risk-based sampling methodology for imported foods inspected by the U.S. Food and Drug Administration (FDA). The sampling methodology was put into operation in a computer aid to assist FDA import inspectors in choosing samples to test for violative substances. The computer aid was designed to choose samples so as to maximize the benefit from the sampling plan. The expected benefit of sampling food depends on the probability that a violation exists, the probability that it will be detected by testing, and the risk of illness associated with the violation. While most of this information is available from data collected by the FDA, very little information has been published regarding the relationship between violative substances and human illness, particularly for microbial pathogens. To narrow this information gap, we recruited the assistance of several experts in the fields of microbiology and epidemiology to evaluate the uncertainty surrounding the intake-response relationships for several microbial pathogens. The information collected from the expert elicitation process and documented here cannot substitute for the scientific data needed to accurately estimate dose-response relationships and their variances. Our goal was simply to gather approximations of these relationships to use in the sampling aid. Our results differ from traditional dose-response curves in that we quantified the uncertainty associated with each probability judgment.


2005 ◽  
Vol 24 (10) ◽  
pp. 487-527 ◽  
Author(s):  
L T Haber ◽  
J Patterson

A peer review panel made up of experts in toxicology, epidemiology, cancer mode of action (MOA), cancer mechanisms, carcinogenicity, genotoxicity, dose–response, US Environmental Protection Agency (EPA) cancer and noncancer methods, pharmacokinetic modeling and acrylonitrile, met on 22–23 September 2003 in Cincinnati, OH. The purpose of the meeting was to provide an independent review of a risk assessment of acrylonitrile that had been prepared by the Acrylonitrile Group (AN Group). Toxicology Excellence for Risk Assessment (TERA) organized the peer review and selected the panel. The panel discussed the toxicity and epidemiology literature of acrylonitrile and MOA information, and reached conclusions regarding its MOA, weight of evidence (WOE) for carcinogenicity, preferred approach for dose-response assessment and risk values. This paper summarizes the discussion and conclusions of the panel regarding the acrylonitrile assessment. Subsequent to the peer review, the authors of the acrylonitrile assessment revised their report and the panel reviewed the revised report. A manuscript of the revised assessment is being published in Regulatory Toxicology and Pharmacology.


2000 ◽  
Vol 19 (1) ◽  
pp. 32-40 ◽  
Author(s):  
E J Calabrese ◽  
L A Baldwin

Despite the substantial development and publication of highly reproducible toxicological data, the concept of hormetic dose-response relationships was never integrated into the mainstream of toxicological thought. Review of the historical foundations of the interpretation of the bioassay and assessment of competitive theories of dose-response relationships lead to the conclusion that multiple factors contributed to the marginalization of hormesis during the middle and subsequent decades ofthe 20th century. These factors include: (a) the close-association of hormesis with homeopathy lead to the hostility of modern medicine toward homeopathy thereby creating a guilt by association framework, and the carry-over influence of that hostility in the judgements of medically-based pharmacologists/ toxicologists toward hormesis; (b) the emphasis of high dose effects linked with a lack of appreciation of the significance of the implications of low dose stimulatory effects; (c) the lack of an evolutionary-based mechanism(s) to account for hormetic effects; and (d) the lack of appropriate scientific advocates to counter aggressive and intellectually powerful critics of the hormetic perspective.


1998 ◽  
Vol 17 (5) ◽  
pp. 259-262 ◽  
Author(s):  
Robert L Sielken ◽  
Donald E Stevenson

The existence of hormesis should impact quantitative risk assessment in at least seven fundamental ways. (1) The dose-reponse models for bioassay and epidemiological data should have greater flexibility to fit the observed shape of the dose-response data and no longer be forced to always be linearly increasing at low doses. (2) Experimental designs should be altered to provide greater opportunity to identify the hormetic component of a dose-response relationship. (3) Rather than a lifetime average daily dose or its analog for shorter time periods, dose scales or metrics should be used that reflect the age or time dependence of the dose level. (4) Low-dose risk characterization should include the likelihood of bene-ficial effects and the likelihood that a dose level has reasonable certainty of no appreciable adverse health effects. (5) Exposure assessments should make greater efforts to characterize the distribution of actual doses from exposure rather than just upper bounds. (6) Uncertainty characterizations should be expanded to include both upper and lower bounds, and there should be an increased explicit use of expert judgement and weight-of-evidence based distributional analyses reflecting more of the available relevant dose-response information and alternative risk characterizations. (7) Risk should be characterized in terms of the net effect of a dose on health rather than a dose's effect on a single factor affecting health - for example, risk would be better expressed in terms of mortality from all causes combined rather than a specific type of fatal disease.


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