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Water and the Science of Pollution
Published in Daniel T. Rogers, Environmental Compliance Handbook, 2023
Another important measure of toxicity is the lowest observed adverse effect level (LOAEL) or threshold effect value. The LOAEL is the lowest tested dose of a chemical or substance causing a harmful or adverse health effect (ATSDR 2021). Factors influencing the LOAEL include: The chemical's solubility in body fluidsThe particle size and state of the chemicalRoute of exposureResidence time of the chemical in the bodyIndividual susceptibility
Land Contamination
Published in Daniel T. Rogers, Environmental Compliance Handbook, 2023
Another important measure of toxicity is the lowest observed adverse effect level (LOAEL) or threshold effect value. The LOAEL is the lowest tested dose of a chemical or substance causing a harmful or adverse health effect (ATSDR 2021a). Factors influencing the LOAEL include: The chemical’s solubility in body fluidsThe particle size and state of the chemicalRoute of exposureResidence time of the chemical in the bodyIndividual susceptibility
The Science of Air Pollution
Published in Daniel T. Rogers, Environmental Compliance Handbook, 2023
Toxicity is measured by the effects on a whole organism, an individual organ, tissue, or even a cell. Populations are most often used to measure toxicity since any one individual may have a different level of response to a toxin at a certain dose or concentration. The most common measure of chemical or substance toxicity is termed the LD50, defined as the concentration or dose that is lethal to 50% of the population being tested (USEPA 1989a). When direct data are not available the LD50 is estimated by comparing the substance to other similar chemicals and organisms. Another important measure of toxicity is the lowest-observed adverse-effect level (LOAEL) or threshold effect value. The LOAEL is the lowest tested dose of a chemical or substance causing a harmful or adverse health effect (ATSDR 2021a). Factors influencing the LOAEL include: The chemical’s solubility in body fluidsThe particle size and state of the chemicalRoute of exposureResidence time of the chemical in the bodyIndividual susceptibility
A Bayesian Monotonic Non-parametric Dose-Response Model
Published in Human and Ecological Risk Assessment: An International Journal, 2021
Faten S. Alamri, Edward L. Boone, David J. Edwards
Since the establishment of the USEPA the literature has rapidly expanded on how to determine the dosage associated with an acceptable level of adverse effect. Initially ANOVA based methods produced general dosage thresholds by conducting the experiment at a variety of predefined dosages and finding the No Observable Adverse Effect Level (NOAEL) which is the highest dose at which there is no observed effect. In addition the Lowest Observed Adverse Effect Level (LOAEL) approach finds the lowest dose developed at which an adverse effect is observed. For more on NOAEL and LOAEL, see Cox (1987). While very straightforward to conduct and analyze, they are limited in application since it considers just the predefined dosages and ignores any dosages that are between those predefined dosages (Davis et al. 2011).
Exposure to lead, mercury, styrene, and toluene and hearing impairment: evaluation of dose-response relationships, regulations, and controls
Published in Journal of Occupational and Environmental Hygiene, 2020
Research was reviewed to find if there were any relationships between exposure to substances of interest and hearing impairment. When significant associations were identified, exposure levels were evaluated to determine whether concentrations associated with increased risk of hearing loss could be identified including the No Observed Adverse Effect Level (NOAEL) and/or the Lowest Observed Adverse Effect Level (LOAEL). NOAEL is the highest exposure level at which there are no statistically significant increases in the frequency or severity of adverse effects between the exposed group and its appropriate control. LOAEL is the lowest exposure level at which there are statistically significant increases in the frequency or severity of adverse effects between the exposed population and its appropriate control (Lewis et al. 2002).