Human exposure thresholds

Do the intended conditions of use result in an exposure greater than the human exposure threshold for the structural class ... 

Cumulative distributions of the logarithms of NOELs were plotted separately for each of the stmcmral classes. The 5th percentile NOEL was estimated for each stmctural class and this was in mrn converted to a human exposure threshold by applying the conventional default safety factor of 100 (Section 5.2.1). The stmcmre-based, tiered TTC values established were 1800 p,g/person/ day (Class I), 540 pg/person/day (Class II), and 90 pg/person/day (Class III). Endpoints covered include systemic toxicity except mutagenicity and carcinogenicity. Later work increased the number of chemicals in the database from 613 to 900 without altering the cumulative distributions of NOELs (Barlow 2005). 

Neurotoxicants, immunotoxicants, and teratogens were also further explored, and it was concluded that, except for the organophosphorous neurotoxicants, such compounds would be covered by the stmcmre-based, tiered TTC approach. For organophosphates, a human exposure threshold of... 

Human Exposure Threshold of Toxicological Concern (TTC) Values... 

The human exposure threshold was calculated by multiplying the fth percentile NOEL by 60 (assuming an individual weighs 60 kg) and dividing by a safety factor of 100. 

ILSI is publishing its proposals for Threshold of Toxicological Concern (ToTC), aimed at establishing a human exposure threshold below which no toxicity data would be necessary, avoiding the need to expend valuable resources, costs and time on developing safety materials and their uses, and ensure that they comply with national and international legislation. 

Threshold of Toxicological Concern The threshold of toxicological concern (TTC) is a principle that refers to the establishment of human exposure threshold value for all chemicals below which there would be no appreciable risk to human health. The concept that safe exposure thresholds or levels can be identified for individual chemicals is already widely used for toxicology profiles. However, the TTC concept goes further in proposing that de minimis values can be identified for many new chemicals including those of unknown toxicity base on their similarity to known chemicals. The TTC concept can be used to assess and set a safe level of exposure for a... 

Hazard characterization is a quantitative or semi-quantitative evaluation of the nature, severity, and duration of adverse health effects associated with biological, physical, or chemical agents that may be present in food. The characterization depends on the nature of the toxic effect or hazard. Eor some hazards such as genotoxic chemicals, there may be no threshold for the effect and therefore estimates are made of the possible magnitude of the risk at human exposure level (dose-response extrapolation). 

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