A Critical Appraisal of the Threshold of Toxicity Model for Non-Carcinogens

Most regulatory agencies assume that there is no safe level of exposure to carcinogens but that a threshold, or “safe” exposure level exists for non-carcinogens. However, recent discoveries have cast serious doubt on the validity of this concept. Five examples of non-carcinogens without an apparent threshold (neonicotinoids, dioxin, dieldrin, endocrine disruptors, and sulfhydryl-reactive metals) are presented. It is also clear by now that the threshold model for non-carcinogens may seriously underestimate actual risk. Risk assessments can no longer assume thresholds for non-carcinogens when the shape of the dose-response curve is linear at low concentrations. Risk management of such chemicals should be based on the ALARA principle (“as low as reasonably achievable”). *Corresponding author: Henk A Tennekes, Experimental Toxicology Services (ETS) Nederland BV, Frankensteeg 4, 7201KN Zutphen, The Netherlands, Tel: +31(0)575547717; E-mail: [email protected] Received September 22, 2016; Accepted September 28, 2016; Published September 30, 2016 Citation: Tennekes HA (2016) A Critical Appraisal of the Threshold of Toxicity Model for Non-Carcinogens. J Environ Anal Toxicol 6: 408. doi: 10.4172/21610525.1000408 Copyright: © 2016 Tennekes HA, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Citation: Tennekes HA (2016) A Critical Appraisal of the Threshold of Toxicity Model for Non-Carcinogens. J Environ Anal Toxicol 6: 408. doi: 10.4172/2161-0525.1000408