Edward J. Calabrese. Muller’s Nobel Prize data: Getting the dose wrong and its significance. Environmental Research 176 (2019) 108528
This paper evaluates the significant historical paper of Muller and Mott-Smith (1930), which successfully disputed the proposal of Olson and Lewis (1928) that background ionizing radiation is the driving mechanism of evolution. While the present analysis supports the general conclusion that background radiation is not a quantifiable factor affecting evolution, the paper reveals methodological errors and questionable conclusions in the Muller and Mott-Smith (1930) paper, which may have impacted the acceptance of the linear non-threshold (LNT) model. Most importantly, this paper reveals that in Muller’s (1927) Nobel Prize research he used a treatment exposure (total dose) that was 95 million-fold greater than the average background exposure, a value far greater than the 200,000 fold reported by Muller and Mott-Smith (1930). Such a large exposure rate dis- crepancy may be historically important as it may have led to the over-reliance on Muller’s research in support of the derivation and use of the LNT single-hit model.
“Coincident with the 2017 Presidential inauguration, real GDP growth changed from underperforming experts’ forecasts to outperforming them (Tankersley 2019). The CEA’sfindings on the aggregate effects of regulations and deregulations may help explain this state of affairs. Regulatory actions and their aggregate effects may be easily overlooked and underestimated because the actions are numerous and, if not seen through the lens of economic analysis, may appear cryptic to the general public. This report helps to narrow this information gap by showing the importance of the deregulatory agenda for everyday Americans as well as the national economy.” click here
The Environmental Protection Agency (EPA) is proposing a drinking water regulation for perchlorate and a health-based Maximum Contaminant Level Goal (MCLG) in accordance with the Safe Drinking Water Act (SDWA). The EPA is proposing to set both the enforceable Maximum Contaminant Level (MCL) for the perchlorate regulation and the perchlorate MCLG at 0.056 mg/L (56 µg/L). The EPA is proposing requirements for water systems to conduct monitoring and reporting for perchlorate and to provide information about perchlorate to their consumers through public notification and consumer confidence reports. This proposal includes requirements for primacy agencies that implement the public water system supervision program under the SDWA. This proposal also includes a list of treatment technologies that would enable water systems to comply with the MCL, including affordable compliance technologies for small systems serving 10,000 persons or less.
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“… overpowering influence of low dose biostatistical modeling perspectives that swayed the quantitatively overwhelmed chemical toxicologists. This resulted in the LNT policy going forward, becoming broadly institutionalized across many governmental agencies and in multiple countries. The rest is history.”
Edward J. Calabresea, Robert J. Golden. Why toxicologists resisted and radiation geneticists supported EPA’S Tadoption of LNT for cancer risk assessment Chemico-Biological Interactions Volume 310, 1 September 2019, 108736
The linear non-threshold (LNT) dose response model for cancer risk assessment has been a controversial concept since its initial proposal during the 1930s. It was long advocated by the radiation genetics community in the 1950s, some two decades prior to being generally adopted within the chemical toxicology community. This paper explores possible reasons for such major differences in the acceptance of LNT for cancer risk assessment by these two key groups of scientists.
Bradley PM, et al. Reconnaissance of Mixed Organic and Inorganic Chemicals in Private and Public Supply Tapwaters at Selected Residential and Workplace Sites in the United States. Environmental science & technology. 2018 Nov 21. doi: 10.1021/acs.est.8b04622
Safe drinking water at the point-of-use (tapwater, TW) is a United States public health priority. Multiple lines of evidence were used to evaluate potential human health concerns of 482 organics and 19 inorganics in TW from 13 (7 public supply, 6 private well self-supply) home and 12 (public supply) workplace locations in 11 states. Only uranium (61.9 μg L-1, private well) exceeded a National Primary Drinking Water Regulation maximum contaminant level (MCL: 30 μg L-1). Lead was detected in 23 samples (MCL goal: zero). Seventy-five organics were detected at least once, with median detections of 5 and 17 compounds in self-supply and public supply samples, respectively (corresponding maxima: 12 and 29). Disinfection byproducts predominated in public supply samples, comprising 21% of all detected and 6 of the 10 most frequently detected. Chemicals designed to be bioactive (26 pesticides, 10 pharmaceuticals) comprised 48% of detected organics. Site-specific cumulative exposure-activity ratios (∑EAR) were calculated for the 36 detected organics with ToxCast data. Because these detections are fractional indicators of a largely uncharacterized contaminant space, ∑EAR in excess of 0.001 and 0.01 in 74 and 26% of public supply samples, respectively, provide an argument for prioritized assessment of cumulative effects to vulnerable populations from trace-level TW exposures.
Mian HR, Hu G, Hewage K, Rodriguez MJ, Sadiq R. Prioritization of unregulated disinfection by-products in drinking water distribution systems for human health risk mitigation: A critical review. Water Res. 2018 Sep 29;147:112-131. doi: 10.1016/j.watres.2018.09.054
Water disinfection involves the use of different types of disinfectants, which are oxidizing agents that react with natural organic matter (NOM) to form disinfection by-products (DBPs). The United States Environmental Protection Agency (USEPA) has established threshold limits on some DBPs, which are known as regulated DBPs (R-DBPs). The human health risks associated with R-DBPs in drinking water distribution systems (DWDSs) and application of stricter regulations have led water utilities to switch from conventional disinfectant (i.e., chlorination) to alternative disinfectants. However, the use of alternative disinfectants causes formation of a new suit of DBPs known as unregulated DBPs (UR-DBPs), which in many cases can be more toxic. There is a growing concern of UR-DBPs formation in drinking water. This review prioritizes some commonly occurring UR-DBP groups and species in DWDSs based on their concentration level, reported frequency, and toxicity using an indexing method. There are nine UR-DBPs group and 36 species that have been identified based on recent published peer-reviewed articles. Haloacetonitriles (HANs) and haloacetaldehydes (HALs) are identified as important UR-DBP groups. Dichloroacetonitrile (DCAN) and trichloroacetaldehye (TCAL) are identified as critical UR-DBPs species. The outcomes of this review can help water regulators to identify the most critical UR-DBPs species in the context of drinking water safety and provide them with useful information to develop guidelines or threshold limits for UR-DBPs. The outcomes can also help water utilities in selecting water treatment processes for the mitigation of human health risk posed by UR-DBPs through drinking water.
“The emissions reduction leadership role for California championed by the L A Times is touted despite the fact that our state doesn’t have the foggiest idea of how it can achieve its SB 32 emissions goals nor does it have any idea of how many tens of billions it will cost nor care at all about how the state will end up dictating how all Californians must live their lives.” click here