A House Natural Resources Committee Oversight Hearing held July 22, 2015 on “An Analysis of the Obama Administration’s Social Cost of Carbon” can be viewed here and is well worth viewing.
The Administration’s social cost of carbon assessment and estimates are not science-based, speculative, and are heading us all in the wrong direction.
The premises that emission of greenhouse gases somehow causes environmental damages that can be prevented by regulation or by limiting greenhouse gas emissions based on the social cost of carbon are simply unsupportable.
Excuse me, but Mr. Lowenthal’s minority statement is simple posturing. There is no connection between a person objecting to the application of the social cost of carbon in the National Environmental Policy Act and that person’s desire to take action to address the impact of changes in climate. Changes in climate will happen and will have an impact regardless of a fictitious social cost of carbon. It’s time for the administration to stop poisoning the well by pushing approaches developed in secret that are politically motivated and not science based.
The “social cost of carbon” approach to address an undefined “climate change” is counterproductive.
“According to a recent AP-GFK poll, support for gay marriage among U.S. citizens has dropped six percentage points since their last poll in April, with more Americans disapproving of the Supreme Court ruling making gay marriage the law of the land than those approving it.” News article is here.
We’ve known for quite some time now that a single compound called MX (after the MX missile of years past) is very genotoxic. The relative toxicities reported here are very interesting. Chloral hydrate (for example) was of great concern when it was identified as a DBP decades past but here it tests negative.
The most important question not addressed here is what action to take when studies like this are published. The D/DBP rule and current water treatment practice is intended to control both regulated and known DBPs as well as those not known. By focusing efforts on precursor removal all DBPs are controlled.
Zhang SH, Miao DY, Tan L, Liu AL, Lu WQ. Comparative cytotoxic and genotoxic potential of 13 drinking water disinfection by-products using a microplate-based cytotoxicity assay and a developed SOS/umu assay. Mutagenesis. 2015 Jul 17. pii: gev053.
The implications of disinfection by-products (DBPs) present in drinking water are of public health concern because of their potential mutagenic, carcinogenic and other toxic effects on humans. In this study, we selected 13 main DBPs found in drinking water to quantitatively analyse their cytotoxicity and genotoxicity using a microplate-based cytotoxicity assay and a developed SOS/umu assay in Salmonella typhimurium TA1535/pSK1002. With the developed SOS/umu test, eight DBPs: 3-chloro-4-(dichloromethyl)-5-hydroxy-2[5H]-fura3-chloro-4-(dichloromethyl)-5-hydroxy-2-[5H]-furanone (MX), dibromoacetonitrile (DBN), iodoacetic acid (IA), bromochloroacetonitrile (BCN), bromoacetic acid (BA), trichloroacetonitrile (TCN), dibromoacetic acid (DBA) and dichloroacetic acid (DCA) were significantly genotoxic to S. typhimurium. Three DBPs: chloroacetic acid (CA), trichloroacetic acid (TCA) and dichloroacetonitrile (DCN) were weakly genotoxic, whereas the remaining DBPs: chloroacetonitrile (CN) and chloral hydrate (CH) were negative. The rank order in decreasing genotoxicity was as follows: MX > DBN > IA > BCN > BA > TCN > DBA > DCA > CA, TCA, DCN > CN, CH. MX was approximately 370 000 times more genotoxic than DCA. In the microplate-based cytotoxicity assay, cytotoxic potencies of the 13 DBPs were compared and ranked in decreasing order as follows: MX > IA > DBN > BCN > BA > TCN > DCN > CA > DCA > DBA > CN > TCA > CH. MX was approximately 19 200 times more cytotoxic than CH. A statistically significant correlation was found between cytotoxicity and genotoxicity of the 13 DBPs in S. typhimurium. Results suggest that microplate-based cytotoxicity assay and the developed SOS/umu assay are feasible tools for analysing the cytotoxicity and genotoxicity of DBPs, particularly for comparing their toxic intensities quantitatively.