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These on-site inspections of water sys jud '-'cnt. They have wi-:.stood the test and sulfates. The National Drinking tems arc more effective in assuring safe of . and of profession. ' review. They Water , sory Council has recom water to the public than individual tests arc ueing subjected to fir 'her review by mended i....t consideration be given to taken in <110 absence of sanitary surveys. the National Academy of icuccs in con tlic monitoring of these constituents, but The regulations provide that monitor nection with development f data for the has not recommended U10 adoption of ing frequencies for coliform bacteria can Revised Primary Drinkiiv: Water Regu maximum contaminant levels because be changed by the entity with primary lations. available data do not support the adop enforcement responsibility for an indi vidual non-community system, and in MCL's Based on Temperature tion of any specific levels. EPA has re quested the National Academy of Sci certain circumstances for an individual A question was also raised as to ences to Include sodium and sulfates community system, based on the results whether ranges of maximum contami among the contaminants to be studied of a sanitary survey. nant levels should be established on the by NAS. and to include information on Maximum Contaminant Levels basis of the climate in the area served the health effects of sodium and sulfates by the public water system, as was done in the report to be made by NAS in Numerous comments were received by with fluoride. EPA believes that the use December 197G. ., EPA on the substances selected for the of a temperature scale for fluoride is Since a number of persons suffer from establishment of maximum contaminant more appropriate than for other chemi diseases which are influenced by dietary levels and on the levels chosen. Congress cals because of the studies available on sodium intake and since there are others anticipated that the initial Interim Pri the fluoride-temperature relationship who wish to restrict their sodium in mary Drinking Water Regulations would and because there is a small margin with ' take. it is desirable that the sodium con be based on the Tublic Health Service fluoride between beneficial levels and tent of drinking water be known. Those Standards of 19G2, and tins Congres levels that cause adverse-health effects. affected can, bv knowing tiro sodium con sional intent has been followed. Com ments received on the various levels did MCL's Deleted centration in their drinking water, make adjustments to their diets or. in extreme not contain new data sufficient to re Three proposed maximum contami cases, seek alternative sources of water quire the establishment of levels differ nant levels have been eliminated in the to be used for drinking and food prepara ent from those contained in the Public ffflrti regulations because they are not tion. It Is recommended that the States Health Service Standards. iustITIgff~Py 1116 available data. One of institute programs for. regular monitor Water Consumption these is carbon chloroform extract ing of the sodium content of drinking <CCE). which is discussed separately water served to the public, and for in The maximum contaminant levels are below. The others are the proposed levels forming phvsicians and consumers of the bned. directly or indirectly, on an as- for the standard bacterial plate count sodium concentration-in drinking water.. "d consumption of two liters of water and cyanide. In the case of the plate A relatively high concentration of sill- > day. The same assumption was used count, it is believed that the coliform fate in drinking water has little or no In the 1962 Standards.- This assumption limits contained in the regulations, com known laxative effect on regular users of has been challenged because of instances bined with the turbidity maximum con the truii'i, but ti'ahscicnts using such where much higher water consumption taminant level, adequately deal with watgnuwutHUes experience a laxatlve rates occur. EPA's justification for using bacterial contamination. However, EPA effect, rt IS retfimiHeflacd that the States the two-liter figure is that it already continues to believe that the standard institute monitoring programs for sul represents an above average water or plate count is a valid indicator of fates, and that transients ,bc notified if water-based fluid in Lake. Moreover, while bacteriological quality of drinking water, the sulfate content of the water is high. the factor of safety may be somewhat re and recommends that it be used in ap Sucii notification should include an as duced when greater quantities of water propriate cases in conjunction with the sessment of tire possible physiological are ingested, the maximum contaminant coliform tests as an operational tool. effects of consumption, of the water. levels based on the two-liter figure pro The proposed maximum contaminant vide substantial protection to virtually level for cyanide was eliminated because PCB's and Asbestos all consumers. If, as has been suggested.. the possibility of cyanide contamination An interagency comment expressed a water consumption rate of eight liters can be effectively addressed only by the concern for asbestos and FOB'S in the per day is used as the basis for maxi use of emergency action, such as under environment and noted the need for at mum contaminant level, all of the pro Section 1431 of the Act. EPA's 1SC9 Com- least a monitoring requirement, if not posed MCL's would have to be divided by .munity Water Supply Study did not for MCL's, for these contaminants. EPA four, greatly increasing the monitoring reveal a single instance in which cyanide is also concerned, but for the moment difficulties, and in some eases challeng was present in a water system at a level lacks sufficient evidence regarding ana ing the sensitivity of accepted analytical greater than one-thousandth of the level lytical methods, health effects, or occur procedures. It could be expected, in such at which cyanide is toxic to humans. rence in the environment to establish 3 c, that tne maximum contaminant Available data indicate that cyanide MCL's. The Agency is conducting re 1 would be exceeded to a significant will be present in water systems at toxic search and cooperating in research proj degree, and that specialized treatment levels only in the event of an accident, ects to develop criteria for establishing techniques would be required to order such us a spill from a barge collision. needed limits as quickly as possible. A that tlic contaminant levels would be re Maximum contaminant levels are not monitoring study on a number of organic duced. The economic impact of a move tlic appropriate vehicle for dealing with chemical contaminants, including PCB's, in tliis direction would be enormous. It such ra-r accidental contamination. for which MCL's are not being estab- Is not technically or economically feasi Henl.nrnnr. hcntachlor epoxide lished at this time, will be contained in ble to base maximum contaminant levels and chlordane have also been removed an organic chemical monitoring regula on unusually high consumption rates. iYarntne list 51 maximum contaminant tion that is being promulgated with these levels at least temporarily in view of the regulations. Regarding asbestos. HEW Safety Factohs pending cancellation and suspension and EPA are sponsoring a number of A question was raised about the fact proceedings under tlte Federal Insecti studies tiffs year at an approximate cast that different safety factors arc con cide. Fungicide and Rodcnticidc Act in of S16 million to establish health effects, tained in various maximum contaminant volving those pesticides. When the re anr.yltical methods and occurrence. levels. The levels are not intended to sults cf there proceedings are available. have a uniform safety factor, at least EPA will again consider whether maxi Point of Measurement ' partly because the knowledge of and the mum contaminant levels should be es .Other comments on maximum con nature of the health risks of the various tablished for those three pesticides. taminant levels focused on the proposed contaminants vary widely. The levels set are the result of experience, evaluation Sodium and Sulfates requirement that such levels be tested at the consumer's tap. Concern was ex A number of comments were received pressed over the inability of the public of the available data, and professional on the potential health effects of sodium water system to control potential sources FEDERAL REGISTER, VOl. 40, NO. 248--WEDNESDAY, DECEMBER 24, 1975 SH-111S DPMC- LAM 015952 D PM C 05085.1 5, * lam 015951