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LETTERS

Air cleanup Dear Sir: In the editorial (ES&T,

June 1974, p 487), you state that this issue includes information on . . . "an- other [utility's experience] with fuel cleaning prior to its burning." This implies that information is included about a utility attempting to burn cleaned coal, a topic of intense inter- est. (Well-cleaned coal of very low sulfur and ash content may not be burnable without severe boiler tube coating problems. This has been tested briefly with rumored disastrous but unpublished results.) Yet I fail to find reference to this topic in the June issue beyond the report, page 510, on solvent-refined coal (which is not adequately tested by a utility and may require boiler redesign for use). I fear this topic remains uncer- tain or perhaps has been deferred to a subsequent issue.

Your editorial policy of separating features from current research pa- pers is excellent and extremely im- portant for topics that do not include original information but are of broad interest and of conflicting reasonable opinions. R. F. Stewart Bu Mines Morgantown, W. Va. 26505

Water pollution companies Dear Sir: Your special report,

"Water Pollution Control Industry," (ES&T, Oct. 1974, p 882) contains a claim by Osmonics, Inc. of being the first company to promote reverse os- mosis for industrial waste treatment.

This is a gross misstatement that will mislead the readers of your fine magazine: Our Mill Division was op- erating pilot reverse osmosis equip- ment and discussing a production plant with vendors in 1968; Osmon- ics, Inc. was not even founded yet.

An intensive wastewater reuse program has been incorporated in our mill process; included in this pro- cess is a production reverse osmosis plant built by the Fluid Sciences Divi- sion, Universal Oil Products Co. David C. Morris Green Bay Packaging, Inc. Green Bay, Wis. 54305

Solar energy correction Dear Sir: In the article entitled,

"Plenty of energy out there in the sunshine," (ES&T, Nov. 1974, p 976) you stated that "a 28-V voltaic cell array costs $7000." This is not true. A 28-volt array could cost as little as $700 depending on the load require- ments (amp hours). Solar arrays are manufactured to accommodate spe- cific amp hour requirements and it is misleading to your readers to inform them that a 28-volt array costs $7000. I?. W. Willis, President Solar Power Corp. Braintree, Mass. 02184

Uproar about chlorine Dear Sir: The sudden tumultuous

publicity around possible adverse ef- fects of chlorine disinfection of water in my opinion is wide of the mark.

One of the items in "Currents" ( fS&T, Sept. 1974, p 781) was that EPA Administrator Train called on chlorine producers to give priority at- tention to supplying chlorine for water supply and wastewater disin- fection. One month later EPA re- search director Robeck went on the warpath against the use of chlorine. He quoted from my publication in Water Treatment and Examination (Vol. 23, 1974, pp 234-243), that ha- loforms are produced during chlorin- ation of humic substances in natural waters, and added that the World Health Organization (WHO) "lists" chloroform as a carcinogen.

As far as we know the evidence is very slender, as according to WHO Expert Group IARC's Monograph: "On the Evaluation of Carcinogenic Risk of Chemicals on Man" (Vol. 1, 1972). It is based on only one report of experiments on too small a num- ber of laboratory animals, carried out in 1945. It is a different thing, of course, whether we should continue to use our surface waters for dispos- ing of waste. Consumers in our afflu- ent society, including the environ- mental analyst, all sin wittingly or un- wittingly.

The author found by headspace analysis traces of trichloroethylene in samples of the Rivers Thames,

92 Environmental Science & Technology