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1') ~ 0' , . -" Health The Environmental Protecuon Agenc~. Dnnkmg Water Office. Health Impacb Laboratory \pon!'ored a conkrence In 198-1 on "Inorganic:;, in Dnnkmg \\':Jler and Cardio\la~cular DI~ea"e." The conference was. directcod b~' Dr. Edward Calabrese. one of the anglOa] Cntled Stales re~earchers in the realm of the health impacts of sodium. It was the slUdy by Drs. Cabbecs.: and Tuthill concerning schoolchildren In twO ~1a<;sachuselts communities that sparked the imtlation of many studies around the world CauS'J5 and ImDdCi5 01 Sa,llr1lty Damages vs Salinity , t , o . , ~ e . . . . E . o n. .'. ." ." " .()OSOO$QD'OOftOOaoo'ooo"oo s.;","Y 01 Impou' Oom f'''Q'LI Figure 5.-Annual damages Increase With salinity, In the study by Drs. Calabrese md Tuthill. a difference of :! to 5 mJilimelers mercury of blood pressure was found betw~en thIrd grader... wllh a drinking water ~upply of about 10 mgIL sodium and those drinkmg: water of about IO~ mgfL sodium. Subsequent auempu. by Drs. Calabrese and Tuthill 10 validate the..e resuhs with other groups or by other methods (bottled water) have proven inconclusive. Sludie.. reported from the :-';elherland.. did support finding~ of slightly elevated blood pressure among schoolchildren consuming high ..odium ....ater. but most other studies were either inconclu~lve or sho.....ed that there wa~ no effect. T.....o areas of concern rn~ntion~d dunng the dlscu!>s;ons were the u~e of zeolLte water softeners on the kitchen cold water faucet and the cooking of vegetables in high sodIUm water. as the vegetable.. can absorb large amounts of sodium during cooking. In most cases. avoidanc~ of these twO actions would be more significant than any reduction in raw water concentration Other conference discussions on hard water versU'i soft water pnmarlly concluded that soit water was not harmful. but hard wat~r contained some beneficial property. possibly calcium. which reduced the ability of the body 10 absorb trace metals and. thus. lowered the overall exposure to such e1em~nts as cadmium and lead. Addllionally. while water softeners help reduce pipe scaling and soap usage. several speakers stressed that a bypass should be placed on the kitchen cold water tap. the tap mosl used for dnnkmg and cooking waler, to maintain a certain level of h3Idness. Other papers focused primml)" on the health effects of cadmium. barium. and lead in dnnking water. Studies seem to Indicate that barium has no effect on cardiova.scular disease below a level of J.boul 10 mgfL. while cadmium and lead do have a definite adverse impact. :\'one of these elements are present in any sigmficanl concentrations in the mainstem reaches of the Colorado River. It appears from discussions al the conference that no adverse health impacts related to present sodium or hardness I~vels occur from dnnkmg water from the Lo\\er Colorado River. An)" health effecI of a reduClion in sodium and hardness expected from the Colorado Ri\'er Salmity Control Program would be negligible. 15