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Feasibility Study <br />Water Treatment Plant <br />City of Lino Lakes, MN <br />WSB Project No. 015822-000 Page 9 <br />Lead and Copper Rule (LCR) <br />Lead and copper enter drinking water primarily through plumbing materials. Exposure to <br />lead and copper may cause health problems ranging from stomach distress to brain <br />damage. On June 7, 1991, EPA published a regulation to control lead and copper in <br />drinking water. This regulation is known as the Lead and Copper Rule (also referred to as <br />the LCR or 1991 Rule). The treatment technique for the rule requires systems to monitor <br />drinking water at customer taps. If lead concentrations exceed an action level of 15 ppb <br />or copper concentrations exceed an action level of 1.3 ppm in more than 10% of <br />customer taps sampled, the system must undertake a number of additional actions to <br />control corrosion. If the action level for lead is exceeded, the system must also inform the <br />public about steps they should take to protect their health and may have to replace lead <br />service lines under their control. <br />EPA’s proposed Lead and Copper Rule (LCR) includes a suite of actions to reduce lead <br />exposure in drinking water where it is needed the most. The proposed rule will identify <br />the most at-risk communities and ensure systems have plans in place to rapidly respond <br />by taking actions to reduce elevated levels of lead in drinking water. <br />The agency’s proposal takes a proactive and holistic approach to improving the current <br />rule—from testing to treatment to telling the public about the levels and risks of lead in <br />drinking water. This approach focuses on six key areas: <br />1. Identifying the areas most impacted <br />2. Strengthening drinking water treatment requirements <br />3. Replacing lead service lines <br />4. Increasing sampling reliability <br />5. Improving risk communication <br />6. Protecting children in schools and childcare facilities <br />Based on Lino Lakes’ relatively low lead and copper levels in the distribution system, the <br />proposed LCR should have minor impact on Lino Lakes. <br />Chromium <br />Chromium is a heavy metal that occurs throughout the environment. The trivalent form is <br />a required nutrient and has very low toxicity. The hexavalent form, also commonly known <br />as “chromium 6,” is more toxic and has been known to cause cancer when inhaled. In <br />recent scientific studies in laboratory animals, hexavalent chromium has also been linked <br />to cancer when ingested. <br />Chromium found in drinking water is naturally occurring but has been detected from the <br />manufacturing of textile dyes, wood preservation, leather tanning, and anti-corrosion <br />coatings, where hexavalent chromium contaminated waste has migrated into the <br />underlying groundwater. The federal MCL of hexavalent chromium is 100 ppb federal <br />MCL. The total chromium MCL was established in 1977 to address the noncancer toxic <br />effects of hexavalent chromium. EPA could propose a new MCL for hexavalent <br />chromium. Treatment processes currently considered effective for chromium removal <br />include adsorption, granular activated carbon, and ion exchange. Chromium has not <br />been detected in Lino Lakes’ raw water supply, so this proposed rule should not affect <br />Lino Lakes.