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WATER GREMLIN PUBLIC HEALTH ASSESSMENT: PUBLIC. COMMENT DRAFT The second critical study showed heart defects in rats whose mothers were exposed to TCE in drinking water during pregnancy. • Effect Ievel finding -- For women in the first eight weeks. of pregnancy exposed to TCE at -20 µg/m3, there may be a small risk of fetal heart defects. At this Ieve1,very few women ono more than 1 in 100) would have an.amount of TCE in their body that inight cause a fetal heart defect less than 1% of the time. • A third rodent study showing kidney toxicity was considered a supporting study. ■ Effect level finding -- A small. risk of kidney impacts, including toxic nephropathy and .increased kidney weights may exist for people exposed to TCE levels at or exceeding —80 µg/m3 continuously over a long time period. To be protective in accounting for uncertainty, EPA divided the effect .]eve Is from these two critical studies by uncertainty factors of 1.00.in the first tase and 10 in the second, to arrive:at the safe Inhalation value of 2 µg/m3. Note however; that exposure to arnaunts..of TC .greater than 2 µg/m3 does not mean health effects will, or are likely to, occur; although the risk of health effects increases as the amount;and duration of.TCE exposure increases. Other health effects have been shown to possibly occur at much greater exposures than the effect levels in the three studies. EPA chose for its evaluation — at amounts of TCE much greater than exposures that Were predicted to be possible.in the community due to the ern issiorig from Water Gremlin. Cancer Effects Occupational studies of high TCE exposure have shown an increased risk of kidney cancer in people. There is also evidence of an association between high levels of TCE exposure in people iand.mclentsj and non-Hodgkih's iymphorn:a and liver cancer. Less. evidence is found fo.r:an association between TCE exposure and some other types of cancers. According to EPA'.s.2011 assess ment.described above, breathing TCE at the following concentrations arid durations maytheoretically result in the following incremental cancer risks: • Breathing 2 µg/m3 TCE continuously for a lifetime is expected to result in no more than 1 additional cancer in 100,00.0 exposed: people; • Breath!rig 20 µg/m3. TCF continuously for a Ilfetime is expected to result. in no more than 1 additional cancer in 10,000 exposed people; and • 13reathing.200 µg/m3 TCE continuously for a.lifetime:is.expected to result in no more than 1 additional cancer in 1;000 exposed people Any such increase Is%un11kely to be. measurable compared to the background cancer rate that already exists from all causes, For comparison, recent estimates show nearly half (four or five people out of ten) of Minnesotans.will be diagnosed with cancer sometime. in their life. Cancer -- a group of many different diseases with many different .causes -- is much more common than people realize. For an example of how risk assessors calculate increased cancer risk based on environmental exposures,: see the calculation and explanation in Appendix C. Are.Some People at Greater Risk? Do I Need Medical Testing? MDH has stated that there is no need for people to go to the doctor solely because they live near Water Gremlin or did so in the past. TCE does not accumulate or stay in the. body for more than a few days. 13