2022 05-17 CC PACKET - Laserfiche WebLink

Home

WATER GREMLIN PUBLIC HEALTH ASSESSMENT: PUBLIC COMMENT DRAFT The 2020 RAA values are. based on the amount of t-DCE (approximately 50,000 pg/m3) where an immune system effect was observed. in. a subchronic-animal Study. Therefore,. it is expected that a. small risk of immune. system. effects m.ay exist for people exposed to t-DCE repeatedly at 50,000.µg/m3. The RAA is much lower than this to reflect uncertainties in the data and the .desire to develop a safe exposure level for the population, including vulnerable subgroups. Table 5 presents the MDH's 2019 and 2020 RAA vaIues.for t-DCE in air to. compare, and illustrate. the evo.lutio.n of, health -based values used to evaluate air monitoring results and communicate to the public . about potential for health risks due.to t-DCE emissions from the Water Gremlin facility. Table.6: MDH Risk Assessment Advice (RAA) for trans-1,2-Dlchloraethylene (,uglm3) -;'�.� s irr , _ ;'�� .'�� ii _r • .. t �, � • rr�k '. ' �, �I- y 3-I- �✓�. � � ;++,-�, ti 7•. cs� j r` ;z%;.�•.t • -s k'7A�k.63R�, �.,,�;��. �t'•. �� y - _ �.�. - �.� •� �' • �::.. �� y. .�:. d� :ts : " _. °:.e t . _�' °� a3[]y}� $ _ I I r'�"�•��L.•i-:,Ch��i: �1-� �rµi 1:�. �-'� -:�� 1, _ � i�. J'cj-V.'� Acute (up to.24 hours) _ _ w ND. ND. Short-term (> 24 hours to 30 days) ND ND 5ubchronic (>.30 days to 10% of a lifetime) ND 200 l Immune System Chronic:(> 10% of a lifetirne:to a lifetime) 70 I 20N Immune 5.ystem Cancer (lifetime) ND ND Nb = Not derived Other t-DCE Air Values EPA Screening Values .In September 2020, EPA published inhalation "scree ning'values" for t-D.CE.for chronic. and subchronit durations of 40 µg/m3 and 400 Wjm3, respectively (U.S.. EPA, 2020). EPA.determined once again that the data for t-DCE are insufficient to:support deriving a toxicity value und.ertheir guidelines, however they provided the screen 1 ng va Ives they developed to assist in risk.assessment. These screening values were derived using the .unpublished subchronic rodent study (Du Pont, 1998..) mentioned above. The health end polnt was determined to. be the immune system.. While there is wide agree mentthat .toxicity data needed to derive. a chronic air value for t-DCE is lacking, it is arguably helpful to have some value that limits air emissions, or provides some assessment of health risk, rather than no value at all. MDH's profess iona1judgment.about developing an inhalation value for t- DCE appears to generally be in line with decisions other states. have made. to address this chernica1. Occupational Values While occupational limits can provide context for ambient air concentrations, MDH believes that some of these values are not. protective of worker health over the long-term, and they certainly are. not adequate to protect the general populat"ion. The Occupational Safety and Health Administration (OSHA),. the. National Institute far Occupational Safety.and Health (NIOSH), and the American Conference of Governmental Industrial Hygienists all have adopted occupational criteria for.1,2-DCE (note this is a mixture of t-DCE.and cis-.1,2-DCE) of 200 parts per million in air over a workday -- equivalent.to 790,000 Vg/m3.. N10SH lists. symptoms of occupatio naI exposure. as irritation of the. eyes and respiratory system, as well as a central nervous system depression (N105H; 2019). These values are intended to allow workers to be able to. do their work.safely and.may not be.protective far all possible health effects. for long-term exposure. 19