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WATER GREMLIN PUBLIC HEALTH ASSESSMENT: PUBLIC COMMENT DRAFT Results of the investigations from 2019to the present are organized below by environmental media - groundwater, soil, soil vapor,3ed€ment,. and surface water. Drinking water from both.public.and private wellis discussed in the following section. MDH uses the environmental data from these investigations to evaluate whether people may be exposed to contaminants and to make recommendations to protect public health if needed. A. Groundwater The:Water. Grerrilln-property is located in an area where approximately 200 feet of glacial deposits overliethe bedroek.The water table is encountered within these deposits�from the:surface-to.depths of 11.5 feet below the ground.surface (the water table Is the surface below wbich.all spaces, lin the glacial deposits and bedrock atef)led with water).. in. Most.places the water talile.ls at*the same: elevation as the nearby surface vyatert; The area around*the Water Gremlin north campus building is directly underlain by 5-10 feet -of recent fill from construction activities at the site overlying 15-30 feet of water=bearing, fine -sand and silty sand . that thins. to the south. Based on geologic and hydrologic-data.collected at the site,: the shallow sand unit likely does not extend beyond the property boundaries. As the sands are underlain WA-45-85 foot thick "Semi -confining" layer (meaning water-passesjhrough it only very slowly, if at all), the groundwater in the sands°may not be con#tected to deeper groundwater. This semi -confining layer consists ofthin layers ofsilt, siltysond, fine sand, clayey sand, and clay. The. southern part of the Water Gremlin north campus (near Lambert Creek) and the south campus are underlain by 30-40 feet of wetland and lake deposits of peat and silt .-and sandy clay, which in turn *overlie the semi -confining layer. 6el6w1he semi-confining.layer Is.a 30-100 footw#e*f-bearing sand unit referred to hereafter as -theburied sand *aquifer' (wenck, 2021; Minnesota. Geological.Survey, 1992). Below the glacial deposits described above, the uppermost bedrock formation below the northwest part of the Water Grenilin property is the St. Peter Sandstone, Which Is w derialn, In-tui"n,.bythe. Prairie du Chien group oflimestone and dolomite and followed by the Jordan 59ridstorie.TheSt. Peter Sandstone is not present below the glacial deposits below the southeast parts of the Water Gremlin property, so the Prairie du Chien is the first bedrock unit encountered*at this portion of the site. Municipal wells in the area (White Bear lake, White Bear township, Vadnais Heights.) -are over 350 feet deep and draw water from the iordan.Sandstone; some of the wells also draw water from the lower units of the Prairie du Chien group. Many private (residential) drinking water wells in this. area were Installed.before drilling records were consisteritlykept,.but the records that are: available suggest that. most -private wells are over 100 ft deep and draw waterfrohl the buried sand aquifer{ although there are some wells completed in the St. Peter .Sandstone.orpralfie du Chien grout} bedrock aquifers. The regional direction of groundwaterflow in the buried sand aquifer is generallytothe west.in this part of Ramsey County (Minnesota Geological Survey.,1992). However, on the local scale, groundwater flow 22