2022 05-17 CC PACKET - Laserfiche WebLink

Home

WATER GREMLIN PUBLIC HEALTH A-SSESSMENT: PUBLIC COMMENT DRAFT The limited mobility of lead in groundwater due to its strong.attraction to a wide range of soil and aquifer materials (Clausen, Bostick, and Korte, 2011), ina149 it unlikely to pose a risk to the buried sand aquifer.o. private :or public drinking water supply wells near the Water Gremlin facility oi'further downstream 1h the surface Water system. 1,4-Dioxane is extremely mobile in groundwater, so infiltration-frorh surface water to groundwater or transport through the surface water:system-theoretically could pose a .risk to riearby drinking watei^ supplies. However,1,4-dioxono was detected.tri only two of the surface Water -samples at concentrations just above the HRL of 1 ppb in the stormwater pond (at 1.1 ppb) and below. the HRL In Lambert Creek (0.35 ppb). These.concentrations would..be diluted as the water eit4e0 infiltrates. into *the groundwater ortravels downstream in the sirrface.water system before possibly reaching any source of -drinking water:1,4-Dioxane was not detected in samples collected from Alce Lake or Gem Lake; so It It unlikely that -surface water transport or infiitration of. 1,4-dioxane currently poses a risk to. publi.chealfh. Given the high mobility of 1,4-dioxane in water, it is impossible to evaluate whether past transport of dioxane in Lambert Creek surface water may have contaminated the*groundwater. Water'Gremlin operations have contributed to lead.concerttratioris above the surface=water criteria in stormwater ponds and othersurface.waters on the company's property. Samples frofn*the downstream .portions of Lambert Creek on the Water Gremlin property were below the surface watercAteria for lead, as were samples from nearby lakes. Based on these results, there is expected to be little.to.no human exposure to the lead in the surfacewater of the Creek or the noted lakes outside thtboundaries. of Wateir Grerlilln: property: Water Gremlin operations have. also contributed to low ievels-of.1,4-dioxane In stormwatgr ponds and other surface waters on their prbperty; but 1,4-dioxane-Was notdetected in nearby. lakes or wetiands: there is expected to be little to no human exposure to 1,4-dioxane in the sur-face:wateron the company's property. G. Past Remedial investigations and Historical Actions—1994-2004 Soil and groundwater contamination was investigated on the Water Gremlin property*ln the past: Soli contaminated with lead was excavated frornVthe property in 1995-1996. The groundwater on site was monitored for a number of -compounds found in the shallow aquifer from 1997-2004. This section has been iilcluded-for completeness and to acknowledge what is known about cQntam.inationfrorq the facility in the past. In*1994, Ramsey County Haiardous Waste staff conducted a routine site visit-atthe Water Gremlin facility.and observed sand spilled out of a 55-gallon drum in an outside drum- torage area near the southeast corner of the facility (Braun, 1994). The sand was analyzed and contained high concentrations of lead. As a result, Ramsey County requested that Water Gremlin test the surrounding sollsfor lead, Fourteen soil.samples were collected. in and around the drum storage area. Coficentfations of lead in soil at the depth of 0-6 inches ranged. from 32 to 4,200 ppm (Braun,1994). In 1995, Water Gremlin hired. Braun, an environmental consultant, to conduct a Phase I Environmental Site Assessment (13raun,1995). Braun identified.four areas that may -contain contamination, listed below: • Areas of spilled, used:oil,.potentially contaminated with lead, were identified;Qn the:concrete floor and -cinder block-walls*ofthe.manufacturing building and on the gravel -paved exterior -areas berieath the lea d-melting pot exhaust -vents. 34