2024-06-07_PERMIT FILE - M2024026 (23)

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Environmental Impacts d Water Treatment Chemicals at Industrial Sand Mies _ BARR microbial community had previous exposure to acryl- Table 1.Estimated steady-state acrylamide monomer amide monomer. For soil microbial communities not pre- concentrations viously exposed to acrylamide, higher initial acrylamide Reservoir Concentration of Acrylamide(tight.) concentrations correspond to slower initial degradation K Value(hr-') Clarifier Fresh Water Quarry Pit Tank kinetics'. One of the slower reported acrylamide bio- degradation rates was for a previously unexposed soil 0 11.7 115 10.3 sample subjected to a high initial acrylamide loading 0.0027 1.45 1.29 013 (999 mg acrylamide/kg soil), a low temperature (10°C), 0.125 0.54 0.41 0.0010 and aerobic conditions. The corresponding apparent first order rate constant was 0.0027 hr 1 �e of acrylamide monomer in soil and groundwater The acrylamide monomer exits the clarifier/sand wash With prior exposure and acclimation to acrylamide, aero- loop through wet sand and reject material produced by bic microbial communities can biode grade acrylamide the sand washing process. Virtually all of the polyacryl- at much faster rates.Apparent first-order rate constants amide flocculants introduced to the clarifier are expect- can approach 0.125 hr-1.7 8 ed to adhere to soil particles and exit the clarifier in the underflow, and are ultimately disposed with filter cake analysis of kinetic model (or alternatively in clarifier mud ponds.) The system of reservoirs provided in Figure 1 was evalu- ated using three apparent first-order biodegradation rate Because acrylamide readily breaks down in soil and wa- constants: K=0.0 hr-1(no biodegradation), K=0.0027 ter, biodegradation should occur in the sand piles as well ()hr-1 (slow biodegradation), and K=0.125 hr-1 (rapid as in the soil and groundwater beneath them. In natural biodegradation).The estimated steady-state reservoir aerobic and anaerobic environments,the half-life for concentrations (clarifier,fresh water tank, and quarry the acrylamide monomer can be less than a day.9 This pit) associated with the three K values are provided in means more than 90 percent of the original monomer Table 1.With no biodegradation,the estimated steady- from these sources would be biodegraded in less than state acrylamide concentrations were between 10 and three days. 12 µg/L.With biodegradation,the estimated steady- state acrylamide concentrations ranged from 0.001 to The Department of Land Conservation and Forest Man 1.5 µg/L. This compares to the de facto standard of 0.5 agement (DLCFM) in Chippewa County, Wisconsin, has ug/L for potable drinking water, required four permitted mine sites to periodically moni- tor groundwater for the acrylamide monitor downgradi- 5 Lande S.S.,Bosch S.J.,and Howard P.H. 1979.Degrada- ent from where the wash water and flocculated solids tion and leaching of acrylamide in soil.Journal of Environ- are placed into or on the ground surface. As of January mental Quality 8(1): 133-137. 18, 2013 (personal communication, Chippewa County), all samples collected and analyzed for the department 6 Abdelmagid 11 M.and Tabatabai M.A. 1982.Decomposi- have been non-detect for the acrylamide monomer.This tion ofacrylamide in soils.Journal of Environmental Quality 11(4):701-704. represents more than one year of data. One of the sites in Chippewa County, known as the Bloomer Mine, uses a 7 Arimitu H.,Ikebukuro H.and Seto I. 1975.The biological series of wash water trenches to dewater the flocculated degradability of acrylamide monomer.Journal of the Japan fines accumulated during the wash process. (The mine Water Works Association 487: 31-39.Cited in WHO.2011. Acrylamide in Drinking Water. Background Document for does not utilize a belt press filter.)Acrylamide has not Development of WHO Guidelines for Drinking-Water Quality. been detected in soil samples collected from the native World Health Organization,Geneva,Switz httpJ/www.who. soil at the base of the trenches providing evidence that int/water_sanitation_health/dwq/chemicals/acrylamide.pcif biodegradation is occurring even at cooler temperatures 8 U.S.EPA. 1994.Chemical Summary for Acrylamide.Of- found in the subsurface. fice of Pollution Prevention and Toxics,U.S.Environmental Protection Agency,EPA 749-F-94-005a.http:I/www.epa.gov/ 9 EPA. 1994.Chemical Summary for Acrylamide.http:// chemfact/s_acryla.txt www.epa.gov/chemfact/s_acryla.txt Page 4