Laserfiche WebLink
Pollution and Human Health <br /> The groundwater pollution is found between i <br /> 25 feet and 100 feet belowground surface and <br /> extends approximately as shown in Figure 2. ' - 1� <br /> The concentration of dry cleaning solvents <br /> (PCE) range from a high of 600 micrograms \, <br /> per liter (µg/L) in the area where this first <br /> cleanup action is proposed, to about 9 µg/L at F' <br /> the edges of the plume. These concentrations <br /> E.'hwr sin i / <br /> are above the drinking water standard of 5 <br /> pg/I UNIFIRST � 1 <br /> L W " � <br /> The pollutants are not in tap water, and _ a l• �� � <br /> drinkingwater is provided b California Water --Y �J <br /> P Y -) <br /> Service, which regularly tests for these _ ,- <br /> pollutants. Figure !.-Extent of groundwater pollution <br /> Proposed Groundwater Cleanup Method <br /> UniFirst proposes to degrade the dry cleaning solvents in groundwater by adding food for micro- <br /> organisms to the groundwater. The additive is a food-grade lactate compound called HRCO, which <br /> stands for"hydrogen releasing compound". For more information, see the manufacturer's website <br /> www.regenesis.com. The micro-organisms naturally occur in groundwater and are already slowly <br /> degrading the solvents. The food will help them grow and degrade the solvents even faster. <br /> Figure 3 is a diagram illustrating the effect the additive is expected to have on the pollution. <br /> This has been done successfully at other sites where dry cleaning solvents have polluted the <br /> groundwater. Initially, this method will be used for a trial period (also known as a "pilot test") of <br /> about two years to evaluate how well the method is working at this site. <br /> Proposed Activities <br /> The HRC will be injected into <br /> groundwater through the sidewalk on <br /> Hunter Street in front of the UniFirst <br /> building. A drill rig will drill through <br /> the sidewalk and inject the HRC. <br /> The sidewalk and southbound lane of <br /> Hunter Street will be closed while the <br /> drilling and injections are taking <br /> Treated Groundwater place, which is expected to be about <br /> 4 days. The sidewalk will be repaired <br /> upon completion of the injections. <br /> Figure 3. Effect of additives on groundwater <br /> Road closures will be posted in <br /> advance. <br />