COMPLIANCE INFO_2020 - Laserfiche WebLink

Home Browse Search

Mr. Brendan Kenny October 7, 2020 Page 6 ambient environmental conditions at a waste management unit, could be released in concentrations exceeding applicable water quality objectives or that could reasonably be expected to affect beneficial uses of the waters of the state as contained in the appropriate state water quality control plan." This allegation is unfounded because: (1) the discharges cannot reasonably be expected to affect beneficial uses of the waters of the state, and (2)the discharges were not, and will not be, released to waters of the state for the reasons specified in the section above. Soil Sample Analysis Shows Results Well Below Regulatory Thresholds The NOV mentioned that the County requested that SFPUC collect soil samples from the grit pond to evaluate mercury concentrations. The McCord memorandum summarizes the soil sampling results as follows: "Soil samples collected by AEW Engineering (2018) reported mercury at concentrations ranging from below the detection (< 0.017 mg/kg) to 0.42 mg/kg with an approximate average concentration of 0.07 mg/kg, which is well below the lowest respective threshold (4 mg/kg). If all the mercury from discharges (assuming 11,000 gallons at 2.7 ug/L total Hg based on trench water monitoring data) is sequestered in the upper one inch of soil in Grit Pond#1, it would take about 680 lamp breaks for the soil to reach the lowest threshold. [..]Thus, use of Grit Pond #1 is considered a best management practice, providing on-site treatment with no off-site discharge needed and no measurable accumulation in surficial sediments to be expected." McCord's technical memorandum, which elaborates on the conclusions mentioned herein, is attached for your review. Release Water Stored in Baker Tanks Is Not Hazardous Waste In May 2019, SFPUC retained Baseline Environmental Consulting to evaluate whether the water from the Baker tanks needed to be disposed of in a hazardous waste facility. Bruce Abelli-Amen is the Managing Principal of Baseline Environmental Consulting, and has extensive experience analyzing and resolving complex water quality and hydrogeology challenges. Abelli-Amen reviewed the characterization of the water in the Baker tanks by McCampbell Analytical Inc. (lab report attached), as well as the state and federal hazardous waste regulations that apply to the mercury-contaminated water. Below is an excerpt from his memo to the SFPUC dated June 10, 2020.