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HomeMy WebLinkAbout4104_CityHighPointKerseyValley_MSWLF_ASDAddendum1_DIN28392_20170626 June 26, 2017 Ms. Jaclynne Drummond, Compliance Hydrogeologist Division of Waste Management, Solid Waste Section Asheville Regional Office 2090 US Highway 70 Swannanoa, North Carolina 28778 Re: Proposed Scope of Work Alternate Source Demonstration Addendum Kersey Valley MSWLF Permit No. 4104-MSWLF-1991 High Point, Guilford County, North Carolina Dear Jackie, In response to correspondence dated June 8, 2017 from the Solid Waste Section, this Scope of Work is proposed to address the Appendix I inorganic constituent exceedances in monitoring well 4104-MW4 at the Kersey Valley MSWLF. The tasks outlined below are proposed to develop the information necessary to prepare an Alternate Source Demonstration Addendum: Background Historically, monitoring well 4104-MW4 has shown minor concentrations of cadmium over the past three years, ranging from a low of Below Quantitation Limits (BQL) in May 2017 to a high of 20.3 ug/l in April 2015. No other inorganic compounds have been reported above the NC 2L Groundwater Standards in monitoring well 4104-MW4. Monitoring well 4104-MW4 is a flush-mount well located in the driveway of the former Convinence Center at the landfill. Photographs showing the well location and top view of the well are provided in Attachment A. This well was damaged by vehicular traffic in 2013 which required repair to the manhole vault during September 2013. The reported date of manhole vault damage and repairs coincides with a noted increase in cadmium concentrations starting in the spring of 2014. A summary of the reported cadmium concentrations in monitoring well 4104-MW4 over the past ten years is provided in Table 1 which is attached to this correspondence. Proposed Response Actions To develop the information necessary for preparation of the Alternative Source Demonstration Addendum, the following actions are proposed: Monitoring Well Installation and Soil Sampling A new monitoring well is proposed to replace the existing 4104-MW4. The new well will be located out of the driveway area approximately 75 feet to the east as shown on the figure provided in Attachment B. The existing 4104-MW4 monitoring well is 25 feet in total depth and only has 4-5 feet of water in the casing so the new well will be drilled to a depth of 30-35 feet if possible. The well will be constructed in accordance with the NC Well Construction Standards and will be completed with a lockable steel above-grade protector and a 2’x2’ concrete pad. During drilling of the new well, soil samples will be collected for laboratory analyses of total RCRA metals. The number of soil samples will be based on the soil types encountered, however, we estimate 3-4 soil samples for total metals analyses. After installation, the well will be developed to remove as much fines and sediment as possible. The well will be developed using either a pump or bailer depending on the quantity of water in the well and the recharge rate. Groundwater Sample Collection A groundwater sample will be collected from the new well on the morning following well installation and development. The sample will be collected for total and laboratory filterable cadmium. The sample will be collected using a new disposable bailer and placed directly into the laboratory prepared containers. A temperature blank will be provided to assure proper shipment of the samples. The samples will be hand delivered to the analytical laboratory. Report Preparation The field information gathered during well installation along with the laboratory analytical results developed from the soil and groundwater samples will be used to support the Alternate Source Demonstration Addendum. A written Addendum will be prepared to address the requirements of the NC Solid Waste Section Guidelines for Alternate Source Demonstration Submittals. Thank you for reviewing this scope of work and we appreciate any comments or suggestions regarding these proposed response actions. Pending approval and finalization of this scope of work, the field activities are tentatively planned for late July 2017. Respectfully, Babb & Associates, P.A. Gary D. Babb, P.G. President Enclosures Cc: Mike Spencer, City of High Point Robby Stone, City of High Point TA B L E 1 Mo n i t o r i n g W e l l 4 1 0 4 - M W 4 H i s t o r i c a l C a d m i u m C o n c e n t r a t i o n s Ke r s e y V a l l e y M S W L F Hi g h P o i n t , N o r t h C a r o l i n a Pe r m i t # 4 1 - 0 4 Ye a r S p r i n g S a m p l i n g E v e n t F a l l S a m p l i n g E v e n t 20 1 7 < 0 . 3 6 u g / l 20 1 6 2. 3 2 u g / l ( < 0 . 3 6 u g / l * ) 0 . 5 8 3 u g / l J 20 1 5 20 . 3 u g / l 2 . 5 3 u g / l 20 1 4 6. 4 9 u g / l 1 1 . 4 u g / l 20 1 3 < 0 . 6 0 u g / l 0 . 0 7 2 8 u g / l J 20 1 2 < 0 . 6 0 u g / l < 0 . 6 0 u g / l 20 1 1 1 . 7 9 u g / l J < 0 . 6 0 u g / l 20 1 0 < 0 . 1 5 8 u g / l < 0 . 1 5 8 u g / l 20 0 9 0 . 1 6 u g / l J < 1 . 0 u g / l 20 0 8 < 0 . 1 3 4 u g / l < 0 . 1 3 4 u g / l 20 0 7 < 0 . 3 3 2 u g / l < 0 . 1 3 4 u g / l 20 0 6 < 1 . 0 u g / l < 1 . 0 u g / l No t e s : Bo l d c o n c e n t r a t i o n s e x c e e d 2 L G r o u n d w a t e r S t a n d a r d o f 2 . 0 u g / l * R e s a m p l e c o l l e c t e d i n A u g u s t 2 0 1 6 J - E s t i m a t e d c o n c e n t r a t i o n , b e l o w m e t h o d r e p o r t i n g l i m i t Attachment A Monitoring Well 4104‐MW4 Monitoring Well 4104‐MW4 Location Monitoring Well 4104‐MW4 Top View