Previous Sampling and Analysis Plans.docx

Previous Sampling and Analysis Plans for Duncan Landfill and Robins Pond February 3, 2020 Duncan Quality Data The groundwater samples from the monitoring wells sampled at Robbins had detections of VOCs, SOVCs, and metals. The detected compounds were above the laboratory detection level, but were below EGLE RBSLs with the exception of chromium, lead, selenium, and silver which exceeded DW and/or GSI in multiple samples and monitoring well locations. A summary of detected compounds is presented in the table below.

Duncan Twp. Landfill Compounds Detected

MW-8A, MW-9, and

MW-10

Bis (2-ethylhexyl) phthalate

MW-1, MW-2, MW-3,

MW-5, MW-6, MW-7,

MW-7A, MW-8, MW-

8A, MW-9, MW-10,

MW-11

1,2-Dibromo-3-chloropropane

and MW-11

Arsenic, Barium, Cadmium

MW-1A, MW-8 (DW

100 ug/l)

MW-7, MW-9, MW-

10, and MW-11 (DW 4ug/l)

except MW-3

MW-9, MW-10, MW-

11 (GSI 5 ug/l)

except MW-7A

MW-1A, MW-2, MW-

7, MW-10 (GSI 0.2

ug/l)

Review of analytical results indicate that all eight RCRA metals were detected above the laboratory detection levels in all samples collected. Chromium, Lead, Selenium, and Silver were detected above DW and GSI Criteria in a majority of the monitoring wells. Monitoring wells MW-1 and MW-1A had the highest concentrations of detected compounds. The detected compounds were stable the first three quarters. Some of the detected compounds decreased in the fourth quarter. Mercury was detected in monitoring well MW-1 at 0.22 ug/l for the first quarter and was not detected again in any other samples. This single detection appears to be a spurious laboratory result.

Robins Pond Quality Data The groundwater samples from the monitoring wells sampled at Robbins had detections of VOCs, SOVCs, and pesticides. The detected compounds were above the laboratory detection level, but were below Michigan Department of Environment, Great Lakes, and Energy (EGLE) Risk Based Screening Levels (RBSLs) with the exception of bis (2-ethylhexyl) phthalate) and 4,4’ DDT. bis (2-ethylhexyl) phthalate) was detected above EGLE Drinking Water Criteria (DW) and Groundwater Surface Water Interface Criteria (GSI) in all the samples collected. 4,4’ DDT was only detected above GSI criteria in the four quarterly groundwater samples collected from MW-1. A summary of detected compounds is presented in the table below.

Robins Pond Compounds Detected

MW-5, MW-6,

MW-7, MW-8,

MW-9

Bis (2-ethylhexyl) phthalate

MW-1, MW-4,

MW-5, MW-6,

MW-7, MW-8,

MW-9

monitoring wells (GW 6 ug/l) and (GSI 25 ug/l)

MW-6, MW-7,

MW-8, MW-9

MW-5, MW-6,

MW-7, MW-8,

MW-9

(GSI 0.00011 ug/l)

Review of analytical results indicate that the first quarter (November-December 2018) had the highest concentrations of detected compounds. The detected compounds decreased or were non detect the following three quarters. The second quarter had the most pesticide compounds detect above the laboratory detection level, but below EGLE GW criteria.