Last week, Policy Watch published a story about groundwater contamination in wells around four of Duke Energy’s coal ash ponds. We covered Marshall and Cliffside on Monday; today, we look at the contamination at the Allen plant. Next week, we’ll publish results of the contamination at Sutton, Buck, Roxboro and Dan River.

The Allen plant sits along the Catawba River and Lake Wylie in Gaston County, shortly upstream from the Charlotte Yacht Club. With five coal-fired units ranging from 57 to 61 years old, Allen has two ash ponds, one active, and the other inactive.

Combined, those ponds contain at least 11 million tons of coal ash, according to Duke Energy data from 2014. And beneath the ponds, the groundwater is contaminated with at least nine pollutants, some of them at levels far exceeding state standards. The results at Allen and 11 other plants were in 20,000 pages of data released by Duke Energy, as required by federal coal combustion residuals rules.

The wells are not used for drinking; however, groundwater can travel into surface water and drinking water wells.

One of these contaminants is beryllium, a known carcinogen. A silver-white and lightweight metal, beryllium is commonly found in coal, particularly that sourced from Appalachia. The chemical composition of coal is determined by a region’s geology; coal from the Powder River Basin in Wyoming, for example, has different properties than that in the Eastern US. Variations can occur even within the same coal bed.

(Beryllium is also found in computer motherboards and other electronics, which is why it’s important to keep that equipment out of landfills. It’s also used in the manufacture of golf clubs.)

Beryllium concentrations were detected in some samples as much as nine times the state’s groundwater standard. Arsenic, another carcinogen, was found at eight times the standard.

Selenium, which is also naturally occurring, nonetheless has been linked at high levels to coal ash. Duke University scientists found high levels of selenium in fish tissue in two lakes that received discharges from coal-fired power plants. When eaten, selenium at high levels can harm other aquatic life and birds that feed on it.

The highest level of selenium in a groundwater well near Allen was 1,970 parts per billion. The groundwater standard is 20 ppb.

The data was made public as part of the federal coal combustion residuals rules. However, Duke Energy has been conducting groundwater tests for many years and making the data publicly available. “It’s important to note than no tests have shown an unsafe impact to drinking water,” said Duke Energy spokesman Bill Norton. “While we believe dewatering and closing our basins will safely address any groundwater contamination, we will continue monitoring the thousands of test wells placed all around our sites during and long after the closure process. if the monitoring shows we need to take additional measures to ensure our neighbors’ safety, then we will do so.”

The EPA is using the recent tests results to determine whether to close more than 1,000 ash basins nationwide, but Norton noted that Duke is already planning to close the coal ash basin at Allen and all of its plants. At most plants, the basins will be fully excavated and the coal ash recycled or moved offsite; but at several, the coal ash will stay onsite in a capped and lined landfill. The basins are unlined, which allows them to leak. Lined landfills are supposed to help protect against leaks.

Allen 53 wells sampled 434 samples Contaminant Maximum contaminant level, groundwater and drinking water Range of exceedances, lowest to highest (ppb) Number of exceedances % of samples that exceeded maximum contaminant levels Antimony 1 part per billion 2.1 – 10.5 5 1 Arsenic 10 ppb 4.6 – 88.3 8 1.8 Beryllium 4 ppb 4.4 – 35.5 16 3.6 Boron 700 ppb 702 – 2340 115 26.4 Cadmium 2 ppb 3.1 – 8.5 15 3.4 Chromium 10 ppb 10.4 – 210 17 3.9 Cobalt 1 ppb 1.1 – 4750 201 46.3 Selenium 20 ppb 678 – 1970 11 2.5 Thallium 0.2 ppb .21 – 3.1 21 4.8