Columbus City Utilities has awarded a contract to a Westfield company to drill test and monitoring wells in the city’s southside well field to map the extent of chemical contamination in the aquifer supplying Columbus’ drinking water.
Utility Service Board members voted unanimously Thursday to pay Peerless Midwest Inc. $68,300 to drill the three test wells and three monitoring wells in the south well field near now-closed city wells where 1,4 dioxane was detected in 2017.
Columbus is one of several Indiana cities that tested above the .35 parts per billion Environmental Protection Agency recommended limit for the industrial solvent, testing at .48 parts per billion in the city water system in 2013.
Columbus wells No. 14 and 15 were shut down in October 2017 after the chemical was detected, and are still offline, utility officials said. The wells are located east of State Road 11 and south of Garden City, near the East Fork White River.
City officials and investigators emphasized there is no federal standard for 1,4 dioxane limits. Other Indiana cities testing above the EPA recommendations in 2013 were La Porte and Evansville.
In earlier interviews, utility officials have said that typical household water filters probably do not have the capacity to remove even the small amounts of 1,4 dioxane. The chemical is not a regulated contaminant for drinking water under federal or Indiana drinking water regulations.
The city has 15 to 20 wells in the southern well field, but only the two have been shut down at this time because of detection of 1,4 dioxane.
Scott Dompke, who took over as city utilities director last year, said monitoring wells are being drilled north and south of the two wells that have been shut down in an attempt to define the limits of the 1,4 dioxane contamination, and where the solvent can actually be found.
The test wells will be drilled to determine where the city could place new wells within the south well field to replace the two closed wells, he said. The city utility needs to build up more capacity for water production with the closing of the two wells, he said.
Officials from Intera, a geoscience and engineering solutions company with offices in Bloomington, completed a report on the status of the city’s south well field last year.
The company could not say where the chemical originated or how far north or south it may have spread, only that it has been detected at the bottom of the aquifer between the wells and the river. That means the company has determined the contamination appears to be to the east of the wells rather than the west, according to a presentation given by Rhett Moore, Intera’s principal hydrologist, to the utilities board last year.
That finding deepens the mystery as to how the chemical got there and whether other wells close to wells 14 and 15, and near the river, namely wells 16 and 17, could be in danger of contamination in the future because of where the chemical has been found.
Moore explained the company began its investigation by sampling the well water in the two now-closed wells, and also sampled along the river banks, where they found higher 1,4 dioxane levels compared to the wells. No 1,4 dioxane was detected in the river itself, he said.
To test water in the aquifer, the company installed a network of monitoring test wells and did soil borings looking for the location of the chemical and how far it had spread. It placed shallow Piezometer monitors in the river and repaired two multi-level monitoring wells already in the well field to obtain results.
The company also did what Moore described as an exhaustive search of Indiana Department of Environmental Management records and historic aerial photos of different entities that had been located in the area near the wells and the river.
Moore said there were many legacy sites identified by IDEM on the west side of the river, but all had been evaluated by the agency and had been determined not to be a threat to the well field, leaving that part of the investigation inconclusive.
Sonic core testing of the subsurface around the wells did not find any source of the contamination, he said.
The city’s most recent water testing report showed the city’s water complied with all current standards in place for drinking water. The city utilities serves about 35,575 people in Columbus and 8,445 people for the Southwestern Bartholomew Water Co., which obtains its drinking water from Columbus.
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Environmental Working Group, a Washington D.C.-based nonprofit working on environmental issues, said that more than a million pounds of 1,4 dioxane was produced in the U.S. or imported to the country in 2015, and 675,000 pounds of the substance has been released into the environment nationwide.
The group said the chemical is a common impurity in cosmetics and household cleaning products, and is found in shampoos, foaming soaps, bubble baths, lotions and laundry soap.
Because the chemical is man-made, it can be detected in groundwater, and has been in a large number of Indiana cities, including a large cluster around Indianapolis that did not test above the EPA guidelines but did test positive for the chemical, the nonprofit said.
Environmental Working Group said water at .35 parts per billion with 1,4 dioxane would cause one cancer case in a lifetime. At .48 parts per billion, a slightly higher risk was predicted, the nonprofit said.
Exposure to the chemical can lead to cancer, liver or kidney damage, lung irritation and eye and skin irritation, according to the nonprofit.
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