In June of 2020, the South Carolina Department of Health and Environmental Control (SCDHEC) conducted testing of per- and polyfluoroalkyl substances (PFAS) at the City of Columbia’s two drinking water treatment plants at Lake Murray and the Columbia Canal as they conducted PFAS sampling at 44 water systems across the state of South Carolina.

In an effort to develop reliable information about PFAS in Columbia’s drinking water, Columbia Water is continuing to perform testing for these compounds twice per year.  The first set of these additional bi-annual samples was collected in October of 2020, and Columbia Water is pleased to share the results with our customers, as well as provide information about PFAS.

Background

PFAS is an acronym for man-made chemicals used globally since the 1940s in a variety of industrial and commercial products. PFAS resist heat and repel oil and water, so they are found in such products as firefighting foams, stain- and water-resistant coatings, and non-stick coatings. 

The same properties that make PFAS useful for industrial and consumer products make them difficult to degrade and very persistent in the environment, leading to PFAS being found literally everywhere on earth. Because of this persistence, it is not unusual for some PFAS to be found anywhere, including the City’s drinking water.

Health Impact

High exposures to two of the most common and most-studied PFAS compounds, perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) have been associated with several health conditions. Out of an abundance of caution EPA established a health advisory for PFOA and PFOS even though additional research is needed in order to determine if definitive epidemiological effects exist and how they are related to exposure to PFOA and PFOS (as well as the over 4000 other PFAS compounds known to exist).

A health advisory (HA) is a concentration in drinking water that is not expected to cause adverse health effects based on a specified exposure duration. Health advisories are informal guidance and not regulatory or legally enforceable. The health advisory level is 70 parts per trillion (ppt) for PFOA and PFOS, both individually and in combination.

Previous Testing Results

June 2020

Test results indicate that PFAS levels in the Columbia’s drinking water are well below EPA’s health advisory levels.

General Results: SCDHEC recently sampled the finished drinking water from 44 of the drinking water treatment plants around the state of South Carolina, including Columbia’s two drinking water treatment plants. Only eight of the twenty-nine compounds tested for were detected in Columbia’s water and those were found at very low levels. Most of the eight compounds found in either or both of the City’s drinking water plants also appeared in a majority of the other 42 drinking water plants that DHEC sampled.

Sampling – Specific Results: Both PFOA and PFOS were detected in SCDHEC’s test results from the finished water at both of the City’s water treatment plants. For the two different testing methods used, combined levels were 8.9 and 10.2 ppt at the Canal Plant, and 4.2 and 5.3 ppt at the Lake Murray Plant, all well below the 70 ppt health advisory. It is important to note that this is just one set of samples, and that more sampling is needed to establish solid data.

Moving Forward: Of the other six compounds detected in the City’s drinking water, no result exceeded 6.6 parts per trillion. In order to continue to develop information about PFAS levels going forward, Columbia Water will be conducting its own PFAS testing every six months.

October 2020

Test results indicate that PFAS levels in Columbia’s drinking water are well below EPA’s health advisory levels.

Summary: The City of Columbia collected finished drinking water samples from each of its two water plants on October 28, 2020, just as DHEC did on June 8, 2020, and had those samples analyzed for the same 29 PFAS compounds using the same two testing methods. The City also collected samples from each of its two source waters, the Columbia Canal and Lake Murray, and had those samples analyzed for the same 29 compounds using a third testing method.

Finished Drinking Water Sample Results: The same eight PFAS compounds that were detected in DHEC’s June drinking water samples were also detected in the City’s October samples. Two additional compounds were also detected in the Canal Plant’s October samples, resulting in a total of ten PFAS compounds detected in the drinking water samples from one or both of the City’s water treatment plants. All compounds detected in the October samples were found at low levels similar to those found in the June samples. Combined levels of PFOA and PFOS were 12.58 and 12.70 parts per trillion (ppt) for the two testing methods in the Canal Plant samples, and 3.94 ppt for both methods in the Lake Plant samples, all well below the 70 ppt health advisory level. There are no health advisories for any of the ten detected compounds other than PFOA and PFOS.

Source Water Sample Results: Eleven of the 29 PFAS compounds tested for were detected in one or both of the Columbia Canal and Lake Murray source water samples, including seven of the ten compounds found in the drinking water samples plus four additional compounds, all at low levels. The highest level of any compound found in the source waters was 7.25 ppt, and five of the eleven compounds were found at levels less than one ppt. There are no health advisories for source water samples.

Columbia PFAS Results for April 2021

Columbia Water continues to proactively sample for perfluorinated compounds in its drinking water every six months. April 2021, samples show PFAS levels varying slightly from earlier test results in both the Canal Water Treatment Plant and Lake Murray Water Treatment Plant raw and finished water, with levels continuing to be well below the EPA health advisory targets.

Summary: The City of Columbia collected finished drinking water samples from each of its two water plants on April 20, 2021 utilizing the same parameters as DHEC sampling that occurred in June of 2020. The City also collected samples from each of its two source waters, the Columbia Canal and Lake Murray, and had those samples analyzed for the same 29 compounds using a third testing method.

Finished Drinking Water Sample Results: April, 2021 finished drinking water samples showed mixed results at the two water treatment plants with some levels going up, and others going down. Combined levels of PFOA and PFOS were 14.54 and 15.3 parts per trillion (ppt) for the two testing methods in the Canal Plant samples, and 13.17 and 7.29 ppt for the two testing methods in the Lake Plant samples, all well below the 70 ppt health advisory level. Only nine of the 29 compounds tested for have been detected in the finished water from each plant.  There are no health advisories for any of the compounds detected other than PFOA and PFOS.

Source Water Sample Results: One new compound appeared at a very low level in the source water samples for the Canal Water Treatment Plant, which means 15 of the 29 PFAS compounds tested have been detected in one or both of the Columbia Canal and Lake Murray source water samples, all at low levels. There are no health advisories for source water samples, but Columbia Water is gathering source water samples to develop our body of knowledge on this subject.

For More Information: In order to continue to develop information about PFAS levels going forward, Columbia Water will conduct its own PFAS testing every six months.

Please visit the EPA’s PFAS web page at www.ep.gov/pfas for tools, resources, and EPA actions to address PFAS. SCDHEC also has a resource page at www.scdhec.gov/BOW/perfluoroalkyl-substances-pfas which includes results from all the drinking water systems they sampled.