Discharged from Greensboro, toxic chemical 1,4-Dioxane has arrived downstream, contaminating Pittsboro’s drinking water

The Haw River at Bynum Bridge, near Pittsboro’s drinking water intake (Photo: Lisa Sorg)

Levels of 1,4-Dioxane, a likely carcinogen, have increased in Pittsboro’s drinking water over the past week, as an illegal discharge makes its way downstream, according to town officials.

The release came from Greensboro’s TZ Osborne wastewater treatment plant on April 5. The plant discharges into South Buffalo Creek, a tributary of the Haw River, which is Pittsboro’s drinking water supply.  Lanxess, an international chemical company with a plant in south Greensboro, discharges into the Patton trunk line, one of several that feed the wastewater treatment plant. Lanxess informed the city that self-monitoring showed it’s the source of the 1,4-Dioxane, according to a press release.

A day after the release, on April 6, levels of 1,4-Dioxane in Pittsboro’s finished drinking water — which has been treated — were 5.12 parts per billion. On April 8, the levels had more than doubled, to 11.9 parts per billion. Traditional drinking water treatment systems don’t remove the compound, according to Town Manager Chris Kennedy. Additional sampling is ongoing, he said.

The EPA does not regulate 1,4-Dioxane in drinking water. The agency has set a health advisory goal of 35 ppb, which is equivalent to a 1-in-10,000 additional cancer risk over a lifetime. In surface water the rules are stricter: 0.35 ppb, is the legally binding standard. It represents a 1-in-1 million additional cancer risk. The compound has several industrial uses, including as a degreaser, and can be a byproduct of plastics manufacturing.

Preliminary levels of toxic 1,4-Dioxane were reported at 52 parts per billion in Greensboro’s wastewater. Further testing on April 5 and 6 showed lower levels, ranging from 22.1 ppb to 37.9 ppb.

A consent order and settlement agreement among Greensboro, state regulators, Haw River Assembly and Fayetteville Public Works Commission caps the amount of 1,4-Dioxane that can be released at 35 ppb. Starting May 1, the threshold decreases to 31 ppb.

Greensboro has installed monitoring stations on trunk lines within its citywide sewer system. Surveillance data shows the Patton trunkline measured 1,4-Dioxane at 95 ppb. Lanxess discharges into that trunkline.

However, additional data shows even higher levels of the compound — 599 ppb — entered the Bryan Park trunkline between April 1 and 4. That trunkline is south of Shamrock Environmental, in Browns Summit. That company was responsible for a previous discharge in 2019 that also contaminated Pittsboro’s drinking water. The source of two other 1,4-Dioxane releases last year have not been identified.

A map showing the location of the TZ Osborne wastewater treatment plant in Greensboro and the town of Pittsboro downstream

This map shows the location of Greensboro’s TZ Osborne Wastewater Treatment Plant and Pittsboro’s water intake on the Haw River downstream. The distance is roughly 50 miles. (Google maps)

This story has been corrected to reflect the legally binding standard of 1,4-Dioxane in surface water.

Chemical facility reports it’s the source of latest 1,4-Dioxane spike in Greensboro

This story has been updated with information from Pittsboro.

The City of Greensboro again violated the terms of a Special Order by Consent this week after reporting elevated levels of 1,4-Dioxane had been released from its TZ Osborne wastewater treatment plant and into a drinking water supply.

Preliminary levels of toxic 1,4-Dioxane were reported at 52 parts per billion in discharge into South Buffalo Creek on April 5. The consent order and settlement agreement — among Greensboro, state regulators, Haw River Assembly and Fayetteville Public Works Commission — caps the amount of 1,4-Dioxane at 35 ppb.

Lanxess, an international chemical company with a plant in south Greensboro, discharges into the Patton trunk line, one of several that feed the wastewater treatment plant. Lanxess informed the city that self-monitoring showed it’s the source of the 1,4-Dioxane, according to a press release.

The company does not manufacture, use or store 1,4-Dioxane. However, the compound is often a byproduct of manufacturing processes, including plastics.

 

The samples are undergoing retesting to verify the results. (Update at 2 p.m., April  The Town of Pittsboro released a statement saying that the most current sampling information reports the Patton trunk line, the entry point for the discharge, showed a concentration of 95.1 ppb on April 4.)

As a result, Greensboro has ordered several industries to conduct further testing: In addition to Lanxess, Ecolab, Elastic Fabrics, Precision Fabrics and Vertellus.

Therese Vick, research director for the Blue Ridge Environmental Defense League, alerted Policy Watch to the exceedance. “Here we go again, Greensboro violated the Special Order by Consent,” she said. “Why did the Department of Environmental Quality not inform the public and issue a press release?”

A spokesperson for the NC Department of Environmental Quality said all Greensboro followed all notification protocols, including to the state, the public and downstream communities. The state is not required to issue a press release, the spokesperson said.

South Buffalo Creek feeds the Haw River, the drinking water supply for the town of Pittsboro; the Haw is a tributary of Jordan Lake, a major drinking water source for Raleigh, Cary and other municipalities in the Triangle. Traditional wastewater and water treatment systems do not remove the compound.

Because it has the first drinking water intake downstream, Pittsboro receives the brunt of Greensboro’s discharge. Pittsboro officials couldn’t be immediately reached for comment. [Update: Pittsboro Town Manager Chris Kennedy said in a press release that the town will continue to monitor the situation with “additional precautionary sampling.” Initial drinking water results are not yet available for the town.]

1,4-Dioxane is a toxic chemical used in degreasers that the EPA has classified as a likely carcinogen. There is no regulatory standard for 1,4-Dioxane, but the EPA has set a health advisory goal of 35 parts per billion for drinking water, which equals a 1-in-10,000 lifetime excess cancer risk. In surface water the rules are stricter: 0.35 ppb, is the legally binding standard.

This week’s release was the fourth reported exceedance from Greensboro since 2019. However levels of the compound in previous exceedances were much higher, ranging from 540 ppb to 1,210 ppb. The 2019 exceedance was traced to Shamrock Environmental, which has a facility in Browns Summit in northern Guilford County.

The sources of exceedances in 2021 are still unknown, officials from the NC Department of Environmental Quality reported last month. The City of Greensboro lists 29 Significant Industrial Users that discharge into the sewer system. Of those, six discharge into the Patton trunk line: GSO Plating, Vertellus, Elastic Fabrics, Lanxess, Precision Fabrics and Shamrock Environmental.

Greensboro officials said in the press release that they are meeting with Lanxess “to discuss next steps.”

This story has been corrected to reflect the legally binding standard of 1,4-Dioxane in surface water.

No culprit identified in Greensboro 1,4-Dioxane spills from 2021; investigation continues

This graph shows levels of 1,4-Dioxane during the June and November spills, represented by the spikes. The original limit in the Special Order of Consent is shown in orange; the amended order limit is shown in red. There is no drinking water standard for 1,4-Dioxane, but the EPA has set a health advisory goal of 35 ppb. That represents a 1-in-10,000 elevated cancer risk.

Four months after the most recent 1,4-Dioxane spill that contaminated Pittsboro’s drinking water, the City of Greensboro has not pinpointed a source of the hazardous chemical that entered its sewer system. However, city officials are focusing on the Patton trunk line, a part of the city’s sewer system that sends wastewater to the TZ Osborne treatment plant.

The spills occurred in June and November 2021, and resulted in high levels of the compound, a likely carcinogen, to enter the Haw River, which is Pittsboro’s water supply. Although unregulated in drinking water, the EPA has set a health advisory goal of 35 parts per billion for 1,4-Dioxane. Surface water goals are even stricter, at 0.35 ppb. In Pittsboro,  levels of the compound exceeded those goals during both events, including in water flowing from private taps.

Traditional water and wastewater treatment systems can’t remove 1,4-Dioxane.

Sampling of wastewater from the Patton trunk line, located in south Greensboro, showed concentrations of 1,4-Dioxane at 369 parts per billion during the November spill. (There was not a sampler in place on that trunk line when the June spill occurred.) Considering that line transports 10 million gallons of wastewater per day — and the level of 1,4-Dioxane was that high even after dilution — a significant amount of the chemical must have entered the system, said Jenny Graznak, assistant regional supervisor at the NC Department of Environmental Quality’s Winston-Salem office.

Graznak updated the Environmental Management Commission today on the investigation.

The City of Greensboro lists 29 Significant Industrial Users that discharge into the sewer system. Of those, six discharge into the Patton trunk line. And of those industrial users, five — Vertellus, Elastic Fabrics, Lanxess, Precision Fabrics and Shamrock Environmental — had results higher than 15 ppb. GSO Platers, the sixth user, did not. However, based on the five users’ sampling results and the amount of their wastewater discharges, Greensboro officials have ruled them out as the source of either the June or November spills.

The Airport trunk line, which has five Significant Industrial Users, also feeds the Patton trunk line, Graznak said.

Since the June spill, the City has installed continuous surveillance samplers at four trunk lines, including Patton and Airport.

The spills violated a Special Order of Consent between the City and DEQ. (Greensboro was fined $5,000 for the violation; it’s been paid.) That order stemmed from a previous incident, in mid-2019, in which extremely high levels of 1,4-Dioxane entered the city’s wastewater treatment plant and then proceeded downstream and contaminated Pittsboro’s drinking water. In that instance, Shamrock Environmental was the source, city officials said at the time. Since then, Shamrock has instituted more diligent sampling protocols and pre-treatment systems, Greznak said. DEQ officials visited the Shamrock facility last year.

Fayetteville Public Works Commission, which is also downstream from Greensboro, and the Haw River Assembly sued over the Special Order of Consent, arguing it was too lenient. As part of a settlement agreement, the number of sampling locations increased from 26  to 57.

In addition, Significant Industrial Users whose wastewater sampling — conducted by the City — shows levels of 1,4-Dioxane above 100 ppb must complete a source investigation, evaluation and survey for their facility. These facilities meet that criteria: Chemol and Evonik, which discharge into the Arlington trunk line; Ecolab, which sends its wastewater into the Airport trunk line; and Vertellus, which is on the Patton trunk line.

On May 1, the level of 1,4-Dioxane that triggers a source investigation becomes more stringent — 31.5 ppb. And in May 2023, the level decreases further to 23 ppb.

Assistant DEQ Secretary Sushma Masemore told the EMC that the state is continuing to investigate. “We’re trying to get a better understanding of possible sources,” Masemore said, including examining closed industrial sites where groundwater wells have high levels of 1,4-Dioxane.

Levels of 1,4-Dioxane above health advisory goal in untreated drinking water in Pittsboro

One sample of raw — or untreated — drinking water in Pittsboro contained levels of 1,4-Dioxane above the health advisory goal, and concentrations in treated water continue to rise, according to test results released late this afternoon by the town.

On Nov. 16, a sample of raw water contained 38.1 parts per billion of 1,4-Dioxane, a likely carcinogen. The EPA’s and the state’s health advisory goal is 35 ppb; that’s equivalent to a 1-in-10,000 excess cancer risk over a lifetime of exposure. That goal is not as protective as the surface water goal of 0.35 ppb, which represents a 1-in-1 million excess cancer risk.

Finished drinking water at the town’s treatment plant rose from 16.8 ppb to 21.3 ppb over just one day: Nov. 15-16. However, the town can instead use water in storage tanks, which have much lower concentrations, between 1 ppb to 4.6 ppb.

“Town staff remains concerned by the increase in 1,4-Dioxane levels seen in raw water samples,” Town Manager Chris Kennedy said in a press release, “and will continue to exert our energies toward manipulating our water operations in an effort to reduce the concentration levels in our water distribution lines.

The source of the 1,4-Dioxane is Greensboro’s TZ Osborne wastewater treatment plant, which on Nov. 3 illegally discharged high amounts of the compound — 767 ppb — into a tributary of the Haw River. The river serves as Pittsboro’s drinking water supply.

The ultimate source of the 1,4-Dioxane is likely an industrial customer of Greensboro’s. The city has not publicly announced the responsible industry.

The EPA has yet to regulate 1,4-Dioxane in drinking water.

On Nov. 8 and 9, town officials found low levels of 1,4-Dioxane in the water supply and believed the slug of the compound had passed the raw water intake during a time of low demand.

But dry weather has slowed the water flow in the Haw, and several residents said at the time that levels in the town’s drinking water supply were low only because the slug had not arrived yet.

That turned out to be true.

When the most recent spill occurred, Greensboro had a goal of just 45 ppb in its discharge, according to a Special Order by Consent between the NC Department of Environmental Quality and the city. That order was the result of a major 1,4-Dioxane spill in 2019; a subsequent spill last year also violated the terms of the order.

The Haw River Assembly and Fayetteville Public Works, whose water supply is also degraded by these releases, legally challenged the order and asked for stronger environmental protections.

Today the Environmental Management Commission approved a settlement agreement that reduces the goal to 35 ppb in the first year, and 23 ppb by the third year of the order.

Greensboro must also sample its industrial sources, publicly post its sampling data and information about its investigation of pollution sources. It further requires Greensboro to sample downstream at Pittsboro’s drinking water intake on the Haw River and in Jordan Lake.

“The agreement puts Greensboro on the path to controlling its 1,4-dioxane pollution and protecting downstream communities, but it isn’t the last word,” said Geoff Gisler, senior attorney at the Southern Environmental Law Center, which represented the Haw River Assembly and the City of Fayetteville. “We’ll monitor the sampling and watershed investigations secured as part of this settlement and ensure polluters are held accountable. We encourage DEQ to go beyond those investigations and act on Greensboro’s pending permit application to impose strict limits on 1,4-dioxane pollution to protect communities downstream over the long-term.”

“Without these legal challenges brought by Haw River Assembly and City of Fayetteville, the original order would have allowed Greensboro to continue polluting the Haw River with higher levels of 1,4-dioxane, and with much lower penalties for extraordinarily high discharges,” said Emily Sutton, the Haw Riverkeeper. “The monitoring required under this agreement will identify the industries responsible for these toxic discharges in Greensboro and put the responsibility of safe and clean water on polluters, instead of the downstream users.”

After thinking it had “dodged a bullet,” Pittsboro reports increase in 1,4-Dioxane in drinking water

The Haw River, as viewed from the Bynum bridge. The river has been contaminated with 1,4-Dioxane; sources include the City of Greensboro, which is upstream. (File photo: Lisa Sorg)

Just days ago, Pittsboro officials said they considered the town “lucky,” thinking a slug of 1,4-Dioxane from the City of Greensboro had bypassed its water intake on the Haw River. But new test results today have prompted town staff to say they are “concerned by the uptick in concentration in in raw water samples.”

Those samples of untreated water from Nov. 12 show levels of the likely carcinogen at 9.8 parts per billion, almost five times the levels in raw water just two days earlier. Treated water, which is sent to homes, contained concentrations of just above 4 ppb.

The EPA has set a health advisory goal of 35 ppb in drinking water, which represents a 1-in-10,000 excess lifetime cancer risk. That is not as protective as the 1-in-1 million cancer risk that the EPA uses for chemicals that have no safe dose; if that standard were applied to 1,4-Dioxane, the maximum amount in drinking water would be 0.35 ppb — far above what Pittsboro is reporting.

However, research is incomplete on 1,4-Dioxane, and the EPA has yet to set legally enforceable standards for the compound.

“While the numbers remain under the EPA advisory level, staff is concerned that sample results may soon eclipse that suggested concentration level” — 35 parts per billion, Town Manager Chris Kennedy said in a press release. “The Town is continuing to draw only the bare minimum of raw water to keep from inundating our system with contaminated water.

Routine sampling showed Greensboro’s TZ Osborne wastewater treatment plant illegally discharged the contamination on Wednesday, Nov. 3, but the city did not receive the lab results until Monday, Nov. 8, at 11:20 a.m.  The amount of 1,4-Dioxane in the original discharge was 767 parts per billion; that’s more than 2,100 times the EPA’s and the state’s health advisory goal for surface water.

Pittsboro officials believed the slug of 1,4-Dioxane had passed its water intake during a time of low demand. However, several residents commented on social media that the slug was merely delayed by low stream flow in the Haw River. Based on today’s results, those concerns appear to be valid.

According to Greensboro data, on Nov. 8, five days after the discharge, samples of the Haw River near Glencoe, showed levels of 1,4-Dioxane at 99 ppb. Glencoe is 35 miles north and upstream of Pittsboro.

On Nov. 10 and 11, Pittsboro reported low levels of 1,4-Dioxane in raw and treated water, but on Nov. 12, a spike occurred, which could coincide with the contamination making its way down the Haw from Glance.

Town staff continues to pull samples for expedited results. The next round is expected within 24 hours.