Manganese health advisory and Colorado public water utilities.
Many water professionals do not realize that the United States Environmental Protection Agency (USEPA) issued a public health advisory for manganese in the year 2004. The language in the advisory may be alarming to the public and speaks of possible developmental effects in children (especially bottle-fed infants) if the water contains high levels of manganese and too much is consumed by users. The language sounds similar to the warnings issued about lead poisoning. The message in the advisory states that if the total manganese concentration exceeds 0.3 mg/L in the finished water, then infants under 6 months should not consume the water. The message also states that if the manganese exceeds 1.0 mg/L, then nobody should consume the water. Even though there is a health advisory limit for manganese, it is not regulated under state regulations and the regulations do not mandate a maximum manganese level in the drinking water. Per Colorado Primary Drinking Water Regulations (Regulation 11), manganese is a secondary contaminant meaning that systems are not required to test for manganese like they are required to test for primary contaminants (e.g. e.Coli). Manganese is not
regulated and there is no mandated maximum manganese level for drinking water.
The secondary maximum contaminant level for manganese in Regulation 11 is 0.05 mg/L. Any samples tested above this concentration, could result in colored water. Because manganese typically oxidizes and makes the water discolored, it is considered a nuisance chemical by public water utilities and is typically removed.
There are many groundwater wells in Colorado and elsewhere that have high levels of manganese. These wells may be regularly used for drinking water on a backup basis. They might be treated with chemicals that keep the manganese from turning the water brown, but do not remove the manganese.
In January of 2019, it was discovered that the Town of Empire was serving water from a backup well that contained manganese greater than 2.0 mg/L. The town, in consultation with our department, decided to issue a warning to users to not drink the water given the 2004 health advisory and the health threat. This was the first time the CDPHE has worked with a system to issue a Tier 1 Public Notice due to the 2004 manganese health advisory. Currently, the town is evaluating whether to install treatment on this source or seek a lower manganese source as a backup water source.
Questions you might have
- Why did the department decide to issue public notice on a 2004 health advisory?
- What is a health advisory and why do we use it to make public notification requests?
The EPA started to encourage states to work with systems to notify the public of health threats even on unregulated contaminants at the start of 2014. This practice led to a public notification in Toledo, Ohio for drinking water in August 2014. This was due to a toxic algal bloom that affected almost half a million drinking water customers. In May 2016 a public notice was also issued when it was discovered that as many as 60,000 people south of Colorado Springs were drinking water above the health advisory for PFAS. In both of these cases, the contaminants in question could potentially lead to permanent health impacts from a relatively short term exposure. Public notice events were deemed necessary given the EPA guidance and the evidence at hand. These cases set a precedent for proper response to health advisories. CDPHE follows the guidance of the EPA to require public notification if one of the following three specific pollutants are above the health advisory limits: manganese, microcystins and PFAS.
Our department recommends that water systems test their raw and finished water manganese levels regularly and ensure that installed treatment techniques are capable of adequately removing manganese in order to avoid incidents such as the ones described above. We are willing to assist water systems with technical guidance, loans, or other aid in helping communities understand the public health risks and need to remove manganese from the drinking water. Our department expects public water systems to keep us informed of any high manganese results from the drinking water and to consult with the us on best courses of action case-by-case. More broadly, we are committed to keeping water systems informed of the shifting climate of public health advisories and to work with systems to find the best solutions. CDPHE does have authority to require a Tier 1 Public notice in “situations with significant potential to have serious adverse effects on public health as a result of short-term exposure, as determined by the Department either in Colorado Primary Drinking Water Regulations or on a case-by-case basis” Regulation 11 section 11.33(2)(a) and will utilize that authority if needed to ensure that the public is aware of that kind of situation. Working together with water systems to make the public aware of health threats is critical to maintaining public trust.
CASE 1: Harmful Algal Toxins - Microcystin
In August 2014, the City of Toledo, Ohio issued a “DO NOT USE” public notice for their drinking water because of the presence of a toxin in the water called microcystin. The City had detected about 1.6 parts per billion (ppb) of this toxin in their finished drinking water. At the time, the World Health Organization had a published a lifetime (long-term) exposure limit of 1.0 ppb. The toxin is a byproduct of blue-green algae decay and has been known to cause the death of dogs and other animals through liver failure after ingestion of the toxin while swimming in lakes or reservoirs. While little was known about its short term effects in humans, many swim beach and lake closures have occurred as a preventive measure in the midwest over the years due to the presence of the toxin.
In 2015 the EPA weighed in on the legitimacy of Toledo’s “DO NOT USE” advisory by publishing values called ‘health advisory’ values stating that water over the health advisory numbers represented levels that were a threat to human health even with short term exposure. Contaminants with health advisory limits may not be regulated contaminants but they are still contaminants deemed by the EPA to have a significant public health threat based on toxicological evidence. In this case limits of 1.6 ppb for adults were set while the limit was set at 0.3 ppb for all under 6 years old. By establishing health advisory limits for microcystin, the EPA essentially endorsed the City of Toledo’s decision to issue an immediate “DO NOT USE” advisory. The Health Advisory document reiterates that once levels of toxins are detected in the finished water above a certain level, the only recourse and safest course of action is for the public water system and the corresponding state and local agencies to warn all users that the water is unsafe to drink.
CASE 2: Perfluorinated Compounds (PFCs)
Similarly in Colorado in 2016, the presence of PFAS was detected in the drinking water of three large utilities south of Colorado Springs (Security, Widefield, and Fountain) at levels that caused concern. These substances are likely a result of fire training areas spraying aqueous film forming foam (AFFF); a firefighting foam that contains PFAS. Over many years of using the foam in training, it may have entered the Widefield aquifer and impacted the drinking water sources for those three cities.
Prior to May 2016, the levels measured in the drinking water were considered a concern but not unsafe. This was because they were below the EPA’s interim health advisory at the time. In May 2016 the EPA modified the health advisory and lowered the number to 70 nanograms per liter (ng/L) or parts per trillion (ppt). Most of the drinking water coming from wells in the Security/Widefield/Fountain area were then above the new health advisory. Therefore, the CDPHE, local health department, and the public water systems issued public notification recommending that people consider an alternate source of water.
Summary of Cases
In both of the above cases, the contaminants in question have a potential to have a permanent health consequence from a relatively short term exposure. Therefore, public notice events were deemed necessary given the EPA guidance and the evidence at hand. An acute public notice would not necessarily be required for a contaminant that was a chronic cancer risk, as those risks are incurred over long term exposure time frames. For chronic issues, public education would be necessary but could be rolled out to inform the public in a less alarming manner.
➽ Tyson Ingels, lead drinking water engineer
