The Hubbard County Board approved the purchase and installation of two water filtration units last month.
"This was recommended by the Minnesota Pollution Control Agency after a water quality assessment was completed by the county that showed levels of boron and/or manganese that were above the drinking water standard in two residential wells," said County Solid Waste Administrator Josh Holte at the Jan. 23 meeting.
The residences are downgradient of the county's demolition landfill in Park Rapids, Holte said.
The low quote of $4,650 was from Ecowater Systems of Park Rapids and includes installation of a water softener, reverse osmosis system and booster pump at the two residential locations.
Last fall, the county sent surveys to 18 properties that are downhill from the landfill, where the groundwater flows, Holte said, noting that nine properties responded.
"Of those nine, two showed levels that exceeded the health standard," he said.
"There could be more, but no one else sent them in?" asked county commissioner Tom Krueger.
All the properties neighboring these two were surveyed, Holte replied, and showed no signs of a health risk.
Hubbard County's landfill is an unlined, construction/demolition debris disposal facility. The MPCA issued the original permit for the operation of a mixed municipal solid waste transfer station and demo landfill in 1988. The landfill currently occupies about 11.3 acres.
In a phone interview, Courtney Ahlers-Nelson, supervisor of the Land Permits Unit at Minnesota Pollution Control Agency (MPCA), explained that onsite monitoring wells at the landfill are checked twice per year. The county submits semi-annual and annual report to the MPCA.
"Because we'd seen some contamination issues in their onsite monitoring wells on the downgradient side, we asked them to look further at the residences that were downgradient, so they identified 18 properties that had wells and they sent them letters offering to sample their wells. Nine people took them up on it," said Ahlers-Nelson.
One of the residences had both boron and manganese, the other only had manganese in their drinking water.
According to the Minnesota Department of Health (MDH), boron is "a naturally occurring element and is used in many consumer products...Once boron is in the environment, it does not break down. Boron has been detected in Minnesota drinking water, groundwater and surface water."
MDH developed the risk assessment value for boron in drinking water at 500 parts per billion (ppb). In animal studies, says a MDH fact sheet, exposure to high levels of boron caused decreased fetal weight and improper fetal development as well as disruptions to the male reproductive system.
Another MDH fact sheet says "manganese occurs naturally in rocks and soil across Minnesota and is often found in Minnesota ground and surface water. Your body needs some manganese to stay healthy, but too much can be harmful."
Children and adults who drink water with high levels of manganese for a long time may have problems with memory, attention and motor skills. Infants (babies under one year old) may develop learning and behavior problems if they drink water with too much manganese in it, according to MDH. The MDH recommends less than 100 ppb of manganese in drinking water.
According to MDH water sampling test results completed in October and November 2018, one residence northwest of the landfill had between 900 to 967 ppb of boron and 215 to 226 ppb of manganese in their water supply. The second residence had between 426 to 432 ppb of manganese in their well.
Statewide, Ahlers-Nelson said, "we do know there have been two other sites, which are also construction/demo debris landfills, where the (Minnesota) Department of Health has issued a well advisory for residences downgradient of those landfills."
This is the first time that neighboring wells have been contaminated by Hubbard County's landfill. "I'm not aware of any previous other wells being impacted offsite," Ahlers-Nelson said.
Walker Smith, MPCA public information officer, pointed out that boron comes from the debris in the landfill, but manganese comes from the soil.
Ahlers-Nelson explained that landfill conditions enhance the release of manganese from soils.
Hubbard County is in the process of seeking a new permit for the new transfer station and continued operation of the demo landfill. A draft permit is available for review on the MPCA website (www.pca.state.mn.us/publicnotices).
As part of reissuing the permit, Ahlers-Nelson said the MPCA met with county officials in August 2018 about "modifying management practices at the site, including we recommended consolidating their waste footprint. In other words, the landfill is spread out over a pretty large area, so it would be advantageous to consolidate it into a smaller area. That would be one option. Also, enhancing the cover over their existing waste footprint. In other words, covering it up more so you wouldn't have infiltration into the groundwater, or increasing the slopes over the waste to improve run-off - again, to try to get water to go off to the side and not through the waste and then impact groundwater. Those are just some of the ideas we put forward."
Ultimately, when portions of the landfill are closed, Ahlers-Nelson said an "enhanced cover" will be placed to prevent precipitation from running through the waste.
A public comment period on the draft permit ends Feb. 19. To submit comments or petitions to the MPCA through the mail or email, you must state your interest in the permit application, the action you wish the MPCA to take, including specific references to the section of the draft permit you believe should be changed, and the reasons supporting your position. The MPCA contact person is Lisa Mojsiej, 520 Lafayette Road, St. Paul, MN 55155 or email@example.com.