SANGERVILLE – The use of sludge to manufacture topsoil for reclaiming portions of the so-called Barrett Pit has significantly affected groundwater in down-gradient monitoring wells.

Although the sludge has changed the water chemistry in the monitoring wells, Department of Environmental Protection officials believe it has not affected the quality of Black Stream, a tributary of the Piscataquis River, which lies below the pit. There are no dwellings between the river and the pit.

“We don’t think it affects the quality of Black Stream, but we don’t know for sure,” Dick Behr, a geologist with DEP’s Bureau of Remediation and Waste Management, said Friday. The gravel pit overlays a sand and gravel aquifer.

While there has been little effect on groundwater microbiology as measured by fecal coliform and total coliform counts, there have been significant other changes, according to Behr. These include notable increases in concentrations of iron, manganese and arsenic in down-gradient samples.

DEP officials said that even though the arsenic was likely not generated from the sludge, but rather from existing sediments or parent material at the site, the toxic metal has increased to levels in excess of Maine’s drinking water standard, in all down-gradient wells.

The findings were not well-received by Sangerville planning board members, who are pushing for a water quality control ordinance. “That’s the largest aquifer and we need to protect it,” Gerald Peters, planning board chairman, said Sunday.

The pit, now owned by Barrett Paving Co., was approved for the application of sludge by the DEP in the late 1990s as part of a reclamation project.

Approval was given to Kimberly-Clark of Winslow, formerly Scott Paper Co., to apply paper mill sludge – a mixture of sewage sludge and commercial fertilizer and bioash from its mill – as a substitute for topsoil in the reclamation of 10 acres of the gravel pit.

When the company closed its mill in June 1998, the DEP transferred the license on the remaining 5 acres not used by the paper company to Anson-Madison Sanitary District of Madison to be used as a test site for the recycling of biomix sludge.

The sanitary district last dumped at the pit two years ago, and as required by DEP, AMSD has monitored and sampled the groundwater on the 2 acres the district used.

John Leslie of New England Organics of Unity, the contractor for the recycling of biosolids for AMSD, called the changes in the groundwater a seasonal reflection. He acknowledged that there have been impacts to the down-gradient monitoring wells, but noted that the water quality is actually improving and is returning from an anaerobic environment to an aerobic environment.

Leslie believes the drought and the lack of sufficient upgradient water to dilute the site contributed to the changes. “I don’t see this as affecting Black Stream,” he said.

Leslie said the sanitary district intends to continue monitoring the test wells until the levels return to pre-treatment quality, and will add another down-gradient well to test.

Monitoring has shown that hardness, calcium, magnesium and alkalinity have increased in the down-gradient monitoring wells, apparently because of high lime content of the AMSD sludge, according to Behr.

Of primary concern, he said, is the occurrence of forms of nitrogen in the down-gradient wells which indicates that nitrogen has leached from the manufactured topsoil into groundwater.

Another concern is an abrupt, substantial decrease in dissolved oxygen, which was observed in all down-gradient wells shortly after application of the manufactured topsoil.

The findings were troublesome to Peters. He said that a year ago, the planning board requested the installation of another down-gradient well and sanitary district officials agreed to install it, but that they still have not done so.

What the community needs is more rights regarding water quality control, Peters said. Having a water quality control ordinance would provide the community with some clout should a dispute arise that needed to be resolved in court, he said.