PINE RIVER — In our previous column we began to look at concerns about the quality of water in our lakes and streams as well as in our drinking water. We discussed the issues of nitrates, herbicides, pesticides and insecticides in our water.
In this column we will continue by looking at the issues of mercury, synthetic organic compounds and chloride contamination and concerns about the quantity of groundwater we use.
Many of our lakes and streams are contaminated with mercury. Sources of mercury include coal-fired power plants, incineration of garbage, mining of some metals and some natural sources including volcanic eruptions.
Mercury becomes airborne from these sources and can travel thousands of miles before settling in our lakes.
Once in surface water, it is converted to elemental mercury and stays in the environment indefinitely. Mercury concentrations increase as it makes it way up the food chain. More than 1,600 lakes in Minnesota (11%) are presently contaminated with mercury limiting the number of fish we can safely consume from our Minnesota lakes.
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A variety of synthetic organic compounds are accumulating in our surface and groundwater. We discussed these in previous columns concerning our sewage.
One particularly troubling group of chemicals accumulating in our waters are PFAS. These polyfluoroalkyl substances (PFAS) are found in many personal care products, including bar soap, cosmetics, dental floss, moisturizers, lubricants, etc.
PFAS are know as “forever chemicals” because they survive in the environment indefinitely. Concern has grown about this large group of chemicals because they have been found in fish and other animals, in vegetables grown on land treated with sewage sludge, in our drinking water and in our own bodies.
PFAS have been associated with some forms of human cancer, decreased fertility, and developmental and behavioral changes in children.
Another contaminant in our lakes and streams is chloride. Chloride is found in salts. Sodium chloride is common table salt. Sodium chloride is used for de-icing roads and sidewalks and is the most common type of salt used in water softeners. Calcium chloride is spread on gravel roads to control dust.
The chloride from the use of all of these products ends up in our soil, streams and lakes. In soil, chloride kills plants and trees, and in our lakes it is toxic to fish and other aquatic wildlife.
Fifty of our Minnesota lakes and streams have chloride levels that are too high to meet standards set to protect fish and other aquatic wildlife. Another 75 lakes and streams are very close to exceeding this standard.
In addition to water contamination, our increasing use of water is a concern. In recent years, increased water usage is due both to an increase in local population and increased irrigation of farmland.
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Farmers raising corn, soybeans and potatoes in our sandy soils are using more and more water for irrigation. In 1976, there were 45 irrigation wells in the Central Pinelands Sand Area of Minnesota.
At present, one company (RD Offut Co.) has more than 200 irrigation permits in this region. Other farmers who have relationships with this company have many more wells. Each year, this company alone pumps millions of gallons of groundwater to irrigate their potato fields.
Although most groundwater levels are reported by the Department of Natural Resources to be stable around the state, some groundwater levels have decreased here in the Central Pinelands Sand Area where there is heavy pumping via irrigation wells. Because groundwater is directly connected to wetlands, depleted groundwater is replaced by water from wetlands and streams which can bring surface contaminants, such as nitrates, herbicides and pesticides, into the groundwater.
Further, the water level in wetlands and streams will decrease as groundwater is depleted. The resultant decrease in wild game, fish and amphibian habitat places stress on those populations.
In the next column we will discuss some possible ways to reduce the pollution of our surface and groundwater.
(References to all factual information quoted provided on request and comments and questions are encouraged: BalsamMoon3148@gmail.com)
Douglas J. Weiss and Barb Mann are caretakers/directors of the nonprofit Balsam Moon Preserve in Pine River, a spiritual place of peace, sustainability and renewal.
The Trust Project
