Dr. Aleta Borrud (left) highlighted the dangers of pesticides used by many farmers, specifically the pesticide Atrazine. In 1995, middle school children visiting Henderson, Minn., found deformed frogs in the area. Research determined 50 percent of the frogs had deformities. After years of studies and testing, it was determined that the popular herbicide, Atrazine, was linked to the wide-spread deformities. Additionally, it has been linked to cancers, premature births and birth defects. Atrazine, which is banned in Europe, is still used widely in America, with 75 percent of corn cropland receiving treatment.
By Denise Lana,
Dr. Aleta Borrud (left) highlighted the dangers of pesticides used by many farmers, specifically the pesticide Atrazine. In 1995, middle school children visiting Henderson, Minn., found deformed frogs in the area. Research determined 50 percent of the frogs had deformities. After years of studies and testing, it was determined that the popular herbicide, Atrazine, was linked to the wide-spread deformities. Additionally, it has been linked to cancers, premature births and birth defects. Atrazine, which is banned in Europe, is still used widely in America, with 75 percent of corn cropland receiving treatment.
Spurred by information presented at the Lanesboro, Minn., water forum Nov. 16, this is the first in a series of three articles exploring the issue, with further detail from each of the presenters. The first article includes an introduction to the principles of what impacts the watersheds of the region. Further articles in the series will run in the Driftless Journal over the next few weeks. A video of the entire water forum was recently uploaded on YouTube (search “Fillmore County Water Quality Forum 2023”) and is available to the public.
Nitrates, a combination of nitrogen and oxygen, are a common compound found in green leafy vegetables, meats and water, and are found naturally in human sewage and livestock manure.
In small doses, nitrates have a variety of benefits, ranging from preventing bacteria growth in meats to improving blood pressure, increasing heart function and boosting athletic performance in humans. Nitrates can act as antimicrobials in the human body, helping kill bacteria like salmonella. Many people take nitrate-rich nitroglycerin to prevent chest pains.
Nitrates are also necessary nutrients for plants, aiding in growth, development and survival. Nitrates are highly mobile in soil and reach plant roots quickly, so they are often a key ingredient in fertilizers. Using nitrate-rich fertilizer isn’t necessarily bad, as nitrates protect plants against heat and cold stress and improve plants’ water-use efficiency. Nitrogen is a major component of chlorophyl and is vital for plant photosynthesis. Plants need nitrogen to grow and thrive.
But what happens when high levels of nitrate fertilizer are captured in runoff water? Soil is a natural water filter. It contains a negative chemical charge that naturally attracts and captures positively charged pollutants from water and holds onto them, naturally filtering the water in the process.
Liken this to two magnets being drawn together, the negative pole of one magnet is attracted to the positive pole of the second magnet. But two negative poles or two positive poles do not attract. Nitrates are negatively charged chemicals and are not attracted to the negatively charged soil, so the nitrates remain in the water.
Karst under the soil
Compounding the soil filter/water pollution issue in the Driftless area is the vast karst landscape that spans across northeast Iowa, southeast Minnesota and southwest Wisconsin. Karst is made up primarily of porous, swiss cheese-like rock that crumbled and dissolved, creating sinkholes, sinking streams, caves and springs. Because karst soil is so porous, water flows through it quickly and receives very little natural filtering. Karst areas are usually linked together underground like a conduit flowing with water, that seeps through the soil and collects in large cracks and crevices in rocks.
These large crevices full of water are known as aquifers. A private well is created by drilling down into an aquifer and pumping the water out as needed. The well water is replenished over time with stormwater or melting snow as the process repeats. Some of the water in the aquifers gets pushed into cracks and tunnels and flows to the surface naturally, creating springs. Some springs feed into streams which, in turn, can feed rivers.
In the karst regions of the Driftless area, after a crop is planted and a nitrate fertilizer is applied to that crop, stormwater and irrigation runs off the crop and flows almost directly through the porous soil, carrying fertilizer and pesticide pollutants from the crop at the surface to the aquifers beneath. Any connected springs or streams will also contain the pollutants. Any water drawn from the aquifers through private wells would contain pollutants, and aquatic life in springs and streams could be affected.
NO3 impacts on health
Dr. Aleta Borrud, a retired general physician with a master’s degree in public health in epidemiology, was one of five speakers at the forum. She is a co-owner of a small graze farm in Minnesota and focuses on the health effects of drinking water containing elevated levels of nitrates. “Most of the vegetables that contain high nitrates also have beta carotene, vitamin c and vitamin e, which completely cancel out the effects of nitrates.” Borrud stressed.
Although meats cured using nitrates are a main source of nitrates, she adds, the amount from meats “pales in comparison to the quantity of nitrates we get from water that has been contaminated by runoff from inorganic fertilizers or manure that is spread on fields.”
According to Borrud, health effects from nitrates became an issue in the 1940s when babies who had consumed baby formula mixed with contaminated water developed ‘blue baby syndrome,’ where high levels of nitrates from the water in the formula combined with babies’ red blood cells and prevents those blood cells from carrying oxygen throughout the babies’ bodies. The babies’ skin turned blue due to a lack of oxygen.
As a result, the government set a maximum safe level of nitrogen in water in the 1960s, which was 10.4 parts per million. But according to Borrud, hundreds of studies performed since then have focused on contaminated drinking water since nitrates are absorbed through ingestion, and water is a main source of high nitrates.
Many of those studies have since linked elevated nitrate levels (much lower than 10.4 ppm) to spontaneous miscarriages, cleft palate, cancers, and midline neural tube birth defects like spinal bifida and anencephaly, where portions of the brain, skull and scalp are absent during embryonic development.
One study followed 45,000 women for 25 years. The results showed a direct correlation between bladder, ovarian and thyroid cancers and women who were exposed to water with nitrate levels of 5 ppm or higher. A second study took place in Denmark and followed 1.7 million people for more than 30 years. The vast study showed a spike in colorectal cancer in those whose water had nitrate levels of 4 ppm or greater.
Cited by Borrud was an agricultural health study published this year that sampled tap water from Northeast Iowa farm wells. In eight of 47 wells, “Pesticides were found, no surprise!” she exclaimed, adding, “More than one third had elevated levels of nitrates and dangerous levels of coliform bacteria. People will say it is just the septic system leaking, but this study shows they measured things that might be excreted by humans into the septic system — hormones, pharmaceuticals — but the levels of those were very low relative to the high quantities of pesticides. It’s not the septic systems that are the problem.”
Look for part two in this series in upcoming Driftless Journal issues, when the relationship of water quality and farmland usage will be discussed.
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