Researching the Long-Term Existence of Antibiotics in Minnesota Waterways

In a recent study, a group of scientists examined decades of sediment they had extracted from the bottoms of Minnesota lakes. They discovered while examining the sediment layers that antibiotics used in pharmaceuticals are accumulating in Minnesota lakes. Earlier studies had already demonstrated the presence of antibiotics in the water of the state’s lakes and streams. The University of Minnesota researchers sought to explain how long those drugs remain in lakes.

Using samples taken from sources that take in water from sewage plants, they tested sediment from Lake Pepin, Lake Winona and the Duluth harbor. The researchers focused their studies on 19 specific antibiotics and discovered that ten of the antibiotics were consistently showing up at low levels.

The problem with persistent low doses of antibiotics in the Minnesota waterways is that these antibiotics can lead to bacteria that are resistant to antibiotic treatment. It becomes evident that the pharmaceuticals that people are taking and or disposing of via the public sewers are winding up in Minnesota’s lakes and not just for a short time. Researchers had assumed that the discharged wastewater from treatment plants would see the antibiotics and other pharmaceuticals rapidly dissipate and be rendered harmless in the long term, but the scientists are now confirming that they are being introduced into the lakes’ sediment layers and persisting.

The World Health Organization has identified antibiotic resistance as one of the most significant threats to human health and food security. Synthetic antibiotics proved to be the most persistent of the drugs found in the sediment samples. This explains why antibiotics made through natural processes, which break down more readily than synthetic forms, were found in fewer incidences and at lower levels.

Antibiotic Samples in Sediment Date Back to the 1950s

The University of Minnesota research team dated the sediment extracted from the lake bottoms and were able to find antibiotics that traced back as far as the 1950s. By dating the sediment layers, the scientists were able to create a timeline that correlated to when specific antibiotics came to market. This modeling provides the scientists reasonable certainty to expect that as new pharmacological products reach the public, they will also show up in future sediment samples.

The fact that antibiotics are used more widely for agriculture than for human treatments poses an interesting question, in that the extracted lake samples showed little evidence of the drugs commonly used to treat livestock. The scientists cannot prove that agriculture antibiotics are not insinuating themselves into the environment. Scientists are almost sure the antibiotics are doing just that, but assume they are not looking in the right place to find them. The theory is that farm animal waste applied to the land as fertilizer causes the antibiotics to bind to soil and keeps it from washing into lakes and streams. However, more research is necessary to reach any firm conclusion.

Currently, scientists are conducting DNA analyses to determine if there is a connection between antibiotics found in the lake sediments and the development of resistant bacteria. The desired goal would be to develop a predictive model that could assist in determining where antibiotic-resistant hot spots are most likely to grow in the environment.

Flushed Medications Pose a Significant Problem

This study proves that pharmaceuticals are making their way into the nation’s waterways and that serious consideration of eliminating the disposal or flushing of pharmaceutical products into sewer systems is a must. While there is no way to limit the levels of antibiotics entering the sewer systems in the form of human waste, everyone should be aware of the dangers presented by flushing medications of any kind down a toilet.

The problem of pharmaceuticals in our lakes and waterways is not limited to antibiotics – opioids, amphetamines, cocaine, nicotine and caffeine are showing up in considerable amounts. Some communities are taking preventative steps to protect the environment by creating drop-off sites for the collection of unused pharmaceuticals. The drugs are then sent to a central location and burned for energy.

What Can We Do to Reduce the Level of Pharmaceuticals in Lakes and Rivers

Individuals who care about the rising levels of pharmaceutical in our waters can do their part by never flushing or pouring unused medications into sinks or toilets. Almost all medicines can be thrown into the household trash. This includes prescription and over-the-counter drugs in pill form, liquids, drops, patches, creams, and inhalers.

While scientists continue to do the research needed to find a solution to the problem pharmaceuticals present in the creating strains of antibiotic-resistant bacteria, we can all take a more informed stance and never dispose of our unused medications by flushing them down the toilet and into the water supply.