A new study of Minnesota’s rivers and streams finds that several commonly used pharmaceuticals and other commercial chemicals are present in most of the state’s flowing waters. Water samples containing some of these chemicals were found to have measurable effects on fish exposed to them.
The study is an update of work the Minnesota Pollution Control Agency has done for several years to sample lakes and rivers for chemicals of emerging concern that may adversely affect aquatic ecosystems and human health. Past work has demonstrated that pharmaceuticals and personal care products (PPCPs), and similar contaminants that are "endocrine active compounds," are frequently present in Minnesota’s surface water. These contaminants are typically detected at only part per trillion (ppt) concentrations in water. However, the new study adds weight to other work that has shown some of these chemicals can be harmful to fish and wildlife at very low levels, both to individual organisms and to populations.
Purpose of study
The purpose of this study was twofold. First, it was designed to expand our understanding of the extent to which these chemicals of concern are present in rivers and streams throughout Minnesota. Second, it investigated, on a genetic level, how the chemicals that were detected in those water samples are likely affecting fish and wildlife. Thus, unlike previous studies, this investigation combined monitoring of these emerging contaminants in water with a powerful "effects analysis" showing how those chemicals are affecting aquatic organisms.
What was found
For this study, water from 50 river and stream locations across Minnesota was analyzed in 2014 for 146 PPCPs, and other contaminants. Forty-seven of the 50 lakes were found to contain at least 1 chemical, and 38 of the 125 chemicals analyzed — including antidepressants, alkylphenols, hormones, illicit drugs, and antibiotics -- were detected at least once.
Among the pharmaceuticals detected, iopamidol, an X-ray contrast agent, was the most frequently detected, found at 78% of the locations sampled. The antidepressants sertraline, amitriptyline, and fluoxetine were detected in water from 48%, 44%, and 10% of the locations, respectively, and the antibiotics sulfamethoxazole and erythromycin were detected in water at 24% and 14% of the locations, respectively. Metformin, a medication used to treat type II diabetes; triamterene, a diuretic; and carbamazepine, an anticonvulsive medicine, were detected at 18%, 16%, and 14% of the locations, respectively. The insect repellent DEET, the plastic component bisphenol A, the corrosion inhibitor benzotriazole, and benzotriazole breakdown products were also widespread.
What is the MPCA doing?
Shannon Lotthammer, director of the MPCA's Environmental Analysis & Outcomes division, said, "This work is an important part of our efforts to understand how best to address chemicals in the environment, including pollution prevention, safer chemistries, proper disposal of leftover medicines, and other issues. In addition, we are faced with the challenge of considering how these types of contamination compare to more conventional pollutants in terms of urgency for action."
Why it's important
Overall, this study reveals that PPCPs, and other chemicals of emerging concern can be found in most of the state’s river and stream water. The predictions made by EPA’s ToxCast database, together with the laboratory analysis of genetic expression when fish were exposed to water samples containing these contaminants, suggest that the pharmaceuticals and other chemicals of concern in river and stream surface water have impacts on genes that are associated with reproduction, development, growth, and tumor formation.
While it is too early to determine if adverse effects are actually occurring in fish populations based on these molecular-based effects studies, these chemicals are clearly causing changes in gene expression that have the potential to cause adverse physiologic or reproductive effects.
The study was made possible through funding by the Minnesota Clean Water Fund.