Baltimore is a city known for its seafood, but the waters it fishes from is full of a contaminant named Nitrate. It’s a compound containing nitrogen, and is used heavily in agriculture to promote plant growth, but when digested in excessive amounts can lead to conditions like blue baby syndrome in babies (according to the Maryland Geological Society). As of 2021, the city of Baltimore has 2.11 parts per million Nitrate in the water, which is over double the national average and 15 times greater than the Environmental Working Group’s recommended limit of 0.14 parts per million.
How could a compound used for farming make its home in Baltimore water sources? To answer this question, we went to Dr. Maren Blohm, a Biology professor at Loyola University Maryland who specializes in plant stress. Here’s what she had to say:
“Plants really need nitrogen, its super super important. It’s one of the most important nutrients for plant growth, and that’s because it’s a part of so many different—so it’s a part of proteins and DNA, which are two really important macromolecules that plants need. And so when you have farms, nitrogen is often limiting in the soil because nitrate is a negatively charged compound. The soil is also negatively charged, and so… That means that those two—we know that opposites attract but similar things repel, and so this case nitrogen is very easily washed out of the soil because it’s not— it isn’t attracted to the soil particles.”
Of course, it can be hard to tell how clean a body of water is from a glance. Not everyone has the equipment to check on their own, but the presence of a certain insect does that job well! According to a study, stoneflies are not fans of dirty water themselves, opting to stay near the cleanest water sources. To learn more about these aquatic insects, we reached out to Dr. Chloe Garfinkel, another biology professor at Loyola specializing in insects and insect ecology.
“Yeah Stoneflies, their order name is plecoptera. They’re actually a part of a common water quality indicator that’s based on three groups—Ephemeroptera, plecoptera, and trichoptera—the EPT index. It’s based on mayflies, stoneflies, and caddisflies. But I would agree that stoneflies in particular tend to be very sensitive to poor water quality and so we can actually use them to understand what state a stream is in.”
If you want to keep yourself safe at home, it is recommended you filter any tap water you drink and be on the lookout for stoneflies next time you’re on the water; both can keep you safe in more ways than one.