Researchers say they've found traces of cocaine and pesticides in shrimp.

The study, conducted by King's College London, also found lidocaine, alprazolam, diazepam and ketamine, a drug commonly known as Special K.

Environmental toxicologist Thomas Miller told NPR, however, that the "potential for any effect is likely to be low."

Scientists say they're not particularly surprised by the findings, but everyday consumers might be.

"Pharmaceuticals and personal care products and pesticides and these types of illicit drugs have been detected in surface waters all over the world, because when we use them, our waste isn't always treated properly, and so they come out in rivers and streams," Emma Rosi, an aquatic ecologist at the Cary Institute of Ecosystem Studies, told NPR.

Rosi has done studies similar to the one conducted by King's College in the past.

"What's very worrying is we don't know what the effects are, the ecological effects," she said.