It’s no secret that American medicine cabinets are overflowing these days, and there is a growing concern about how many of those pharmaceuticals are finding their way into the environment.
Although there has been research into the impact of drugs on some types of animals, researchers at the Society of Environmental Toxicology and Chemistry noticed that there wasn’t much precedent for detecting drugs in predators residing in polluted waterways.
Rebecca Lazarus of the U.S. Geological Survey’s Patuxent Wildlife Research Center was one of several researchers who decided to help establish a precedent. The team examined the levels of 24 pharmaceuticals and other compounds in osprey in 12 sites around the Chesapeake Bay area, which is known to take on substances from nearby water treatment facilities.
Lazarus said that osprey’s diet of fish makes them an excellent prism through which to examine how chemical compounds may move up the food chain, a process referred to as bioaccumulation. They also tend to nest in urban or industrialized levels, so their exposure to whatever is found in wastewater or runoff could be considerable.
The researchers took samples of the water, the fish, and the birds’ blood, then analyzed the samples for contaminants which included 113 pharmaceuticals. About 18 compounds were found in the water, and only seven pharmaceuticals were found in fish, in addition to the artificial sweetener sucralose, which is used as a measure of human activity in the area. Of those 19 compounds, just one was found in a significant level in osprey plasma—the antihypertensive drug diltiazem.
Not surprisingly, the highest levels of the compounds were detected around wastewater treatment facilities.
Lazarus did note that the lack of research at this stage made it challenging to analyze the data, so scientists had to use what they know about the drugs in humans to help make sense of the numbers.
"There are limited data for wildlife regarding effect levels for many of the pharmaceuticals,” she said. "The human therapeutic dose and plasma concentrations were the only information available about a ‘threshold’ that may or may not produce an effect in wildlife depending on how sensitive birds are compared to humans.”
Learning more about those sensitivity levels could change the picture—especially if they’re exposed to the wrong mixture of substances.
There are still a paucity of data on species sensitivities, pharmaceutical behavior and effect thresholds in wildlife. Some avian species can be quite sensitive as we have seen with diclofenac and Asian vultures,” she warned.
Until we know more about how these substances affect ospreys, Lazarus said it doesn’t appear that dilitizaem levels are making a significant impact on the birds’ health.
That doesn’t mean that the issue of pollution in waterways is insignificant to creatures like osprey, however—they rely on catching fish to feed their young, and contamination risk to the fish population in the Bay could interfere with their food supply. It’s also unknown to what extent other predators could be affected by those compounds, and a disruption to the population of another species could work its way through the interconnected web of the food chain. Lazarus also believes that contamination, combined with other conservation challenges, could pose problems for the birds.
"There are many other anthropogenic factors that impact osprey populations including contaminants,” she said. "However, in the Bay not just pollution, but overfishing (e.g., Atlantic menhaden) may have a larger influence on fish populations.”Previous: These Parrot Anatomy Videos Are The Coolest Thing Ever