PhD candidate, Monash University
Pharmaceuticals are an emerging contaminant and little is known about their environmental effects
Human use and incorrect disposal of pharmaceuticals has led to their detection in streams, rivers, wetlands and other water bodies worldwide. Pharmaceuticals are a group of organic chemicals that are designed to interact with biological systems. For this reason, there is growing concern about their presence in the environment, and little is currently know about their possible effects in aquatic ecosystems. The release of pharmaceuticals into the environment is currently not regulated in most countries, including Australia. Standard waste-water treatment procedures do not effectively remove pharmaceuticals. Leaky septic or sewage infrastructure and runoff from the agricultural use of pharmaceuticals also contributes to their detection in a wide variety of aquatic environments. Research to date suggests that even at extremely low concentrations, pharmaceuticals can significantly alter ecosystem processes, such as photosynthesis and denitrification (the conversion of nitrate to nitrogen gas, a crucial process for avoiding eutrophication and algal blooms). Pharmaceuticals have also been seen to disrupt invertebrate and fish lifecycles. Relative to other aquatic contaminants, such as heavy metals and pesticides, there is very little published research regarding pharmaceutical contaminants. A huge number of research questions remain, and we are only beginning to scratch the surface of what these contaminants are capable of. My research primarily focuses on the effects of very low concentrations of pharmaceuticals on algal and microbial communities, and the functions that they perform in the environment. I endeavour to look at effects in as realistic a scenario as possible - low concentrations, in a mixture, and looking at subtle whole-stream effects rather than just mortality. At this conference I will present new data that shows low concentrations of pharmaceuticals suppressing key ecosystem processes (photosynthesis, respiration, decomposition and denitrification) in a realistic artificial stream scenario.
Abstract: The presence of pharmaceuticals, including illicit drugs in aquatic systems, is a topic of environmental significance because of their global occurrence and potential effects on aquatic ecosystems and human health, but few studies have examined the ecological effects of illicit drugs. We conducted a survey of several drug residues, including the potentially illicit drug amphetamine, at 6 stream sites along an urban to rural gradient in Baltimore, Maryland, USA. We detected numerous drugs, including amphetamine (3 to 630 ng L-1), in all stream sites. We examined the fate and ecological effects of amphetamine on biofilm, seston, and aquatic insect communities in artificial streams exposed to an environmentally relevant concentration (1 μg L-1) of amphetamine. The amphetamine parent compound decreased in the artificial streams from less than 1 μg L-1 on day 1 to 0.11 μg L-1 on day 22. In artificial streams treated with amphetamine, there was up to 45% lower biofilm chlorophyll a per ash-free dry mass, 85% lower biofilm gross primary production, 24% greater seston ash-free dry mass, and 30% lower seston community respiration compared to control streams. Exposing streams to amphetamine also changed the composition of bacterial and diatom communities in biofilms at day 21 and increased cumulative dipteran emergence by 65% and 89% during the first and third weeks of the experiment, respectively. This study demonstrates that amphetamine and other biologically active drugs are present in urban streams and have the potential to affect both structure and function of stream communities.
Pub.: 12 Aug '16, Pinned: 23 Aug '17