A Survey of Pharmaceutical Pollution in Marine Waters and Benthic Flora of the Southern Australian Coastline

Pharmaceuticals are emerging pollutants of concern with a range of adverse consequences for organisms and ecosystems. Their ubiquitous presence in freshwater and estuarine systems has been well documented, but less is known about their prevalence in open ocean, or about their uptake by benthic flora. This study measured the concentration of three common pharmaceutical pollutants (Carbamazepine, Tramadol and Venlafaxine) in (1) samples from wastewater treatment plants that discharge directly to the ocean, (2) ocean surface waters, and (3) several species of benthic flora. Surface waters and benthic flora were sampled at two sites near WWTP discharges, and one site away from any discharge. All three pharmaceuticals were detected in benthic flora, and particularly in brown macroalgae; Tramadol was measured at a maximum of 34.7 ng/g in Hormosira banksia, and Venlafaxine was recorded at a maximum of 17.3 ng/g in Caulocystis cephalornithos . The calculated bioconcentration factors suggest the concentration in marine flora was up to ~24,000 times higher in the benthic flora than in the surface waters. There was also evidence that proximity to WWTP outfalls influenced the concentrations of pharmaceuticals in both surface waters and benthic flora. The results suggest that the potential impacts of pharmaceutical pollutants in marine ecosystems demand further investigation