diatoms as an indicator of pharmaceutical contamination in a freshwater system
abstract
historically, microalgae have been used as bio-indicators of aquatic health and this can
be seen in several studies across the world. often at the bottom of the food chain, microalgae
constitute the primary producer of energy of many freshwater ecosystems. diatoms, a group of
microalgae, have been shown to exhibit extreme sensitivity to varying environmental parameters
thereby making them as an excellent candidate for studying the impacts of pollutants such as
pharmaceuticals and personal care products (ppcps). the contamination of ppcps is common
in our inland water bodies with a potential to get into our drinking water supply. this study
explores 1. the single and mixture effects of ppcps on two isolated microalgal species
belonging to the diatom community. 2. the presence of ppcps (ibuprofen, estrone, and
triclosan) in the nearshore waters of lake simcoe and their impacts on algal community. the
laboratory studies consisted of assessment of the toxicological effects of the three ppcps
(ibuprofen, 17-β estradiol, and triclosan) on two diatom species, asterionella formosa and
diatoma tenuis, by performing growth inhibition tests. the field component involved assessment
of several environmental and algal parameters in the surrounding areas of three waste water
treatment plants (wwtps) that discharge their effluents via a creek to lake simcoe. the results
indicated that 1. the toxicological values of ppcps on the two diatom species varied amongst
one another. 2. the combined effects of ppcps were higher than the effects of single toxicity. 3.
ppcp contamination is prevalent in the water outside of wwtps (as far as the point of
confluence with lake simcoe). 4. the algal parameters varied according to the presence of
ppcps in the surface waters. 5. estrone exhibited negative effects on the diatom community.