Date of Award
Dr. Tim Knight
Dr. Ruth Plymale
Dr. Byron Eubanks
Algae contribute to self-purification of streams and rivers and are necessary as food for fish and as components of aquatic food webs (1). However, too much or too little algae may create or be indicative of a problem. If nutrients are present in large amounts, algae growth may become excessive, resulting in algal “blooms.” These algal blooms can change the chemistry of the water, making it toxic to other aquatic occupants, including fish, birds, animals, and other plants (1). On the other hand, if nutrients in the water are limiting or are exhausted, algae growth is inhibited, which results in lower oxygen production via photosynthesis (1). In other words, the composition and abundance of algae directly affect water quality. In addition, algae composition and abundance is a direct result of the availability of nutrients. In order to compare algal growth potentials from a number of widely different water sources there are advantages in using a single representative species of alga. It is ideal for the alga being used to be readily available and for its growth to be measured easily yet accurately (1).
For this study, the freshwater green alga Selenastrum capricornutum was used as a model for the aquatic environment. S. capricornutum was first isolated in 1959 by O.M. Skulkberg in the River Nitelva in Akershus, Norway (4). The taxonomy of S. capricornutum is as follows:
S. capricornutum is a crescent-shaped freshwater green alga which has a single chloroplast found within the algal cell and occasionally forms non-mucilaginous colonies of four to sixteen cells. These colonies are rarely intertwined and, instead, form a matrix by attaching their dorsal sides to other cells.
S. capricornutum is important in bioassays of water quality and environmental assessment (2). It is a sensitive species and is one of the three chosen organisms by the Environmental Protection Agency as a toxicity test species in the National Pollutant Discharge Elimination System (NPDES). Algae have long been used in water quality assessment as in situ bio-monitors, but have not been commonly used in toxicity tests (6). Therefore, a small toxicity database exists which is not consistent with the ecological importance of algae in aquatic ecosystems (6). In response to this, Terry W. Snell, Joy L. Mitchell, and Susan E. Burbank performed a study that focused on rapid toxicity assessment in four different species of algae (6). This study tested seven different toxicants: pentachlorophenol, naphthol, chlorpyrifos, cadmium, mercury, copper, and phenol. The four algae species tested were Selenatrum capricornutum, Tetraselmis suecica, Cyclotella sp., and Synechococcus leopoliensis. In the study, S. capricornutum was the most sensitive alga used for five of the seven toxicants (6).
My study involves studying the effect of Pharmaceuticals and Primary Care Products (PPCPs) on water quality in the environment. PPCPs can be drugs, soaps, lotions, and other such compounds. These PPCPs affect the environment when they enter water systems via, flushing the toilet and human and animal excretions. The question that this study tries to address is how these seemingly harmless drugs affect our environment and water quality.
The PPCP being studied is the over-the-counter drug Theraflu, containing diphenhydramine HCl, acetaminophen, and phenylephrine HCl. These three drugs are the active ingredients in several nighttime cold and allergy medicines, e.g. Sudafed, Delsym, Theraflu (5). Diphenhydramine HCl is an active ingredient in most sleep aids and antihistamines, particularly Benadryl and ZzzQuil (7). Theraflu was chosen to study based on its widespread popularity and its availability in liquid form.
S. capricornutum functions in this study as a test species for the aquatic environment. The hypothesis is that if the growth of S. capricornutum is inhibited, then it is possible that a component of Theraflu—diphenhydramine HCl, acetaminophen, or phenylephrine—affects the environment negatively.
Boren, Hannah Gray, "Studying the Effects of Theraflu on the Growth of Selenastrum Capricornutum" (2015). Honors Theses. 173.