Pharmaceuticals in Wastewater Treatment Plant Effluent Waters

Pharmaceuticals are being used at an increasing rate, and end up in wastewater through excretion and disposal. They also end up in the effluent water of wastewater treatment plants because they are not specifically designed for pharmaceutical removal. Several studies suggest diverse negative effects on aquatic life that are exposed to these trace amounts of pharmaceuticals in their habitats. There is also a concern for human exposure in areas that utilize wastewater reuse, although there is limited study in this area. Despite these concerns, there are very few policies that address the issue of pharmaceutical pollution. The evaluation of the treatment methods of activated sludge, advanced membrane treatment, and constructed wetlands help to determine which of these options should be improved or replaced by different strategies. Additionally, there are other ways of solving this issue, such as developing more environmentally-friendly drugs and different ways of treating health problems. Pharmaceuticals have been detected in effluent waters of wastewater treatment plants worldwide (Daughton 2004). This is because of their increased use (CDC 2010) as well as them not being targeted for removal during wastewater treatment. This issue should be of concern because these trace amounts have the potential to cause potentially harmful changes in aquatic life and possibly humans (EPA 2010). Current wastewater treatment has been researched to determine how well treatment plants in operation removal pharmaceutical compounds. Through 1 Deziel: Pharmaceuticals in Wastewater Treatment Plant Effluent Waters Published by University of Minnesota Morris Digital Well, 2014 this research, conclusions can be drawn about whether to utilize current wastewater treatment plants or instead find other practical solutions. Pharmaceuticals are commonplace today in both prescription and over-the-counter (OTC) varieties. The FDA has approved over 100,000 drug compounds which make up over 10,000 drug products. The latter number is actually less because of multiple brand names of drug products, but this amount is still striking. Additionally, there are drugs and drug compounds in use that have not been counted because they have not been approved by the FDA which should be taken into consideration when estimating the amount of pharmaceuticals in the waste stream (National Center for Biotechnology Information 2012). Based on a 2007 survey of U.S. residents, it can be estimated that almost half of the population has used at least one prescription drug in the past month, which breaks down to one out of every five children and 9 out of 10 adults (Qiuping et al 2010). This is a high rate, especially considering that only prescription drugs were included in the survey. OTC drugs are used at a much higher rate, with another survey estimating that 79 percent of Americans have used at least one in the past year (Consumer Healthcare Products Association 2010). In order for pharmaceuticals to work properly, they must be able to remain stable in the harsh conditions of the human body. This results in the inability of the compounds in many drugs to break down after they are excreted or otherwise disposed of. This is why pharmaceuticals are commonly found in wastewater both before and after going through treatment plants (Keil 2008). Pharmaceuticals may enter the water through excretion, disposal down drains, as well as through hospital and industry effluent. These routes encompass a range from the time they are being produced until their use or disposal. There are also many classes that pharmaceuticals can be 2 Scholarly Horizons: University of Minnesota, Morris Undergraduate Journal, Vol. 1 [2014], Iss. 2, Art. 12 http://digitalcommons.morris.umn.edu/horizons/vol1/iss2/12 grouped into, such as antibiotics, antidepressants, anti-inflammatory, antiepileptic, as well as various hormones (EPA 2010). The concentrations of these pharmaceuticals are measured in micrograms or nanograms per liter, depending on equipment sensitivity. One microgram per liter is equivalent to one part per million, and one nanogram per liter is equivalent to one part per trillion. These seem too small to be significant, but even in these trace amounts, suspicions have arisen that they are changing the appearance and behavior of aquatic-dwelling organisms (Ternes 2004). Aquatic life has a higher risk than humans of being affected because of the direct and constant exposure that they have to the contaminated water; their habitat may consist of effluent wastewater treatment plant water. Several different aquatic organisms have been studied, and it is important to realize that organisms may have different reactions to pharmaceutical compounds based on how their systems process them (EPA 2010). Some compounds are hormones or mimic the properties of hormones, which are capable of feminizing or masculinizing fish (Ternes 2004). In some cases, it has been observed that male fish have produced a protein that is typically only found in female fish because it is used for egg production (Gilbert 2012). The impact of neuroactive pharmaceuticals has also been an area of study. Some of these studies suggest that this group of pharmaceuticals may alter the reproductive behavior of fathead minnows which could potentially decrease their populations. Additionally, the accumulation of neuro-active pharmaceutical metabolites in brain tissues has been observed in white suckers as well as brook trout, with the suggestion of negative impacts (EPA 2010). Finally, another drug, the antiinflammatory, diclofenac, has shown to have damaged the gills and lungs of fish (Gilbert 2012). The “cocktail” effect is an important concept when discussing the possible effects of these pharmaceuticals. This phrase refers to the mixture of many different pharmaceuticals that are 3 Deziel: Pharmaceuticals in Wastewater Treatment Plant Effluent Waters Published by University of Minnesota Morris Digital Well, 2014 present in the effluent water. These trace amounts of several different drugs make it difficult to predict exactly which drugs are affecting each other, and how this might contribute to the organisms that are exposed to this “cocktail” of drugs. The “cocktail” effect is a large reason why researching the impact pharmaceuticals have on aquatic life is very difficult (Ternes 2004). Human exposure to these trace levels of pharmaceuticals differs because of the lack of constant and long-term exposure to the contaminated water (EPA 2010). However, in some areas, water scarcity has resulted in the practice of wastewater reuse, and the drinking water has been detected to have parts per million or trillion levels of pharmaceuticals, including iburofen, carbamazepine, and sulfamethoxazole (Luo et al 2014). Wastewater reuse involves treating wastewater so that it can be consumed again instead of using the often scarce resource of groundwater. (Bixio et al 2006). However, these wastewater treatment processes are often not designed to remove trace levels of pharmaceuticals (EPA 2010). One major study was executed to see if humans could potentially be affected by trace pharmaceutical levels. In this study, human embryos were exposed to a mix of 13 different pharmaceuticals meant to mimic the levels that would be found in the treated effluent wastewater (Potami et al 2006). This is an example of an attempt to account for the “cocktail” effect of the variety of pharmaceuticals that would be consumed in a scenario such as wastewater reuse. Physical changes to the shapes and appearance of the cells were observed in this study, indicating that these low levels carry potential to effect humans (Potami et al 2006). It is important to realize, however, that the results of this study are difficult to compare to interaction with reused wastewater in fully-developed