Micro-Pollutants: An Emerging Concern for Aquatic Organisms
Pharmaceuticals are used in the protection of public health and the wellbeing of farm and domestic animals. Pharmaceuticals and Personal Care Products (PPCPs) enter the environment through effluent discharge from sewage treatment plants, inappropriate disposal of expired or unused medications and runoffs from agricultural soils receiving bio-solid amendments/animal farms. Pharmaceuticals may take many routes into the environment, but the ultimate domain is the aquatic environment. The occurrence of PPCPs in surface and ground water resources on a global scale has become an environmental and public health issue. Recent studies indicate some PPCPs are being detected in fish tissues obtained from surface waters receiving effluents from municipal sewage treatment plants. PPCPs have the potential to harm aquatic organisms and disrupt algal productivity. The presence of PPCPs in the environment therefore deserves attention and further research on their eco-toxicological effects.
Public health agencies, environmentalists and researchers all over the world are concerned about the presence of pharmaceuticals and personal care products in surface waters and sediments. PPCPs have been around as long as human existence and are also described as micro-pollutants because of the concentration in which they occur in different environmental matrices. According to the United States Environmental Protection Agency (EPA), pharmaceuticals are prescription medications (such as antidepressants, hormones, anticoagulants, blood pressure medications, antibiotics, etc.), over-the-counter medications (such as vitamins, antihistamines, etc.), and medications used in agribusiness to promote growth and enhance wellbeing of livestock (such as antibiotics, pesticides, and steroids), while personal care products are cosmetics (such as beauty care products, fragrances, shampoo, sunscreen, etc.1 These chemicals enter the environment through waste treatment plants effluent discharge into surface waters and also through application of bio-solids as soil amendment to agro-ecosystems.2
In Xia, Bhandari, Das, and Pillar, attempts to decipher the presence and toxicological effects of manmade chemicals on living
things in the last forty years have been focused on chemicals used in industrial processes and in agribusiness. This was appropriate at that point because industrial pollutants were released in large concentrations and their toxicological effects widely studied.3 Researchers are now detecting PPCPs in environmental samples at levels within the parts per billion ranges and 1-5.5 µg/L.4 It is only recently that analytical techniques to detect those pollutants in environmental samples have become widely available.5 In 2004, Cahill et al. described the use of a combination of solid-phase extraction isolation and High Performance Liquid Chromatography Electro-Spray Ionization Mass Spectrometry (HPLC-ESI-MS) as an analytical technique for the detection of PPCPs in environmental samples.6 Suarez et al. state that the occurrence of PPCPs in different environmental matrices is an emerging concern due to the lack of information on their potential effects on living systems.7 Several active compounds in PPCPs are known to have detrimental effects on aquatic life and settle in the sediments; sediments therefore play a role in exposing aquatic organisms to PPCPs.8 An example would be the endocrine disrupting effects experienced by alligators in Lake Apopka, near Orlando, Florida.9
Researchers need to pay attention to PPCPs for the following reasons:
(i) "Because of their continuous introduction into the environment via effluents from sewage treatment facilities and from septic systems…PPCPs are referred to as 'pseudo-persistent' contaminants (i.e. high transformation/removal rates are compensated by their continuous introduction into the environment)."
(ii) "In the case of pharmaceuticals they are developed with the intention of performing a biological effect."
(iii) "PPCPs often have the same type of physic-chemical behavior as other harmful xenobiotics (persistence in order to avoid the substance from becoming inactive before having a curing effect, and lipophilicity in order to be able to pass through membranes)."
(iv) "PPCPs are used by man in rather large quantities just as with the use of pesticides."10
The use and stream of PPCPs into the environment is likely to increase in the future as PPCPs are used worldwide on a steady basis. There is the need to understand the sources, fate, environmental endpoints and control of PPCPs in the environment. It is only when the sources, fate and eco-toxicology effects have been identified before control measures can be established and communicated with the overall goal of ecosystems and public health protection. This review paper is aimed at addressing the sources, effects and control of PPCPs in the environment to create awareness to help alleviate the problem of the occurrence of PPCPs in different environmental matrices and hence exposure of organisms in such environments.
Sources of Pharmaceuticals and Personal Care Products in the Environment
PPCPs are used to ensure public health and the wellbeing of farm animals. Different PPCPs are discharged into the sewer system en route to water treatment plants via excretion (urine and feces) as "parent compounds," "conjugated compounds," or "metabolites."11 Also through direct disposal by emptying of prescription and over-the-counter medications into drains; washing PPCPs off the surface of our skin during regular showers and clothing during the laundry process. In the United States alone, animal husbandry contributes huge amounts of pharmaceuticals into the environment. According to Cunningham and Cunningham, more than half of all antibiotics used each year in the United States are fed to farm animals to make them disease free and gain weight (those confined are said to be constantly dosed with antibiotics).12 About 50% of the 100 million antibiotics doses prescribed each year in the United States for humans are unnecessary or are the wrong medications.13 These antibiotics and steroids are excreted by confined animals in urine and feces and eventually end up in any close surface water following rainy weather.
According to the EPA, other sources of PPCPs in the environment include: leakage from underground sewage systems, overflow of untreated sewage from storm events and sewer systems failure following malfunction, land application of bio-solids for soil amendment and fertilization, discharge of untreated sewage from homes and house boats directly into surface waters.14 In many parts of the world, especially third-world countries, untreated sewage is discharged into surface water without regard to environmental consequences. Also residues from pharmaceutical manufacturing, residues from hospitals, nursing homes, hospices, run off from poorly engineered landfills and cemeteries, pest control and illicit drugs.15 PPCPs may take many routes into different environment matrices; the ultimate fate of most PPCPs is the aquatic environment.
Fate of PPCPs in the Environment
The presence of PPCPs in the environment raises concerns about their possible bioaccumulation and biomagnifications within the food web. Upon discharge into the environment most PPCPs end up in the aquatic domain where they settle in the sediments and play a role in exposing aquatic organisms. PPCPs are an emerging class of micro-pollutants and may become persistent in the environment because of their continual influx from many routes into the environment.16 Their continuous influx compensates for their transformation and removal rates and may lead to chronic exposure of aquatic organisms.17 PPCPs undergo many chemical reactions, such as: photo-transformation, which can be both direct and indirect via ultra violet light; volatilization of some PPCPs, such as fragrances; and uptake by plants and physiochemical alteration via degradation and ultimate mineralization.18 Degradation of PPCPs as in any chemical can produce intermediates that are more harmful or less harmful to living tissues.
Triclosan is an antimicrobial agent used in household products and personal care cosmetics all over the world. It was recently detected in waste water effluent and has the potential to react with chloramines to form chlorinated triclosan byproducts.19
Triclosan is highly photodegradable in the dissociated form; while the byproduct methyl triclosan and the non-dissociated triclosan are relatively stable to photo-degradation and also methyl triclosan may reach concentrations similar to those of persistent
organic pollutants due to accumulation.20
Effects of PPCPs in Living Tissues
The effects of PPCPs in living tissues are largely unknown, but a few studies have revealed that PPCPs in the environment have the potential for harmful effects in aquatic organisms. According to Daughton and Ternes, unnoticeable effects from exposure to low concentrations of bioactive PPCPs in non-target organisms could lead to deleterious effects that could be defined as "adaptation" or "ecological succession."21 Some of the PPCPs detected in low concentration in the aquatic environment have the potential to harm organisms. Also there exist many evolutionary pathways and target receptors that have been conserved within and among biological organization, therefore, leading to the conclusion that PPCPs may eventually induce harmful effects in aquatic organisms.22 In the aquatic environment, algae are primary producers and responsible for a large portion of aquatic ecosystem productivity. Triclosan (antimicrobial agent), Ciprofloxin (antibiotic) and Tergitol NP (surfactant) have the potential to disrupt algal community structures and functions in freshwater ecosystems receiving effluents from waste treatment plants.23 It has now been shown that triclosan and many other compounds contained in PPCPs has direct effect on thyroid receptor hormones and may disrupt normal hormone function.24
The American Medical Association states that "Despite their recent proliferation in consumer products, the use of antimicrobial agents such as triclosan in consumer products has not been studied extensively. No data exist to support their efficacy when used in such products or any need for them, but increasing data now suggest growing acquired resistance to these commonly used antimicrobial agents. Studies also suggest that acquired resistance to these antimicrobials in bacteria may also predispose these organisms to resistance against therapeutic antibiotics, but further research is needed. In light of these findings, there is little evidence to support the use of antimicrobials in consumer products such as topical hand lotions and soaps. However, there is also little evidence to link the use of these agents in consumer products to the general problem of increased resistance to therapeutic antibiotics. Considering the available data and the critical nature of the antibiotic resistance problem, it may be prudent to avoid the use of antimicrobial agents in consumer products."25
In a recent study conducted by EPA on water samples and fish tissues collected from urban streams that received effluents from municipal waste treatment plants and a reference site, none of the target PPCPS were detected. However, diphenylhydramine, norfluoxetine, and sertraline were the pharmaceuticals that occurred frequently in samples from urban streams. Norfluoxetine and sertraline (antidepressants) were detected in livers at all five sites and in fillets at three and two sites, respectively. Diphenylhydramine (antihistamine) occurred in livers at four sites and in fillets at three sites. For Personal Care Products (PCPs), data galaxolide, and tonalide, which are both fragrances (musks), were detected in all five sites sampled.26
In another study conducted by Haggard et al. of Northwestern Arkansas streams, PPCPs were detected in a majority of the samples.27 Contaminants were prevalent downstream from an effluent discharge point and have the potential to harm organisms downstream following chronic exposure. PPCPs are detected in the drinking water supply in parts per billion (ppb), because these chemicals are present in the source water. However, researchers have not demonstrated to date any harmful effects to humans from the trace amount that occurs in drinking water.28
Control of PPCPs in the Environment
The United States of America has federal guidelines for proper drug disposal. They state:
(i) "Prescription medications should not be flushed unless the accompanying instructions say so."
(ii) "Participate in community drug take back programs or hazardous waste disposal programs. Call the waste disposal company to know if there is one in your area."
(iii) "Where a drug take back program is unavailable, remove all personal information; take the medication out of the original container, mix with undesirable substance such as used ground coffee or litter and place in a disposal container with lid before putting it in a trash."
(iv) "Proper disposal of medicines, vitamins and other supplement can help prevent unintentional poisoning of children and pets."
(v) "Prevent misuses by teenagers and adults."
(vi) "Prevent health problems from accidently taking the wrong medicine, over-dose or expired medicines and protect freshwater resources."
(vii) "Also labels of household and personal care products should be read to understand if they contain any ingredient that will pose a public and environmental health concern."29
Pharmaceuticals and personal care products are employed in the protection of public health and in agribusiness. Research has shown these chemicals occur in surface waters and sediments. PPCPs are used on a global scale and humans consume large quantities of PPCPs through medications and cosmetics. PPCPs disposed through the sewage system may end up in the aquatic environment as waste treatment plants are not equipped to filter those off. Many communities use the freshwater as their drinking water resource on a global scale. Research has also revealed that some of these chemicals occur in fish tissues, while scanty literature is available to date on the effects of PPCPs on human health/aquatic organisms. Proper disposal of pharmaceuticals and over-the-counter medications can help protect our environment/freshwater resource and prevent PPCPs from reaching unintended targets. PPCPs can fit into the point sources and nonpoint sources of pollutants classifications. As in the case of any pollutant, all sources cannot be controlled but with proper education and management some sources can be minimized. Therefore, the control of the steady stream of PPCPs into the environment is a necessity to help protect aquatic organisms, freshwater ecosystems, and ultimately public health.
1 United States Environmental Protection Agency, www.epa.gov/ppcps/basic2html, January 9, 2010.
2 Mats Larsbo, David R. Lapen, Edward Topp, Chris Metcalfe, Karim C. Abbaspour and Kathrin Fenner, "Simulation of Pharmaceuticals and Personal Care Product Transport to Tile Drains after Biosolid Applications," Journal of Environmental Quality 38:1274-1285, n3, May-June 2009.
3 Kang Xia, Alok Bhandari, Keshav Das and Greg Pillar, "Occurrence and Fate of Pharmaceuticals and Personal Care Products
(PPCPs) in Biosolids," Journal of Environmental Quality 34:91-104, n1, January-February 2005.
4 José Benito Quintana and Thorsten Reemtsma, "Sensitive Determination of Acidic Drugs and Triclosan in Surface and Wastewater
by Iion-Pair Reverse-Phase Liquid Chromatography/Tandem Mass Spectrometry," Rapid Communications in Mass Spectrometry 18:765-774, n7, April 15, 2004.
5 Jeffery D. Cahill, Edward T. Furlong, Mark R. Burkhardt, Dana Kolpin, and Larry G. Anderson, "Determination of Pharmaceutical Compounds in Surface- and Ground-Water Samples by Solid Phase Extraction and High-Performance Liquid Chromatography/Electro Spray–Ionization Mass Spectrometry." Journal of Chromatography A 1041:171–180, n1-2, July 2, 2004.
7 Sonia Suárez, Marta Carbella, Francisco Omil and Juan M. Lema, "How are Pharmaceuticals and Personal Care Products (PPCPs) Removed from Urban Wastewaters?," Reviews in Environmental Science and Biotechnology 7:125-138, n2, June 2008.
8 E. Nielsen, R. Rosenbauer, E. Furlong, M. Burkhardt, S. Werner, L. Greaser and M. Norlega, "Oregon Water Science Center," or.water.usgs.gov/proj/Emergingcontanminants/ppcpsposter2.pdf, January 29, 2010.
9 Jay H. Withgott and Scott R. Brennan, Essential Environment: The Science Behind the Stories, 2nd ed. (San Francisco: Pearson Benjamin Cummings, 2007), p. 218.
10 Damià Barceló and Mira Petrovic, "Pharmaceuticals and Personal Care Products (PPCPs) in the Environment," Analytical and Bioanalytical Chemistry 387:1141–1142, n4, February 2007.
11 Xia, loc.cit.
12 William P. Cunningham and Mary Ann Cunningham, Environmental Science: A Global Concern, 10th ed. (New York City: McGraw Hill, 2008), p. 161.
14 U. S. Environmental Protection Agency: Water Science: Pharmaceuticals and Personal Care Products in Water, www.epa.gov/waterscience/ppcp, January 7, 2010.
16 C. G. Daughton and T. A. Ternes, "Pharmaceuticals and Personal Care Products in the Environment: Agents of Subtle Changes?"
Environmental Health Perspectives 107: 907-938, Suppl 6, December 1999.
18 U. S. Environmental protection Agency, loc. cit.
19 Aimee E. Greyshock and Peter J. Vikesland, "Triclosan Reactivity in Chlorinated Waters," Environmental Science and Technology 40:2615-2622, n8, April 2006.
20 Anton Lindström, Ignaz J. Buerge, Thomas Poiger, Per-Anders Bergqvist, Markus D. Müller and Hans-Rudolf Buser, "Occurrence and Environmental Behavior of the Bactericide Triclosan and Its Methyl Derivative in Surface Waters and in Wastewater," Environmental Science and Technology 36:2322–2329, n11, June 2002.
21 Daughton and Ternes, loc. cit.
22 Richard A. Brian, Mark L. Hanson, Keith R. Solomon, and Bryan W. Brooks, "Aquatic Plants Exposed to Pharmaceuticals: Effects and Risks," Reviews of Environmental Contamination and Toxicology 192:67-115, 2008.
23 Brittan A. Wilson, Val H. Smith, Frank de Noyelles, Jr., Cynthia K. Larive, "Effects of Three Pharmaceuticals and Personal Care products on Freshwater Algal Community Assemblages," Environmental Science and Technology 37:1713-1719, n9, May 1, 2003.
24 Elizabeth N. Pearce and Louis E. Braverman, "Environmental Pollutants and the Thyroid," Best Practice and Research Clinical Endocrinology and Metabolism 23:801-813, n6, December 2009.
25 American Medical Association, "Summaries and Recommendations of Council on Scientific Affairs Reports, 2000 AMA
Annual Meeting: Use of Antimicrobials in Consumer Products," www.ama-assn.org/ama1/pub/upload/mm/443/csaa-00.pdf, February 17, 2010.
26 United States Environmental Protection Agency, loc. cit.
27 Brian E. Haggard, Joel M. Galloway, W. Reed Green and Michael T. Meyer, "Pharmaceuticals and Other Organic Chemicals in Selected North-Central and Northwestern Arkansas Streams," Journal of Environmental Quality 35:1078-1087, July-August 2006.
28 Portland Water Bureau, www.portlandonline.com/water/index.CFM?a=244726&c=47676, accessed February 6, 2010.
29 Office of National Drug Control Policy, www.WhiteHouseDrugPolicy.gov, accessed February 8, 2010.