In part, the increased detection of pharmaceuticals in drinking water is due to advances in analytical technology that support the measurement of concentrations to levels as low as the nanogram per liter range. However, the effects of prolonged exposure to even small concentrations of pharmaceuticals in water are not well understood. Further, since the use of pharmaceuticals and other personal care products is expected to increase, the risk from their introduction into the water system will also rise. As such, water supply stakeholders, including government officials, drinking water regulators, water suppliers and the general public, are increasing attention on pharmaceutical concentration levels in drinking water.
This two-part article provides an overview of the issues related to the presence of pharmaceuticals and personal care products (PPCPs) in drinking water. The paper discusses the possible effects of PPCPs on humans and on the environment and summarizes recent research on PPCP concentrations found in public drinking water supplies and wastewater facilities. The article also discusses available water treatment options for reducing PPCP concentrations and their relative effectiveness.
Types and sources of PPCPs in drinking water
In general, the term PPCP refers to any product used for either personal health or cosmetic reasons as well as any product used in the agricultural industry to maintain the health or enhance the growth of livestock. Specifically, PPCPs comprise a diverse collection of thousands of chemical substances, including prescription and over-the-counter therapeutic drugs for humans and animals, biopharmaceuticals, diagnostic agents, vitamins and other nutritional supplements, cosmetics and fragrances and growth-enhancing chemicals used in livestock operations.
PPCPs enter the water supply as a result of multiple industrial, commercial and agricultural activities and pharmaceutical manufacturing (although the latter is tightly regulated). PPCPs also enter the water supply in the form of residue from hospitals and other healthcare facilities and as a byproduct of veterinary drug use, most notably antibiotics and steroids. Water-borne PPCPs can also result from the surreptitious disposal of illegal drugs.
Individual consumers are also an important source, both intentionally and unintentionally, of PPCPs found in water. Consumers often dispose of unused prescription medications by including them with household refuse or flushing them through their home plumbing systems. But, unintentional PPCP contamination of water by consumers also occurs through the simple elimination of waste material from the body since drugs are not always fully metabolized by the body and also through bathing or showering, when soaps and cosmetic creams are washed from the body into the wastewater system.
The impact of PPCPs in drinking water
While there are no confirmed adverse human health effects associated with PPCPs in drinking water, PPCP contamination remains a significant concern. For example, pharmaceuticals are designed to interact with cellular-level receptors at low concentrations to induce specific biological effects and the side effects caused by interaction with nonreceptor targets are unpredictable and poorly understood. Further, certain strains of bacteria subject to prolonged exposure to antibiotics can develop resistance to those antibiotics, resulting in strains of drug-resistant bacteria.
Other PPCPs, such as steroid hormones like estrone, progesterone and testosterone and fragrance additives like galaxolide, have been identified as endocrine-disrupting compounds (EDCs). EDCs are synthetic chemicals that block or mimic natural hormones in the body, disrupting normal organ function. It is important to note that EDCs, even at extremely low concentrations, can have effects on the human endocrine system.
Beyond potential effects on human health from exposure, PPCPs in water also have potential consequences for aquatic life — where the exposure risk is potentially much greater. Fish and aquatic organisms can experience continual exposure to PPCP concentrations, often at higher concentrations than found in treated water. In addition, prolonged multi-generational exposure can lead to effects that accumulate over time.
Research on PPCPs in water
Research on PPCPs in water has been ongoing for nearly 20 years, with the first Environmental Protection Agency (EPA) studies on conventional, nonconventional and toxic pollutants in water dating to 1982. The EPA website lists more than 100 separate research projects related to PPCPs in which the EPA has been or is currently involved, and the agency maintains an extensive database of published literature on PPCPs as environmental contaminants. The following is a brief summary of some of the key research that has been conducted concerning PPCPs in water.
National reconnaissance of pharmaceuticals, hormones and other organic wastewater contaminants in streams of the U.S. from 1999-2000
This important field study was conducted by researchers at the U.S. Geological Survey in 1999 and 2000 to provide baseline information on the occurrences of pharmaceuticals, hormones and other wastewater contaminants in water resources. Concentrations of 95 separate organic wastewater contaminants (OWCs) were measured in water samples taken from 139 streams in 30 states across the U.S. Researchers found OWCs in 80 percent of the streams sampled, with coprostanol (a fecal steroid), cholesterol (a plant and animal steroid), tridosan (an antimicrobial disinfectant), 4-nonylphenol (a non-ionic detergent metabolite) and caffeine as the most frequently detected compounds.
According to the results of this field study, the measured concentrations of OWCs found were low — generally, less than one part per billion — and rarely in excess of drinking water guidelines or health advisories. However, researchers noted that concentration guidelines have been established for only 14 of the 95 identified compounds. The study”s report recommended further research to “fully understand not only the fate and transport of OWCs in the hydrologic system but also their ultimate overall effect on human health and the environment.”
Study of occurrence of contaminants of emerging concern in wastewater
This multi-stage study was conducted by the EPA from 2005 through 2008 to identify contaminants of emerging concern (CECs) found in untreated and fully treated wastewater at publically-owned water treatment facilities in the U.S. The CECs evaluated in this study included PPCPs, steroids and hormones, bisphenol A (BPA), commercial flame retardants and pesticides. A total of 72 different PPCPs were tested in both influent and effluent samples.
According to the final report issued in August 2009, detectible amounts of 44 different PPCPs were identified in at least one influent sample collected and 27 different PPCPs were detected in 75 percent or more of the influent samples analyzed. For effluent samples, 33 separate PPCPs were detected in at least one sample and 16 were detected in less than 25 percent of the effluent samples analyzed. Pharmaceutical antibiotics represented the category of PPCPs most frequently identified, accounting for half of the total PPCPs identified in both influent and effluent samples.
EPA researchers cautioned that the results of this study were not statistically representative of all public-owned treatment works. Further, although the study measured PPCP concentrations in both influent and effluent samples from water treatment facilities, researchers noted that the data was insufficient to draw any conclusions about the effectiveness of various treatment methods.
An important byproduct of this EPA study was the development of new analytical methods for detecting the occurrence of PPCPs and other contaminants in untreated and fully treated wastewater and sludge. These methods include, “Method 1694: Pharmaceuticals and Personal Care Products in Water, Soil, Sediment and Biosolids by HPLC/MS/MS” and “Method 1698: Steroids and Hormones in Water, Soil, Sediment and Biosolids by HRGC/HRMS.” The methods cover over 100 separate chemicals, 74 PPCPs and 27 steroids and hormones.
“Pharmaceuticals in Drinking Water”
Published in June 2011 by the United Nation”s World Health Organization (WHO), this technical report is based on work conducted by a WHO working group that included experts in water quality and health, water treatment, drinking water regulation and policy and water quality and health. The chief goal of the working group was to review and summarize available scientific knowledge about pharmaceuticals in drinking water and recommend steps for managing the problem.
The WHO report determined that concentration levels of pharmaceuticals in drinking water fall outside the scope and sensitivity of the analytical methodologies that are prescribed for compliance analysis of drinking water. However, WHO experts acknowledged that there are “very few systematic monitoring programs or comprehensive, systematic studies on the occurrence of pharmaceuticals in drinking water.” Further, according to the report, the “limited occurrence data present one of the key challenges in assessing the potential risks associated with trace concentrations of pharmaceuticals in drinking water.” The report concluded that “future research … may be beneficial to better characterize potential health risks from long-term, low-level exposure to pharmaceuticals.”
In next month’s issue, this two-part article concludes with areas for further research and a preview of possible future regulatory actions.
Hank Lambert is General Manager, Global Food and Water Businesses for Underwriters Laboratories (UL). Lambert joined UL in November 2010, bringing extensive food industry general management, supply chain management and business building experience. He is focused on leveraging UL”s brand equity and business model into the food supply chain and food safety business as well as driving the growth of UL”s food safety, water quality and water systems businesses. Prior to UL, Hank spent over 20 years with Nabisco Inc. in finance, strategic planning and business development.