![[logo] US EPA](https://webarchive.library.unt.edu/web/20090831033701im_/http://www.epa.gov/epafiles/images/logo_epaseal.gif){kind=logo}
Water: Elixir of Life
Posted: July 22, 2009
EPA Researchers Recognized for Advancing the Science of Risk Assessment
The EPA conducts risk assessments to determine the likelihood that human health or the environment are adversely impacted by exposures to stressors such as chemicals, land use, disease, invasive species, and climate change. Ecological risk assessments focus on impacts to the environment from these same stressors.
Recently the Society of Toxicology (SOT) announced results of their 2008 Best Papers Competition which included research developed and conducted by Mitchell Kostich, Ph.D., and James Lazorchak, Ph.D., from the National Exposure Research Laboratory. Their research paper — titled Risks to Aquatic Organisms Posed by Human Pharmaceutical Use (Sci Total Envir 389 (2008) 329-339) — was named one of the Society of Toxicology’s “Top 11” ecological risk assessment papers for 2008. It was selected from among 480 scientific articles by an independent committee of experts.
The paper describes a science-based, conservative approach for estimating potential effects on aquatic life from exposure to active pharmaceutical ingredients in municipal wastewater. Their evidence-based approach narrowed to approximately 50 the number of active pharmaceutical ingredients of concern and identified which aquatic animals to include in initial ecotoxicity testing.
Although pharmaceuticals are rigorously evaluated for human safety prior to coming to market, information about the effects of specific pharmaceutical drugs and drug mixtures on aquatic organisms has not been thoroughly investigated.
Before coming to market, new drugs are approved by the U.S. Food and Drug Administration to ensure they provide effective treatment and are safe to use. Doctors prescribe drugs and people take them to reduce, manage or alleviate illness. However, drug residues can sometimes pass through human bodies unchanged and become deposited into nearby water systems.
There is a plethora of data about how drugs affect people. However, less is known about which drugs, in what quantities, impact bacteria, small invertebrates, and other aquatic animals, like frogs, that live in the watery environment 24/7/365.
While many wastewater treatment processes reduce or virtually eliminate many pharmaceutical drugs, others are somewhat resistant to wastewater treatment.The EPA is required by Congress, under the Clean Water Act, to establish water quality standards that protect aquatic life. In support of this mission, Mitch Kostich, Ph.D. and Jim Lazorchak, Ph.D., of the EPA’s National Exposure Research Laboratory, recently developed new science-based tools to help the EPA make sound-science predictions about the effects on aquatic animals of drugs designed for human consumption.
Looking back on this undertaking, Kostich admits the new approach was easier to conceive than to complete. With more than 1,800 drugs to consider, excluding agricultural and industrial sources, their mission was to develop science-based tools and then evaluate their predictions against a limited number of real-world samples from U.S. municipal wastewater plants. Kostich admits there were some unanticipated challenges.
Marketing data, for example, is reported inconsistently throughout the pharmaceutical industry. Some companies report information in dollars sold or prescriptions written, neither of which translates easily into the amount of active ingredient or number of therapeutic doses in prescriptions. Pharmacological data is abundant but also complex. Don’t forget about the vast number of active ingredients and possible combinations or mixtures.
Another part of the puzzle, Kostich said, relates to how wastewater is treated. Some U.S. plants discharge wastewater that has only been ‘settled’ while other plants employ more technically-advanced methods to eliminate pollutants. With scores of possible active ingredients and ingredient combinations, and thousands of municipal wastewater treatment facilities, it would be impractical, if not impossible, to determine the potential toxicity for aquatic life of every possible ingredient combination.How did Kostich and Lazorchak approach the problem?
They began by computing concentrations of drugs from pharmaceutical sales and prescription data to determine the highest possible concentrations of active ingredients in wastewater. Next, they converted these concentrations to therapeutic dose equivalents which allowed them to account for dramatic differences in therapeutic potency among the different ingredients.
They conceived a hypothetical, worst-case scenario: that any particular active pharmaceutical ingredient or combination they were investigating would be found in all untreated (raw) wastewater. In this scenario, there would be no removal of drugs by wastewater treatment. While this is not the case in the United States, it helped the researchers frame a conservative approach for making appropriate calculations and reliable predictions to protect aquatic life.
As a result of their work, Kostich and Lazorchak were able to develop an evidence-based risk assessment approach that is useful to both the research community and the EPA for establishing new and better-informed water quality criteria standards that protect all types of aquatic animals as they navigate through water — their elixir of life.
Their effort identified the highest likely rate at which each of 371 widely prescribed human drugs is being introduced into the environment. Ultimately their approach narrowed the number of active pharmaceutical ingredients that sound-science suggests should be the focus of further investigation to approximately 50.
In their paper, Risks to Aquatic Organisms Posed by Human Pharmaceutical Use, published in Science of the Total Environment in January 2008, Kostich and Lazorchak found that the potential effects of some active ingredients are likely restricted to fish and amphibians while other active ingredients probably affect a wider range of aquatic life forms, including bacteria and blue-green algae. This new knowledge is underpinning ongoing research at EPA.
Pharmaceuticals and personal care products (PPCP) have probably been present in water and the environment for as long as humans have been using them. With advances in technology that have improved the ability to detect and quantify these chemicals, EPA scientists are now beginning to identify what effects, if any, these chemicals have on environmental and human health. EPA is committed to investigating this topic and developing strategies to protect the health of the public and the environment. To date, no evidence has been found of human health effects from pharmaceuticals and personal care products in the environment.
Kostich and Lazorchak are among a handful of experts in the field of pharmaceutical and personal care products (PPCP) in water. Kostich holds a doctorate in molecular biology and Lazorchak’s doctorate is in aquatic toxicology. Both specialize in microbiological and chemical exposure assessment research at the EPA’s National Exposure Research Laboratory.