Analytical and chemical tools for elucidating fate processes controlling exposure to emerging environmental pollutants

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Chemical pollution is a serious and increasing problem in our society today. To understand the risks such chemicals may pose on human and ecosystem health, we must thoroughly understand their environmental behavior and fate. However, this understanding is at best limited and at worst nonexistent for many current-use chemicals, such as drugs and their degradation products. Chemicals such as drugs are designed to have profound biological effects, and are of increasing environmental concern for that reason. Current measurement techniques typically rely on sampling that only accounts for levels at that point in time. However, there is increasing evidence that release of such chemicals, for example from discharge of treated wastewater, changes over time with daily and seasonal use patterns, and with changes in water supply (such as storms) and water use. While many drugs are well known to be metabolized and excreted in the human body, almost nothing is known about these degradation products in the environment aside from suspicions that they may rival the original drugs in concentrations, and that some forms can turn back into the original compound. We will address these severe knowledge gaps. First, we will improve our understanding of how passive water samplers work. These are small inexpensive unobtrusive devices, requiring no power, that collect chemicals when placed in waters, and provide continuous measures of chemical levels--if we can overcome the many problems with their use. Our proposed research will relate chemical collection by these devices in the laboratory, to fundamental chemical properties and to environmental factors such as water flow rate, pH, and interference by natural dissolved materials. We will also develop new ways to separate and quantify drug metabolites from the original chemicals in waters, and remove any interfering compounds. We will use these methods to study how wastewater treatment can more efficiently remove drugs, both in the laboratory and at actual wastewater treatment plants of various types, and their receiving waters. Such work will ultimately play a significant role in remediating, maintaining, improving, and protecting our precious water resources.