Poster Presentations on the Pharmaceutical Screening Project

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Pharmaceuticals in the Water: A comprehensive approach to prioritization for monitoring, analysis, and evaluation of the potential risk to human health

Screening and Prioritization of Pharmaceuticals in Water for Monitoring and Assessment

Title: Pharmaceuticals in the Water: A comprehensive approach to prioritization for monitoring, analysis, and evaluation of the potential risk to human health

Authors: Ashley E. Suchomel, Helen M. Goeden, and Julia M. Dady

Presented at: Society of Environmental Toxicology and Chemistry (SETAC), 2014 Annual Meeting

Abstract: Pharmaceuticals are increasingly detected in drinking water sources throughout the world. The levels that have been detected are generally in the parts per trillion (ppt) range, leading to questions of the possible toxicological consequences at these low levels. However, these occurrences pose a concern because active pharmaceutical ingredients (APIs) are formulated for maximal potency directed toward specific biological targets, unlike many other chemicals that may be found in water at higher concentrations. Evaluating the potential risks of pharmaceuticals is limited by a lack of occurrence data for a broad range of pharmaceuticals and a lack of health-based drinking water criteria for the majority of these APIs. The data are rich for APIs with high public responsiveness, such as antidepressants, resulting in study after study monitoring the same high profile APIs.

The Minnesota Department of Health (MDH) analyzed the potential risk of the most-prescribed (2011 and 2012 data) APIs used in the U.S. to help fill the risk context void and prioritize which APIs should be monitored for in water. Protective drinking water guidance values (in ug/L) were calculated for 90 unique APIs using a toxicity value based on the Lowest Therapeutic Dose (LTD) published on the drug label. The available occurrence data for surface, waste effluent, ground, and finished drinking water were gathered and compared to the calculated drinking water guidance values to yield a risk ratio. This ratio was used to rank the pharmaceuticals based on potential to cause harm to human health as well as to prioritize future water monitoring.

Risk ratios could only be calculated for 34 of the 90 APIs evaluated due to the limited availability of occurrence data. Of the 34, ten were identified as current potential risks to human health in at least one of the four different water media categories and time points, and should be more thoroughly evaluated. MDH found that even trace concentrations of pharmaceuticals, as low as 0.23 ng/L (with a corresponding dose of 8.0X10-8 mg/kg-day), in water may pose a concern or merit further evaluation and monitoring efforts. These findings suggest that APIs monitored for in water need to be expanded to give a more complete representation of the potential risk posed to human health.

Pharmaceuticals in the Water: A comprehensive approach to prioritization for monitoring, analysis, and evaluation of the potential risk to human health (PDF)

Title: Screening and Prioritization of Pharmaceuticals in Water for Monitoring and Assessment

Authors: Ashley E. Suchomel and Helen M. Goeden

Presented at: Fourth International Conference on Occurrence, Fate, Effects, & Analysis of Emerging Contaminants in the Environment (EmCon)

Abstract: Pharmaceuticals are increasingly detected in surface and ground water in Minnesota and throughout the rest of the world. The levels of detection are generally in the low parts per billion (ppb) range, leading to questions of the possible toxicological consequences at these low levels. However, these occurrences pose a concern because pharmaceuticals are formulated for maximal potency directed toward specific biological targets, unlike many other chemicals that may be found in water at higher concentrations. Evaluating the potential risks of pharmaceuticals is limited by a lack of health-based drinking water criteria. The goal of MDH’s pharmaceutical risk assessment project is to develop a rapid screening methodology to assess potential risks.

Creation of drinking water criteria to better understand risks from pharmaceuticals at a screening level is a special project of the Minnesota Department of Health Contaminants of Emerging Concern Program (funded through the Minnesota Clean Water Fund). Initially, we examined the 100 most-prescribed (2011 and 2012 data) pharmaceuticals used in the United States. The lowest therapeutic dose calculated from the publicly available drug label was selected as the point of departure, and a toxicity screening value (in mg/kg-day) was then developed using uncertainty factors. Drinking water values protective of highly exposed populations were calculated based on the toxicity values and infant water intake rates. Occurrence data for surface, source, and finished drinking water was gathered from a review of the available primary literature, Minnesota Pollution Control Agency water reports, National Park Service reports, and United States Geological Survey water contaminants reports. MDH-derived drinking water screening values were compared to occurrence data to yield a potential risk ratio. This ratio was used to rank the pharmaceuticals with the most potential to cause harm to human health as well as to prioritize which pharmaceuticals should be monitored in Minnesota in the future.

An initial set of over 70 pharmaceuticals has been evaluated. The toxicity screening values ranged across seven orders of magnitude from 8.3E-09 to 2.1xE-02 mg/kg-day as did the corresponding drinking water values, ranging from 5.8E-03 to 1.44E+04. Potential risk ratios could be calculated for 21 of the pharmaceuticals based on available occurrence data. Nine of these pharmaceuticals were identified as possible threats to human health and should be more thoroughly evaluated. MDH found that even trace concentrations of pharmaceuticals in source water may pose a threat to human health or merit further evaluation due to the low toxicity screening values. Additional pharmaceutical monitoring studies are needed to ascertain the level of potential exposure to the population based on these results.

This initial assessment resulted in screening toxicity values, water values, and potential risk ratios that provide risk context to the available occurrence data, prioritize pharmaceutical monitoring efforts, inform detection limits for analytical methods, and identify pharmaceuticals that should be more thoroughly evaluated.

Screening and Prioritization of Pharmaceuticals in Water for Monitoring and Assessment (PDF)