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Pharmaceuticals in Coastal Waters Study
A pilot project was recently initiated by NOAA’s Center for Coastal Monitoring
and Assessment to investigate the presence of selected prescription and nonprescription
pharmaceutical compounds in coastal waters. The goals of this pilot project
include validation of a set of analytical protocols and a small field study
to assess the presence of pharmaceuticals
at selected sites.
The identification of previously unknown or unrecognized risks in the aquatic
environment has long been a major concern and thrust of environmental science.
One significant class of chemicals that has received relatively little attention
in the past are the
pharmaceuticals. Prescription and nonprescription drugs are used in large quantities
in the U.S. (estimated at over 1 million kg/year for prescription drugs) and
around the world.
Use of some individual compounds is estimated to be on par with agrochemicals. Unlike the agrochemicals, however, which tend to be delivered to the environment in pulses, pharmaceuticals are continuously added through the use and excretion/discharge of these compounds. Although the persistence of pharmaceuticals can be low, their continual infusion into the environment may produce the same exposure potential as truly persistent pollutants.
Some compound types such as lipid regulators or antidepressants could, for example, interfere with an aquatic organism’s basic metabolism or put it at a competitive disadvantage. While the impact of these compounds in the aquatic environment is unknown, the first step in addressing this emerging issue is to understand the occurrence of the parent compound or metabolic products in waters adjacent or downstream of likely points of discharge such as wastewater treatment facilities, pharmaceutical manufacturing or agricultural operations. These areas would appear more likely to have measurable concentrations of pharmaceuticals and perhaps impacts on aquatic organisms living in those locations.
Currently, the Environmental Protection Agency and the U.S. Geological Survey are investing significant resources to assess the contamination of freshwater systems with prescription and nonprescription drugs. In response to the need for addressing their presence in coastal waters, NOAA’s Center for Coastal Monitoring and Assessment has initiated a pilot project, the goals of which include the validation of a set of analytical protocols, along with a small field study to determine the concentrations of selected pharmaceuticals in coastal water samples.
Human pharmaceuticals targeted for study are being selected based on their
estimated use (number of prescriptions x dose x units/ prescription), physical
properties and where available, reported detections in the environment. A group
of 23 candidate compounds has been selected and are listed on the following
page. This list may change somewhat as the analytical protocols are refined
and validated, or as other compounds are added. The
candidate pharmaceuticals represent a wide array of compound types and uses,
ranging from lipid regulators and antibacterials to antidepressants and analgesics.
Click here to see the molecular
structure of two of the compounds being considered, Gemfibrozil, a lipid regulator,
and Prozac, an antidepressant. Ten of the compounds selected were among the
top 20 prescriptions in the U.S. in 2000.
The validation of the analytical techniques, as well as analysis of water samples
will be carried out at the University of Maryland at College Park. High performance
liquid chromatography (HPLC) coupled with electrospray ionization (positive)/mass
spectrometry will provide a highly sensitive (low µg/L to ng/L) means
of detecting the compounds and determining their concentrations.
A number of areas have been chosen for the field study. The first is in Biscayne
Bay in Florida. A NOAA project to assess sediment toxicity in the Bay has
shown a number of sites to be toxic using one or more bioassays. Water samples
will be taken and analyzed for pharmaceuticals which may be present in the Bay
as a result of groundwater discharge or inputs from drainage canals. Pharmaceuticals
could be used as an indicator of sewagerelated inputs to the Bay, or could conceivably
be contributing to observed toxicities in the area.
Samples will also be taken adjacent and downstream of selected wastewater treatment
facilities in the Chesapeake Bay, from Norfolk to Baltimore. Sampling on the Potomac River near Washington, D.C. will be used to refine the collection
and analytical techniques. Following completion of the pilot project, a decision
will be made as whether to expand the study to other sites and/or compounds.
For example, pharmaceuticals used in concentrated animal feeding operations
may find their way into coastal waters and could be included in the project.
Although many of the pharmaceuticals and metabolites are water soluble, some
tend to be hydrophobic. Analysis of pharmaceuticals adsorbed to sediments could
also be added to the project. Initial results from the first phase of the work
are expected by June 2003.
For more information, please contact:
Tony Pait
NOAA
National Centers for Coastal
Ocean Science, Center for Coastal
Monitoring and Assessment
301.713.3028, x158
email: tony.pait@noaa.gov