Pharmaceuticals in Coastal Waters

Coastal waters provide homes for an amazing array of plants and animals and are recreational havens for millions of visitors each year. But recently, scientists have raised concerns about pharmaceutical residues detected in rivers and coastal waters and their potential to cause adverse effects in humans and aquatic species.


Wastewater typically contains any number of medications and hormones that people have either used or discarded. Many of these chemical compounds remain biologically active. And some of them, especially hormones such as estrogen, appear to significantly alter aquatic organisms.

Pharmaceuticals can reach the environment from many sources. In addition to wastewater, they can also come from leaking landfills, and in runoff from lands where sewage wastewater and sludge have been applied. Veterinary pharmaceuticals can come from aquaculture, and animal feeding operations also contribute to the problem.

Recent studies have confirmed the presence of low levels of pharmaceuticals in estuaries, rivers, streams, and ground water as well as in sediments. The ecological effects of these contaminants in coastal waters are largely unknown. However, there is growing evidence that some of these chemicals may have negative effects on reproduction in aquatic species or stimulate the development of antibiotic resistant bacteria.

A Prescription for Preservation

NOAA scientists collect water samples for pharmaceutical analysis.

NOAA scientists collect water samples for pharmaceutical analysis.

High resolution (Credit: NOAA)

To help protect our coastal waters and aquatic life, NOAA is expanding its capabilities to assess effects of pharmaceutical compounds in the coastal environment, increasing monitoring efforts, conducting research to determine the effects of pharmaceutical compounds in marine animals and plants, and developing risk assessments.

Measuring Pharmaceuticals

NOAA chemists are working to develop new procedures to better identify and measure a growing list of pharmaceutical compounds in marine waters and sediments. Methods are being developed for a wide range of pharmaceutical compounds that include synthetic hormones, lipid regulators, antibiotics, and antidepressants.

Environmental Monitoring

NOAA scientists are conducting monitoring studies in several locations, including the Chesapeake Bay and the Southern California Bight (coastal southern California, the Channel Islands, and part of the Pacific Ocean). For example, NOAA and its research partners detected 13 different pharmaceuticals in water samples from the Chesapeake Bay. Antibiotic-resistant bacteria, which may be an indicator of long-term environmental exposure to antibiotics, were found in coastal waters and bottlenose dolphins. These and other studies will help describe the extent of pharmaceutical pollution in coastal waters.

Tracking Sources

Effluent from wastewater treatment facilities is often used for irrigation on golf courses and other green spaces. NOAA scientists in South Carolina are conducting research to determine if pharmaceuticals present in this wastewater persist long enough to reach coastal ecosystems.

Treated sewage effluents may be used to irrigate golf courses and other green spaces.

Treated sewage effluents may be used to irrigate golf courses and other spaces.

High resolution (Credit: NOAA)

Risk Assessment

NOAA researchers are performing laboratory tests to determine the potential for pharmaceuticals to cause toxicity in algae or fish. Scientists also are compiling information on the number of prescriptions, chemical characteristics, and the environmental detection for more than 300 different compounds. This information is available to other researchers, resource managers, and the public on a Web-accessible database.

Many questions remain unanswered concerning the potential for pharmaceuticals to harm our coastal ecosystems. NOAA scientists and their partners continue to work towards improving our understanding of this emerging environmental issue — preserving coastal resources for future generations. NOAA logo.