Occurrence of pharmaceuticals, hormones, and organic wastewater compounds in Pennsylvania waters, 2006-09 Report Released
Posted: September 17, 2012
Reconnaissance sampling was conducted by the U.S. Geological Survey (USGS), in cooperation with the Pennsylvania Department of Environmental Protection for contaminants of emerging concern in Pennsylvania groundwater, streamwater, and streambed sediment. The study was conducted during a 4-year period, 2006 to 2009, to assess levels of pharmaceutical compounds, hormones, and organic wastewater compounds (OWCs).
Contaminants of emerging concern were assessed in groundwater from wells used to supply livestock; streamwater upstream and downstream from animal-feeding operations, and streamwater upstream from and streamwater and streambed sediments downstream from municipal wastewater-effluent discharges in south-central Pennsylvania. These contaminants were found at higher concentrations, and more often in samples from sites downstream from a municipal wastewater discharge site than those from sites upstream from a municipal wastewater discharge site.
The most commonly found contaminants in streamwater downstream from municipal wastewater discharge sites were an anticonvulsant (carbamazepine), an antibiotic (sulfamethoxazole), and a flame retardant (tri(dichloroisopropyl)phosphate). Contaminants most commonly detected in streambed sediment samples collected downstream from wastewater discharges were ofloxacin and trimethoprim (antibiotics), estrone (a natural estrogen), and the polycyclic aromatic hydrocarbons: benzo[a]pyrene, fluoranthene, phenanthrene, and pyrene confirming the finding of other researchers, that wastewater effluents are a source of these compounds.
Pharmaceutical compound detections in water samples collected from wells in agricultural areas and streamwater both upstream and downstream from animal-feeding operations were rare. Many of the compounds detected in these samples were human use- rather than veterinary use compounds, suggesting that agricultural land use and animal-feeding operations were not a major source of pharmaceuticals.
Samples from sites distant from- or without a wastewater discharge also contained detectable levels of contaminants of emerging concern. On-lot septic systems, combined sewer overflows, and agricultural land use are potential nonpoint sources of this contamination.
Streams within 5 miles of drinking-water intakes, and streams where additional studies of fish health were being conducted were also assessed at sites statewide. Nineteen contaminants of emerging concern were reported from the drinking-water intake sites. Human sources, representing a wide variety of uses, account for the 10 most frequently detected compounds. None of the most commonly detected compounds are typically used in agricultural operations, indicating most of the contaminants of emerging concern detected near the 27 drinking-water intake sites entered the stream environment via municipal wastewater treatment effluent or on-lot septic systems.
Concentrations of contaminants of emerging concern at the stream sites near drinking-water intakes were generally very low (less than 50 nanograms per liter). Most of the compounds analyzed were never or rarely detected. Forty-two of the 63 compounds were never detected at concentrations greater than their reporting level, and only 8 compounds were detected in more than 5 percent of the samples analyzed. No guidelines for drinking water standards are established for these compounds.
The most commonly detected compounds were caffeine; the pharmaceutical compounds acetaminophen, carbamazepine, sulfamethoxazole, and trimethoprim; and the hormone estrone. All concentrations of pharmaceutical compounds measured at the sites near drinking-water intakes were within the range of concentrations reported in a national reconnaissance of sites near drinking water sources. The compounds frequently detected near the 27 drinking water intake sites also were the same as those previously reported in another national reconnaissance.
Wastewater sources, land use, and in-stream dilution are the major factors that seem to influence detection of contaminants of emerging concern at the stream sites located near drinking-water intakes.
The greatest number of detections of pharmaceutical compounds and hormones occurred in samples from sites in watersheds on mid-sized to large rivers with mixed urban and agricultural land that had many wastewater discharges per unit of drainage area and a high percentage of non-forested land. These findings support the hypothesis that most contaminant inputs are most likely from wastewater effluent discharge. Sites on small- to mid-size streams in heavily forested watersheds with few point discharges generally had the fewest detections of contaminants of emerging concern.
Unlike fish and other aquatic organisms, humans are not in constant contact with water. Ingestion is likely the primary human exposure to contaminants of emerging concern. A mix of a few targeted contaminants of emerging concern was found in the drinking-water sources examined in the present study. However, those contaminants were measured in low concentrations; many times lower than a typical human pharmaceutical dose. It appears that acute effects on human health or aquatic biota from contaminants of emerging concern are limited because of the low concentrations detected in the environment. However, it is possible subtle, chronic effects from constant low-level environmental exposure will occur in aquatic biota.
The full report is available online.