Pharmaceuticals and personal care products (PPCPs) are a class of emerging contaminants that include, but are not limited to, prescription and non-prescription drugs, perfumes, detergents and soaps, body lotions and sun block. PPCPs reach the environment primarily through two routes, the release of treated waste via wastewater treatment plants' effluent stream and through agricultural run-off. Since the 1980s, PPCPs have been recognized as having the potential to cause adverse effects in the environment and are identified by the US EPA as potentially hazardous compounds, even at low parts-per-billion or parts-per trillion concentrations. Among other effects, studies have linked PPCPs to antibiotic resistance in bacteria and viruses and to the feminization of certain fish species. Unfortunately, there is a significant limit in the peer reviewed literature on both the occurrence of these compounds and their effects in the environment.
One reason for this information gap is the lack of analytical equipment/protocols with sensitivities low enough to detect these compounds at their environmental concentrations. The purpose of this study was to establish a reliable method to detect four PPCPs in aquatic samples within the state of New Hampshire, and to pilot test the method on environmental samples from rivers, lakes and private septic systems in Central New Hampshire.
The method this study adapted was originally established by the US Geological Survey's (USGS) National Water Quality Lab in Denver, CO. It uses solid phase extraction (SPE) and high performance liquid chromatography coupled with mass spectroscopy (HPLC/MS) to identify and quantitatively measure 14 different PPCPs. Generally, SPE separates compound targets from the sample of water, while HPLC separates the target compounds from each other and MS produces a signal from each compound that is proportional to its concentration. This study adapted the USGS method to use methanol instead of acetonitrile as the HPLC mobile phase and limited the detection to four PPCPs, each from different therapeutic drug classes: acetaminophen (a common analgesic), caffeine (a stimulant), carbamazepine (an anti-epileptic, mood stabilizer) and trimethoprim (an antibiotic).
As a result of these adaptations, many instrumental parameters were optimized for instrument sensitivity. The adapted method has interim reporting levels ranging between 8 and 100 ng/L for the targeted compounds while the USGS reports detection limits of 25 ng/L to 40 ng/L for these compounds. The adapted method demonstrates fair accuracy; mean percent recovery of compounds in reagent-free water was within 20% of the true value, while fortified environmental samples had mean percent recoveries within 35% of the true value. A standard operating procedure for this method was written and is on-file with the NH Department of Environmental Services.
A pilot study used this adapted method to document the occurrence of these four compounds in water resources in Central New Hampshire, US. A total of 16 samples were collected: 6 lake samples were collected along with 7 river samples, 2 samples from wastewater treatment plants' wastewater effluent stream and 1 from the distribution box of a private septic system. None of the compounds were detected in any of the lake samples. One river sample had 79 ng/L caffeine. One wastewater treatment plant was found to have acetaminophen (720 ng/L), caffeine (1200 ng/L) and carbamazepine (280 ng/L) while the other was found to have only carbamazepine (330 ng/L). The private septic system's distribution box was found to have >2,000ng/L of both acetaminophen and caffeine. The most commonly occurring PPCP was caffeine (three occurrences: 19%), followed by carbamazepine and acetaminophen (two occurrences each: 12.5%), trimethoprim was not detected in any of the 16 samples collected.