Pharmaceutical formulation facilities as sources of opioids and other pharmaceuticals to wastewater treatment plant effluents

Abstract

Facilities involved in the manufacture of pharmaceutical products are an under-investigated source of pharmaceuticals to the environment. Between 2004 and 2009, 35 to 38 effluent samples were collected from each of three wastewater treatment plants (WWTPs) in New York and analyzed for seven pharmaceuticals including opioids and muscle relaxants. Two WWTPs (NY2 and NY3) receive substantial flows (>20% of plant flow) from pharmaceutical formulation facilities (PFF) and one (NY1) receives no PFF flow. Samples of effluents from 23 WWTPs across the United States were analyzed once for these pharmaceuticals as part of a national survey. Maximum pharmaceutical effluent concentrations for the national survey and NY1 effluent samples were generally <1 microg/L. Four pharmaceuticals (methadone, oxycodone, butalbital, and metaxalone) in samples of NY3 effluent had median concentrations ranging from 3.4 to >400 microg/L. Maximum concentrations of oxycodone (1700 microg/L) and metaxalone (3800 microg/L) in samples from NY3 effluent exceeded 1000 microg/L. Three pharmaceuticals (butalbital, carisoprodol, and oxycodone) in samples of NY2 effluent had median concentrations ranging from 2 to 11 microg/L. These findings suggest that current manufacturing practices at these PFFs can result in pharmaceuticals concentrations from 10 to 1000 times higher than those typically found in WWTP effluents.

Figure 1

Concentrations of seven pharmaceuticals analyzed in effluent from 23 wastewater treatment plants sampled across the United States between 2006 and 2009. Box plots depict range of concentrations, with top whisker equal to 90th percentile of concentrations, bar at the top of box equal to the 75th percentile, bar at the middle of the box equal to the 50th percentile, bar at the bottom of the box equal to the 25th percentile, and bottom whisker equal to the 10th percentile. Dots above the top of the whisker represent maximum concentrations, number above boxplot refers to percent of samples with a positive detection. Dashed line at bottom of boxplot or whisker denotes method detection limit.

Figure 2

Total concentration of seven pharmaceuticals detected in wastewater treatment plant (WWTP) effluent samples for (A) individual samples from 23 WWTPs across the United States, and (B) multiple samples from WWTPs NY1, NY2, and NY3. NH = WWTPs that do not receive discharges from hospitals. H = WWTPs that receive discharges from hospitals. Individual concentrations are plotted for NH sites because less than 12 samples are available for this category. Concentrations plotted along x-axis (at 0.01 ug/L) denote nondetects. Site NY1 does not receive discharge from a hospital or a pharmaceutical formulation facility (PFF). Site NY2 receives discharge from a hospital and approximately 20% of its discharge from a PFF. Site NY3 receives approximately 20% of its discharge from a PFF, but does not receive discharge from a hospital. For sites NY1, NY2, and NY3, only those samples with determinations for all seven analytes are included in the total concentration calculation. An explanation of a box plots is given in Figure 1. Total concentrations for H site type are not significantly different from NH site type for Wilcoxon sum rank test. Total concentrations for NY3 are significantly greater than NY1 and NY2, and total concentrations for NY2 samples are significantly greater than NY1 samples by Tukey nonparametric test. For sites NY1, NY2, and NY3, only those samples with determinations for all seven analytes are included in the total calculation (samples collected before 2006 did not include analysis for carisoprodol).

Figure 3

Concentrations of seven pharmaceuticals analyzed in samples of effluent from wastewater treatment plants (WWTPs) NY1, NY2, and NY3 during 2004−2009. Site NY1 does not receive discharge from a hospital or a pharmaceutical formulation facility (PFF). Site NY2 receives discharge from a hospital and approximately 20% of its discharge from a PFF. Site NY3 receives approximately 20% of its discharge from a PFF, but does not receive discharge from a hospital. Box plots depict range of concentrations, and are explained in Figure 1. Number above boxplot refers to percent detection. Numbers of samples for each site are indicated next to the site name. Twenty four samples were analyzed for carisoprodol at each site. Concentrations of methadone, oxycodone, carisoprodol, and phendimetrazine above 40 μg/L and metaxalone above 400 μg/L were frequently censored because many of these concentrations were above the maximum point on the calibration curve. Concentrations quantified above these levels plotted as open circles were below the maximum point on the calibration curve. Boxplots for pharmaceuticals with censoring in more than 25% of the samples (including methadone, oxycodone, and metaxalone in NY3 samples) were denoted by a boxplot truncated at the upper end with a bar. Dashed line at bottom of boxplot or whisker denotes method detection limit.