Eric D. Nelson

Diurnal variability of pharmaceutical, personal care product, estrogen and alkylphenol concentrations in effluent from a tertiary wastewater treatment facility.

Hourly samples of tertiary wastewater effluent were analyzed for 30 pharmaceuticals, personal care products, estrogenic steroids, and alkylphenols in order to better understand the rate at which these compounds enter the environment. Several distinct patterns of daily cycling were observed, and were characterized as three separate categories. The concentrations of compounds such as trimethoprim, sulfamethoxazole, naproxen, estrone, and triclosan varied greatly during a daily cycle, with relative standard deviations exceeding 100% of their daily mean. Less extreme daily cycles were seen for other compounds such as azithromycin, atenolol, tert-octylphenol, iopromide and gemfibrozil. Peak concentrations for most compounds occurred in the early evening (5-8 pm). However, some compounds including carbamazepine, primidone, fluoxetine, and triclocarban exhibited little or no variability.

Occurrence of halogenated transformation products of selected pharmaceuticals and personal care products in secondary and tertiary treated wastewaters from southern California.

Final effluent samples from 10 southern California (United States) wastewater treatment facilities, employing four distinct treatment schemes, were surveyed for selected pharmaceuticals, personal care products (PPCPs), alkylphenols, and 21 of their halogenated disinfection byproducts. Chlorinated and brominated standards and isotopically labeled internal standards were synthesized and purified to confirm and more accurately quantify selected disinfection byproducts of salicylic acid, bisphenol A, gemfibrozil, naproxen, diclofenac, technical 4-nonylphenol, and 4-tert-octylphenol using high-performance liquid chromatography and tandem mass spectrometry. Concentrations of parent compounds ranged from <10 to 3830 ng/L (gemfibrozil), and those of chloro/bromo byproducts ranged from <4 to 370 ng/L (dibromo nonylphenol). The highest concentrations of parent compounds were measured in effluent that was not subjected to tertiary treatment. The chlorinated and brominated byproduct concentration may be affected by the influent concentration of parent compounds, hydraulic retention times, and chlorine contact times. Salicylic acid was readily halogenated, which is evident from the ratio of halogenated to nonhalogenated species. There were no measured chlorinated byproducts of bisphenol A despite occasionally high concentrations of the parent compound. Not surprisingly, higher concentrations of most brominated species were measured in the treatment plant with the highest bromide concentrations. These results demonstrate the occurrence of novel halogenated byproducts of PPCPs that have limited toxicological data and significant uncertainty with regard to their risk to ecological systems.

Processes controlling diurnal variations of PCDD/Fs in the New Jersey coastal atmosphere

Consecutive 12 hour day–night air samples (500 m3 each) were taken over 7 days at three land-based sites and an over-water site in coastal New Jersey (NJ) in July 1998, in a campaign designed to shed light on factors controlling ambient PCDD/F concentrations. The sampling sites were chosen to reflect contrasting environments: urban/industrial from the center of the New York (NY)–NJ metropolitan area (Liberty Science Center, LSC); coastal Atlantic (Sandy Hook, SH); suburban NJ (New Brunswick, NB); over-water in Raritan Bay (RB). Despite proximity to the major NY/NJ conurbation, ambient PCDD/F concentrations in the region were low compared to literature data for other urban locations. Mean ∑Cl4–8DD/Fs and ∑TEQ (in fg/m3) were: 1400 and 16 at NB; 1000 and 9.5 over RB; 880 and 8.5 at LSC; and 830 and 6.6 at SH. Di- and tri-chlorinated dibenzo-p-dioxins and -furans (PCDD/Fs) were also measured and dominated the ∑Cl2–8DD/F concentrations. Air–water exchange calculations demonstrated the relative importance of Cl2–3DD volatilizing from the Lower Hudson River Estuary for ambient concentrations (25% of advection), but was of minor importance for the other PCDD/Fs. The study provides evidence that advective transport, local inputs and atmospheric processes combine in a complex manner to control ambient PCDD/F concentrations. These processes generally dominate any local diurnal influence of OH-radical-mediated depletion, which we had hypothesized would be detectable by measuring higher night- and day-time concentrations. Rather, it is implied that changes in the mixed boundary layer height resulted in higher night- than daytime concentrations at the urban and coastal sites. A strong diurnal signal, dominated by the lower chlorinated dioxins and furans, was detected at the rural site (NB) during a period of lower wind speeds.