Gregory D. Foster

Tracking acidic pharmaceuticals, caffeine, and triclosan through the wastewater treatment process

Pharmaceuticals are a class of emerging contaminants whose fate in the wastewater treatment process has received increasing attention in past years. Acidic pharmaceuticals (ibuprofen, naproxen, mefenamic acid, ketoprofen, and diclofenac), caffeine, and the antibacterial triclosan were quantified at four different steps of wastewater treatment from three urban wastewater treatment plants. The compounds were extracted from wastewater samples on Waters Oasis hydrophilic-lipophilic balance solid-phase extraction columns, silylated, and analyzed by gas chromatography-mass spectrometry. For the chemicals studied, it was found that the majority of the influent load was removed during secondary treatment (51-99%), yielding expected surface water concentrations of 13 to 56 ng/L.

Baseflow and stormflow metal fluxes from two small agricultural catchments in the Coastal Plain of the Chesapeake Bay Basin, United States

Annual yields (fluxes per unit area) of Al, Mn, Fe, Ni, Cd, Pb, Zn, Cu, Cr, Co, As and Se were estimated for two small non-tidal stream catchments on the Eastern Shore of the Chesapeake Bay, United States—a poorly drained dissected-upland watershed in the Nanticoke River Basin, and a well-drained feeder tributary in the lower reaches of the Chester River Basin. Both watersheds are dominated by agriculture. A hydrograph-separation technique was used to determine the baseflow and stormflow components of metal yields, thus providing important insights into the effects of hydrology and climate on the transport of metals. Concentrations of suspended-sediment were used as a less-costly proxy of metal concentrations which are generally associated with particles. Results were compared to other studies in Chesapeake Bay and to general trends in metal concentrations across the United States. The study documented a larger than background yield of Zn and Co from the upper Nanticoke River Basin and possibly enriched concentrations of As, Cd and Se from both the upper Nanticoke River and the Chesterville Branch (a tributary of the lower Chester River). The annual yield of total Zn from the Nanticoke River Basin in 1998 was 18,000 g/km2/a, and was two to three times higher than yields reported from comparable river basins in the region. Concentrations of Cd also were high in both basins when compared to crustal concentrations and to other national data, but were within reasonable agreement with other Chesapeake Bay studies. Thus, Cd may be enriched locally either in natural materials or from agriculture.

Determination of nonsteroidal anti-inflammatory drugs, caffeine, and triclosan in wastewater by gas chromatography-mass spectrometry.

Abstract Pharmaceuticals are a class of chemicals whose fate in the environment has received increasing attention in the past few years. A quantitative method was developed for the determination of acidic pharmaceuticals (ibuprofen, naproxen, ketoprofen, mefenamic acid, and diclofenac), caffeine and the antibacterial triclosan in wastewater effluent. The compounds were extracted from wastewater samples on Waters Oasis HLB solid-phase extraction columns, derivatized with N,O-bis [Trimethylsilyl] trifluoroacetamide (BSTFA) and analyzed using gas chromatography–mass spectrometry. Estimated method detection limits ranged from 6 to 45 ng/L based on replicate analyses (n = 10). This method was applied to the analysis of effluent from a wastewater treatment plant and compounds were detected at concentrations of 18–72 ng/L.

Investigation of unrecognized former secondary lead smelting sites: confirmation by historical sources and elemental ratios in soil.

Twelve suspected former secondary lead smelting sites were investigated. Ten of the sites were confirmed to be former secondary lead smelters or lead works by historical fire insurance maps and contemporaneous metal industry trade directories. At eight sites sampled, the ratio Sb:Pb was closer to ratios from 10 known lead smelting sites than were the As:Pb and Cd:Pb ratios. Data from the 10 known lead smelting sites showed that the Sb:Pb ratio is most characteristic of secondary lead smelting sites. This is because the primary alloy smelted at such sites is antimonial lead. Lead contamination at the eight sites investigated here can be attributed At least in part to the former smelters because of the association between Sb and Pb.

Polychlorinated biphenyls in stormwater runoff entering the tidal Anacostia River, Washington, DC, through small urban catchments and combined sewer outfalls

To investigate the loadings, solid-water partitioning, transport dynamics, and sources of polychlorinated biphenyls (PCBs) in urban stormwater runoff entering into the lower tidal Anacostia River, which flows south of Washington, DC, USA, storm and base flow samples were collected in six branches. Stormwater runoff contained elevated levels of PCBs (9.82 to 211 ng/L) higher than base flow by up to 80-fold. The present study suggests that input of PCBs from Lower Beaverdam Creek is likely to be greater than those from the two major branches (Northeast and Northwest Branches) that were believed as primary source areas. PCBs in storm flow were significantly enriched in the particle phase, which accounted for more than 90% of the total PCBs. Particles were the primary vector transporting PCBs into the Anacostia River, suggesting that removal of particles in stormwater runoff using best management practices (BMPs) such as post treatment system likely decrease PCBs significantly. PCB congener patterns found in stormwater samples clearly explain stormwater runoff is a major transport pathway adding substantial amount of PCBs to the tidal Anacostia River.

Estimated Annual Loads of Selected Organic Contaminants to Chesapeake Bay via a Major Tributary.

The aim of the Chesapeake Bay Fall Line Toxics Monitoring Program has been to determine the annual loads for selected organonitrogen, organophosphorus, and organochlorine pesticides, polychlorinated biphenyls, and polynuclear aromatic hydrocarbons to Chesapeake Bay derived from above the fall line of the Susquehanna River, the bays largest tributary. Load results are presented in this report for 15 samples collected from March 1992 through February 1993. Annual load estimates were obtained using 14 methods, grouped according to whether they are of averaging, ratio, or regression type to ensure convergence to an approximate mean load value for each contaminant. The results indicated a high degree of uniformity across the methods with most yielding relative deviations 1.5 or less when normalized to the mean load derived from all 14 load estimation methods.

PAHs and PCBs deposited in surficial sediments along a rural to urban transect in a Mid-Atlantic coastal river basin (USA)

PAHs and PCBs were measured in river sediments along a 226 km longitudinal transect that spanned rural to urban land use settings through Valley and Ridge, Piedmont Plateau and Coastal Plain physiographic provinces in the Potomac River basin (mid-Atlantic USA). A gradient in PAH concentrations was found in river bed sediments along the upstream transect in the Potomac and Shenandoah Rivers that correlated with population densities in the nearby sub-basins. Sediment PAH concentrations halved per each ∼40 km of transect distance upstream (i.e., the half-concentration distance) from the urban center (Washington, DC) of the Potomac River basin in direct proportion to population density. The PAH molecular composition was consistent across all geologic provinces, revealing a dominant pyrogenic source. Fluoranthene to perylene ratios served as useful markers for urban inputs, with a ratio > 2.4 observed in sediments near urban structures such as roadways, bridges and sewer outfalls. PCBs in sediments were not well correlated with population densities along the river basin transect, but the highest concentrations were found in the urban Coastal Plain region near Washington, DC and in the Shenandoah River near a known industrial Superfund site. PAHs were moderately correlated with sediment total organic carbon (TOC) in the Shenandoah River and Coastal Plain Potomac River regions, but TOC was poorly correlated with PCB concentrations throughout the entire basin. Although both PAHs and PCBs are widely recognized as urban-derived contaminants, their concentration profiles and geochemistry in river sediments were uniquely different throughout the upper Potomac River basin.

Pesticides, polycyclic aromatic hydrocarbons, and polychlorinated biphenyls in transport in two atlantic coastal plain tributaries and loadings to Chesapeake Bay.

Abstract Concentrations of current-use pesticides, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and organochlorine (OC) insecticides were determined above the reach of tide in the Chesterville Branch and Nanticoke River on the eastern shore of Chesapeake Bay during base-flow and storm-flow hydrologic regimes to evaluate mass transport to Chesapeake Bay. The two rivers monitored showed relatively high concentrations of atrazine, simazine, alachlor, and metolachlor in comparison to previously investigated western shore tributaries, and reflected the predominant agricultural land use in the eastern shore watersheds. The four current use pesticides showed the greatest seasonal contribution to annual loadings to tidal waters of Chesapeake Bay from the two rivers, and the relative order of annual loadings for the other contaminant classes was PAHs>PCBs>OC insecticides. Annual loadings normalized to the landscape areas of selected Chesapeake Bay watersheds showed correlations to identifiable source areas, with the highest pesticide yields (g/km2/yr) occurring in eastern shore agricultural landscapes, and the highest PAH yields derived from urban regions.

Determination of chlorothalonil residues in coffee

Coffee beans were treated with the fungicide chlorothalonil (2,4,5,6‐tetrachloro‐1,3‐benzene‐dicarbonitrile) and the residues were determined by high‐performance liquid Chromatograph (HPLC). Several techniques including Soxhlet extraction (SE), microwave‐assisted extraction (MAE) and accelerated solvent extraction (ASE) were compared for the extraction of residues. A column clean‐up procedure was developed to remove the co‐extractives in the extract before HPLC analysis. The overall mean recoveries from extracts obtained by SE, MAE and ASE were 89.2 ±3.9, 88.4 ±1.9 and 82.8 ±0.3, respectively. The results show that MAE followed by HPLC is a viable alternative to the commonly used SE and gas Chromatographic analysis for the determination of chlorothalonil in coffee.

Supercritical fluid extraction of synthetic organochlorine compounds in submerged aquatic plants

Abstract Supercritical carbon dioxide was used to extract nine synthetic organochlorine compounds (SOCs) from tissues of the aquatic plant Hydrilla verticillata in an off-line supercritical fluid extraction configuration. Lyophilized plant tissues (50 to 100 mg) were fortified with the SOCs at a level of 5 to 10 mg/kg and subjected to supercritical carbon dioxide extraction at 50°C and 38 MPa for 15 min. Mass recoveries of the SOCs amended to plant tissues averaged between 89 and 109%. When Florisil was present in the outlet end of the extraction vessel for the purpose of direct in-line clean-up during supercritical carbon dioxide extraction, mass recoveries of the amended SOCs were markedly lower for four of the nine analytes.