Sorption and diffusion of per-polyfluoroalkyl substances (PFAS) in high-density polyethylene geomembranes.

The objective of this study is to investigate the fate and transport of per-polyfluoroalkyl substances (PFAS) through a high-density polyethylene (HDPE) geomembrane (GM) that is commonly used in landfill composite liner systems. Tests were conducted to measure the sorption and diffusion of per-polyfluoroalkyl substances (PFAS) with varying number of carbons in chain and functional groups on HDPE GM. Perfluoroalkyl carboxyl acids (PFCAs), perfluoroalkyl sulphonic acids (PFSAs), alkyl-sulfonamidoacetic acids (FOSAAs), fluorotelomer sulfonic acids (FtSAs), alkane sulfonamides (FOSA) and ether carboxylic acids (Gen X) were investigated in this study.

Plant responses to per- and polyfluoroalkyl substances (PFAS): a molecular perspective.

Per- and polyfluoroalkyl substances (PFAS) constitute a large class of toxic manmade compounds that have been used in many industrial and household products. Dispersion of PFAS in the environment has raised concerns because of their persistence and toxicity for living organisms. Both terrestrial and aquatic plants have been shown to take up PFAS from contaminated soil and groundwater, and to accumulate these compounds inside their tissues.

Pharmaceutical chemicals, steroids and xenoestrogens in water, sediments and fish from the tidal freshwater Potomac River (Virginia, USA).

Selected pharmaceutical chemicals, steroids and xenoestrogens (PCSXs) consisting of 29 endocrine modulators, therapeutic drugs, pesticides, detergents, plastics, and active ingredients in household products were measured in water, riverbed sediments and fish collected in a tributary embayment of the Potomac River (Hunting Creek, Alexandria, VA, USA) in the vicinity of wastewater discharge. A total of 17 PCSXs were found in the Hunting Creek samples, with steroid hormones (e.g.

Parts-per-trillion LC-MS(Q) analysis of herbicides and transformation products in surface water.

The goal of this study was to develop a robust method of analyzing surface water samples for S-triazine herbicides, chloroacetanilide herbicides, and their transformation products (TPs) using solid-phase extraction (SPE) followed by liquid chromatograph-mass spectrometry (LC-MS) with electrospray ionization (ESI) by in-source collision-induced dissociation (ISCID) capability of an orthogonal electrospray ionization probe on a single quadrupole LC-MS system. The method developed here met the goals of the study and yielded estimated method detection limits (EMDLs) averaging 0.3 ± 0.

Surface water concentrations and loading budgets of pharmaceuticals and other domestic-use chemicals in an urban watershed (Washington, DC, USA).

Pharmaceuticals and domestic-use chemicals (PDCs) are classes of emerging chemical contaminants thought to enter the aquatic environment primarily through wastewater treatment plant (WTP) discharges. The intent of this study was to quantify loadings of PDCs in an urban watershed. The watershed has two major branches but with wastewater discharge occurring in only one of the two major branches.

The maximum of phosphate adsorption at pH 4.0: why it appears on aluminum oxides but not on iron oxides.

We conducted a series of phosphate adsorption experiments with alumina and hematite at a range of initial P concentrations and pH values. We found that at low initial P concentration of <323 micromol/L for alumina and <194 micromol/L for hematite, phosphate adsorption showed a plateau from pH 2.5 to pH 6.

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 approximately 40 km of transect distance upstream (i.

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.

Determination of thiophanate methyl and carbendazim residues in vegetable samples using microwave-assisted extraction.

Microwave-assisted extraction (MAE) was carried out for the determination of the fungicides thiophanate methyl [1.2-alpha-(3-methoxycarbonyl-2-thioureido)benzene] and carbendazim (methyl benzimidazol-2-ylcarbamate) in vegetable samples. Two vegetable samples, cabbage and tomatoes, were fortified with the two pesticides and subjected to MAE followed by cleanup to remove co-extractives prior to analysis by high-performance liquid chromatography (HPLC).

Composting rapidly reduces levels of extractable oxytetracycline in manure from therapeutically treated beef calves.

Oxytetracycline (OTC) is a broad-spectrum antibiotic used in livestock production. The widespread use and relative persistence of OTC may encourage development of antibiotic-resistant bacteria. The objective of this study was to determine whether composting would substantially reduce the concentration of OTC found in manure from medicated animals.

Characterization of polycyclic aromatic hydrocarbons in urban stormwater runoff flowing into the tidal Anacostia River, Washington, DC, USA.

To investigate the sources, fate, and transport dynamics of PAHs (polycyclic aromatic hydrocarbons) in stormwater runoff that is a leading source of pollution in urban watersheds, storm and base flow samples were collected in six branches along the lower Anacostia River. PAHs in storm flow (1510-12,500 ng/L) were significantly enriched in the particle phase, which accounted for 68-97% of the total PAHs. It suggests that reducing particles in stormwater using post-treatment system would decrease PAHs considerably.

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.

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

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.

Microwave-assisted extraction for the simultaneous determination of thiamethoxam, imidacloprid, and carbendazim residues in fresh and cooked vegetable samples.

Microwave-assisted extraction (MAE) was carried out for the simultaneous determination of the insecticides thiamethoxam [(EZ)-3-(2-chloro-1,3-thiazol-5-ylmethyl)-5-methyl-1,3,5-oxadiazinan-4-ylidene(nitro)amine], imidacloprid [1-(6-chloro-3-pyridylmethyl)-N-nitroimidazolidin-2-ylideneamine], and the fungicide carbendazim (methyl benzimidazol-2-ylcarbamate) in vegetable samples. Five crop samples consisting of cabbage, tomatoes, chilies, potatoes, and peppers were fortified with the three pesticides and subjected to MAE followed by cleanup to remove coextractives prior to analysis by high-performance liquid chromatography. Using the selected microwave exposure time and power setting, the recoveries of the three pesticides from the fortified vegetable samples ranged from 68.

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

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.

Analysis of ethyl carbamate in wines using solid-phase extraction and multidimensional gas chromatography/mass spectrometry.

The method describes a rapid and accurate procedure for the analysis of ethyl carbamate in wines. The separation of the ethyl carbamate (EC), the target analyte, from alcohol and the sample matrix is a challenge to many analytical chemists. After alcohol removal from the sample, EC was extracted and concentrated by solid-phase extraction.

Comparison of soxhlet and microwave-assisted extractions for the determination of fenitrothion residues in beans.

White and black "niebe" beans [Vigna unguiculata (L.) Walp] from Senegal were treated with fenitrothion (O,O-dimethyl O-4-nitro-m-tolyl phosphorothioate), and the residues were determined by high-performance liquid chromatography (HPLC) and electron capture gas chromatography (EC-GC). Fenitrothion residues from the beans were extracted by Soxhlet extraction (SE) and microwave-assisted extraction (MAE).

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.