Million B. Woudneh

Pesticide Multiresidues in Waters of the Lower Fraser Valley, British Columbia, Canada. Part I. Surface Water

In Part I of this work we presented pesticide levels in the surface waters of the Lower Fraser Valley (LFV) region of British Columbia, Canada. In Part II pesticide levels in the groundwater of the LFV are presented. During the period 2003 to 2005 a study was conducted to determine the occurrence and spatial distribution of 78 pesticides in the groundwater of the LFV. Samples were collected and analyzed from one reference, nine agricultural, one urban, and three urban-agriculture mixed sites. Overall 24 different pesticides were detected in the sites monitored. The maximum single pesticide concentration observed was for simazine (90 ng L(-1)) at one of the agricultural sites. All concentrations of pesticides detected in groundwater samples were below Canadian surface water quality criteria and below available drinking water quality criteria set by World Health Organization (WHO), Health Canada, USEPA, and the European Union (EU). Pesticide levels in surface and groundwater were compared in the Abbotsford area. Generally, a pesticide with a high groundwater concentration tended to also have a high surface water concentration (Simazine 29 ng L(-1) in groundwater and 58 ng L(-1) in surface water, atrazine 5.5 ng L(-1) in groundwater and 14 ng L(-1) in surface water). For pesticides that were detected above 1 ng L(-1) concentration the only exception to this was desethylatrazine that showed greater concentration in groundwater (2.2 ng L(-1)) than surface water (1.5 ng L(-1)). Herbicides were the predominant pesticides detected in the agricultural sites and insecticides were predominant in the urban sites. Pesticide data presented in this study provide reference levels for future pesticide monitoring programs in the region.

Biodegradation of N‑Ethyl Perfluorooctane Sulfonamido Ethanol (EtFOSE) and EtFOSE-Based Phosphate Diester (SAmPAP Diester) in Marine Sediments

Investigations into the biodegradation potential of perfluorooctane sulfonate (PFOS)-precursor candidates have focused on low molecular weight substances (e.g., N-ethyl perfluorooctane sulfonamido ethanol (EtFOSE)) in wastewater treatment plant sludge. Few data are available on PFOS-precursor biodegradation in other environmental compartments, and nothing is known about the stability of high-molecular-weight perfluorooctane sulfonamide-based substances such as the EtFOSE-based phosphate diester (SAmPAP diester) in any environmental compartment. In the present work, the biodegradation potential of SAmPAP diester and EtFOSE by bacteria in marine sediments was evaluated over 120 days at 4 and 25 °C. At both temperatures, EtFOSE was transformed to a suite of products, including N-ethyl perfluorooctane sulfonamidoacetate, perfluorooctane sulfonamidoacetate, N-ethyl perfluorooctane sulfonamide, perfluorooctane sulfonamide, and perfluorooctane sulfonate. Transformation was significantly more rapid at 25 °C (t(1/2) = 44 ± 3.4 days; error represents standard error of the mean (SEM)) compared to 4 °C (t(1/2) = 160 ± 17 days), but much longer than previous biodegradation studies involving EtFOSE in sludge (t(1/2) ∼0.7-4.2 days). In contrast, SAmPAP diester was highly recalcitrant to microbial degradation, with negligible loss and/or associated product formation observed after 120 days at both temperatures, and an estimated half-life of >380 days at 25 °C (estimated using the lower bounds 95% confidence interval of the slope). We hypothesize that the hydrophobicity of SAmPAP diester reduces its bioavailability, thus limiting biotransformation by bacteria in sediments. The lengthy biodegradation half-life of EtFOSE and recalcitrant nature of SAmPAP diester in part explains the elevated concentrations of PFOS-precursors observed in urban marine sediments from Canada, Japan, and the U.S, over a decade after phase-out of their production and commercial application in these countries.

Observation of a Novel PFOS-Precursor, the Perfluorooctane Sulfonamido Ethanol-Based Phosphate (SAmPAP) Diester, in Marine Sediments

The environmental occurrence of perfluorooctane sulfonate (PFOS) can arise from its direct use as well as from transformation of precursors ((N-alkyl substituted) perfluorooctane sulfonamides; FOSAMs). Perfluorooctane sulfonamidoethanol-based phosphate (SAmPAP) esters are among numerous potential PFOS-precursors which have not been previously detected in the environment and for which little is known about their stability. Based on their high production volume during the 1970s-2002 and widespread use in food contact paper and packaging, SAmPAP esters may be potentially significant sources of PFOS. Here we report for the first time on the environmental occurrence of SAmPAP diester in marine sediments from an urbanized marine harbor in Vancouver, Canada. SAmPAP diester concentrations in sediment (40-200 pg/g dry weight) were similar to those of PFOS (71-180 pg/g). A significant (p < 0.05) correlation was observed between SAmPAP diester and N-ethyl perfluorooctane sulfonamido acetate (an anticipated degradation product of SAmPAP diester). ∑PFOS-precursor (FOSAM) concentrations in sediment (120-1100 pg/g) were 1.6-24 times greater than those of PFOS in sediment. Although SAmPAP diester was not detected in water, PFOS was observed at concentrations up to 710 pg/L. Among the per- and polyfluoroalkyl substances monitored in the present work, mean log-transformed sediment/water distribution coefficients ranged from 2.3 to 4.3 and increased with number of CF(2) units and N-alkyl substitution (in the case of FOSAMs). Overall, these results highlight the importance of FOSAMs as potentially significant sources of PFOS, in particular for urban marine environments.

Rapid characterization of perfluoralkyl carboxylate, sulfonate, and sulfonamide isomers by high-performance liquid chromatography-tandem mass spectrometry.

A rapid (<23 min) new HPLC-MS/MS method was developed for simultaneous characterization of 24 per- and polyfluoroalkyl compounds in landfill leachate. In addition to isomer-specific analysis of perfluorooctane sulfonate and perfluorooctanoate, branched from linear isomer separation was accomplished for C6 and C10 perfluoroalkyl sulfonates, C6, C7 and C9-C11 perfluoroalkyl carboxylates, perfluorooctane sulfonamide and, for the first time, 3 perfluorooctane sulfonamidoacetates. The method utilizes a fused-core pentafluorophenylpropyl (PFP) stationary phase and is approximately 4 times faster than previous comprehensive isomer-specific HPLC-MS/MS methods. This is the first isomer-specific methodology which can be adopted for routine analysis without sacrificing throughput from lengthy run times or limited target lists.

PARTITIONING OF CURRENT-USE AND LEGACY PESTICIDES IN SALMON HABITAT IN BRITISH COLUMBIA, CANADA

Current regulatory paradigms have favored a shift from persistent pesticides that amplify in aquatic food webs to pesticides with reduced persistence and bioaccumulative potential (low log K(OW)). Although these new generation pesticides preferentially partition away from food web-associated lipids, aquatic biota may nonetheless be exposed to them via other environmental compartments. To characterize pesticide patterns in coho salmon (Oncorhynchus kisutch) habitat, we studied two salmon-bearing watersheds (agricultural and urban) in British Columbia, Canadas Fraser River valley and one in a remote area of the provinces central coast. The agricultural and remote sites exhibited pesticide patterns dominated by current-use pesticides, whereas the urban site was largely dominated by legacy organochlorine pesticides. When adjusted to trans-chlordane concentrations across environmental matrices, correlations were observed between water to sediment ratios for the pesticides and their octanol:water partitioning coefficients (log K(OW); r2=0.48, p < 0.0001); between air to water ratios and Henrys Law coefficients (r2=0.55, p<0.0001); and between fish to water ratios and log K(OW) (r2=0.74, p<0.0001). These relationships underscore the importance of physicochemical properties in determining the fate of pesticides in freshwater salmon habitat, and highlight the need for research on the nature of health risks associated with exposure where little or no accumulation occurs.

Quantitative determination of 13 organophosphorous flame retardants and plasticizers in a wastewater treatment system by high performance liquid chromatography tandem mass spectrometry

A method for quantitative determination of 13 organophosphorous compounds (OPs) was developed and applied to influent, primary sludge, activated sludge, biosolids, primary effluent and final effluent from a wastewater treatment plant (WWTP). The method involved solvent extraction followed by solid phase clean-up and analysis by high performance liquid chromatography positive electrospray ionization-tandem mass spectrometry (HPLC(+ESI)MS/MS). Replicate spike/recovery experiments revealed the method to have good accuracy (70-132%) and precision (<19% RSD) in all matrices. Detection limits of 0.1-5 ng/L for aqueous samples and 0.01-0.5 ng/g for solid samples were achieved. In the liquid waste stream ∑OP concentrations were highest in influent (5764 ng/L) followed by primary effluent (4642 ng/L), and final effluent (2328 ng/L). In the solid waste stream, the highest ∑OP concentrations were observed in biosolids (3167 ng/g dw), followed by waste activated sludge (2294 ng/g dw), and primary sludge (2128 ng/g dw). These concentrations are nearly 30-fold higher than ∑polybrominated diphenyl ether (BDE) concentrations in influents and nearly 200-fold higher than ∑BDE concentrations in effluents from other sites in Canada. Tetrekis(2-chlorethyl)dichloroisopentyldiphosphate (V6), tripropylphosphate (TnPrP), and Tris(2,3-dibromopropyl)phosphate (TDBPP) are investigated for the first time in a WWTP. While TnPrP and TDBB were not detected, V6 was observed at concentrations up to 7.9 ng/g in solid waste streams and up to 40.7 ng/L in liquid waste streams. The lack of removal of OPs during wastewater treatment is a concern due to their release into the aquatic environment.

Quantitative determination of hydroxy polycylic aromatic hydrocarbons as a biomarker of exposure to carcinogenic polycyclic aromatic hydrocarbons.

A high-resolution gas chromatography/high-resolution mass spectrometry (HRGC/HRMS) method was developed for quantitative analysis of hydroxy polycyclic aromatic hydrocarbons (OH-PAHs). Four hydroxy metabolites of known and suspected carcinogenic PAHs (benzo[a]pyrene (B[a]P), benz[a]anthracene (B[a]A), and chrysene (CRY)) were selected as suitable biomarkers of PAH exposure and associated risks to human health. The analytical method included enzymatic deconjugation, liquid - liquid extraction, followed by derivatization with methyl-N-(trimethylsilyl) trifluoroacetamide and instrumental analysis. Photo-induced oxidation of target analytes - which has plagued previously published methods - was controlled by a combination of minimizing exposure to light, employing an antioxidant (2-mercaptoethanol) and utilizing a nitrogen atmosphere. Stability investigations also indicated that conjugated forms of the analytes are more stable than the non-conjugated forms. Accuracy and precision of the method were 77.4-101% (<4.9% RSD) in synthetic urine and 92.3-117% (<15% RSD) in human urine, respectively. Method detection limits, determined using eight replicates of low-level spiked human urine, ranged from 13 to 24pg/mL. The method was successfully applied for analysis of a pooled human urine sample and 78 mouse urine samples collected from mice fed with PAH-contaminated diets. In mouse urine, greater than 94% of each analyte was present in its conjugated form.

Bisphenol A is not detectable in media or selected contact materials used in IVF

There is a lack of data regarding potential exposure of gametes to bisphenol A during IVF. Detectable concentrations of bisphenol A were not found in commonly used IVF plastic culture dishes, suction tubing or growth media under normal-use conditions.