Temporal Trends in Polybrominated Diphenylethers (PBDEs) in Blubber of Ringed Seals (Pusa hispida) from Ulukhaktok, NT, Canada Between 1981 and 2015.

Blubber taken from ringed seals (Pusa hispida) during a subsistence hunt at Ulukhaktok, NT (formerly Holman, NWT) at intervals between 2002 and 2015 was analysed for polybrominated diphenyl ether (PBDE) congeners. Results from these analyses were combined with others previously published to yield a data set of 18 tri- to hepta-substituted PBDE congeners in 102 animals sampled over a span of 19 year (females) and 34 year (males). In females, mean total PBDE concentrations increased between 1996 and 2015 by approximately 50%, from 1940 to 2780 pg/g wet wt., although not significantly so (p > 0.05) by one-way ANOVA. In males, concentrations ranged from 376 to 6470 pg/g wet wt. between 1981 and 2015 (p < 0.05). In males, the most rapid increase in PBDE concentrations occurred before 2000, but between 2002 and 2015 mean total PBDE concentrations increased by a further 50%. ANCOVA showed PBDE concentrations in females to be correlated (p < 0.05) with sampling year but not with age or condition (as measured by blubber thickness); in males, PBDE concentrations were strongly correlated (p < 0.01) with year, age and condition. The relative proportions of tetra-bromo- congeners declined weakly in both sexes over the sampling period, with a compensatory increase in penta-bromo-congener distribution. Overall, the results show no evidence yet of a decline in PBDE concentrations in western Arctic ringed seals in response to voluntary and regulated restrictions on PBDE use in the early 2000s.

Trends of persistent organic pollutants in ringed seals (Phoca hispida) from the Canadian Arctic.

Ringed seals (Phoca hispida) have been used as bioindicator species of environmental contamination in Canada since the 1970s. In the present study, seals were harvested during subsistence hunts in four regions of the Canadian Arctic: Beaufort Sea, Arctic Archipelago, Hudson Bay, and coastal Labrador. An extensive suite of persistent organic pollutants (POPs) was determined in seal blubber collected for multiple years between 1972 and 2016. Results from this long-term study indicate geographical differences in the contaminant concentrations in seals and the significant general decrease of most POPs, including polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane (DDT) and related compounds, chlordanes (CHL), and hexachlorocyclohexanes (HCH) over time in ringed seals. The highest decrease rates (up to -9.1%/year for α-HCH) were found in seals from the Hudson Bay region where all chemicals investigated have significantly decreased since 1986. Significant increases in concentrations of hexachlorobenzene (HCB) in seals from Labrador and ß-HCH in Sachs Harbour, NT and Arctic Archipelago were observed. Site-specific and contaminant-specific associations between climate pattern (i.e., Arctic Oscillation, North Atlantic Oscillation, and Pacific/North American pattern) and mean ice-coverage (total, first-year ice, and old-ice) were found at sites with the longest time trend data (i.e., Arviat, Sachs Harbour/Ulukhaktok and Resolute Bay). Overall, results suggest that North American and international regulations have led to the long-term reduction of most POPs in Canadian Arctic ringed seals by reducing emissions from primary sources. However, other sources of legacy compounds (e.g., environmental reservoirs) as well changes in food web composition and structure in relation to climate changes could also be influencing the very slow rates of decline, or stable levels, of contaminants found in seals at some sites. Further work is warranted to discern between co-variation of climate changes and contaminant concentrations and cause-and-effect relationships.

Temporal trends in "legacy" organochlorine contaminants in blubber of ringed seals (Phoca hispida) from Ulukhaktok, NT, Canada between 1972 and 2010.

In blubber of ringed seals (Phoca hispida) from Ulukhaktok, NT, residues of DDT, other organochlorine pesticides, and PCBs declined between 1972 and 2010. The rate of decline varied: concentrations of the DDT-group began to fall after 1981, whereas those of PCBs fell rapidly between 1972 and 1981, and then slowed. Concentrations of cis- and trans-chlordane and of HCB in both sexes, and of cis-nonachlor in males, declined slowly between 1978 and 2010; those of other organochlorine pesticides remained steady. Exponential half-lives of p,p'-DDT and p,p'-DDE in female seals are about 9 and 36 y (corresponding to initial declines of 7.8% and 1.9% per year, respectively) and those of PCB congeners from about 20 to 60 y (declines of 3.2% to <1.5% per year); the more refractory residues may be detectable for centuries to come. Exploratory PCA of PCB congener distribution identified temporal changes apparently not related to molecular structure.

Does proximity to aquatic pollution affect reproductive traits in a wild-caught intertidal fish?

How chronic exposure to aquatic pollution affects reproductive traits was assessed in nesting wild-caught plainfin midshipman Porichthys notatus in areas with low and high contaminant exposure on Vancouver Island, British Columbia. Males in high-exposure areas had a greater degree of testicular asymmetry, sperm with shorter heads and fewer live eggs in their nests. The results of this study provide important insights into the potential consequences of contaminant exposure on the reproductive physiology of wild-caught fishes.

Properties of blood, porphyrins, and exposure to legacy and emerging persistent organic pollutants in surf scoters (Melanitta perspicillata) overwintering on the south coast of British Columbia, Canada.

The surf scoter (Melanitta perspicillata) is a little-studied species of North American sea duck. Estimates suggest it has experienced a precipitous decline in breeding numbers over the latter half of the past century. To investigate the potential role of contaminant uptake and toxicity in the population decline, this study undertook to measure blood chemistry, porphyrin concentrations, EROD, and organic contaminants in mature surf scoters wintering in the Strait of Georgia, BC, Canada. Hepatic organochlorine pesticide, polychlorinated dibenzo-p-dioxin, polychlorinated dibenzofuran, polychlorinated biphenyl (PCB), polybrominated diphenyl ether, and nonylphenol concentrations were relatively low; for example, SigmaTEQs (toxic equivalents) for PCBs, dioxins, and furans combined ranged from 4.7 ng/kg wet weight in reference-site (Baynes Sound) birds to 11.4 ng/kg wet weight in birds from Vancouver Harbour. Nonetheless, elevated EROD activity indicated that birds in Howe Sound were responding to an Ah-receptor-mediated stressor, which was also affecting hematocrit values and possibly vitamin A status. In addition, a low proportion of lymphocytes in individuals across locations in early spring samples was associated with poor body condition. The apparent loss of fitness just prior to the onset of northerly migrations to breeding grounds is of particular concern. Compromised health of mature birds at this point in the season might impact negatively on the productivity and survival of some individuals, particularly those overwintering in Howe Sound.

A comprehensive gas chromatography coupled to high resolution mass spectrometry based method for the determination of polybrominated diphenyl ethers and their hydroxylated and methoxylated metabolites in environmental samples.

We report here an efficient and comprehensive analytical methodology based on gas chromatography with high resolution mass spectrometry (GC-HRMS) to simultaneously determine PBDEs from mono to deca brominated and hydroxy (OH-) and methoxy (MeO-) PBDE metabolites in environmental samples, particularly, sediment, fish tissue and milk. Among a number of extraction and clean-up methods tested, pressurized liquid extraction followed by gel permeation chromatography and florisil clean-up proved to be simple, robust and optimized so that all target analytes (parent compounds and metabolites) were collected in a single fraction. Extracts were analyzed by GC-HRMS to identify PBDEs. Following, the same extracts were derivatized and re-analyzed by GC-HRMS to determine 11 target and 35 non-target OH- and MeO-PBDEs. Monitoring of the M(+) for MeO-PBDEs and the [M-CH(2)CO](+) ions for derivatized OH-PBDEs at 10,000 resolution permitted unequivocal identification of the PBDE metabolites in the environmental matrices examined. The method was validated in terms of accuracy, precision, detection limits and long-term stability. The analytical precision obtained with this method was between 0.3 and 17%, and the limits of quantification were lower than 3.28 pg/g dry weight, 20.5 and 41.4 pg/g lipid weight in sediment, milk and fish, respectively. The method was applied to determine PBDEs and target and non-target metabolites in all three matrices.

Hexachlorocyclohexanes (HCH) in ringed seal (Phoca hispida) from Ulukhaktok (Holman), NT: trends from 1978 to 2006.

Trends in alpha-, beta-, and gamma-hexachlorocyclohexane (HCH) concentrations were examined in blubber lipid of ringed seals (Phoca hispida) from Ulukhaktok (Holman), NT (Canada) sampled at intervals between 1978 and 2006. alpha-HCH usually represented approximately 90% of the total HCH isomers. alpha-HCH and gamma-HCH concentrations showed no change over the sampling interval, but beta-HCH concentrations increased significantly, about 8-10-fold in females and 4-5-fold in males. Residue concentrations showed no dependence on age. Concentrations (all data as ng/g lipid, GM (range)) of alpha-HCH were significantly higher (P<0.001 by t-test) in males (217 (93.9-517), n=37) than those in females (138 (40.9-402), n=38). beta-HCH concentrations did not differ between the sexes. Concentrations of gamma-HCH were significantly higher (P<0.05) in males (6.74 (0-46.7)) than in females (4.35 (0-19.0)). Although global emissions of both alpha-HCH and beta-HCH have declined since the early 1980's, the "signal" of HCH emission changes has not yet resulted in a "response" in ringed seal residue concentrations. In the light of our current understanding of the dynamics of HCH in the Arctic, we conclude that any such response may not be detected by retrospective analyses of the sort describe here at least for another decade or so, because of the longevity of the seals.

Polybrominated diphenyl ethers (PBDEs) in seal populations from eastern and western Canada: an assessment of the processes and factors controlling PBDE distribution in seals.

Polybrominated diphenyl ether (PBDE) concentrations were measured in the blubber of five mother-pup pairs of grey seals (Halichoerus grypus) from Sable Island, Nova Scotia (NS) sampled in 1995 and in 20 harbour seals (Phoca vitulina) from British Columbia (BC) sampled in 1991-1992. Concentrations in maternal grey seals from Sable Island averaged 112+/-55.2 ng/g lipid (mean+/-s.d.) and were over twice the concentrations measured in their pups; higher brominated PBDEs showed a distinct decline in PBDEs transfer efficiency in mother-pup pairs as a function of increasing K(o/w). Hepta-BDEs and higher molecular weight (MW) congeners appear not to be transferred efficiently from the grey seals mother to pup during lactation on the basis of lipid/water partitioning (as indicated by ln K(o/w)) and this may be a consequence of molecular size (MW>600 Da) which may limit diffusion and partitioning. PBDE concentrations in blubber from harbour seals from the Strait of Georgia averaged 319+/-132 ng/g lipid (mean+/-s.d., n=13), while those from the more remote and less contaminated Quatsino Sd. averaged 27.8+/-11.8 ng/g (mean+/-s.d., n=7). Tri- to hexa-BDEs were appreciably enriched in Strait of Georgia harbour seals relative to those from Quatsino Sd, suggesting that the former were closer to PBDE sources. The main congeners identified in all samples were BDEs 47, 99, 100, 153 and 154. Data were compared to those in ringed seals sampled from Holman, North West Territories (NWT), in 1996. The Holman samples had a higher proportion of lower bromination congeners, and a lower proportion of higher bromination congeners, than did the Sable Island and BC seal samples, consistent with selection in favour of more volatile compounds during atmospheric transport to the Arctic.

Flesh quality of market-size farmed and wild British Columbia salmon.

This study compared the flesh quality of farmed and wild sources of British Columbia (BC) salmon with respect to concentrations of polychlorinated biphenyl compounds, polychlorinated dibenzodioxins/dibenzofurans and their associated toxic equivalents, total mercury (THg), methylmercury (MeHg), and selected fatty acids of known importance for human health viz., omega-3 (n-3) highly unsaturated fatty acids (n-3 HUFAs) and (n-6) fatty acids. Skinned fillets from known sources of farmed Atlantic, coho, and chinook salmon (n = 110) and wild coho, chinook, chum, sockeye, and pink salmon (n = 91) were examined. Atlantic salmon contained higher PCB concentrations (means, 28-38 ng/g) than farmed coho or chinook salmon, and levels in these latter species were similar to those in wild counterparts (means, 2.8-13.7 ng/g). PCB levels in Atlantic salmon flesh were, nevertheless, 53-71-fold less than the level of concern for human consumption of fish, i.e., 2000 ng/g as established by Health Canada and the U.S. Food and Drug Administration (US-FDA). Similarly, THg and MeHg levels in all samples were well below the Health Canada guideline (0.5 microg/g) and the US-FDA action level (1.0 microg/g). On average, THg in farmed salmon (0.021 microg/g) was similar to or lower than wild salmon (0.013-0.077 microg/g). Atlantic salmon were a richer source (mean, 2.34 g/100 g fillet) of n-3 HUFAs than the other farmed and wild sources of salmon examined (means, 0.39-1.17 g/100 g). The present findings support the recommended weekly consumption guidelines for oily fish species (includes all BC salmon sources) for cardio-protective benefits as made by the American Heart Association and the UK Food Standards Agency.

PCDD/F and PCB concentrations in Arctic ringed seals (Phoca hispida) have not changed between 1981 and 2000.

Concentrations of polychlorinated dibenzo-p-dioxins (PCDD) and dibenzofurans (PCDF) and of non-ortho-, mono-ortho- and di-ortho-substituted polychlorinated biphenyls (NO-CB, MO-CB and DO-CB) were measured in blubber of ringed seals sampled at Holman, NWT, in 1981, 1991, 1996 and 2000. Total PCDD and PCDF concentrations were usually below approx. 10 and 5 pg/g wet wt., respectively, and did not change significantly between 1981 and 2000, although there were sporadic temporal differences in some congeners. Total NO-CB, MO-CB and DO-CB concentrations were below approx. 1 ng/g, 250 ng/g and 1 microg/g wet wt. respectively; none of the total PCB concentrations changed significantly over the sampling period. Neither PCDD nor PCDF concentrations differed between males and females, nor did they increase with age in male samples. MO-CB and DO-CB concentrations increased with age in males, but not in females, and concentrations of total MO-CB and DO-CB were usually lower in females than in males. Changes in the distribution of PCB congeners between the 1980s and the 1990s are consistent with atmospheric transport processes becoming increasingly important in the introduction of PCBs to the Arctic in recent years.

Modern and historical fluxes of halogenated organic contaminants to a lake in the Canadian arctic, as determined from annually laminated sediment cores.

Two annually laminated cores collected from Lake DV09 on Devon Island in May 1999 were dated using 210Pb and 137Cs, and analyzed for a variety of halogenated organic contaminants (HOCs), including polychlorinated biphenyls (PCBs), organochlorine pesticides, short-chain polychlorinated n-alkanes (sPCAs), polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), and polybrominated diphenyl ethers (PBDEs). Dry weight HOC concentrations in Lake DV09 sediments were generally similar to other remote Arctic lakes. Maximum HOC fluxes often agreed well with production maxima, although many compound groups exhibited maxima at or near the sediment surface, much later than peak production. The lower than expected HOC concentrations in older sediment slices may be due to anaerobic degradation and possibly to dilution resulting from a temporary increase in sedimentation rate observed between the mid-1960s and 1970s. Indeed, temporal trends were more readily apparent for those compound classes when anaerobic metabolites were also analyzed, such as for DDT and toxaphene. However, it is postulated here for the first time that the maximum or increasing HOC surface fluxes observed for many of the major compound classes in DV09 sediments may be influenced by climate variation and the resulting increase in algal primary productivity which could drive an increasing rate of HOC scavenging from the water column. Both the fraction (F(TC)) and enantiomer fraction (EF) of trans-chlordane (TC) decreased significantly between 1957 and 1997, suggesting that recent inputs to the lake are from weathered chlordane sources. PCDD/Fs showed a change in sources from pentachlorophenol (PeCP) in the 1950s and 1960s to combustion sources into the 1990s. Improvements in combustion technology may be responsible for the reducing the proportion of TCDF relative to OCDD in the most recent slice.

PCDD/F and PCB in harbour seals (Phoca vitulina) from British Columbia: response to exposure to pulp mill effluents.

Blubber of harbour seals (Phoca vitulina) sampled from the Strait of Georgia, BC, in 1991 and 1992 contained higher concentrations of polychlorinated dibenzo-p-dioxins and furans (PCDD/F) than did samples from Quatsino Sound on western Vancouver Island. The higher proportions of 1,2,3,6,7,8-hexachlorodibenzodioxin and 2,3,7,8-tetrachlorodibenzofuran in the Strait of Georgia samples probably reflect contamination arising from the discharge of effluents from bleached kraft mills. Higher concentrations of non-ortho- and mono-ortho substituted polychlorinated biphenyls were also found in the Strait of Georgia samples, probably as a result of general industrial activity in the region. Principal components analysis showed that residues were distributed differently between males and females. Within males, concentrations of PCDD, PCDF and PCBs appeared to increase with age. Toxic equivalents (TEQ) to 2,3,7,8-tetrachlorodibenzodioxin in the Quatsino Sd. samples were close to the working guidelines for edible fish used by Health Canada; TEQ calculated for the Strait of Georgia samples exceeded these guidelines by up to a factor of five.

PCB and PCDD/F totals, TEQs, and congener patterns in Korean coastal marine environments, 1987, 1988, 1990, and 1996-1999.

Various mussel and oyster samples and select top sediment samples were taken over 27 industrial and pristine coastal sites form South Korea's west, south, and east coasts. Site-specific total PCB, PCDD/F, and organochlorine TEQ levels in biota were 1-306 ng/g ww, 3-9,400 pg/g ww, and 0.3-200 pg/g ww, respectively. Temporal trends showed a general decrease in total TEQ with an increase in TEQ contribution by PCDD/Fs at most locations over the past decade. Linear regression was used to establish a relationship between each contaminant total and the respective TEQ contribution. Principal component analysis was used to model the congener-specific PCB and PCDD/F data, and two three-component models were developed that describe the congener-specific patterns based on the variance between samples over the entire data set. Unique PCDD/F patterns were identified and discussed with respect to outliers identified in the previously established TEQ regressions and a distinct PCDD/F pattern was found that related to a single industrial source (i.e., steel mill). PCB patterns were explored in relation to those of common commercial mixtures of PCBs (i.e., Aroclors) and patterns were discussed with respect to TEQ. It was found that sites with relatively high PCB-TEQs showed an Aroclor 1254-like contamination.

PCB levels and congener patterns from Korean municipal waste incinerator stack emissions.

Congener specific polychlorinated biphenyl (PCB) data from the stack gas of nine Korean municipal waste incinerators was used to determine characteristic congener patterns of emitted PCBs. Principal component analysis revealed three classes of incinerators according to their pattern of PCB congener emissions: those resembling the background sampling material; those producing large quantities of a few tetra-chlorinated congeners; those producing large proportions of mono (MO-) and non-ortho (NO-) congeners relative to di-ortho (DO-) levels. Also, correlations between individual PCB congeners and polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs) were discovered for several NO-PCBs and tetra and penta chlorinated PCDFs. Full PCB congener data is presented along with operating conditions for each incinerator.

A gas chromatography/high-resolution mass spectrometry (GC/HRMS) method for determination of polybrominated diphenyl ethers in fish.

A method for the determination of polybrominated diphenyl ethers (PBDEs) in biota for routine analysis is described. The mass spectroscopic (MS) evaluation of 23 brominated diphenyl ethers, under electron ionization and electron capture negative ion conditions using magnetic sector and quadrupole mass spectrometers, showed that high-resolution mass spectrometry (HRMS) under electron ionization conditions was the most reliable technique, with high selectivity and adequate sensitivity. The instrument detection limit for this method ranged for individual congeners between 4.8 and 0.1 pg for 3-bromodiphenyl ether (BDE-2) and 2,3',4,4'-tetrabromodiphenyl ether (BDE-66), respectively, and method detection limit for each homologue group ranged between 5 pg/g for salmon certified reference material (CRM) and 93 pg/g for lake trout CRM. The effectiveness of this method was evaluated by analyzing the occurrence of PBDEs in commercially available CRMs comprising Lake Ontario lake trout, Pacific herring, and sockeye salmon. The average coefficients of variation for the replicate analyses of PDBEs in several tissue samples were: 25% for lake trout, 36% for Pacific herring, and 34% for sockeye salmon. The average deviations in the inter-laboratory study were: 14% for lake trout, 15% for Pacific herring, and 37% for sockeye salmon. Results indicated that the described method, based on gas chromatography/high-resolution mass spectrometry, is reliable for determining PBDE concentrations in biological tissues.

Characteristics of PAHs, PCDD/Fs and PCBs in sediment following forest fires in northern Alberta.

Extensive forest fires occurred in northern Alberta, Canada, in 1998. Polynuclear aromatic hydrocarbons (PAHs), polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and polychlorinated biphenyls (PCBs) were studied following these forest fires in order to explore natural and anthropogenic influences on the affected forest fire area. Specifically, concentrations and profiles of these compounds were determined in sediment samples. A predominance of alkylated PAH derivatives over parent PAHs were observed at the burned and reference sites. Naturally dervied PAHs were abundant at all sites. A high proportion and concentration of retene was observed at the totally burned site and indicates some inputs from forest fires. Very low concentrations of PCDD/Fs and PCBs were observed at all sites, and the profiles were very similar. This likely reflects common atmospheric contributing sources to the study area.

Similarity of an Aroclor-based and a full congener-based method in determining total PCBs and a modeling approach to estimate Aroclor speciation from congener-specific PCB data.

Polychlorinated biphenyls (PCBs) have entered the environment in North America as Aroclor technical mixtures. Most methods used for the determination of total PCB levels in environmental samples visually match patterns of sample peaks to those in Aroclor standards. Concern over the accuracy of Aroclor-based measurements on compositionally modified samples coupled with advancements in analytical techniques have led to congener-specific PCB analysis. In this study, the PCB data from 27 tissue samples determined by an Aroclor-based method and a full congener method were compared in terms of total PCB concentration to assess the reliability of this Aroclor technique for total PCB determination. Our data show a strong correlation between the sum of Aroclors and the total PCBs obtained from the full congener determinations. We also developed a model using the compositional data from three Aroclors (1242, 1254, and 1260) to determine the amount of compositional alteration from original Aroclor patterns in environmental samples. Full congener data, from a variety of tissue types and trophic levels, examined using this method showed that compositional modification from original Aroclor patterns increases with trophic level, with the greatest modification observed in seal and killer whale samples. This result agrees both with expectation and with what has been found in other studies. Such techniques, which connect congener-specific PCB data to Aroclor contamination, may prove useful to investigations into environmental and metabolic fate and transfer processes.

Characterization and evolutionary relevance of the sperm nuclear basic proteins from stickleback fish.

We have characterized the sperm nuclear basic proteins (SNBPs) of the sticklebacks in the suborder Gasterosteoidei. The complete amino acid sequence of the protamines from Aulorhynchus flavidus, Pungitius pungitius, Gasterosteus aculeatus, (anadromous) and G. wheatlandi, as well as the sequences of the protamines of several species pairs of freshwater G. aculeatus, have been determined. Analysis of the primary structure of these proteins has shown that: a) despite the relatively low amino acid complexity and small molecular mass of these basic proteins, they are very good molecular markers at the generic level. The bootstrap parsimony analysis using their sequences provides a phylogenetic relationship for the old anadromous species of Gasterosteoidei which is identical to that obtained from morphological and behavioral analysis; b) the comparison of the sequences also suggests that protamines from the suborder Gasterosteoidei have most likely evolved from a common gene in the early Acanthopterygii by an extension of the carboxy terminal portion of the molecule; c) protamines are not good markers for recent postglacial freshwater isolates of G. aculeatus. However, in the unique case of Enos Lake (British Columbia), we have been able to detect an additional minor protamine component in the benthic forms of G. aculeatus that is not present in the limnetic forms. Thus, this new protamine must have appeared during the past 12,000 years concomitantly with the speciation of benthics and limnetics in this lake.

Uptake rates of semipermeable membrane devices (SPMDs) for PCDDs, PCDFs and PCBs in water and sediment.

Uptake rates of several PCDDs, PCDFs and PCBs were measured for semipermeable membrane devices (SPMDs) under controlled conditions in bulk water and sediment. The study was performed at 19 degrees C and 11 degrees C, and water and sediment concentrations were measured during the exposure. Linear uptake rates for specific PCDD/Fs and PCBs in 19 degrees C water varied from 34 to 111 l/m2 day and in 11 degrees C water from 8.8 to 96 l/m2 day for the whole SPMD. Uptake rates at 19 degrees C sediment ranged from 9.0 to 80 mgOC/m2 day and in 11 degrees C sediment, from 3.0 to 31, mgOC/m2 day. Partitioning of the compounds between membrane and lipid was also measured during the linear uptake phase. The membrane-lipid concentration ratios ranged from 0.02 to 1.11 depending on the compound, temperature, and bulk medium.

Quantitative determination of nonylphenol polyethoxylate surfactants in marine sediment using normal-phase liquid chromatography-electrospray mass spectrometry.

A new comprehensive analytical method based on normal-phase liquid chromatography-electrospray ionization mass spectrometry (LC-ESI-MS) has been developed for the quantitative determination of individual nonylphenol ethoxylate (NPEO) surfactants in complex environmental matrices. Clean-up of sample extracts was performed on cyanopropyl silica solid-phase extraction cartridges. Complete NPEO oligomer separation was achieved by using normal-phase LC. Because the non-polar solvents used in normal-phase LC are incompatible with ESI, unique LC-ESI-MS interface conditions were adopted that provided a functional interface and also enhanced the detection response of NPEOs. These provided enhanced ESI signal intensity and stability and facilitated the detection of NPEOs as sodium adducts at parts-per-billion concentration levels. The overall analytical method was validated for accuracy and precision by analyzing sediment samples spiked with known amounts of NPEOs. The method is superior to those currently used for NPEO analysis (LC-UV, LC-fluorescence, LC-thermospray-MS, LC-field desorption-MS, LC-particle beam-MS and GC-MS) in terms of detection limits, specificity and speed of analysis. The validated method was successfully applied to determine levels of NPEOs in sediments from the Strait of Georgia, British Columbia. This work also demonstrates that by proper selection of normal-phase LC-ESI-MS interface conditions this technique is capable of solving separation problems which are not amenable with reversed-phase LC-ESI-MS.