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Sample preparation represents about two-thirds of the cost of analysis and often presents logistical bottlenecks in analytical and environmental chemistry laboratories, thus reducing our capacity and preparedness to quantify organic pollutants rapidly and accurately. Selective pressurized liquid extraction (SPLE) is an analytical technique that builds upon PLE by incorporating matrix-compound (i.e. interference) retainers into the extraction step, thereby reducing sample-preparation steps and increasing sample throughput. SPLE methods offer distinct advantages over traditional methods, namely reduction in the costs intrinsic to sample preparation (i.e. time, solvents, labor, laboratory space, training, and potential loss of analytes). The ability to analyze and to evaluate rapidly a large number of samples directly increases the analytical capacity and preparedness of a laboratory for certain situations (e.g. large-scale studies or environmental emergencies). We review the analytical improvements via SPLE and its wide-ranging applications.

Analytical methods for unique and rare samples, such as marine mammal tissue, strive to reduce opportunities for analyte loss and contamination. Historically, analytical methodologies for marine mammal tissues required an extraction followed by multiple cleanup and concentration steps. These steps increase the opportunity for analyte loss and sample contamination. Selective pressurized liquid extractions (SPLE; an analytical technique that combines PLE with in-cell adsorbent cleanup) have the potential to reduce and/or eliminate the number of steps. A SPLE method was developed for the simultaneous extraction of polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), and organochlorine pesticides (OCPs) from bowhead whale blubber. This SPLE utilized acidic silica with a fat-to-fat retainer ratio of 0.02 as well as eliminated post-extraction cleanup steps, such as size-exclusion chromatography step. In addition, neutral silica was placed beneath the acidic silica as an acid buffer, thereby preventing acid from contaminating the extraction system. Analysis was performed using gas chromatography/mass spectrometry in electron capture negative ionization mode. PBDE, PCB and OCP triplicate recoveries averaged 84±1%, 83±3%, and 76±11%, respectively. Overall, measurements of NIST Whale Blubber SRM 1945 were within±30% of certified values. PBDEs were measured for the first time in bowhead whale blubber; average concentrations ranged from 0.2 to 1.4 ng g(-1) wet weight (ww). Average OCPs and PCBs concentrations ranged from 0.4 to 37 ng g(-1)ww and 0.1 to 3.0 ng g(-1)ww, respectively, which were within one order of magnitude lower than those previously reported in bowhead whale blubber.

Embryonic zebrafish were used to compare the uptake and metabolism of six polybrominated diphenyl ether (PBDE) congeners (BDEs 28, 47, 99, 100, 153, and 183) and identified metabolites from static exposures at 24 and 120 h postfertilization (hpf). An inverse relationship was observed between uptake of PBDEs and their octanol-water partitioning coefficients (uptake of BDEs 28 and 47>99 and 100>153 and 183). Debromination metabolites were identified in all congeners (excluding BDE 28) tested in the 120-hpf tissue samples. Interestingly, BDE 153 underwent meta-debromination, forming BDEs 47 and 99. Gene transcription analysis was conducted at 120 hpf to identify potential metabolic pathways for the PBDEs examined in the present study (gstpi, deiodinases 1 and 2, cyp1a1, cyp1b1, and ugt5g). The greatest induction was of ugt5g for all congeners and deiodinase transcription was also upregulated by BDEs 28, 47, and 183. The cyp1a1 and cyp1b1 were upregulated by BDEs 28, 47, 99, and 183. The least alterations in gene transcription were in the BDE 153-exposed embryos. A clear primary pathway of debromination metabolism was not identified; however, upregulation of these different genes indicated that fish were responding to exposure of PBDEs. Furthermore, the present study demonstrated that the most bioavailable congeners are also those with the highest reported toxicity.

Polybrominated diphenyl ethers (PBDEs) have become ubiquitous environmental contaminants with potential for bioaccumulation and maternal-fetal transfer that has led to regulatory bans and/or phasing out of several technical mixtures of PBDEs. In the present study, six PBDE congeners (BDE 28, BDE 47, BDE 99, BDE 100, BDE 153, BDE 183) were evaluated for developmental effects on embryonic zebrafish. These congeners were chosen because they are environmentally relevant and cover a wide range of physical-chemical properties. Alterations in behavior, physical malformations, and mortality were scored daily until 168 h postfertilization (hpf). A concentration-dependent increase in spontaneous movement indicated an early onset of behavioral responses to PBDE exposures. Spontaneous movement was affected the most by BDE 47 and BDE 28, whereas BDE 183 did not alter behavior at any concentration tested. Swimming rates were significantly increased by BDE 28 at 96 and 120 hpf, but decreased swimming activity at 168 hpf. Additionally, BDE 47 significantly decreased the swimming rate at 168 hpf. Other endpoints included malformations and mortality. Congeners with fewer bromines (BDE 28, 47, 99, and 100) also induced a curved body axis starting around 120 hpf, which was followed by mortality. BDEs 153 and 183, however, did not elicit these adverse effects. A relationship was found between log KOW and median lethal concentration (LC50) and median effective concentration (EC50). Structure–activity relationships in this study suggest that PBDE acute toxicity results from a receptor-mediated effect and further studies are necessary to determine these pathways. Environ. Toxicol. Chem. 2011; 30:1865–1872. © 2011 SETAC

To quantify the contributions of fossil and biomass sources to the wintertime Arctic aerosol burden source apportionment is reported for elemental (EC) and organic carbon (OC) fractions of six PM10 samples collected during a wintertime (2012-2013) campaign in Barrow, AK. Radiocarbon apportionment of EC indicates that fossil sources contribute an average of 68 ± 9% (0.01-0.07 μg m(-3)) in midwinter decreasing to 49 ± 6% (0.02 μg m(-3)) in late winter. The mean contribution of fossil sources to OC for the campaign was stable at 38 ± 8% (0.04-0.32 μg m(-3)). Samples were also analyzed for organic tracers, including levoglucosan, for use in a chemical mass balance (CMB) source apportionment model. The CMB model was able to apportion 24-53% and 99% of the OC and EC burdens, respectively, during the campaign, with fossil OC contributions ranging from 25 to 74% (0.02-0.09 μg m(-3)) and fossil EC contributions ranging from 73 to 94% (0.03-0.07 μg m(-3)). Back trajectories identified two major wintertime source regions to Barrow: the Russian and North American Arctic. Atmospheric lifetimes of levoglucosan, ranging from 50 to 320 h, revealed variability in wintertime atmospheric processing of this biomass burning tracer. This study allows for unambiguous apportionment of EC to fossil fuel and biomass combustion sources and intercomparison with CMB modeling.

Lifetime contaminant and hormonal profiles have been reconstructed for an individual male blue whale (Balaenoptera musculus, Linnaeus 1758) using the earplug as a natural aging matrix that is also capable of archiving and preserving lipophilic compounds. These unprecedented lifetime profiles (i.e., birth to death) were reconstructed with a 6-mo resolution for a wide range of analytes including cortisol (stress hormone), testosterone (developmental hormone), organic contaminants (e.g., pesticides and flame retardants), and mercury. Cortisol lifetime profiles revealed a doubling of cortisol levels over baseline. Testosterone profiles suggest this male blue whale reached sexual maturity at approximately 10 y of age, which corresponds well with and improves on previous estimates. Early periods of the reconstructed contaminant profiles for pesticides (such as dichlorodiphenyltrichloroethanes and chlordanes), polychlorinated biphenyls, and polybrominated diphenyl ethers demonstrate significant maternal transfer occurred at 0–12 mo. The total lifetime organic contaminant burden measured between the earplug (sum of contaminants in laminae layers) and blubber samples from the same organism were similar. Total mercury profiles revealed reduced maternal transfer and two distinct pulse events compared with organic contaminants. The use of a whale earplug to reconstruct lifetime chemical profiles will allow for a more comprehensive examination of stress, development, and contaminant exposure, as well as improve the assessment of contaminant use/emission, environmental noise, ship traffic, and climate change on these important marine sentinels.

Lipid-rich matrices are often sinks for lipophilic contaminants, such as pesticides, polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs). Typically methods for contaminant extraction and cleanup for lipid-rich matrices require multiple cleanup steps; however, a selective pressurized liquid extraction (SPLE) technique requiring no additional cleanup has been developed for the simultaneous extraction and cleanup of whale earwax (cerumen; a lipid-rich matrix). Whale earwax accumulates in select whale species over their lifetime to form wax earplugs. Typically used as an aging technique in cetaceans, layers or laminae that comprise the earplug are thought to be associated with annual or semiannual migration and feeding patterns. Whale earplugs (earwax) represent a unique matrix capable of recording and archiving whales’ lifetime contaminant profiles. This study reports the first analytical method developed for identifying and quantifying lipophilic persistent organic pollutants (POPs) in a whale earplug including organochlorine pesticides, polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs). The analytical method was developed using SPLE to extract contaminants from ∼0.25 to 0.5 g aliquots of each lamina of sectioned earplug. The SPLE was optimized for cleanup adsorbents (basic alumina, silica gel, and Florisil ® ), adsorbent to sample ratio, and adsorbent order. In the optimized SPLE method, the earwax homogenate was placed within the extraction cell on top of basic alumina (5 g), silica gel (15 g), and Florisil ® (10 g) and the target analytes were extracted from the homogenate using 1:1 (v/v) dichloromethane:hexane. POPs were analyzed using gas chromatography–mass spectrometry with electron capture negative ionization and electron impact ionization. The average percent recoveries for the POPs were 91% (±6% relative standard deviation), while limits of detection and quantification ranged from 0.00057 to 0.96 ng g −1 and 0.0017 to 2.9 ng g −1 , respectively. Pesticides, PCBs, and PBDEs, were measured in a single blue whale ( Balaenoptera musculus ) cerumen lamina at concentrations ranging from 0.11 to 150 ng g −1 .

There is an increasing demand for high-throughput analytical methods specifically designed for the quantitation of organic contaminants in biological matrices. This demand exists in the broad fields of environmental chemistry and toxicology as well as medicine, food safety, drug discovery, and criminal forensics. Analytical chemists seek to develop techniques to reduce or eliminate method bottlenecks, which will improve the flow of information and downstream decisions. Advances in analysis of organic contaminants in biological matrices require the development of a novel sample preparation technique as well as more detailed MS/MS optimization. These analytical methods improve the laboratory’s ability to provide routine analysis and scale up its capability for larger, time-sensitive projects, such as environmental disasters. In addition, these advances reduce labor, training, consumption of and exposure to hazardous organic solvents, and laboratory space, thus reducing the time and cost of analysis.

Embryonic zebrafish were used to compare the uptake and metabolism of six polybrominated diphenyl ether (PBDE) congeners (BDEs 28, 47, 99, 100, 153, and 183) and identified metabolites from static exposures at 24 and 120 h postfertilization (hpf). An inverse relationship was observed between uptake of PBDEs and their octanol-water partitioning coefficients (uptake of BDEs 28 and 4799 and 100153 and 183). Debromination metabolites were identified in all congeners (excluding BDE 28) tested in the 120-hpf tissue samples. Interestingly, BDE 153 underwent meta-debromination, forming BDEs 47 and 99. Gene transcription analysis was conducted at 120 hpf to identify potential metabolic pathways for the PBDEs examined in the present study (gstpi, deiodinases 1 and 2, cyp1a1, cyp1b1, and ugt5g). The greatest induction was of ugt5g for all congeners and deiodinase transcription was also upregulated by BDEs 28, 47, and 183. The cyp1a1 and cyp1b1 were upregulated by BDEs 28, 47, 99, and 183. The least alterations in gene transcription were in the BDE 153-exposed embryos. A clear primary pathway of debromination metabolism was not identified; however, upregulation of these different genes indicated that fish were responding to exposure of PBDEs. Furthermore, the present study demonstrated that the most bioavailable congeners are also those with the highest reported toxicity.

Muscle samples were collected from pup, juvenile and adult Weddell seals (Leptonychotes weddellii) near McMurdo Sound, Antarctica during the austral summer of 2006. Blubber samples were collected from juvenile and adult seals. Samples were analyzed for emerging and legacy persistent organic pollutants (POPs) including current and historic-use organochlorine pesticides, polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs). Of the 41 target analytes, 28 contaminants were recovered from the Weddell seal blubber, in this order of prevalence: p,p'-DDE, p,p'-DDT, trans-nonachlor, mirex, cis-nonachlor, PCB 153, PCB 138, dieldrin, heptachlor epoxide, nonachlor III, PCB 187, oxychlordane, cis-chlordane, PCB 118, PBDE 47, PCB 156, PCB 149, PCB 180, PCB 101, PCB 170, PCB 105, o,p'-DDT, PCB 99, trans-chlordane, PCB 157, PCB 167, PCB 189, and PCB 114. Fewer POPs were found in the muscle samples, but were similar in the order of prevalence to that of the blubber: p,p'-DDE, o,p'-DDT, trans-nonachlor, nonachlor III, oxychlordane, p,p'-DDT, dieldrin, mirex, cis-nonachlor, PCB 138, and PCB 105. Besides differences in toxicant concentrations reported between the muscle and blubber, we found differences in POP levels according to age class and suggest that differences in blubber storage and/or mobilization of lipids result in age class differences in POPs. To our knowledge, such ontogenetic associations are novel. Importantly, data from this study suggest that p,p'-DDT is becoming less prevalent temporally, resulting in an increased proportion of its metabolite p,p'-DDE in the tissues of this top predator. In addition, this study is among the first to identify a PBDE congener in Weddell seals near the McMurdo Station. This may provide evidence of increased PBDE transport and encroachment in Antarctic wildlife.