Quantification of bioaccumulative contaminants in biota is time and cost-intensive and the required extensive cleanup steps make it selective toward targeted chemical groups. Therefore tissue extracts prepared for chemical analysis are not amenable to assess the combined effects of unresolved complex mixtures. Passive equilibrium sampling with polydimethylsiloxane (PDMS) has the potential for unbiased sampling of mixtures, and the PDMS extracts can be directly dosed into cell-based bioassays. The passive sampling approach was tested by exposing PDMS to lipid-rich tissue (dugong blubber; 85% lipid) spiked with a known mixture of hydrophobic contaminants (five congeners of tetra- to octachloro-dibenzo-p-dioxins). The equilibrium was attained within 24 h. Lipid-PDMS partition coefficients (Klip-PDMS) ranged from 20 to 38, were independent of hydrophobicity, and within the range of those previously measured for organochlorine compounds. To test if passive sampling can be combined with bioanalysis without the need for chemical cleanup, spiked blubber-PDMS extracts were dosed into the CAFLUX bioassay, which specifically targets dioxin-like chemicals. Small quantities of lipids coextracted by the PDMS were found to affect the kinetics in the regularly applied 24-h bioassay; however, this effect was eliminated by a longer exposure period (72 h). The validated method was applied to 11 unspiked dugong blubber samples with known (native) dioxin concentrations. These results provide the first proof of concept for linking passive sampling of lipid-rich tissue with cell-based bioassays, and could be further extended to other lipid rich species and a wider range of bioanalytical end points.
To simultaneously quantify and profile
the complex mixture of short-,
median-, and long-chain CPs (SCCPs, MCCPs, and LCCPs) in Australian
sewage sludge, we applied and further validated a recently developed
novel instrumental technique, using quadrupole time-of-flight high
resolution mass spectrometry running in the negative atmospheric pressure
chemical ionization mode (APCI-qTOF-HRMS). Without using an analytical
column the cleaned extracts were directly injected into the qTOF-HRMS
followed by quantification of the CPs by a mathematical algorithm.
The recoveries of the four SCCP, MCCP and LCCP-spiked sewage sludge
samples ranged from 86 to 123%. This APCI-qTOF-HRMS method is a fast
and promising technique for routinely measuring SCCPs, MCCPs, and
LCCPs in sewage sludge. Australian sewage sludge was dominated by
MCCPs with concentrations ranging from 542 to 3645 ng/g dry weight
(dw). Lower SCCPs concentrations (<57–1421 ng/g dw) were
detected in the Australian sewage sludge, which were comparable with
the LCCPs concentrations (116–960 ng/g dw). This is the first
time that CPs were reported in Australian sewage sludge. The results
of this study gives a first impression on the distribution of the
SCCPs, MCCPs, and LCCPs in Australia wastewater treatment plants (WWTPs).
To survey the conformity and quality of the results between laboratories for short-chain chlorinated paraffins (SCCPs) determination, we reviewed current and novel analytical methods and organized four worldwide laboratory exercises between 2011 and 2017. Participants were requested to analyse test solutions and extracts of various matrices with their method of choice. Thirty-three laboratories participated (9e22 per round), of which 55e81% were able to submit data. Large differences in results between laboratories were found (CVs 23e137%) but results improved over time, while the levels in the test materials decreased. In the last round acceptable CV values (<25%) were obtained for the test solution. In the last round, results obtained by the GCeECNI-LRMS technique varied most, which is disconcerting as this technique is most commonly applied. We strongly suggest to continue monitoring comparability of laboratories to assess consensus in SCCP analysis, with a focus on quantification procedures applied.
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