Halogenated contaminants in farmed salmon, trout, tilapia, pangasius, and shrimp.

Polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins and dibenzo-p-furans (PCDD/Fs), organochlorine pesticides (OCPs), polybrominated diphenyl ethers (PBDEs), hexabromocyclododecane diastereomers (HBCDs), and perfluorinated compounds (PFCs) were analyzed in popular farmed fish such as salmon, trout, tilapia, and pangasius and in farmed shrimp. The samples originated from southeast Asia, Europe, and South America. Results show the following: (i) Carnivorous species contained higher contaminant concentrations than omnivorous species. (ii) Contaminant concentrations generally decreased per species in the following order of salmon > trout >> tilapia approximately equal to pangasius approximately equal to shrimp. (iii) Most contaminant concentrations decreased in the following order of PCBs approximately equal to dichloro-diphenyl-trichloroethanes (DDTs) >> hexachlorobenzene approximately equal to pentachlorobenzene approximately equal to dieldrin approximately equal to PBDEs approximately equal to alpha-HBCD approximately equal to perfluorooctane sulfonate (PFOS) >> World Health Organization toxic equivalents (WHO-TEQ) [PCDD/Fs and dioxin-like (dl)-PCBs]. (iv) Contaminant concentrations were very low (mostly <1 ng/g wet weight) and far below the European and Dutch legislative limits. (v) Contaminant concentrations in farmed shrimp, pangasius, and tilapia were lower than those in wild fish, whereas contaminant concentrations in farmed salmon and trout were higher than those in lean wild marine fish. From the five species investigated, salmon is predominantly responsible (97%) for human exposure to the sum of the investigated contaminants. The contribution of trout, tilapia, pangasius, and shrimp is small (3%) because contaminant concentrations and consumption volumes were much lower.

Significant improvements in the analysis of perfluorinated compounds in water and fish: results from an interlaboratory method evaluation study.

The 2nd international interlaboratory study (ILS) on perfluorinated compounds (PFCs) in environmental samples was organized to assess the performance of 21 North American and European laboratories on the analysis of PFCs in water and fish. A study protocol was provided to assess accuracy, precision, matrix effects and to study the use of in-house standards. The participants used shared native and mass-labelled standards that were provided for this study to quantify the PFC concentrations in the samples. Matrix effects in the determination of PFCs can be considerable and can decrease the sensitivity, the accuracy and internal standard recoveries. Therefore, two quantification methods were evaluated by all laboratories: standard addition quantification (SAQ) and solvent-based calibration curve quantification (SBCCQ; using mass-labelled internal standards (IS)). The between laboratory reproducibility (i.e. coefficient of variance) was smaller for the SBCCQ results (except for PFBS and PFHxS for which no mass-labelled analogues were available) compared to those obtained by the SAQ method. The within laboratory precision of individual laboratories is good (mean for all PFCs in water 12% and 6.8% in fish). The good performance is partially attributable to the use of well-defined native- and mass-labelled standards. Therefore, the SBCCQ method is recommended. The results show that analytical methods for PFCs in water and fish have improved considerably. Critical steps identified in this study are (i) the use of well-defined native standards for quantification, (ii) the use of mass-labelled internal standards (preferably one for each target compound) and (iii) minimization of matrix effects by a better clean up.

Determination of diuron and the antifouling paint biocide irgarol 1051 in Dutch marinas and coastal waters.

A sensitive LC-electrospray MS-MS method using off-line solid-phase extraction for the determination of diuron and Irgarol 1051 has been developed, enabling determination of both compounds at sub-ppt levels. Diuron and Irgarol 1051 are used as alternatives for tributyltin in antifouling paints that prevent growth on boats, and an increase in their application is anticipated because of the upcoming ban on tributyltin in 2003. In 2000, a survey was carried out to assess contamination with diuron and Irgarol 1051 of a number of Dutch marinas and coastal waters. Depending on the time of year, both compounds were encountered at levels higher than the maximum permissible concentrations of 430 and 24 ng/l for diuron and Irgarol 1051, respectively. Outside marinas at reference locations, concentrations were much lower, depending on the geographical situation and the nature of the water exchange with the environment related to tidal cycles. A seasonal influence was observed with highest levels in summer, corresponding to the yachting season for both compounds. For diuron, use in agriculture could have contributed to the high concentration encountered in surface waters.