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The distribution of pesticides in dissolved aqueous phase (DAP), suspended particulate matter (SPM) and Scrobicularia plana soft tissues from the Tagus River estuary was determined to evaluate the chemicals pollution status and their hazard potential in this area. Samples were collected in 6 campaigns (December 2012-October 2013), from 3 strategical sites, and analysed via different extraction procedures followed by gas chromatography tandem mass spectrometry (GC-MS/MS) determination. The contamination profile among matrices (DAP, SPM, and soft tissue from bivalves (STB)) was marked by average concentrations of 345ng/L, 0.51mg/kg, and 0.02mg/kg, respectively, with several samples above the 2013/39/EU Directive of environmental quality standards (EQS); no differences were observed between sex. A wider range of pesticides was present in STB (n=53) than in SPM (n=36) and DAP (n=19) matrices. Sediment-water partition coefficient, bioaccumulation factor in both DAP and SPM fraction were estimated ranging between 2.5 and 4.4 and 0.008-2799, respectively. The spatial distribution of most pesticides and physicochemical parameters were consistent, indicating a pollution pattern primarily near the Trancão River mouth. Due to the presence of the target compounds, calculated risk quotients pointed out potential hazards for aquatic organisms, mainly to invertebrates. The estimated average daily intake, theoretical maximum daily intake, and hazard quotient of the studied pesticides-via bivalve ingestion-indicated no risk for human health, although it is important to note possible biomagnification processes that may happen along the estuarine food-chain., (Copyright © 2016 Elsevier B.V. All rights reserved.)

A method for quantitative determination of 55 pesticides in a bivalve matrix was established, based on QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) extraction and using gas chromatography (GC)-ion trap (IT) mass spectrometry (MS/MS). Accomplishing the European SANCO guidelines, this method was validated using 5 g of homogenized soft tissue, allowing the quantification of pesticides at ng/g of wet weight (ww). Quantification limits and recovery rates ranged from 0.33 to 10.3 μg/L and from 78 to 119 %, respectively. As an important mollusc, not only from an ecological perspective but also for food consumption, the peppery furrow shell (Scrobicularia plana) was sampled at three strategical sites (Ria Formosa Lagoon, in the south of Portugal) during 2012-2013, over six campaigns. A total of 2160 animals were pooled by place and sex. No statistical differences were found among sites or between sexes. Forty percent of the sampled pools were above quantification limits, reaching total annual average concentrations of ∑800 ng/g ww. Additionally, 83 % of the selected compounds showed concentrations above the legal limits set by the European Directive 2013/39/EU. In conclusion, the applied method was successful and proved that bivalves were contaminated by the selected pesticides. In future work, this methodology can be used to monitor body burdens and obtain data for predicting impacts in shellfish consumers. Graphical Abstract Resume of pesticides extraction and analyses process from S. plana.

The origin and diversification of the metazoan endocrine systems represents a fundamental research issue in biology. Nuclear receptors are critical components of these systems. A particular group named VDR/PXR/CAR (NR1I/J) is central in the mediation of detoxification responses. While orthologues have been thoroughly characterized in vertebrates, a sparse representation is currently available for invertebrates. Here, we provide the first isolation and characterization of a lophotrochozoan protostome VDR/PXR/CAR nuclear receptor (NR1J), in the estuarine bivalve the peppery furrow shell ( Scrobicularia plana ). Using a reporter gene assay, we evaluated the xenobiotic receptor plasticity comparing the human PXR with the S. plana NR1Jβ. Our results show that the molluscan receptor responds to a natural toxin (okadaic acid) in a similar fashion to that reported for other invertebrates. In contrast, the pesticide esfenvalerate displayed a unique response, since it down regulated transactivation at higher concentrations, while for triclosan no response was observed. Additionally, we uncovered lineage specific gene duplications and gene loss in the gene group encoding NRs in protostomes with likely impacts on the complexity of detoxification mechanisms across different phyla. Our findings pave the way for the development of multi-specific sensor tools to screen xenobiotic compounds acting via the NR1I/J group. [ABSTRACT FROM AUTHOR]