The neurotoxin beta-N-methylamino-L-alanine (BMAA) and its putative role in multiple neurodegenerative diseases have been intensely studied since 2005 when the toxin was discovered to be produced by worldwide-distributed cyanobacterial species inhabiting terrestrial, marine, brackish, and freshwater ecosystems. Recently, BMAA production was also associated with one eukaryotic group, namely, diatoms, raising questions about its production by other phytoplanktonic groups. To test for BMAA bioavailability in ecosystems where abundant phytoplanktonic blooms regularly occur, samples of filter-feeding shellfish were collected in two Portuguese transitional water bodies. BMAA content in cockles (Cerastoderma edule) collected weekly between September and November 2009 from Ria de Aveiro and at least once a month from May to November from Ria Formosa, fluctuated from 0.079 +/- 0.055 to 0.354 +/- 0.066 mu g/g DW and from below the limit of detection to 0.434 +/- 0.110 mu g/g DW, respectively. Simultaneously to BMAA occurrence in cockles, paralytic shellfish toxins were detected in shellfish as a result of Gymnodinium catenatum blooms indicating a possible link between this marine dinoflagellate and BMAA production. Moreover, considerable high BMAA levels, 0.457 +/- 0.186 mu g/g DW, were then determined in a laboratory grown culture of G. catenatum. This work reveals for the first time the presence of BMAA in shellfish from Atlantic transitional water bodies and consubstantiate evidences of G. catenatum as one of the main sources of BMAA in these ecosystems. (C) 2014 Elsevier B.V. All rights reserved.
Reductive debromination of nonabrominated diphenyl ethers by sodium borohydride and identification of octabrominated diphenyl ether products
In the proposed new European chemicals regulations - the REACH system - the improved control of persistent and bioaccumulating substances is stated as one of the tasks being of particular importance. In this article, the reliability and validity of the scientific basis for identification of persistent ( P), bioaccumulating ( B), and toxic ( T) substances, and for assessing the risks that these substances may pose, are discussed. We have used the European Union risk assessment of pentabromodiphenyl ether, PentaBDE ( CAS 32534-81-9) as a study case in the analysis. It is concluded that for PBT substances there is room for development both with regard to test methodology and with regard to risk assessment procedures.
Methods for synthesis of nonabromodiphenyl ethers and a chloro-nonabromodiphenyl ether