There are around 3400 mussel farms in the Galician estuaries, making mussel farming one of the main economic activities in the community. This means that the sector and the public administration exercise significant quality control over both the productivity of the crop and its quality and food safety. However, there is a factor that has not been studied much, such as the polluting impact of the products used to clean and waterproof the mussel farms, a topic on which researcher Vladimir Dobal, from the Bivalve Mollusc Reproduction Group at CIM-UVigo, focused his thesis.
Under the auspices of the Do*Mar doctoral program, Dobal warns that this process is usually carried out in situ and using a “mixture of arbitrary composition, based on tars and burnt diesel”. He explains that very little is known about the “polluting impact of these treatments in the immediate surroundings of the raft, as well as their effect on the morphology, cytology, histology, physiology, biochemistry or metabolism of the mollusk”.
His study was based on analyzing the histological and histopathological effects caused in the gills, digestive gland and mantle-gonad of M. galloprovincialis. On the other hand, he also studied the detoxification capacity of this mollusk and the metabolic pathways involved, as well as the participation of each tissue in this process and analyzed the proteome response of the mantle of M. galloprovincialis with a view to shedding light on the molecular mechanisms affected by exposure to the tar mixture.
The effects of tar on mussels
His research presents several conclusions, the first of which states that “exposure to the tar mixture induces several alterations in the respiratory, digestive and reproductive systems of M. galloprovincialis, which increase with the dose and time of exposure, suggesting a cumulative toxic effect of this mixture”. In this sense, Vladimir Dobal highlights that “it is proven that both the gills, the digestive gland and the mantle are necessary organs in the xenobiotic detoxification mechanism of M. galloprovincialis”.
Given these data, the researcher proposes in his thesis a battery of enzymes as potential biomarkers of pollution by mixtures of hydrocarbons and heavy metals in marine environments, mainly in aquaculture areas, although analysis in the natural environment will be necessary to confirm this”. Furthermore, in his study, 132 proteins with biological relevance were identified in response to tar poisoning, “which makes it necessary, as a continuation of this work, to validate them as potential biomarkers of exposure”, adds the scientist. Finally, and due to their functional relevance, Dobal proposes the induction of three proteins involved in the processes of programmed cell death (RAS proteins) and in fertilization (vitelline coat lysin/vitelline envelope receptor for lysin) as possible biomarkers of the harmful effects of tar on mussel reproduction.
The research activity of the bivalve molluscs group at CIM-UVigo is co-financed by the FEDER/FSE Galicia 2014-2020 Operational Program.
Source: DUVI
