Although plastic is an inert material and is not inherently toxic, it contains harmful additives that, in the case of the most dangerous ones and at high concentrations, can interfere with hormone metabolism, causing sex changes or sterility in marine animals. Aware of the risks posed by these alterations, international legislation requires the expansion of the list of marine contaminants, which until now has been limited to heavy metals, polycyclic aromatic hydrocarbons, organochlorines, and organobromines, to include other families of pesticides, pharmaceutical substances, cleaning agents, and plastic additives. It is in this context that the Impacta project was born, involving researchers from the Spanish Institute of Oceanography centers in Vigo and Murcia, as well as the universities of Vigo and A Coruña. The project aims to characterize the distribution of both regulated and emerging contaminants, as well as microplastics, in coastal sediments of the Ría de Vigo and the Mar Menor, and on the continental shelf of the Atlantic and Mediterranean coasts.
Funded through FEDER funds with €482,790, the results of the project will help define which groups of contaminants and associated biomarkers could be included in future European monitoring programs, as well as assess the role of microplastics in the dispersion and transfer of contaminants in the marine environment. To this end, Impacta will determine the biological effects that these contaminants can cause, for which sensitive and selective analytical methods will be developed and validated, allowing easy implementation in marine monitoring programs.
Additionally, the work will evaluate the combined effects of present contaminants through sediment bioassays assessing embryotoxicity, as well as exposure tests on marine species from different trophic levels to a selection of substances including certain pharmaceuticals, phthalates, pesticides, perfluorinated compounds, and personal care products. This will contribute to establishing environmental quality criteria for these contaminants in the marine environment.
The contribution of the University of Vigo to the project
Researcher Ricardo Beiras, from the Department of Ecology and Animal Biology, leads the team from the University of Vigo, which, together with the group from the University of A Coruña led by Soledad Muniategui, will focus on the part of the project related to conducting toxicity bioassays in organisms and assessing the toxicity of coastal sediments. This will be done through embryotoxicity tests and evaluating the endocrine effects of a selection of emerging contaminants on gastropods and other trophic levels.
“In the laboratories and marine facilities at ECIMAT, we will carry out exposure tests of marine species to a selection of substances. That is our part of the project, in which, for example, we expose mussels to plastic additives and observe whether the males synthesize a protein that, in principle, should only be produced by females because it is used to provide energy reserves to the eggs,” explains Beiras. He also confirms that in addition to adult mussels, sea urchins will be used for embryonic tests.
The participation of the group led by Ricardo Beiras, the researcher himself assures, “arose naturally,” the result of a collaboration that they have maintained for almost 18 years with the IEO contamination group. “They are experts in the chemical analysis of contaminants, and we specialize in their toxicity and biological effects. Nowadays, effective contamination monitoring requires integrating both aspects.” Regarding the collaboration with the University Institute of Environment at UDC, Beiras notes that it came later but is “equally productive,” referring to this project in which Victor Manuel León from the Spanish Institute of Oceanography acts as the principal investigator.
Regulated contaminants, emerging pollutants, and microplastics
Over the three years of the project, the research teams will focus their efforts on characterizing regulated contaminants, emerging pollutants, and microplastics in coastal sediments of the Ría de Vigo and the Mar Menor, as well as on the continental shelf along the Atlantic and Mediterranean coasts. These two locations were chosen, according to Beiras, “for their high levels of industrial-origin contamination, for being two well-known bays, and also for logistical reasons, since the IEO centers in Vigo and Murcia monitor contamination along the entire Spanish coastline.”
In the case of regulated contaminants—those that current legislation, particularly European directives, requires to be monitored in water to ensure they do not exceed certain limits known as water quality standards—the project aims to develop techniques to lower detection thresholds, which in some cases are so low that standard analytical methods cannot detect them.
As for emerging contaminants—those that scientific studies have shown to already be problematic for the environment but are not yet included in legislation—the Impacta project aims to study the levels of some of them, such as pharmaceuticals or plastic additives. “The case of pharmaceuticals is curious: draft European standards included them for regulation, but in the end, probably due to the strong lobbying by the pharmaceutical industry, they were removed from the directives,” Beiras points out.
Regarding microplastics, the Vigo-based researcher explains that these are very small plastic particles—a material that does not degrade in the environment but does undergo physical erosion, gradually breaking down into tiny particles that enter the food chain.
A regulatory tangle
Although international legislation itself requires the expansion of the list of marine contaminants—which until now has been limited to a certain group of substances—what is the reality of the existing regulations in this area? While the EU takes the lead on environmental issues and establishes directives that are binding for member states, these directives have no enforcement power until they are transposed and implemented in national legislation.
“The European Water Directive and its derivatives set quality standards for continental and marine waters with maximum limits for 45 chemical substances considered priority pollutants. Much of this legislation is recent and has not yet been transposed into Spanish law, and when it is, it will be little more than paper, because there is neither the technical capacity nor the political will to implement it,” explains Beiras.
In the case of Spain, the hydrographic confederations are responsible for monitoring these priority substances—a task that, according to the Vigo-based researcher, they outsource to private laboratories and consultancies, since they lack the means to carry it out themselves.
“The fact that the standards are not being met, which is common, carries no sanctions, because only the receiving waters are monitored, and the source causing the violation is not investigated,” Beiras denounces, citing as an example the toxic discharge that occurred last summer in the port of Cambados, which went uninvestigated despite the mortality it caused among shellfish resources such as razor clams.
