High levels of plasticizers found in whales from the Atlantic Ocean
Scientists have found for the first time a significant accumulation of organophosphate compounds, which are used as plasticizers and flame retardants in many plastic products, in the tissues of fin whale and of its main prey, krill. Results did not indicate the incidence of bioaccumulation or bioaccumulation processes in these species. However, experts point out the importance of this cetacean as a large-scale bioindicator of marine pollution.
The study, recently published in the journal Science of the Total Environment, and led by the Biodiversity Research Institute at the University of Barcelona (IRBio), the Institute for Environmental Diagnosis and Water Studies (IDAEA) of the Higher Council for Scientific Research (CSIC), and the Institute of Marine Research (Iceland), analyzed samples of fin whale (Balaenoptera physalus) and krill from the Atlantic Ocean, off the coast of Iceland.
Organophosphate compounds were found in all samples analyzed, which included muscle samples from 20 specimens of fin whale, and 10 samples of krill. Results showed levels of organophosphate compounds around one microgram per gram of fat, both in fin whales and krill. According to the scientists, these levels are similar to those observed for other pollutants already subject to regulation, such as chlorinated biphenyl (PCB) or polybrominated diphenyl ethers (PBDEs).
The most abundant plasticizer detected in the study were tributylphosphate (TBP), isopropylphenylphosphate (IPPP) and triphenylphosphine oxide (TPPO). "Although the toxic effects of each of these pollutants are currently unknown, there is evidence that TNBP has the potential to cause neurological damage, endocrine disruption, carcinogenic effects and adverse effects on reproduction," explains Ethel Eljarrat, the CSIC researcher. "The good news is that the levels observed in whales and krill would indicate that these plasticizers do not biomagnify, since their concentrations do not increase from prey to predator," added the researcher.
Of the 19 organophosphate compounds analyzed, seven have been detected in fin whales, five of which were also detected in krill samples, suggesting that the presence of these contaminants in fin whales is mainly derived from the diet. However, two compounds, diphenylcresylphosphate (DCP) and tripropylphosphate (TPP), were detected in the whale muscle but not in krill samples, indicating a different source of intake for them. “One possible explanation would be the presence of micro- and macro-plastics in the oceans, which could release the chemical additives (that is, DCP and TPP) in the whale tissues once ingested by the whale" highlights Eljarrat.
This study shows that fin whales are a species susceptible to being affected by plastics and plasticizers, since these mammals obtain their food by filtering krill from the water, a feature that makes them highly vulnerable to the ingestion of marine plastics. Furthermore, "fin whale is a species that can act as a bioindicator of large-scale contamination, since it carries out long-range migrations from low-latitude areas in winter to high latitudes in summer," highlights the co-author of the study Asunción Borrell, from IRBio.
The use of organophosphate plasticizers started in the 60s of the last century, and increased four decades later, when polybrominated diphenyl ethers (PBDEs) were banned by the Stockholm Convention in 2009 due to their high toxicity, and other flame retardants were proposed as an alternative. Despite being less toxic than their predecessors, scientific studies show that organophosphate compounds can cause neurological damage, endocrine disruption, cancer, and fertility problems.
To this date, only six studies related to the presence of these organophosphate contaminants in cetaceans were published. This is the third study carried out by the research group led by Eljarrat showing that this global problem affects different seas and oceans. In the previous two, organophosphate compounds were detected in different species of dolphins from the Alboran Sea and the Indian Ocean. Concentrations in the dolphins from Alboran Sea were similar to those found in fin whales, while levels in the dolphins from Indian Ocean were an order of magnitude higher.
Odei Garcia-Garin, Berta Sala, Alex Aguilar, Morgana Vighi, Gísli A. Víkingsson, Valerie Chosson, Ethel Eljarrat and Asunción Borrell. Organophosphate contaminants in North Atlantic fin whales. Science of the Total Environment. DOI: 10.1016 / j.scitotenv.2020.137768 https://www.ncbi.nlm.nih.gov/pubmed/32197282
Amelia Ochoa, Ana Sotres - Institute of Environmental Diagnosis and Water Studies (CSIC)
Traducción:IRBio and research Group Large Marine Vertebrates