Last week, I had a chance to catch up with Dr. Chelsea Rochman; School of Veterinary Medicine at the University of California Davis. She is a postdoctoral researcher in the Aquatic Health Program led by Dr. Swee J. Teh. Dr. Rochman sailed with us across the South Atlantic collecting fish to study for pollutants in their tissues. For us policy people, we’ve been anxiously awaiting the results of one Dr. Rochman’s other studies looking at fish that eat toxin laden plastics in a lab setting. The answer confirmed what we expected– toxins DO transfer to fish after ingestion. All of the sudden, this study will be the centerpiece of the human health inpact of plastics on the food we eat. Read and share this post. Everyone needs to know about this study. See Dr. Rochman’s responses to 5 Gyres questions below.
1.) For several years now, environmentalists have been concerned that POPS laden, ocean born plastics may migrate from ingested plastics to fish tissue. Is it fair to say, unequivocally, that this transfer occurs? What are the implications if so?
From this experiment, using Japanese medaka fish, we have shown the transfer of persistent organic pollutants from plastic to fish. Our experiment used environmentally-relevant concentrations of plastic, the type of plastic most often found in the environment Polyethylene (PE) and environmentally relevant concentrations of chemicals sorbed to plastics. In addition, our experiment used a diet contaminated with Persistent Organic Pollutants (POPs) via the cod liver oil in the diet. In this way, due to our results showing significantly greater concentrations in the fish fed the marine-plastic diet, we were able to show that plastics may be an important vector for the bioaccumulation of POPs in wildlife despite the presence of POPs in food webs from other sources. We witnessed toxicity from the ingestion of virgin PE and PE with sorbed pollutants. Specifically, we observed stress in the livers of fish exposed to the virgin and marine plastic treatment with greater effects in fish exposed to marine plastic. The liver is a critical organ for the excretion of toxins in our bodies. A compromised liver could lead to greater effects in organisms if it can no longer eliminate toxins.
2.) What was the question you were trying to answer by conducting this study?
Our objective was to understand if plastics are indeed a source of organic pollutants (POPs) to fish via ingestion. We also wanted to understand the hazards associated with plastic ingestion in fish. We were concerned with how plastics themselves and the mixture of plastic and sorbed contaminants may harm fish. Our overarching goal was to add to the weight of evidence demonstrating whether plastic debris in aquatic habitats may be hazardous to aquatic life.
3.) How many fish are known to ingest micro-plastics? Give us an idea of the scale of the issue?
41 species of fish have been reported to ingest plastic debris globally. Fish are also suggested as a useful indicator for environmental stress and are relevant to human health through exposure via seafood.
4.) After completing this study, what is the next question you look to answer? How will this study affect your future research?
We learned that adverse outcomes arise from the ingestion of clean plastic as well as plastic with sorbed pollutants. Thus, we now would like to understand how this varies by plastic type as some plastics are suggested to be more hazardous than others due to their chemical ingredients. In addition, because of concerns for human health, we want to understand how chemicals from plastics move up the food chain and whether plastic contributes to the magnification of chemicals in apex predators like tuna or sharks.
5.) Beyond the marine ecosystem, do you see any potential risks to humans from consuming fish? What are the human health implications?
I think I talked about this a bit earlier. But, this is one reason we chose fish because it is a source of protein for humans all across the globe. Because we found that plastics do transfer chemicals to fish, and because fish do eat plastic in nature, there is evidence that plastic may be a contributor of POPs in our seafood.
6.) Any thing else you’d like to share about this study?
Future studies should consider effects from both the plastic itself and the mixture or cocktail of plastic debris + priority pollutants.
Read The Full Study, HereTags: chelsea rochman, human health impacts, marine debris, marine litter, medeka fish, plastic ingestion fish, plastic pollution