Scientists from the University of California, Irvine, in collaboration with the University of Queensland and Environmental Defense Fund, Cornell University, yield an alarming discovery after conducting the first landmark study using high technology to examine the contaminants of oysters.
Their study reveals that oysters are contaminated with human bacterial pathogens and micro debris like plastics, kerosene, talc, paint, and baby formula.
The study was conducted in the eastern part of the Andaman Sea, with the help of local researchers in Myanmar in the rural Tanintharyi region. The researchers found that coastal urbanization and lack of sewage treatment contaminates seafood and, in turn, poses health risks for humans.
The findings of their research were published in Science of the Total Environment.
What's Inside the Shellfish?
The study covered nine coral reefs off the Mergui Archipelago of Myanmar situated roughly 40 miles from the city of Myeik that has over 250,000 residents.
The researchers used the next-generation DNA sequencing technology to reveal 5,459 potential human pathogens of 87 species of bacteria. More than 50% of these bacteria are harmful to human health.
Additionally, they used infrared spectroscopy to examine human-derived micro debris found in oysters and found 78 different contaminants.
Study senior author Joleah Lamb, an assistant professor of ecology & evolutionary biology at UCI, said that 48% of the contaminants they found in oysters were microplastics. However, many other particles were also present and not just plastics.
They were surprised to find constituents of fuel, paint, cosmetics, and three different brands of powdered milk that comprise 14% of the micro debris.
The pathogens and microparticles reflect the pervasive presence of sewage and other human-derived micro debris, which implies that coastal urbanization has led to the contamination of vital marine species globally.
Implications for Human Health
The study's implications for human health are very important. Oysters in the study area and anywhere that is part of the local diet consume the shellfish raw and whole. The contaminants found suggest that even areas such as rural Myanmar, far from the urban cities, have significant pollution from agricultural and human waste.
Today, more than 50% of seafood exports come from developing countries, which raises concerns about food safety and security worldwide.
But aside from pathogens present in shellfish, experts are very much concerned about the predominance of microplastics and its other types that are present in seafood that could adversely affect the environment and human health.
Microplastics such as persistent organic pollutants, or POPs carry toxins that enter the seafood and eventually transferred to people through food. That means, microplastics in the marine environment could be an emerging health risk to the people worldwide.
The authors are also concerned that over 50% of the micro debris detected in the Myanmar oyster tissues are polymer materials that are harmful to human health. These are kerosene, saponin, and talc.
Furthermore, the presence of milk supplement reveals that there is a direct fecal-oral link between sewage and human waste that is making its way back to the food chain. Therefore, it elevates further the risk of contamination or, worse, disease transmission.