The study, published in the journal Scientific Reports, is the first evidence that land pathogens
Microplastics with pathogens
The authors studied the pathogens Toxoplasma gondii,Cryptosporidium (Crypto) and Giardia - These can affect both humans and animals. These pathogens have been identified by the World Health Organization as under-recognized causes of illness caused by shellfish consumption. They are found throughout the ocean.
T.gondii, a parasite found only in cat feces, has infected many ocean species with toxoplasmosis. It has also led to the death of sea otters and endangered species, including Hector's dolphins and Hawaiian monk seals. In humans, toxoplasmosis can cause chronic disease, as well as developmental and reproductive disorders.
For the study, the authors conducted laboratoryexperiments to see if their chosen pathogens can bind to plastics in seawater. They used two different types of microplastics: polyethylene microbeads and polyester microfibers. Microbeads are often found in cosmetics such as exfoliators and cleansers, while microfibers are found in clothing and fishing nets.
Scientists have discovered that sticks to microfibersmore parasites than microbeads, however both types of plastic can carry terrestrial pathogens. It is noted that fine particles of microfibers are common in Californian waters and have already been found in shellfish.
The authors said plastic helps pathogens more easily enter marine life, depending on whether it sinks or floats.
Microplastics floating on the surface canmove, spreading pathogens over long distances. Plastics that sink help pathogens concentrate in the benthic environment - near the seafloor. This is where animals live that filter sea water to feed. These are zooplankton, shellfish, mussels, oysters, abalone and others. This makes them more likely to ingest plastic along with the pathogen.
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