MEXICO CITY— Microplastics from product packaging and other sources are present in the stomachs of 20 percent of commercially important fish from three regions in Mexico, according to new tests by conservation groups and scientists from prominent Mexican universities.

The tests examined grey snapper, red grouper, white mullet and king mackerel from the Gulf of California, the Gulf of Mexico and the Caribbean Sea. One-fifth of the sampled fish contained microplastics — tiny pieces that often come from larger plastic debris as it degrades.

The tests are detailed in a new report by scientists from the Autonomous University of Baja California Sur, the Universidad Veracruzana, the National Autonomous University of Mexico, Greenpeace Mexico and the Center for Biological Diversity.

“These disturbing tests highlight how plastic pollution is infesting our oceans and contaminating the fish we eat,” said Alejandro Olivera, the Mexico representative of the Center for Biological Diversity. “Microplastics threaten the environment and public health, in Mexico and around the world. Local efforts to ban plastic bags and straws are important, but we need national lawmakers to step up and help solve the problem.”

The most prevalent plastics came from cellophane and self-adhesive tapes used for wrapping and product packaging. The tests also found plastics from fibers used for clothing and textiles, food containers, fishing gear, bottles, supermarket bags and other sources.

“Although different states and municipalities in Mexico have taken measures to restrict or prohibit single-use plastic items, our national legislators must stop plastic contamination at its source by modifying the General Law for the Prevention and Integral Management of Waste,” said Miguel Rivas, coordinator of the Greenpeace oceans campaign. “Extending responsibility to the producers of the plastic products will stop plastic at its source. It’s time to stop letting big corporations greenwash their plastic pollution.”

Veracruz was the most affected region: The average number of microplastics per fish there was twice as high as in the other two regions. This could be related to the area’s higher level of urbanization, with a greater amount of suspended solid waste in the marine waters because of runoff or wastewater discharges and poor waste management. La Paz in Baja California Sur had the lowest plastic levels, perhaps because of its lower population density.

Recent scientific research suggests that microplastics can break down further and penetrate fish meat. For example, microplastics from shellfish are the third-largest contributor of microplastics to the consumer. It is estimated that consumers could eat, inhale or drink up to 74,000 pieces of microplastics a year.

In the report, Greenpeace and the Center called on companies that pollute oceans the most to assume responsibility and commit to changing product packing to minimize plastic.

They also urged a ban on the disposal of single-use plastics, labeling that inform consumers about the product’s negative environmental impacts have and the correct way to dispose of them, a prohibition on the incineration of containers, packages, and packaging, and a prohibition on the addition of microplastics to cosmetics and creams.

The groups also urged Mexico’s federal authorities to investigate potential health impacts to people who consume these fish and to work with fishing authorities to ensure that the economic activity is maintained in a sustainable manner and without affecting the population.

The full report in Spanish can be viewed at: https://act.gp/reporte-pecesmx

A summary of the report in English can be viewed at: https://www.biologicaldiversity.org/campaigns/ocean_plastics/pdfs/English-Summary-study-on-fish.pdf