Greenpeace Mediterranean said it had discovered hazardous chemical pollutants and heavy metals at locations imported waste had been discarded and burned.
A previous investigation found British food packaging had been dumped in these five same areas, it said.
“This is the toxic fingerprint of Britain’s dangerous pattern of dumping plastic waste out of sight and out of mind,” Megan Randles from Greenpeace UK said.
“This proof of the harm our plastic can cause, when dumped and burned overseas, should spur the government on to do the right thing and ban plastic waste exports.”
In May last year, Greenpeace revealed the UK was shipping out plastic waste to Turkey, where it was dumped and burned.
Days later, the country said it would add ethylene polymer plastics – which includes plastic bags and film – to its list of waste materials banned from being imported. Greenpeace Mediterranean said this would account for nearly three quarters of the plastic waste Turkey imported the year before.
But the environmental group said plastic waste importation had to be “completely banned” to prevent toxic chemicals from contaminating soil, air and water in Turkey in its new report.
The campaigners found dangerous pollutants were present in the soil and ash at five sites in the Adana province where UK and European Union countries’ waste had been dumped. In some of these locations, levels were thousands of times higher than control sites, the group said.
“Some of the organic chemical pollutants identified in the area are not only toxic but highly persistent, and can biologically accumulate once they enter the food chain,” the report by Greenpeace Mediterranean said.
Among the chemicals found were dioxins and furans, which can harm fetuses, premature birth and trigger tumours, metals which can damage the nervous system and be carcinogenic and compounds polycyclic aromatic hydrocarbons which can cause skin lesions and liver disease.
UK legislation bans waste being shipped outside of Europe if it is to be disposed rather than recycled.
The Department for Environment, Food and Rural Affairs spokesperson said: “We are clear that the UK should handle more of its waste at home, and are committed to banning the export of plastic waste to non-OECD countries and clamping down on illegal waste exports – including to countries such as Turkey – through tougher controls. Those found to be exporting waste in contravention of the requirements of the legislation can face a two-year jail term and an unlimited fine.”
They added: “The Environment Agency has not received any repatriation requests from the Turkish authorities for any waste, including plastic, since 2021.”