Pollutants found in crocs and alligators

KRUGER Park crocodiles and American alligators contain high levels of industrial and household pollutants, scientists have found.

It is the first time the compounds – used in water-repellent clothes, stain repellents, non-stick pans and firefighting foams – have been found in “sentinel” reptile species, which the researchers said were useful for investigating long-lived chemicals in the environment.

The chemicals found in 45 crocodiles at sites in and around the Kruger Park have been linked to liver toxicity, reduced fertility and other problems in studies of people and animals.

A team from Hollings Marine Laboratory in Charleston, US, also found the perfluorinated alkyl acids, or PFAAs, in 125 alligators across 12 sites in Florida and South Carolina.

In the South African crocodiles, levels were highest in reptiles that live in and around Flag Boshielo Dam, on the Olifants River near Marble Hall in Limpopo.

The highest level of PFAAs recorded there was 118 000 parts per trillion, while the US Environmental Protection Agency’s human drinking water limit is 70 parts per trillion.

The researchers said this pointed to the presence of a single source of PFAAs in the area around the dam and there may be a need to test the safety of drinking water in the area.

“Alligators and crocodiles play a dominant role in their ecosystems,” US researcher Jacqueline Bangma said.

“Similar to humans, they are long-lived top predators. They stay in a select territory – waterways where runoff from human activities accumulates – and their PFAA burden increases through the consumption of fish.”

It has also been found that amphetamine concentrations in streams in the US state of Maryland are high enough to alter the base of the aquatic food web.

Environmental Protection Agency scientist Sylvia Lee said: “Wastewater entering surface waters contains pharmaceuticals and illicit drugs. We were interested in revealing how amphetamine exposure influences small plants and animals that play a large role in regulating the health of streams.”