Crocodiles in a South African national park suffer from tooth loss and anemia because of the high lead content in the water.
This is what scientists from three South African universities and the National Institute for Biodiversity found out in a recently published study.
Some of the "highest lead concentrations in crocodiles in the world" were detected in the wild crocodiles examined.
Absorbed for decades
Political correspondent for Africa based in Cape Town.
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Some animals would have ingested the toxic metal for decades.
Sport fishing has been practiced in the area since the 1930's, with anglers using lead weights to cast the rod and weigh down the bait.
The researchers examined the blood and tail fat tissue of 25 Nile crocodiles, 22 wild animals and three farmed animals.
Lead has been detected in the blood samples of all wild crocodiles.
Lead in nature is a problem for many wild animals.
The effects on reptiles have so far only been insufficiently documented, it said.
Crocodiles accidentally pick up the lead weights.
The animals eat rocks at the bottom of bodies of water to reduce their body's buoyancy, allowing them to better ambush prey.
The stones also serve - as with some birds or dinosaurs - for better digestion.
Normal stones dissolve the stomach acid after a while.
The lead, on the other hand, remains in the bones of the crocodiles and damages the teeth, the researchers explain.
In severe cases, this can lead to food problems and ultimately the death of the animals.
“We found that several of the male crocodiles examined had broken or missing teeth.
One crocodile appeared unusually pale and showed clear signs of lethargy both when captured and when released.
We suspect the animal was suffering from severe anemia.”
The scientists are calling for anglers to be banned from using lead weights.
There are alternatives that are not toxic and are already common in other countries.
Around 1,000 crocodiles live in the St. Lucia Lake District, some of which grow up to four meters long.
The lake is also home to the largest nesting population of crocodiles in South Africa.
In 1999, the Greater St. Lucia Wetland Park was designated a World Heritage Site by UNESCO.Keywords: