The spectacled caiman, a small cousin of the crocodile, lives on thousands of protected acres in Costa Rica‘s Tortuguero Conservation Area. Recent research published in Environmental Toxicology suggests that living on such protected lands may not be enough to keep caimans and other animals from harm. Scientists from the University of British Columbia have found elevated levels of pesticides in caimans in the reserve; one likely source of the chemicals is the banana plantations located upriver.
Bananas are so commonly available in the United States that it is easy to forget that to eat one is to do the exact opposite of eating locally. As Ars Techica notes, we import millions of bananas every year and expect them to be free of bruises and brown spots.
Growers rely on plenty of pesticides to produce this “commodity fruit.” The plantations mostly grow the Cavendish variety, to provide us with uniformly-shaped yellow fruits. Because Cavendish bananas are seedless, they must be produced with cutting techniques with the result that “all the plants are very closely related, genetically, which creates an easy target for fungus and insects.”
Pesticide use has doubled in Central America in just the past 20 years, not only to keep up with the global demand for bananas but because the heavy tropical rainstorms often wash away the chemicals that growers apply. Pesticide runoff has been linked to the death of fish in the area — and those fish are a major food source for caimans.
Tests on Caimans Find Chemical Contamination
To see the possible risk of pesticide exposure in the ecosystem’s inhabitants, University of British Columbia scientists actually caught 14 caimans (six from areas directly affected by chemical runoff and eight that were in less-affected places) and tested them.
14 is not the biggest sample size. Given that the scientists had to actually catch the 4-to-6-foot long, 80 pound caimans at night (when their red eyes can be seen to glow) and by hand, testing a relatively small number was a practical way to get an idea of possible toxicology levels.
From taking body measurements to asses the caimans’ general health as well as blood samples, the scientists found that all the animals had elevated levels of legacy and current use pesticides; Ars Technica says:
The analysis looked for 70 chemicals of interest, and nine were found, including DDT and other pesticides that are currently banned. They also found legal pyrethroid insecticides. As would be expected, they found more pesticides in the blood of the caimans who lived more directly downstream from the plantations.
The caimans are most likely not being directly exposed to chemicals. The presence of such high levels of chemicals in their blood is most likely due to their eating contaminated fish; it also suggests that other aquatic animals are at risk from exposure to pesticides.
The research published in Environmental Toxicology raises further questions about how safe Costa Rica’s famously biodiverse wildlife is and what measures the government is taking to protect it. Just recently, Costa Rica’s Environment Minister announced that he planned to close the country’s two government-funded zoos.
As Care2 blogger Susan Bird noted, while this might seem like a positive step, many of the zoos’ animals are actually “rescues” who need protecting (from poachers and those who would keep them as illegal pets) and rely on the medical and other care that zoo staff provide.
As the scientists from the University of British Columbia write, their findings cast a harsh light on the “moral sustainability of banana agricultural production.” Any of us who consume bananas needs to pause and think about where these fruits are coming from and what methods were used to get them from a banana plantation to our shopping carts. Organic bananas produced without chemicals may cost a little more but buying them is a small way of showing support for sustainable, ethical farming practices.
Which would you rather have: a pile of cheap, chemically-produced bananas or the real satisfaction of knowing that unique crocidilians, the caimans, are living safely in Costa Rica?
Photo from Thinkstock