Comprehensive coverage

Antibiotics and laxatives - in corals at a depth of 40 meters

For the first time in the world, we tested drug residues in corals on a large scale," says Prof. Noa Shankar, the research leader at Tel Aviv University. "Whoever eats fish, puts into his body all the remnants of the drugs that the fish absorbed."

Corals saturated with drugs in the depths of the Gulf of Eilat. Photo: Tel Aviv University spokesperson
Corals saturated with drugs in the depths of the Gulf of Eilat. Photo: Tel Aviv University spokesperson

Serious environmental pollution: a new study by Tel Aviv University and the Steinhardt Museum of Nature discovered residues of ten common drugs in corals sampled in the shallow waters - and even deep waters - in the Gulf of Eilat. Sulfamethoxazole, an antibiotic used for urinary and respiratory tract infections, was found in no less than 93% of the corals sampled.

The alarming research was conducted under the leadership of Prof. Noa Shankar and PhD student Gal Navon from the School of Zoology and the Steinhardt Museum of Nature at Tel Aviv University, in collaboration with the Hydrochemical Laboratory headed by Prof. Dror Avishar at the Porter School of Environment and Earth Sciences at Tel Aviv University. The results of the study were published in the prestigious journal Environmental pollution.

"For the first time in the world, we tested drug residues in corals on a large scale," says Prof. Noa Shankar. "We sampled 96 corals from two types of stony corals in the Gulf of Eilat,Acropora  and-favorites, in shallow water of 5-12 meters and in deep water of 30-40 meters - which is beyond the limits of sports diving. To our surprise, we found drug residues on a large scale even in the deep corals, which usually manage to escape infections that affect the shallower corals."

The researchers received a list of the most common medications in Israel from the Klalit Health Fund. Of the 18 drugs selected, ten were found in corals, and there was not one coral in which no drugs were found at all - whether in the shallow water, or in the deep. The ten drugs found in the coral's body belong to diverse categories: antibiotics, antihypertensive drugs, antiplatelet agents, calcium channel blockers, laxatives, proton pump inhibitors, statins and antidepressants.

Dr. Noa Shankar dives to investigate stone corals in the Gulf of Eilat. Photo: Tel Aviv University
Dr. Noa Shankar dives to investigate stone corals in the Gulf of Eilat. Photo: Tel Aviv University

"What are drug residues in corals? After all, the coral didn't go to the doctor and get a prescription for antibiotics," explains Prof. Shankar. "These are drugs taken by humans, drugs that were designed in advance to act on some receptor or biological pathway - and they also act on other animals. Previous studies, ours and those of others, have shown, for example, that estrogen found in birth control pills creates female characteristics in male fish, and therefore impairs the reproductive capacity of certain species, that Prozac causes aggressiveness and risk-taking among crabs, and that antidepressants impair the memory and learning ability of squid - and there is no reason to assume that the coral somehow immune to such effects. For example, if our drugs cause problems in synchronizing the reproduction of the corals - this is a problem that will take a long time before we notice it, and then it may already be too late."

"Stone corals are reef-building corals, and the types we chose for the study are among the most common in the Gulf of Eilat." Gal Navon adds. "Coral reefs are critical to the diversity of life in the sea. They provide food, shelter and breeding areas for many species, and support human livelihoods through fishing and tourism. This delicate ecosystem is under pressure from the effects of climate change, pollution and overfishing. The discovery of the drugs in the coral tissues adds another layer of concern, and indicates that human activity also pollutes remote marine environments."

"It is important to understand that these are life-saving drugs, and we have no intention of telling anyone to reduce their use," says Prof. Shankar. "But we do need to think about sewage treatment methods that will treat the drugs - and yes, each of us should be careful to dispose of the old drugs in a way that does not harm the environment. Eventually these drugs come back to us. I know people who really don't want to take medicine, but when they eat fish - they don't actually know they're eating a 'cocktail' of drug residues that the fish absorbed from the environment".

More of the topic in Hayadan:

Leave a Reply

Email will not be published. Required fields are marked *

This site uses Akismat to prevent spam messages. Click here to learn how your response data is processed.