Pharmaceutical residuals found polluting marine life on Israel's coasts

Unlike other pollutants, pharmaceuticals, which are not fully metabolized in the body, are designed to affect biological systems in even very small amounts.

Prof. Noa Shenkar sampling ascidians. (photo credit: TOM SHLESINGER)
Prof. Noa Shenkar sampling ascidians.
(photo credit: TOM SHLESINGER)
Residuals of three commonly used pharmaceuticals have been found at 10 different sites along Israel's coast, discharged into the sea from the sewage system and potentially causing severe damage to local marine life, according to a new study from Tel Aviv University.
The study, which was a multidisciplinary effort from Tel Aviv University and published in the academic journal Marine Pollution Bulletin, examined 11 sites along the coast. Nine of these sites (Acre, Haifa Marina, Sdot Yam, the Hadera power station, Herzilya's Acadia beach, Ashdod Marina, Ashkelon Marina and the HaSelah beach in Bat Yam) were on the Mediterranean coast, while two (Dolphin Reef and the Eilat Marina) were on the Red Sea.
The researchers, led by Prof. Noa Shenkar and graduate student Gal Navon from AU School of Zoology and the Steinhardt Museum of Natural History, found concentrations of pharmaceutical residuals in marine life, specifically in ascidians – a type of filter-feeding invertebrate that is only a few centimeters in size and can be found in the water attached to hard surfaces, like rocks or piers. As ascidians filter-feed from the water, their bodies often accumulate particles from different elements and substances found in the local marine environment, including pollutants.
While analyzing the ascidians, the researchers searched for three specific active compounds frequently used in pharmaceuticals. These include Bezafibrate, which is commonly used to reduce blood lipid content; Carbamazepine, which is used as a mood stabilizer and antiepileptic; and diclofenac, which is used as an anti-inflammatory agent.  These three compounds are extremely durable, and are not fully metabolized by the human body. As a result, they get expelled from the body as waste, leading them to be sent into the sewage system and then the ocean.
All three substances were found from samples from Ashdod, Ashelon, Haifa and Sdot Yam. Five sites – Achziv, Acre, Herzliya, Bat Yam and the Eilat Marina – only had residuals of two of the substances. The Dolphin Reef site only had residuals of one compound, Diclofenac, but it was a "concerning concentration." Especially high concentrations of Diclofenac and Bezafibrate were detected in Acre, Ashkelon and Ashdod.
The Hadera power station, however, had no traces of any pharmaceutical residuals, though the power plant, which uses coal in electricity production, has reputation of being a significant source of pollutants in its own right.
While pollution is bad enough, pollution of pharmaceutical residuals has the potential to cause severe damage to marine life. This is because unlike other common sea pollutants, pharmaceuticals are specifically designed to affect biological systems in even very low amounts.
In addition, this isn't a problem exclusive to Israel, with the researchers emphasizing the fact that the residuals of a wide variety of different pharmaceuticals can be found in marine environments across the globe. This is due in part to lack of awareness seeing people often deposit unused pharmaceuticals in toilets or garbage bins, and because sewage treatment plants are not suited to properly dispose of pharmaceuticals, with these residuals not properly monitored at the sewage treatment endpoint like other pollutants are.
"Many of these compounds are very stable," the researchers explained in a statement.
"These take a long time to degrade in the marine environment, and the damage they cause to marine life could be extremely excessive, since these pharmaceuticals are designed to affect biological systems [the human body]. For example, various studies performed in different sites around the world have shown that Estrogen, present in birth control pills, leads to the development of female features in male fish in certain species, thus damaging their fertility; Prozac triggers increased aggressiveness and risk-taking in crustaceans; anti-depressants impair memory and learning in cuttlefish, and more.”
"We have been studying the chemo-physical fate of drug residuals in groundwater and surface water for the past 15 years, and their detection in marine ecosystems has been surprising," explained Prof. Dror Avisar, head of TAU's Hydrochemistry Lab of the Water Research Center of the TAU Porter School of Environment and Earth Sciences, Raymond & Beverly Sackler Faculty of Exact Sciences, who had participated in the study.
"The results indicate a chronic large-scale pharmaceutical residual contamination, as well as the absorption of micro- and nano-pollutants, measured at very low concentrations in marine organisms."
"Our study shows that Israel is no stranger to the global serious issue of seawater pharmaceutical contamination," Shenkar said.
These findings are especially troubling for much of the marine life found near Israel's coast. However, the implications don't just reflect a danger to marine life, but to humans as well.
“The medications we use end up in the sea, mainly through sewage discharge, and cause great damage to the marine environment, indirectly affecting humans, who feed on seafoods that are exposed to such contamination," Shenkar explained.
"There are different ways to tackle this problem: on the individual level, we recommend that the population as a whole takes personal responsibility, disposing of unused pharmaceuticals into designated containers – which can be found at pharmacies and health maintenance organizations' facilities. In addition, we are working to expand research on monitoring pharmaceutical contamination along the Israeli coastline, using advanced analysis of a greater variety of widely used medication, while examining the changes exerted upon the various organisms exposed to the environmental concentrations of those pharmaceuticals."