Not yet clear how much oil remains in water, sediment and seabed

By HADASSAH BRENNER   APRIL 2, 2021

When Israel’s beaches turned black two months ago, the country faced a massive ecological disaster: the oil slick off Israel’s coast polluted the waters, and storm currents deposited 750 tons of tar along 160 km. of coastline.As the “Tar in the Storm” incident wreaked havoc on its beaches, Israel jumped into action to remedy the effects of the Tier-2 level pollution, with experts tackling environmental, financial, and political repercussions of the oil spill. Concerns were raised at a webinar held last month on changes caused by oil spill pollution featuring a panel of international researchers of the previous major oil spills Deepwater Horizon, Ixtoc-I and Exxon Valdez.Biologist Dr. Steven Murawski from the University of South Florida presented some key questions Israel must address: is the seafood safe to eat? Is it safe to swim and use other natural resources? How fast will oil go away? What marine resources will be affected, and for how long? How will coastal communities be affected in the short- and long-term? Are we better prepared for the next oil spill (which will occur)?”

Is the seafood safe to eat?

The Health Ministry declared Israel’s fish and seafood safe to eat on March 9 after sampling fish species over the course of a month.“There weren’t any fish deaths, and we didn’t see any contaminants in their tissue,” explained Dr. Peleg Astrahan, an organic chemist at the Israel Oceanographic and Limnological Research Institute. The IOLR sampled water and fish throughout Israel’s coast over many days and found no concerning levels of pollutants.There is still a danger that small amounts of petroleum hydrocarbons from the spill will become more concentrated as they make their way up the food chain. While there is no evidence of immediate damage to sea life, IOLR will continue to conduct surveys on fish and marine species in the case that this occurs, said Astrahan.

Is it safe to swim and use other natural resources?

“We couldn’t see any chemical changes,” said Dr. Eyal Rahav, head of the Biology Dept. at IOLR. The lab has autonomous underwater robots with carbohydrate sensors that measured the entire water column.Rahav, who researches the effects of crude oil on marine micro-organisms, explained that if that water was badly polluted it would quickly affect the bottom of the food chain. However, he found no “significant change or decline in productivity or biomass.”While the chemical makeup of the water has not changed, tar is still washing up on shore. Surfers from Herzliya reported this past week that they came out of the water with their boards and legs entirely black, even after the Health Ministry reopened the Mediterranean to water sports on March 9. Lifeguards at the Acadia beach said some swimmers are still experiencing burning eyes, dizziness and headaches.

What marine resources will be affected, and for how long?

Since much of Israel’s water comes from desalination plants, another fear was that such pollution would overload their filters. It seems, however, that the plants have fared well despite the pollution.“We were lucky that in this [recent] event, it was tar, which tends to go directly to the beach and not into the intakes of the desalination plants,” said Rani Amir, director of the ministry’s Marine Environment Protection Division.

How fast will oil go away?

The aftermath of the oil spill is difficult to predict, as it is not yet clear how much remains in the water, sediment and sea-bed.“I expect to find some of the pollution in sediments and the deep sea,” Rahav predicted of the upcoming sea dives to survey the ocean floor. The expedition is expected to take place in the coming month. Scientists will “collect sediments and look for chemical signals of crude oil and see if bacteria were affected by the pollution.”Rahav is concerned about the MOSSFA (Marine Oil Snow Sedimentation & Flocculent Accumulation) phenomenon that causes oil to sink down and cover the sea floor, like snow. This accumulation has the potential to remain for years, and could contaminate fish species that find their food in sea floor micro-organisms.Another marine habitat that could retain the pollution much longer is the “hedge table” – rocks along the coast that house many sedentary species.“The rocky area is characterized by daily cycles of tides where ‘hedge tables’ are formed, where most of the biological activity is concentrated,” Dr. Joshua Shakedi, chief scientist of the Nature and Parks Authority solemnly announced in February. “The pollution…covered and suffocated the animals clinging to the rocks…Only the removal of the tar will allow the algae and animal society to recover on the coastal rocks.”Shakedi suggested that the tar-covered areas be mapped and the rocks be cleaned, “stain after stain,” which will take months to cover manually.Weather factors such as waves, sun, chemical makeup, etc. will also affect the rate at which the oil and tar break down. There are many micro-organisms in the ocean that can digest hydrocarbons from the crude oil as well.Over time, “the ecological system fixes itself on its own,” said Astrahan. Only continued research will reveal when Israel’s coastline will fully recover.

How will coastal communities be affected in the short- and long-term?

Of Israel’s 101 official beaches, 82% of them have passed the “tar index,” after massive cleanup efforts scoured the shoreline to collect tar waste. With the help of volunteers, government officials and the Environmental Protection Ministry, 61% of the beaches have been cleaned with barely any residue left, and only 3% are still closed due to the pollution.The Environmental Protection Ministry has uploaded an interactive map of safe beaches that are now clean and open to the public.

Are we better prepared for the next oil spill (which will occur)?

Following the oil spill, Israel passed a Memorandum of the Preparedness Law and Response to Incidents of Marine Pollution and the Coastal Environment in Oil. It will develop an emergency plan for maritime disasters using advanced technology, ships and assignment of responsibilities to regional bodies affected by the disaster. The law also established the Fund for the Prevention of Marine Pollution, which will have a NIS 25 million budget.Additionally, the Environmental Protection Ministry launched an investigation into the source of the pollution. Through retrospective mapping of the spill, it found the “crude oil tanker called Emerald…illegally carrying cargo from Iran to Syria” to be responsible for polluting Israel’s coast on February 1 and 2, Environmental Protection Minister Gila Gamliel informed Israelis.Israel is working to “claim compensation for the severe damage to Israeli shores,” she announced on March 16. The insurance claim is in compliance with the 2004 Liability for the Compensation for Oil Pollution Damages Law, and will help Israel rebuild from the damages and invest in its newly established prevention plan.Since the Emerald had turned off its AIS (automatic identification system) in a deceptive shipping practice intended to hide its exportation of oil to Syria, the tanker was not discovered until it was too late. Had there been efficient satellite observation of coastal waters, Israel could have detected the spill at the source, said Ami Daniel, CEO of Windward. His company helped Israel analyze and identify the tanker with retrospective satellite imaging and artificial intelligence.Rahav explained how crucial early detection is in containing oil spills. “When it’s at sea, there are ways to clean most of the oil,” he said, but since there are hundreds of tankers passing through the Mediterranean, preparing for the next one is a must. “It’s just a matter of time,” he warned.Daniel is hoping Israel will employ optical satellites and surveillance to help keep tabs on all 2,500+ vessels passing its shores each year, even those that turn off their AIS. Windward’s AI technology can also identify every ship in the sea and the cargo they are transporting.“The strength of our research is our partners and collaborators, looking at a problem through multiple perspectives (biologists, chemists, geologists, engineers),” Murawski told last month’s oil spill panel. “Oil spills do not respect territorial boundaries. And so we need a more integrated multinational approach to this.”It seems Israel has followed Murawski’s advice well, calling upon scientists, engineers, government officials, and international bodies to combat the ecological disaster and ensure that the county is better equipped for the next tanker spill in its waters.•

https://www.jpost.com/israel-news/when-will-israels-beaches-recover-from-the-tar-spill-663893