What are Tarballs, often seen on Mumbai Beaches

Recently, black oil-emanating balls were seen, lying on the shore of some of the Mumbai Beaches. This has drawn the ire of experts and citizens, who said that the problem needs an urgent fix to curb the impact on both marine ecology and public health.

In Mumbai the tarballs have been washing up on city beaches for several years during the monsoon, when strong onshore winds and changing currents bring them to shore

Tarballs:

The Tarballs are dark-coloured, sticky balls of oil that form when crude oil floats on the ocean surface. Some of the balls are as big as a basketball while others are smaller globules, they are usually coin-sized and are found strewn on the beaches. They are formed by weathering of crude oil in marine environments.

How are They Formed:

Wind and waves tear the oil slick into smaller patches that are scattered over a much wider area. Various physical, chemical and biological processes (weathering) change the appearance of the oil. Bunker oil and ballast water discharged into the open sea can also lead to the formation of tarballs, which can be as small as coins or as large as footballs, in other instances, they may emanate naturally from seepages in the ocean bed

Oil Spills and Tarballs:

Most of the time, the presence of several tarballs indicate an oil spill. However, its annual occurrence on the west coast during the monsoon has led marine biologists and experts to demand an investigation in the matter. Oil-well blowouts, accidental and deliberate release of bilge and ballast water from ships, river runoff, discharges through municipal sewage and industrial effluents” also leads to the formation of tarballs.

Concern:

Coastal Tarballs can get stuck to the fishing nets, making it difficult for fishermen to clean. In addition, it can affect marine life. Tarball pollution is a major concern to the global marine ecosystem. Tarballs are difficult to break down, and can therefore travel for hundreds of miles in the sea.

Recently, it was observed dead fish lying amid tar deposits in Mumbai, also a sea turtle was rescued covered in oil and a finless porpoise (protected under Schedule I of the Wildlife Protection Act, 1972) was found dead on Juhu beach amid oil deposits. However it can't conclusively say that the porpoise was dead by Tarballs.