In the pre-monsoon and during monsoon seasons (May to October) the brown, sticky and foul smelling tar balls reaches the sea shores. Many beaches across the world have been facing this acute problem.
Tar balls pollute beaches and disturbs marine ecosystem.
What are Tar balls?
Tar balls or globs are oil residues made up of hydrocarbons.
The type of hydrocarbons found in tar globs is same as that of the ones present in crude oil and petroleum products. . Their size typically ranges from as small as a small coin to as big as 30 cm. Their reaching the shore makes the site of the serene beaches extremely unpleasant and filthy.
Tar ball pollution is a matter of concern not just because of the aesthetic point of view. Instead because their constituent chemicals ‘hydrocarbons’ are a threat to sensitive marine ecosystem such as molluscs and shrimps.
Loss of these organisms may adversely affect fish that feed on them and may disturb the entire food chain. Tar globs harmful for the biodiversity of the marine ecosystem.
Tar balls washed up on the beaches in Goa (India)
In India tar balls come to the beaches on west coast of India during the southwest monsoon. Since 1970 the tar globs have been seen regularly in the pristine beaches of Goa.
Similarly since last seven years the unusual tar globs are been reported from the Juhu beach of Mumbai (India) .
Where do Tar Balls on the Beaches come from?
The reason behind this annual phenomenon could be the washing of the tanks of the ships and boats in the sea a few kilometres offshore.
The untreated oil coagulates in sea and forms tar balls. During the monsoon season some of it may reach to the shore due to monsoon winds. However, this is not the only reason behind the tar globs.
Suneel and his associates tried to find out the origin of tar balls reaching the west coast of India since 2012. They are associated with National Institute of Oceanography (Goa). The results of the study were published in the Journal ‘Science of The Total Environment’ in 2015. They collected tar ball samples from as many as 9 beaches of Goa along with crude oil samples from various oil fields such as from Bombay High and grounded ships. The technique used to identify the source of the oil in the tar globs was ‘Multi-marker fingerprint technique’.
The study suggests that Tanker-wash is not the only source of tar balls deposited on the beaches of Goa. It says that the tar balls have their origin in Bombay High oil field. The oil released from Bombay high oil fields in the Month of April took South western direction and took approx 1 month to reach the Goa coast due to monsoon circulations.
Reasons behind Tar balls reaching beaches in California (USA)
In April 2016 tar balls were reported on various beaches of California (USA). Similarly in 2015 tar globs were reported on the Los Angeles-area of southern California.
Later laboratory testing of the tar globs confirmed their source. The source of some of the globs was spilled crude oil from a ruptured pipeline approx. 100 miles away along the Santa Barbara coast.
According to the reports Four-Mile Stretch of Long Beach Coastline had to be closed due to tar balls cleanup in southern California’s beaches.
After a week tar balls were again washed up in Long Beach area a little farther than the previous one. Samples of the tar balls were collected. It turned out that while some samples matched with the oil spilled from the pipeline operated by Plains All American Pipeline, some other matched with the naturally occurring fissures in the seabed along the Santa Barbara coastline.