Researchers call for cleaning of beaches to avoid tar-balls impact

Researchers call for cleaning of beaches to avoid tar-balls impact
SHWETA KAMAT
PANJIM, OCT 12
The Ocean Researchers have warned that prompt cleaning of the beaches need to be done to avoid long term impact of tar-balls.
The researchers have also suggested that if required even a top layer of the sand should be replaced.
“If the concentration of tar-balls is severe, the top layer of sand containing the tar-balls may be removed and replaced with clean sand. The need mostly arises when freshly formed tar balls, which are soft and brownish in colour, get deposited on the beach,” National Institute of Oceanography (NIO) scientists Dr X N Verlencar and Dr Classy D’Silva has said in their paper.
The scientists believe that the soft tar balls have tendency to melt with the heat of the sun and the petroleum materials present, get absorbed in the sand. 
“Such tainted sand should be removed so that the petroleum does not pose threat to the sand dwelling inter-tidal organisms such as worms,” the paper reads.
South Goa’s beaches had reported unprecedented amount of oil slick and tar-balls ahead of tourist season raising concerns.
NIO, which has predicted two possible reasons for a tar-ball appearance on the beaches, has said that the dumping of oil mid-sea by ship has resulted in the mess on the shore.  The second reason can be attributed to ship mishap.
“Unscrupulous ships violate international rules regarding when, where, and how to clean tanks. Such behaviour can lead to appearance of tar-balls on Goan beaches,” NIO, which has been studying tar-ball appearance since 70s, stated. 
Explaining about the process, scientists have stated that after a spill, initially, the lighter components of the oil evaporate much like a small gasoline spill. In the cases of heavier types of oil, such as crude oil, much of the oil remains behind.
“At the same time, some crude oils mix with water to form an emulsion that often looks like chocolate pudding. This emulsion is much thicker and stickier than the original oil. Winds and waves continue to stretch and tear the oil patches into smaller pieces, or tar-balls,” the paper added.
While some tar-balls may be as large as 30 cm in diameter, most are coin-sized or a bit bigger.
NIO said that the direction of movement of floating tar-balls is very much dependent on winds and waves on the surface of a sea and on currents.
“Stronger and more persistent the wind, faster is the movement of a tar-ball.  Waves on sea surface can also push tar-balls in the direction in which the waves go. Stronger the waves, more effective they are in transporting tar-balls,” they said.
On why the occurrence of tar balls formation is higher during May-October, researchers say that normally winds start blowing towards the coast in May. 
“They keep getting stronger as the monsoon sets and are strongest in July-August.  In September and October the winds weaken, and by November they are no more oriented towards the coast,” scientist said.
As such, under the influence of winds, and to a lesser extent that of waves, tar balls formed from an oil slick, gets transported towards the coast during May-October.