CRI听力:Environmental impact of sunken Iranian oil tanker minimal: experts

Chinese authorities are suggesting the environmental impact from the sinking of an Iranian oil tanker off China's east coast this week is likely to be minimal, despite the massive blaze which engulfed the Sanchi for over a week before it went down.

The Iranian tanker went down on Sunday, nearly eight days after it collided with a bulk freighter on the evening of January 6th, some 160 nautical miles east of Shanghai.

The tanker was carrying around 136,000 tons of a light crude oil known as "condensate" to South Korea when the collision took place.

This created a subsequent fire which burned for over a week before an explosion on Sunday morning sealed the ship's fate.

Chinese chemical expert He Wang says the overall impact from the fire has had little effect on the environment.

"When condensate burns, it generates sulfur dioxide, which is a component of our air. The actual amount of sulpher in the condensate was around 0.26 percent, which means the ship was only carrying a few hundred tons of sulphide materials. Because it turns into sulfur dioxide, the condensate actually only weighs around only 1,000 tons. This is similar to the emissions of a power plant over just a few months."

Besides the impact on the atmosphere, pollution affecting the fishing industry is also among the concerns. 

The Zhoushan fishing ground, off the coast of Zhejiang province, is about 350 kilometers from where the tanker sank.

The fishing ground is one of the largest in the East China Sea. And the East China Sea was China's biggest fishing ground in 2016 with a catch of about 5 million tons. 

Chinese maritime authorities have reported signs of expanding oil spills near the sunken vessel. 

However, experts say most of the condensate, a volatile crude oil, may have been burnt in the fire, while most of the spilled oil will evaporate into the air. 

According to some estimates, a proportion of the spilled condensate will dissolve into the water, and this will be toxic until it dilutes enough to be broken down by natural processes. 

The process should be quite quick. 

A chief ship officer says the the contamination is likely to be limited. 

"The condensate will have an initial impact on the livelihood of fish around the immediate area. However, this is only going to affect aquatic life near the surface. Condensate is light, and evaporates, meaning its not going to go deep into the ocean." 

Despite the minimal effects on the environment, the incident has taken a human toll.

All 32 crewmembers aboard the vessel, including 30 Iranians and two from Bangladesh, have been declared dead.

Only three bodies were recovered before the Sanchi went down.

The rest of the crew is believed to have been trapped inside the ship when the fire broke out.

Rescue crews were able to retrieve the tanker's audio voice recorders - the maritime version of a black box.

It's hoped this will provide critical information as to what led to the disaster.