The number of dead pigs found in the Huangpu River, which supplies over a fifth of Shanghai's drinking water, has risen to almost 15,000. More than 10,000 carcasses have been found in the Huangpu River in Shanghai in the past two weeks, and another 4,600 in Jiaxing in Zhejiang Province, 100 kilometers southwest. Shanghai authorities said they are investigating any potential health hazards. Tests on water and food supplies have been intensified. A swine virus has been found in some carcasses but, according to the authorities, it cannot be transmitted to humans. The pigs are believed to have come from Jiaxing. Eight farmers have been fined for improperly disposing of carcasses. What do Shanghai expat residents think? Are they worried about any potential dangers for their health?

Brian Colin, from France, banker

"The pollution of rivers in China is something I worry about. First, because of the effect it has on potentially everyone - everybody takes a shower or drinks boiled water from the tap, which comes from the Huangpu River. Second, because no responsible person has been found yet, and we do not know the cause of death of the pigs. Finding thousands of cute (dead) piglets in a river is something very unusual and revolting, and it made the news all over the world.

But I am even more concerned by the chemicals and detritus which are dumped in it. I worry about the capacity of people to be able to change their mindsets and take the environment as something as important as their own family. There is still a long way to go before the authorities fully enforce strong laws against pollution!"

Marco Schweighauser, from Switzerland, project manager

"I was not very surprised when I read the story about the dead pigs found in the Huangpu River the first time. The immense size of this incident is probably the only reason it went public.

What strikes me odd is that still, as of today, no real progress has been made finding the people responsible for it. It is very difficult to understand how there can be no evidence or witnesses about this crime as it takes days, many trucks and a lot of people to throw more than 10,000 pigs into the river. The Chinese government should perhaps declare a bounty on information to speed up the investigation.

As the Huangpu River is polluted with different kinds of chemicals and metals, I do not think the dead pigs are much more of a concern regarding the water pollution. The city will probably already do a lot to clean the water and filter it before it is used for the fresh water supply.

In general, for every big city of this size, it's a good idea not to drink from the tap anyway. I'm wondering about the safety of products which are made and sold by private companies. If even the city government cannot guarantee unpolluted water or food sources, I don't think those companies can or will do this better."

Daniel Cheng, from Russia, student

"The stories about the dead pigs floating on the Huangpu River these past two weeks disgust me! I am really worried about the pig pollution problem. But to be honest, I wasn't very surprised that something like this has happened.

It is not the first time this year that Shanghai is tackling a water pollution problem. I remember a few months ago a chemical transporter leaked benzene into the Huangpu River and residents nearby the area were left without tap water for days. It is about time the Chinese government took some measures to tackle issues like this. They need to think about how to balance China's economic development with environmental concerns. New laws and regulations concerning pollution are needed as soon as possible.

The most worrying thing is the fact that still, today, nobody knows what happened, who is responsible, what was the cause of the death of those pigs and also the fact that more dead pigs are being found every day.

Shanghai authorities are saying that there is no health threat in the city's water but I am still very anxious about whether or not it is safe to use it. This affects everyone living in Shanghai as we all use tap water to have showers or wash our clothes. I would really like to see the authorities investigating this incident thoroughly and punishing those responsible for what has happened."