I have had several inquiries as to the "environmental" toll of the Wenchuan earthquake. The short answer is it is hard to say. Defining "environmental" damage in this situation is problematic. A landslide that occurs in an unoccupied area may cause extensive damage to the pre-existing environment, but I don't think that is what most people mean or, at least, should mean when they speak of environmental damage. When nature harms, or let's use a less loaded word, changes nature it is hard to speak of "damage" unless one has, irrationally, assumed that any given temporarily static state of nature represents an eternal "natural" state.

However, even if we adopt a definition of earthquake induced "environmental damage" as a sudden increase (above pre-earthquake baseline levels) in the damage to the environment caused by human activity (which, of course is also a "natural" activity, but I won't take that argument further here), it is still hard at this stage to assess the extent of the damage, but they do not appear to be catastrophic.

The most immediate concerns would be acutely toxic air emissions (Bhopal-like), drinking water contamination, and radiation leaks.  I have not heard reports of any harmful air emissions.

As to drinking water it has been reported that:

Water supply to the populous cities of Chengdu and Chongqing was largely unaffected by the 7.9-magnitude earthquake that struck a wide swathe of northern Sichuan on May 12.

But in smaller towns, like Yingxiu near the epicenter, unclean drinking water is a growing problem for locals and for the refugees trekking in from flattened villages up in the mountains.

In Yingxiu, accessible only by foot in the days after the quake, the only available bottled water appeared to be that scavenged from wrecked homes and hotels.

The source of the drinking water contamination is unclear. I suspect in many cases the drinking water delivery system (pipe network) has been disrupted, and residents have had to resort to open, untreated surface water sources. These sources are easily contaminated with runoff containing, for instance, human and animal waste and lime and anti-bacterial agents used in earthquake remediation efforts.

Given the magnitude of the quake (and the lack of reliable containment structures at most Chinese industrial concerns), there is little doubt that burst process pipes or tanks and vessels at chemical plants, manufacturing facilities, sewage treatment plants, and gas stations, pipelines and terminals have also released pollutants that have made (or will make) their way to drinking water sources. The Ministry of Environmental Protection (MEP) has invoked its water pollution prevention contingency plans in the quake region, and has allocated

35 million yuan ($5 million) to the prevention and control of pollution-related accidents, which could occur in Sichuan province in the wake of [the May 12] earthquake.

Monitoring equipment worth 10 million yuan has been sent to the worst-hit areas, and will be used to treat drinking water and provide protection from pollution caused by pesticide, fertilizer and chemical leakages, and damaged nuclear facilities, it said.

However, Shanghai Daily reports that:

The Ministry of Environment Protection today [May 14] denied a rumor that Chengdu's supply of water was polluted by a chemical plant explosion caused by Monday's earthquake. The rumor caused panic buying and hoarding among residents in the capital of Sichuan Province.

Chengdu's water is safe, the ministry said in a statement.

The ministry said the earthquake damaged a total of three plants in Shifang City and Deyang City, which caused a sulfuric acid and ammonia leak.

The Southwest Environment Protection Monitoring Center launched emergency response procedures after the leaks and took measures to clean water downstream. Tests proved the water met standards except for in some areas of Deyang.

The Shifang and Deyang City chemical fertilizer plants are the only industrial facilities that I have seen publicly acknowledged to have suffered damage and released pollutants as a result of the earthquake. Caijing Magazine has a good story on the damage to the Shifang plants if you're interested.

There was also a report in the United Nations OCHA Situation Report No. 2 that

damaged railway tracks have caused a 40-car freight train carrying gasoline to derail and catch fire in Gansu province. The train burst into flames on Monday and was still burning on Tuesday evening, more than 26 hours after the accident. Fears that the tank cars could explode forced more than 900 local residents to be evacuated from the area.

There have to be other instances of pollutant releasing quake damage, but unless the pollutants released caused immediate and significant human harm, I can certainly understand that there are more important issues to report on at this point. Fortunately for the residents of this devastated region, it was not heavily industrialized.

As to radiation leaks, the situation is a little cloudier (as it is always and everywhere with radiation). "The region has some key atomic sites and the country's chief nuclear weapons research lab," and China has said has activated its contingency plans for nuclear and radiation pollution reports The Hindu. It also states that

China has so far recovered 30 of the 32 radioactive sources which were buried under the debris during the devastating May 12 earthquake, Minister for Environmental Protection Zhou Shengxian said.

He said locations of two other radioactive sources had been detected and they would also be transported to "safe areas" soon.

Altogether, 32 radioactive sources were buried under the debris during the 8 magnitude earthquake that struck last week, he added.

Thirty-two radioactive sources were buried by debris; wtf?! OK I guess we could be talking hospital X-ray equipment or other low-level medical applications, but I would like some confirmation of that fact. I'll try to keep follow up on these reports, but my suspicion is we have heard about all we are going to hear on this score.

If you want more information about continuing landslide risks and damage to dams in the region check out this post from ResponsibleChina and this Wall Street Journal, China Journal post. For an excellent rundown on the energy implications of the quake check out this post from The Green Leap Forward.