The news that China has officially acknowledged that "about 10 percent of farmland had 'striking problems of heavy metal levels exceeding (official) limits'" gives some scale to a human catastrophe that rivals Mao's famines and Stalin's paranoia. Because while 10% is pretty devastating its the follow-on effects that make this a catastrophe. Consider that, according to the CIA, China had 641,410 sq km of irrigated land in 2008, so an area the size of Nebraska is toxic, and presumably unfit for agriculture by biologically sane standards or even western standards. 10% of 640,000 sq km is about two thirds of all the cropland in California.
We should add the usual caveat that the PRC government follows three rules when it comes to statistics: (a) its best to be conservative so as not to make undue haste, i.e. underestimate, (b) its best to make considered decisions in the fullness of time, i.e. allow time for shoring up whatever defense is necessary, and (c) its best to put a cap on what's reasonable, i.e. let's make the number more of a goal that we strive for, and if its a really bad number morale suffers amongst the strivers, so try to keep the "actual" number close to the reported/goal figure. So its very likely the 10% figure will remain "the latest" for quite some time, and its also likely the 10% figure has been around for a few years as it passed through various levels of jurisdiction on its way to official approval.
Parse the sentence and you see many ways in which to understand the scale of this problem and its effects, which are vast. Suppose the actual figure is only and really 10%, an area the size of Nebraska; there's still the issue of "heavy metals exceeding official limits." Do we know what the official limits are? Maybe we could use teh Google for that, but does anyone doubt the official limits are much higher than they'd be in, say, Nebraska? And there's the adjective "striking", which leads one to suspect that those levels don't just exceed the heavy metals limits that would probably be considered beyond all reason in Nebraska, but exceed those limits in jaw-dropping ways.
All of which is pretty wishy-washy, which is what the Chinese equivalent of the EPA is hoping for. There needs to be enough subjectivity in the statement to ensure anyone making serious accusations of malfeasance on the part of the caretakers of the mandate of heaven can be counter-accused of alarmism and the kind of bleeding-heart environmentalism - oh, think of all those poor unicorns drinking dirty water! - that so effectively deflects serious environmental analysis in the West. But its also got to be specific enough to pass the coded message to the people who needs the heads up, whether they're aparatchiks scheduling army maneuvers in the aforementioned zones with striking levels of heavy metals pollution, or buddies on the Shanghai Stock Exchange looking to short.
So it could be that 10% of China's agricultural land would qualify for Superfund status, a program that only came into its own at the tail-end of the US's own great leap forward, when it still supplied most of the world with products that required environmentally-destructive business practices. (Notably, though, not really a lot of its vegetables or fruit or canned goods.) Let's keep in mind that, as a matter of general economic history, the practitioners of environmentally-destructive business in the US moved their factories to China and the Matamoros along the Rio Grande along about the time the EPA came into existence, Love Canal became more than a destination housing development, and it was becoming clear that the accelerating use of processes with heavy metals and other toxic wastes as byproducts was reaching a point of unsustainability. Its the acceleration the caused the problem: The production didn't just increase at a linear rate, it was becoming geometric. Where once it might take decades to create the Butte toxic plume, this contamination was happening in a matter of a decade, and then years. Companies were picking up and moving on at ever faster rates, which is why the whole Superfund program was so controversial, from an industry standpoint - here were companies casting about for more and more land on which to expand production, but they were having to pay for land despoiled back when production was at 1950s revenues and profits, and twenty years later everything was higher, including the costs of cleanup. Cleaning up toxic waste dumps constituted a drag on development, and the cost, as it turns out, increase at roughly the same rate as the revenue. When left-wing economists talk about "externalities" this is what they're talking about. "Externalities" are usually ranked on the modern media's credibility scale with the cost of unicorn tears but they're very real and quantifiable, especially as more and more parts of life have come under the control of business and been subject to accounting. As revenues increased with population and greed, and costs increased accordingly, we've come to understand much better what the implications of Superfund-levels of production entail, and we know how to calculate the downstream costs.
What is more likely given what we know about the perfidy and myopia of business leaders in China and around the world is that we will need a whole new set of categories to describe what's happened to China in the last fifty years. "Superfund" will no longer be the apt metaphor, just as the coal tailings of Newcastle became an inadequate metaphor for what happened at Love Canal a hundred years later. The true extent of the damage has been covered up, and it will take years of lying before we know something like the truth. It will take prosecutions, jail time, fines, the kind of sentimental shame-and-epiphany-and-redemption the business mind wallows in, and then ultimately we'll be left with something more than 10% of Chinese agricultural production strikingly contaminated with heavy metals. Something much more.