Irena Salina's documentary "Flow" begins by comparing the Earth to a human body. Both are roughly 70 percent liquid, both maintain life via a circulatory process (rivers equals arteries), and both can become very sick if their streams get polluted.

Then, to drive the point home, Salina shows us a Bolivian waterway turned blood-red due to slaughterhouse drainage.

Most of the images in "Flow" aren't quite so upsetting — the un-narrated film is like a series of cold, clear facial splashes composed of facts and explanations from scientists, journalists and activists. Nonetheless, it's scarier than the average horror film. What are we doing to our water, and who's responsible?

"Flow" takes us from one point of global concern to another. In Bolivia, the film's sources tells us, one in 10 children dies before his or her 5th birthday due to water-borne diseases like cholera; while in South Africa many can't even afford iodine capsules to kill microbes, let alone get potable water.

Water in the United States isn't concern-free, either: Among the many pollutants tainting our water supply is the widely used herbicide atrazine, which has been banned in the European Union (although it's produced in Sweden), because even in low doses it chemically castrates frogs. And you thought taking their legs was mean.

"Flow" points an accusatory finger in several directions, often returning to the World Bank, which allows multinational corporations like Vivendi and Suez to turn poor countries' water systems into for-profit ventures, under what many consider a false guise of humanitarianism. The film consistently puts human faces on these matters, interviewing people who can't afford to buy water and end up returning to the polluted water sources privatization was supposed to prevent.

The documentary's streams often wind back to the United States, reminding viewers of the connection between what's happening in India or China and our backyard swimming pools. Diverted rivers aren't just destroying ecosystems in the Nile or the Yellow River; they're also radically altering the Colorado River Delta.

"Flow" throws a wet blanket on the bottled-water industry, which sells barely regulated tap water for prices that often exceed those of milk or gasoline. A clip from Penn & Teller's TV show "Bullsh*t!" drives home the gullibility of consumers, who rarely factor in the toxins in bottle plastic (no particular thanks to a government more focused on water-boarding than water safety) or the long-term ramifications of all that extra garbage.

We see a showdown between Nestle, which owns more than 70 bottled-water brands, and a community in Michigan where it pumped so much water that area streams began drying up. Nestle lost the battle, but seems to have won the war, lawyering its way up the appeals courts while opening additional pumping stations in neighboring communities. Meanwhile, Coke and Pepsi also vie to trade in water — they've made billions selling sugar-water, after all, so why not remove sugar from the equation and profit even more?

"Flow" sometimes suffers from its ambition, spreading itself thinly over many subjects and regions; what, no mention of the dried-up Aral Sea or Africa's Lake Victoria? The film also allows few opposing viewpoints — it's as much advocacy as journalism, though thankfully about as far from Michael Moore as you can get without a Mace-filled fire hose. What Salina does provide is a passionate overview of the world's water problems, quietly but firmly asking viewers to pay more attention, and whetting the activist's appetite with examples of those who have effectively taken action.

"Flow." Rating: Not rated. Running time: 1 hour, 23 minutes. 3 stars.

To find out more about Zachary Woodruff and read features by other Creators Syndicate writers and cartoonists, visit the Creators Syndicate website at www.creators.com.

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