By Simran Sethi and Sarah Smarsh

Who says we need to drink eight glasses of water a day? Experts are no longer sure if the average person needs that much.

Today is World Water Day, and this year's theme is devoting to the scarcity of clean, drinkable H20 on our planet.

But innovative ideas, like PlayPumps in South Africa, are solving the problem -- in a surprisingly fun way.

What better way to start the week than to ponder what might be lurking in your water supply - and how it got there. New research is turning up evidence that arsenic used in chicken feed may be contaminating some groundwater and surface water sources.

Chicken droppings, like many other forms of animal excrement, are used as fertilizer because of their concentrations of nitrogen and phosphorous. (These elements can also make their way into water supplies.) According to the web site of the journal Environmental Science and Technology, many chickens raised to be roasted are fed a supplement called roxarsone - a form of arsenic that is relatively harmless but seems to be breaking down into a more harmful variety once it's in the soil.

A new report on fluoride levels in drinking water has advocates on both sides claiming the results support their cause. The report recommended that the EPA lower the maximum allowable levels of fluoride in the nation's water to avoid health risks, but only about 200,000 Americans currently consume water above those levels.

Fluoride occurs naturally in water, but communities where natural levels are lower add additional fluoride. The practice has long been recommended by dentists because it reduces the risk of cavities, saves money, and helps low-income families without access to dental care. According to the American Dental Association, fluoride in water helps reduce tooth decay by as much as 40 percent.

As Americans gorged on turkey and pumpkin pie, a 50-mile-long toxic chemical spill was flowing along the Songhua River through northern China – the worst environmental disaster in the nation’s recent history. The crisis began on Nov. 13, when two explosions at a state-owned petrochemical plant in Jilin killed five workers, injured 70, forced about 10,000 to flee, and dumped 100 tons of benzene (among other nasties) into the Songhua.