University of Burgos

Sodium nitrite is often added to cured meats, in order to prevent spoilage and provide flavor. It can also cause health problems in large amounts, however, which is why a color-changing film has been created to indicate nitrite levels.

​If you eat a lot of large predatory oceanic fish, such as tuna or swordfish, then you're at risk of mercury poisoning. Each individual big fish doesn't necessarily contain a lot of accumulated mercury, though, which is why scientists have created a probe that indicates which ones do.

A new test sheet developed by Spanish researchers can reveal the presence of mercury in water without the use of expensive equipment or the need for technical expertise.