Tiny particles from smoke and soot can also cause redness and itching of the eyes. Airborne organisms like molds and fungus can cause infections of the eyes and eyelids. Too much exposure to the sun's rays can eventually produce a clouding of the lens called a cataract. Even our clearest streams, rivers, and lakes can contain chemical pollutants. Heavy metals like lead and mercury can produce severe organ damage.
Some chemicals can interfere with the development of organs and tissues, causing birth defects.
Others can cause normal cells to become cancerous. Some of our waterways also contain human and animal wastes. The bacteria in the wastes can cause high fever, cramps, vomiting and diarrhea. Xeroderma is a rare condition that people inherit from their parents. When these people are exposed to direct sunlight, their skin breaks out into tiny dark spots that look like freckles.