May occur in boilers and boiler feedwaters treated with sulfite to control dissolved oxygen levels, natural waters containing industrial waste and in wastewater treatment plant effluents using sulfur dioxide to dechlorinate the effluent.

a salt of sulfurous acid.

Acid process of cooking pulp. Also the pulp cooked by this process.

A term for pulp made from wood. Depending on how it is processed for papermaking, it can either be acidic or neutral pH.

any salt of sulfurous acid. Often added to food or medication as a preservative.

Sulfites (also sulphite) are compounds that contain the sulfite ion SO32−. They are often used as preservatives in wines (to prevent spoilage and oxidation), dried fruits, and dried potato products.