Sampling for the presence of optical brightener in a stream
Optical Brighteners are fluorescent white dyes that are added to almost all laundry soaps and detergents because clothing made from cotton fabrics naturally looks yellowish and drab. This occurs because cotton absorbs blue rays that are present in sunlight.
When Optical Brightener is applied to cotton fabrics, they will absorb ultraviolet rays in sunlight and release them as blue rays. These blue rays will then interact with the yellowish color and give the garment the appearance of being “whiter than white”. Because the main commercial use of these dyes is in laundry detergents and textile finishing, Optical Brightener dyes are generally found in domestic waste waters that have a component of laundry effluent. Optical Brighteners can therefore enter the subsurface environment as a result of ineffective sewage treatment (Fay, Spong, and Alexander, 1995) .
The Optical Brightener Handbook describes the process and procedures for using optical brightener as a method for detecting possible sources of pollution in surface water and subsurface drainage.