ABC of Safety in the Biological Sciences
The drainage system is a vital feature of any laboratory and easy access to the system for inspection is important. Select the materials used for the drainage system with care as many chemicals and solvents react with some of the more commonly used ones. Glass is one of the most acceptable materials but it is also one of the most expensive to install. PVC is resistant to attack from most chemicals and solvents and is a cheaper alternative.18
Drainage channels and sumps need to be cleaned regularly as they can become silted with a variety of substances including tissues, wax, insoluble chemical compounds, cleaning powders and glass chips from slides.
Dangerous residues also accumulate in the drainage system, especially after silver staining. Ensure that waste chemicals and solvents are disposed of correctly and if necessary through a specialised waste disposal organisation. If flushing down the sink cannot be avoided use copious quantities of water to dilute the waste as much as possible. While staining allow a tap to run continuously so that the likelihood of chemicals building up to dangerous levels in sumps is kept to an absolute minimum.