Chemical Waste

Chemicals pose a risk to organisms (including humans) in a manner that depends on dose and inherent potential for causing harm. Thus 100g of a fairly "harmless" chemical might represent a greater risk than 0.01mg of a really nasty chemical to an organism. Safe disposal usually takes various forms:

dilution: often simply diluting with water into the waste water system but actually using the sewage treatment system and eventuall the rivers or sea
chemical reaction: changing the properies of a substance by changing its chemical structure, reduding its biological activity, its vulnerability to breakdown, solubility, etc.
isolated storage: avoiding the issue really by simply storing the substance safely

Given there are thousands of different chemicals in use in the Biology Department, we can give no guidelines for each chemical. You the User will have to make judgements using these guidelines:

Water soluble chemicals

If these chemicals are hazard severity level 1 or 2 and the amounts are small (i.e. <100g), they can be washed carefully down the sink. The risk to humans from such chemicals after the masive dilution in the campus sewer is extremely small and most such chemicals will be degraded by organisms in the sewage before or during treatment at the sewage works. This is the most likely disposal route for most aqueous solutions of chemicals used in the Department. Very small amounts (i.e. <1g) of hazard level 3 substances may also be disposed of in this way but consideration should be given to the properties of the individual chemicals. Larger amounts of such chemicals should be taken to the Biology Stores for disposal (see below)

Water insoluble chemicals

These should be taken to the Biology Stores for disposal

Solvents

Water miscible solvents can be treated as described above for water soluble chemicals. However, all water immiscible solvents should be disposed of via Biology Stores and they should be contacted prior to use for advice

Gases

All non-toxic gases except gases which might be greenhouse gases or which can form explosive mixtures should be released slowly in to the atmosphere in a well ventilated space. The release should be vented by qualified personnel in the cylinder store or in the open

Known carcinogens

The disposal route must be defined in the COSHH documentation submitted to the Biology Safety Advisor. This route must be used and the disposal documented

Procedure for disposal of chemicals via Biology Stores

All substances should be labelled with 'Waste for Disposal' labels (available from Biology Stores), stating the substance name, your user name and date

All liquid substances should also be categorised as:

Water miscible (e.g. acetone, acetonitrile, ammonia, ethanol, methanol)
Halogenated (e.g. choroform)
Ethereal (e.g. diethyl ether)
Hydrocarbon (e.g. xylene, toulene, hexane, pentane)

The waste must also be accompanied by a Chemicals_Internal Waste Transfer Note (PDF , 111kb)

All waste should be well packaged so that it is suitable for further transfer from Biology

It is the responsibility of the user to package and label all substances. You are pre-charged for waste disposal, with 4% of the cost of hazardous chemicals purchased and 1% of the cost of biological kits charged to your grant quarterly

Pipette tips contaminated with residual chemical materials

These should be disposed of in the yellow plastic incineration bins