There are many areas of our lives where we can lighten our environmental impact just a little; and one of them is how we deal with medication.

I'm certainly not about to recommend that anyone using prescription medication to cease taking them for the sake of the planet, but how we handle the waste related to our pills and potions does have an effect on the environment. I'm not referring to the packaging, but the drugs themselves.

Old, past-expiry date medication are a common occurrence in the home and these drugs pose a risk to others in your household, so it's certainly a good idea to dispose of them. Old medication should be considered as being household hazardous waste and careful consideration given to their disposal.

Unfortunately, old medication often goes straight down the toilet or the sink, but the problem is sewage wastewater treatment plants aren't equipped to filter out drugs; so they wind up in our waterways.

US Environmental Protection Agency (EPA) studies have found pharmaceuticals present not only in waterways, but also in aquatic creatures. Minute levels have also been found in drinking water. In addition to antibiotics and steroids, over 100 different Pharmaceuticals and Personal Care Products as Pollutants (PPCPs) had been identified by 2007 in environmental samples and drinking water.

Not a lot is known about the environmental and human health impact of the presence of pharmaceuticals in waterways as more research is needed; but it's a disturbing situation.

While most drug residues enter waterways through people taking medications and then passing them through urine or faeces, the addition of old medications that are flushed is just an additional burden on our waterways that can and should be avoided.

How to dispose of old medication

It's important not to flush prescription drugs down the toilet or drain unless information accompanying the medication specifically states you can do so. For people in the USA, you can locate a list of medications that can be flushed on the Food And Drug Administration web site. Something to bear in mind though is that the FDA's recommendations have little to do with the environment. Its opinion is the potential risk to people and the environment from flushing the listed medicines is outweighed by the "life-threatening risks from accidental ingestion of these medicines".

Probably the best first course of action regardless of the country you are in is to contact your local pharmacy and ask them if they have a drug take-back program as these initiatives are becoming increasingly common. Pharmacies that do will ensure the medications are disposed of in the proper manner; usually via incineration.

Another point of contact is your local council's waste department as they may offer a drop-off facility for old medications or may be able to direct you to a service that does.

Failing all that, the general advice is to dispose of the medications in your household trash, but to take some special safety precautions by take the medications out of their original containers and placing them into another airtight container, mixed in with something undesirable - such as used kitty litter or other substances equally as unappealing. It's not ideal as the drugs can contaminate the soil when landfilled and possibly contaminate groundwater; but that's really the only other option and according to authorities; the "lesser of the evils".

By the way, while some disposal programs incinerate old medications, do not attempt to incinerate medications at home as this can be just as environmentally damaging as landfill disposal and hazardous to your health, due to the gases produced. Medicine disposal programs use special incinerators that burn at very high temperatures.