THE BIG QUESTION

How environmentally friendly are biodegradable cleaning products?

QI recently learned that so-called biodegradable soap is only biodegradable when soil breaks it down, so it still shouldn’t be released straight into open water. I don’t think this is very common knowledge as often I see recommendations for the use of biodegradable cleaning/washing products on board to help the environment. I believe there are soap products out there more suitable for harmless release into open water. What is the best product to use onboard? Tom Zwitserlood A This is an interesting question, but it is not actually ‘water v soil’, it is more about the time taken from the plughole to the outside world and the route in between. The EU directives which cover biodegradability of washing up liquids (and other household chemicals) set standards for how long the ingredients take to breakdown into their constituent parts e.g. water, carbon dioxide and salts, and they are designed with a land-based sewage system in mind.

The surfactants in the washing-up liquid used to clean your plates onboard will not go to a sewage treatment works and will, unfortunately, continue to work in the water around your boat.

If you don’t have a holding tank, try and use eco-cleaners on board to protect the environment as much as possible

An eco-cleaner will use less harmful ingredients, will breakdown quicker than non-eco brands and have a lower carbon dioxide footprint. We use small amounts of eco-cleaners onboard, putting a few drops on the sponge rather than into the dishwater, to get the most concentrated cleaning effect before rinsing in salt or freshwater, knowing that the few suds released from our sink (or bucket!) will be rapidly diluted in the sea. If you want to go the extra mile, consider installing a holding tank to capture all grey and black water and empty at a pump out facility. Sarah Brown

Sarah is donating her fee for this piece to www.sea-changers.org.uk, which raises funds for UK marine conservation projects.