Water Matters

dan-reading-2There has been a lot of media attention on microbeads and the effect that these may have on our marine environment.

Dan Reading, Green Blue Sustainability Officer

Firstly, some of you might be asking what microbeads are and why you have not seen any. Essentially they are small (less than 1mm) pieces of plastic which are used for a wide variety of things from medical treatments (this is what they were originally used for) to cosmetics.

It is worth thinking about as a number of boaters use showers on their boats and the majority of boats are not fitted with grey water holding tanks or with anything to treat the water before it is pumped into the environment.

Of course it is possible to fit your boat with a filter for your grey water. Wavestream, a company who make inline bilge filters have also developed a grey water filter system called Wavebright. If you have one of these fitted you can be assured the water going out into the environment is not causing any harm.


Microbeads do not biodegrade and so can build up in the food chain. Image: MPCA

Microbeads do not biodegrade and so can build up in the food chain. Image: MPCA

Microbeads, being plastic, do not biodegrade and therefore can build up in the food chain and the chemicals that are in the plastics and absorbed by them can end up in our food chain. Other pollutants in grey water can be nitrates that cause eutrophication and algal blooms.

Most of us who bathe at home will be connected to the mains foul sewerage network and therefore various cosmetic products and cleaners can be used with the knowledge that your waste water will be treated – most of the time.

The treatment at a waste water plant normally consists of removal of large objects that may block or damage equipment through filtration. The next stage is to separate matter using settlement tanks. Some treatment works also treat the water with aeration tanks where the water is aerated and certain ‘good’ bacteria is mixed in.

Finally the wastewater is passed through a final settlement tank, and then in some works it is slowly filtered through a bed of sand, which acts as a final filter and catches any remaining particles. The treated wastewater is then directed into a river or the ocean.

Of course when you put items in the toilet to be disposed of sometimes they do not make it to the treatment works. This is because some water companies operate something called combined sewage overflows.

Essentially these are used where sewage and storm drains share the same pipes and during heavy rainfall the CSOs discharge to the river/sea to prevent sewage backing up into our homes and streets when the system is full.

Take a walk along the beach in Hamble and it is immediately obvious how many plastic items there are that look very out of place. I say out of place but these days finding cotton bud sticks and plastic sanitary items is fairly common. It is important that things like cotton buds with plastic shafts never be disposed of in the toilet.


Grey water pumped out – you can fit your boat with a filter

Grey water pumped out – you can fit your boat with a filter

When it comes to microbeads the treatment process does not completely filter out all the microbeads and it is estimated that around 10 per cent remain suspended and still end up entering the marine environment.

This problem is all around us. By trawling the water using a very fine mesh net, researchers have found that even in the Solent there are microbeads.

For those of us that have showers on our boats or have a sink that drains to the waterway it is worth thinking about what is being pumped out.

Using chemicals such as bleach and other cleaning products when you do not have a holding tank can be harmful to aquatic life but also to other people who use the water such as dinghy sailors.

Always think about what products you use on your boat. Remember that your sink and shower waste water will probably not be treated as it would if you were using it on shore. If you want to know if your body washes contain microbeads look for ‘nylon’ ‘polypropylene terephthalate’ ‘polyethylene’ ‘polymethylmethacrylate’ or download an app to your phone called ‘beat the microbead’ which tells you if a product has microbeads in it by scanning a bar code,


To find out more about the work of The Green Blue visit www.thegreenblue.org.uk