The problem with un‐encapsulated polystyrene - Styrofoam - in dock floats

Posted:  Thursday, April 20, 2017 - 2:15pm

Those fortunate enough to live on lakes often add to their enjoyment with a floating dock. Such floating docks, when well‐constructed, are both aesthetic and offer shelter and a resting place for water‐loving creatures. When poorly constructed, they cause significant environmental harm.

The culprit is polystyrene (Styrofoam). Polystyrene is a largely inert product, made from petroleum products, and consists of small polystyrene beads fused together. In fact, it is so inert that it is difficult to recycle and takes decades or longer to break down in the environment.

Because of these attributes, polystyrene food containers are banned in numerous cities and states around the country. In Maine, the use of polystyrene is prohibited at any state function and is banned as packaging in such towns as Portland and Freeport.

It is still widely used for flotation in docks because it is lightweight and resistant to environmental and chemical degradation. However, it does break apart when subject to abrasion, and animals, such as muskrats, love to tear it apart. The resulting pieces of blue, virtually‐indestructible polystyrene line the shores of area lakes and rivers, eventually flowing into the ocean. When swallowed by fish and waterfowl, they can clog the intestines, preventing digestion of food and leading to starvation.

To circumvent the problem with the fragility of polystyrene, most dock floats today contain polystyrene that is encapsulated in a hard polyethylene shell. Unencapsulated polystyrene is usually blue or bluegreen in color; the polyethylene shells are usually black. Unencapsulated polystyrene floats are being increasingly banned on lakes and rivers. However, no such ban yet exists in the Megunticook River watershed.

The other important aspect of dock construction is ensuring that the pressure treated wood used in docks sits above the water level. This prolongs the life of the dock and minimizes the release of the copper‐containing compounds used in pressure treating.

Although encapsulated floats are more expensive initially, they last much longer and are less expensive in the long run.

If you own a dock with unencapsulated polystyrene, do yourself, your neighbors and the environment a favor by replacing those floats with encapsulated polystyrene.