Ocean trash disposal... what can and cant go over the side?

As we traverse the oceans we try not to leave too much of an environmental impact from the waste we generate aboard.

There are some types of waste we cannot keep on board for any length of time, black water being the most obvious, although we do have a limited holding capacity for when we are in port or areas where it is against the law to dispose of human waste direct to sea. Out on the deep ocean we have no qualms of disposing of our sewage straight to the sea. The same is true of our vegetable and food waste, which we dispose of over the side in the hope that it will degrade without any measurable impact on sea life.

As a crew we are all agreed that all plastic waste should be kept aboard but what has split the crew straight down the middle is what to do with metal waste?

One view is that as long as you ensure that the tin can is guaranteed to sink, and that the sea bed deep enough, then we should go ahead and throw them overboard. This half of the crew feel that the steel or aluminium can will rust or degrade over a fairly short period of time and not have any significant impact on the organisms inhabiting the seabed environment.

The other view is that tins and cans are easy to clean and crush taking up a fraction of the space they took up when full and that, as with plastic waste, recycling facilities exist in even fairly remote places. This half of the crew feel that the impacts have not been researched, quantified or fully understood, that if you are able to reduce the impact of your passing by storing as much packaging on board as practicable until you reach a port with some recycling system in place, especially as we already do that for plastics.

On the way to the Galápagos Islands there was a 3:1 split about the likelyhood of recycling being something that would be implemented on the islands. One crew member, who was sure that there would be, was vindicated as soon as we stepped ashore to be faced with 3 types of recycling bin for each household and in the streets.

We would like your opinion on whether we should throw or stow our metal waste!
You can answer in the comment box at the bottom of this posting. Looking forward to hearing what you think!