First of, I'm guilty of occassionlly buying environmentally unfriendly products, and losing the odd plastic bag over the side on a fishing trip. It is not intentional, infact a large part of my time at the supermarket is spent going down the list of ingredients and choosing the best washing up liquids, household cleanser, soaps, that are good for the environment and me. Wouldn't it be easier if we just banned the worst of them? I go to great lengths to recover plastic bags from the oceans and lakes lest they be ingested by animals, and to prevent harm from strangulation, or actually ingesting it ourselves one day. So why not just ban them?
And while we're at it, isn't it time we had some biodegradeable / natural fishing products? I hate to see refuse when I am scuba diving, in our rivers and oceans, and again, do my best to clean it up. People, wouldn't we all prefer it if the offending products weren't on our shelves in the first place, and environmentally friendly products existed in their place? There are ways of pricing the alternatives using environmental economics that might make environmentally friendly alternatives a key product category on which to spend a renewable energy credit UBI.

But i do strongly agree that we need to clean up the waterways and would support a coherent policy on this

Simply put, energy is New Zealand is tied to water, and energy accounting can (and in this thread is) tied to environmental economics, or ecological economics if you prefer, and a basic income which should include water as a human right. There are reasonable wikipedia links to those topics, but the best links come later in my post :)
Approximately 70% of New Zealands electricity comes from hydro eg. water. Technocracy's energy credit and my renewable energy credit based UBI depends on having access to electricity, as the underlying mechanism is energy accounting, in UBI, as a parallel domestic currency. It's an improvement on several pilots that have already taken place in other countries, which were, unfortunately still tied to fiat, and lacked flexibility or vision in purpose http://en.wikipedia.org/wiki/Basic_income http://www.archive.org/stream/TechnocracyStudyCourseUnabridged/TechnocracyStudyCourse-NewOpened?ui=embed#page/n173/mode/2up That is the connection between electricity and water in New Zealand. The privatisation of hydro has lead us into water ownership, and away from energy accounting and renewable energy credit UBI. I would like to traverse the slippery slope safely:
Firstly addressing the hydro asset sales as without precedent (most of the country were opposed), they could be bought back.
Secondly, seeking environmentally sound custodianship of our water resources.
This second step, already partially addressed by water ownership (by the people, for the people, a human right), is the link between water treatment (which should be optional, or unecessary) and our consumption of it.
What should effective custodians of New Zealand really want from our aquifers? I threw flouridation in there as a controversial example, but ultimately, I am making the point I want healthy natural water to drink (I was raised on healthy untreated water), and if we don't add anything toxic, or allow anything to be added, then that is what we will have in New Zealand. I would see every flouride loving individual issued with their fluoride pills, but they like the rest of us should be able to enjoy the water at source without additives. This is a problem if water ownership and custodianship are lost, and it relates to the renewable energy credit UBI as water happens to generate the electricity.