The Pacific Northwest Pollution Prevention Resource Center (PPRC) has completed a series of resources (below) on preventing zinc pollution. Please take a moment to view them and pass them on to any contacts – businesses, site managers, compliance officers, friends – who you think might benefit from this information.
RESOURCES ON PREVENTING ZINC POLLUTION
Zinc is a troublesome metal for a lot of businesses trying to prevent stormwater pollution. Because the metal comes from so many sources, businesses likely need a variety of site-specific solutions. Which solutions are working in the Northwest? Note to you boatyards out there: the Port of Port Townsend plays a major role in the film!
ZINC in Stormwater: Galvanizing Business Solutions from pprc on Vimeo.
Emerging Best Management Practices (pdf documents)
Biochar is a promising, versatile, and affordable filtration material. Why is it so effective? How widely is it being used in the Northwest? What do we know and not know about its ability to filter pollutants, especially heavy metals?
There over 55 boatyards in the general Puget Sound area. Many of these boatyards have zinc in their stormwater above permit levels. What cost-effective solutions are boatyards employing to control their zinc sources?
Street and Surface Sweeping to Reduce Stormwater Pollution
While sweeping is a simple idea, things get complicated fast when you’re faced with preparing a specific plan and budget. After all, what is Vacuum Sweeping? How about Regenerative Sweeping? Do you do things differently in the “wet” versus the “dry” season? And how often should you sweep?
An often over-looked, or maybe under-looked, aspect of controlling zinc is coating bare or corroded galvanized roofs. Can coating roofs act as an effective method of reducing zinc pollution? What best management practices should businesses know to effectively coat roofs?
Well, galvanized roofs are adding to zinc pollution, storms or not, whenever it rains. The problem with zinc is that it is “nobler” than iron in the periodic table of elements’ electrochemical potential sequence. However, rust (!) is even “nobler” than e.g. zinc or e.g. stainless steel. This leads to rust flakes “burning holes” into zinc-galvanized or stainless steel surfaces. To prevent zinc getting corroded this way it needs to be kept reasonably clean and protected against electrochemical interactions (e.g. fasteners/screws on e.g. roofs need to be insulated with an intermediate PLASTIC washer to keep the different metals separated, lest they act like a battery and thus corroding the zinc etc.). But you may have missed another point: a lot of zinc is actually applied AFTER the respective surface has been treated with cadmium(!) to provide better bondage for the zinc. At least that was years ago. I would not be surprised if you get a lot of preventable cadmium, though in smaller quantities, which is much more harmful than even zinc.