I couldn't tell from your post what exactly you are wanting to use the aluminum for. But, there are many metals and alloys that corrode very quickly when exposed to salts of any kind, aluminum especially. For example, rarly is aluminum used on salt water fishing boats, stainless steel fittings and riggings are the ones of choice, even the screws.
I'm not sure if the byproduct (corrosion) is toxic from aluminum, it will appear to be a chalky white powerdy substance. I do know that salt water will accelerate this corrosion process. As mentioned above, one might be careful with galvanized steel as well. I do know that the fumes emmiting from welding galvinized steel are extremely toxic to us humans. Look into it if you can find some info, the corrosion may not be harmfull at all especially if it is just a small splashige here and there.
Also, anytime you connect two dis-similiar metals, there will be corrosion at some time, at the point of contact, especially in a salt enviroment. When a electric current is applied it really accelerates the process even at a minimal level, your car's battery terminals are a good example of this, ie. copper leads, lead terminals. Hope this helps, Scott
Here I go again, diving in head first!