Heavy Metal

I know my fish enjoy heavy metal music - because I play it for them regularly, and they seem happy.
But on the topic of heavy metals in their water column - I recently had a thought and would like your opinions on this. I was reading about how Seachem Prime detoxifies heavy metals in aquarium water and I had a light bulb moment (or rather the opposite of a light bulb moment). When setting up my 180 liter a couple of months ago - I used two 100mm chipboard screws to join two pieces of Mopani together. They are the standard hardware type - they have a gold/brass colour - I think they are classified as galvanized. They look similar to the one below.
Is this a problem in my tank, ie. are they (or will they in the future) give off toxic metals into the water?

 

This looks like one of the cut-screws made by Eureka and sold by Builders, etc. The Eureka site says that they have a Ruspert coating. I found this pdf:
https://content.hobson.com.au/documents/article-ruspert-coating-2008071.pdf

The outer layer us a ceramic layer so corrosion resistant. I very much doubt that it will leach anything into the water in normal aquarium water conditions - I wouldn't worry about it.

 

I have occasionally seen these particular screws rusting - obviously at times when that special coating you mentioned has been damaged. Any idea what type of metals would be used on the actual screw, and whether they would be harmful in a tank?

 

I had originally looked for stainless steel screws - but I only needed 2x 100mm which was a bit of a difficult order to fill. I didn't want to have to buy too many with the price of those things!

 

Under the ceramic coating will be a zinc coating. Under that will be a carbon steel core. Most of our water pipes and fittings are made from carbon steel with a zinc (galvanized) coating.

 

Thanks mate!