okay i was totally shocked when i read this. why? cayse in the 70's we had technology ot study the leaching properties of a car tire and how those leached elements would effect the ocean. thats when i said ...duhh! thats not it. they did study that and the amount of leached compounds were minimual and also majoprity was totally non toxic in long run. any case the issue was and i qoute
"While sponges and corals occasionally latched onto tires, most marine creatures had a difficult time finding a home on the unstable rubber surfaces. Studies by the Florida Fish and Wildlife Conservation Commission found that few fish spent much time among the tires and that sponges and other immobile organisms could rarely live on them for long. Worse, the tires began to move. "
the materials began to break down and wash up on beaches. the constant shifting of the tires prevented any long term healthy coral growth.