https://phys.org/news/2018-05-chemicals-leaching-norwegian-roads-tunnels.html > When talking about road traffic and environmental consequences, attention is often paid to greenhouse gas emissions, air pollution and noise pollution. People are usually not as aware of heavy metals, salts, and organic pollutants originating from the traffic. > "There is a general knowledge gap regarding which chemicals are present in various transport related products, and how big amounts we are talking about," says Sondre Meland, researcher at NIVA.