Mercury, the only metal that remains liquid at room temperature, is more than 13 times denser than water. One way of comparing densities of liquids is by combining them to determine which floats on top of the other. However, some liquids dissolve in water, making this method unreliable. Creosote and sulfuric acid are both denser than water, but sulfuric acid is an aqueous solution that mixes with water.
Creosote is a dense nonaqueous phase liquid that sinks in water. Spills of this type of liquid tend to sink in water. They continue sinking through the soil and only stop when they hit bedrock. These liquid spills contaminate surface bodies of water and ground water due to their high density. As of 2014, remediation of the spills remains difficult.
Sulfuric acid is a clear, corrosive liquid created by mixing hydrogen sulfide gas with water. Sulfuric acid absorbs water from the air. Battery acid is 29 to 32 percent sulfuric acid. The acid removes water from other compounds. It reduces table sugar and starch to carbon. Automobiles and volcanoes release hydrogen sulfide into the atmosphere. This gas mixes with water in the air to form acid rain, a type of pollution that damages buildings, alters the pH of soil and surface waters, and affects plant growth.