Chemical Spectroscopy to Help Detect Mercury

It has been known for many years that mercury exists in small doses in many different species of fish that humans consume regularly. Generally, it is safe to eat mercury-containing fish in moderate amounts but it is extremely poisonous and can cause health issues if ingested in large quantities – especially by children. Coal-burning power plants are the main cause of a large portion of mercury pollution. These factories not only emit mercury as smoke, but also use mercury to extract chlorine from salt. In this process, the mercury is disposed of as waste in water. Because it is not soluble, mercury is easily absorbed by organisms. Therefore it becomes concentrated in algae, then travels up the food chain to other species through biomagnification. This causes larger fish such as sharks and swordfish to have higher concentrations of mercury.

It has also recently been discovered through biogeochemical research that deep-sea-feeding fish contain more mercury than fish that feed closer to the surface. Scientists have also determined that chemical reactions of sunlight help destroy the mercury in the well-lit upper depths of water. Using a spectrometer or spectrophotometer, the amount of mercury was measured in a variety of species that fed at different depths of the ocean.

Continuing mercury research using spectroscopy and chemical analysis will help oceanographers learn more about the differing mercury levels within the ocean. It will also keep the fishing industry informed about unsafe mercury concentrations in certain areas or certain species of fish. This research has already helped scientists predict that mercury concentrations in fish from the Pacific Ocean will be on the rise in the coming years. Knowing this can assist food regulators in adjusting the guidelines for safe amounts of consumption over the next few decades.