As science has gotten better, discoveries about our food chain have shocked people for years. It's no surprise that industrialization has polluted our environment, including our water supplies. Since fish and shellfish live in water, they are most vulnerable to our pollutants. It is important for seafood consumers to understand potential risks and how to mitigate them. Importantly, it's vital to understand the modern industry. Many poor practices are no more or are simply not true. This article will cover some of the most important health science topics discussed in seafood.

1. Mercury

Mercury is a heavy found naturally in mineral deposits and rocks in small concentrations. Although the metal occurs naturally in the environment, mercury levels in our air, land and water have increased dramatically since the rise of industrialization in the late 19th century.

What is mercury and why is it in seafood?

Mercury is a naturally occurring toxic metal that exists at low levels throughout the environment, and as an element it never breaks down or disappears. Mercury cycles through the environment, passing between the air, land and water, and affects plants and animals.

According to an EDF report, local sources of mercury—such as coal-fired power plants, waste incinerators, and certain factories and mining operations—can create hot spots of pollution that impact local communities. Mercury emissions are a global problem as well, since mercury can be carried through the atmosphere over large distances.

Mercury enters streams, rivers, lakes and oceans primarily through rain and surface water runoff. Bacteria can then convert it to an organic form called methylmercury -- the form that is dangerous to people.

Most foods have some mercury. Most water has some level of mercury, and all food requires water. When small fish with low mercury levels get eaten by bigger fish, the amount of mercury biomagnifies. For this reason, long-lived fish and top-level predators like swordfish and shark often have higher mercury levels than smaller fish like haddock or salmon.

What to know

For most people, the risk from mercury by eating fish and shellfish is not a health concern. Yet, some fish and shellfish contain higher levels of mercury that may harm an unborn baby or young child's developing nervous system. The risks from mercury in fish and shellfish depend on the amount of fish and shellfish eaten and the levels of mercury in the fish and shellfish. Therefore, the Food and Drug Administration (FDA) and the Environmental Protection Agency (EPA) are advising women who may become pregnant, pregnant women, nursing mothers, and young children to avoid some types of fish and eat fish and shellfish that are lower in mercury. For most adults and adolescents, eating seafood regularly does not pose a concern with mercury. Still, it is best to include variety in your seafood diet since the benefits of seafood, risks included, far outweigh the concerns associated with seafood nutrient deficiency for adults/adolescents. The FDA provides comprehensive guidelines and reviews for most commonly eaten seafood if you want to read more specifics.

2. Aquaculture Dyes

Farmed salmon are not injected with dye or artificial colors. Both wild and farmed salmon get their characteristic reddish color from natural pigments.

Wild salmon hunt and eat small crustaceans like shrimp with high levels of natural pigments. Farmed fish rely on feed supplements which include two naturally-occurring pigments (astaxanthin and canthaxanthin) – to provide them with the proper nutrition and color. Astaxanthin and canthaxanthin naturally pigment crustaceans reddish, as well as the salmon that eat them. The process is no different for farmed salmon and both pigments sourcing's are monitored and deemed safe by every country that imports salmon.