Final answer:
Small children and pregnant women are advised to avoid consuming shark, swordfish, tilefish, and king mackerel due to their high mercury content. These fish accumulate mercury as they move up the food chain, posing a risk to human health.
Step-by-step explanation:
Shark, swordfish, tilefish, and king mackerel are not recommended for small children and pregnant women due to their high mercury content. These fish are at the top of the food chain and biomagnify mercury through the process of ingestion. As smaller fish eat organisms with low levels of mercury, they accumulate more mercury in their bodies. When larger predatory fish consume these smaller fish, they accumulate even higher levels of mercury. This process continues as you move up the food chain, resulting in higher mercury levels in fish like shark, swordfish, tilefish, and king mackerel.
Mercury is a toxic heavy metal that can harm the developing nervous system of fetuses and young children. It can also have negative effects on adults, including impairing brain function. Pregnant women and small children are particularly vulnerable to the harmful effects of mercury, which is why it is recommended that they avoid consuming fish with high mercury content.