The mercury content in general food is low, but with environmental pollution, mercury contamination in food is becoming more and more serious.
Big fish eat small fish, small fish eat shrimp, and shrimp eat water plants. With the biological magnification effect, the amount of mercury entering the human body is very high, reaching tens of thousands of times the mercury content in water. Fish meat is rich in nutrients, so you should choose small fish and don't eat too much. The US EPA (Environmental Protection Agency) recommends that the intake of low-mercury fish (at the bottom of the food chain) should not exceed 700g per week, and it is best not to eat the same type of fish for a long time.
How to judge if you have mercury poisoning? There are several symptoms: you can't touch your nose with your eyes closed, your field of vision is very small when you look at things, and when you put your hand in the water, you cannot tell if the water is cold or hot.