The sea creature with blue blood is the horseshoe crab.

The horseshoe crab's blood contains copper ions, and its blood is blue. This extract of blue blood, the "limulus reagent", can accurately and quickly detect whether the internal tissues of the human body are diseased due to bacterial infection.

In the pharmaceutical and food industries, it is used to monitor toxin contamination. Scientists also use horseshoe crab blood to study cancer. However, after blood was drawn from the horseshoe crabs, they were released.

Hazards of horseshoe crab:

The main component of horseshoe crab plasma is hemocyanin, and every 1ml of hemocyanin contains 0.28~0.31mg of heavy metal organic copper. Calculated based on the average weight ratio of each horseshoe crab, the plasma and meat of adult horseshoe crabs contain 600 to 1,300 mg of copper (Cu2+) respectively.

According to medical research, this heavy metal (Cu2+) enters the human body and mainly accumulates in the liver and kidneys along with blood circulation. For people with liver and kidney dysfunction, it can accelerate the occurrence and development of liver cell necrosis or cirrhosis. and complications such as renal failure and ammonia poisoning. In addition, this (Cu2+) quality can also cause hematopoietic dysfunction in the human body and affect the normal development of the nervous system in young children.

Reference for the above content? Baidu Encyclopedia - Horseshoe Crab