It won't be long before arrowhead season begins. Those who enjoy trying new delicacies will buy arrowheads to make a dish like braised pork with arrowheads or arrowhead chicken soup. However, vegetable experts remind us that arrowheads must be processed with care. Never take shortcuts to avoid excessive lead intake, which can lead to lead poisoning.
Arrowheads are rich in various nutrients such as starch, protein, vitamins, and trace elements, and have effects like reducing inflammation and detoxification, promoting the production of body fluids and moistening the lungs, and tonifying the middle and replenishing qi. However, as an aquatic vegetable, arrowheads have a strong ability to absorb and accumulate heavy metals like lead.
Currently, lead is one of the key environmental pollutants. With the rapid development of industry and the large-scale discharge of "three wastes" (waste gas, wastewater, and solid waste), the concentration of heavy metals like lead in water bodies is increasing. If people consume improperly processed arrowheads, it may lead to chronic poisoning and pose a significant health risk. Studies have found that as the concentration of lead in water and soil increases, the lead content in various parts of the arrowhead also rises. The highest lead residue is found in the corm's skin, followed by the terminal bud, with the peeled corm having the least. When the lead concentration in soil and water reaches 50 milligrams per liter, the lead residue in the arrowhead's terminal bud is 0.22 to 0.25 milligrams per kilogram, and in the skin, it is 0.29 to 0.37 milligrams per kilogram, both exceeding the national standard limit of 0.2 milligrams per kilogram for pollution-free vegetable products.
If the skin of the arrowhead corm is removed, the lead residue drops to 0.11 to 0.12 milligrams per kilogram, which is below the national standard, making it relatively safe to eat.
The arrowhead corm grows in the soil, and its skin directly contacts lead in the soil, leading to higher absorption and accumulation, which is why the skin has the highest lead buildup. To ensure the safety of eating arrowheads, during processing, first, do not be afraid of the trouble and carefully remove the skin. Second, do not be afraid of waste and pinch off the terminal bud.