Some vegetables are hailed as "growing from mud without being tainted," but is this really the case? Experts point out that waste slag from factories and mines can pollute the soil, wastewater can pollute water sources, and exhaust gas can pollute the atmosphere. Just like all plants, vegetables absorb nutrients from the soil and atmosphere as they grow. Therefore, the harmful substances from factories and mines will eventually be found in nearby vegetables and crops. Even if crops are far from factories and mines, the fertilizers and pesticides used in agricultural production can also cause vegetable contamination.
According to research, because roots have the strongest absorption capacity, root vegetables such as sweet potatoes, radishes, carrots, and lotus roots are most sensitive to soil and water pollution. As they grow from a seed (seedling), they mainly rely on absorbing substances from the surrounding soil, so the myth of "growing from mud without being tainted" does not exist. Vegetables in the solanaceous category (such as green peppers and tomatoes), the podded vegetable category (such as beans), and the bulbous vegetable category (such as onions, garlic, and onions) store fewer pollutants. However, if the pollution level of the cultivation environment is severe, it is difficult for any variety of vegetable to escape the fate of being contaminated.
Therefore, consumers should learn to identify vegetables with pesticide residues or those that have been stimulated by hormones. You might want to learn the following three simple methods for selecting vegetables.
First, do not buy vegetables with abnormal shapes or colors.
Abnormal vegetables may have been treated with hormones. For example, when the leaves of chives are particularly wide and thick, twice as wide as normal broad-leaf chives, they may have been treated with hormones during cultivation. Some vegetables also have abnormal colors; for instance, when vegetable leaves lose their usual green and turn dark green, or when green soybeans are abnormally vibrant, they may have been sprayed or soaked in methamidophos pesticides before harvesting and should not be purchased.
Second, buy fewer vegetables that are often infested with pests.
Among many vegetables, some are "favored" by pests, such as bok choy, Chinese cabbage, cabbage, and cauliflower. These are the vegetables that suffer from heavy pest infestation. Due to the high frequency of pests, some growers spray them frequently, which can easily lead to pesticide residues. Some vegetables are less favored by pests, such as crown daisy, lettuce, celery, carrots, onions, garlic, chives, scallions, and cilantro. It is advisable to choose these more often.
Third, do not buy vegetables that have been heavily fertilized.
Excessive application of fertilizers, especially nitrogen fertilizers (such as urea and ammonium sulfate), can cause severe nitrate contamination in vegetables. Testing results of vegetables on the market show that the ranking of nitrate content from highest to lowest is: root vegetables, tubers and corms, leafy vegetables, cabbage-type vegetables, onion and garlic vegetables, legumes, gourds, solanaceous vegetables, and mushrooms. The difference in their nitrate content can be as much as 10 times. Therefore, we should try to eat more gourds, fruits, legumes, and mushrooms, such as cucumbers, tomatoes, green soybeans, and shiitake mushrooms.