Are there really pure and pollution-free American wild carp?

Asian carp invaded the American ecosystem, flooded the Mississippi River and even appeared in the Great Lakes. The U.S. government is at a loss, and has invested heavily in rectification, with little effect. This series of news that happened on the other side of the ocean is already familiar even in China. Some netizens even joked: Leave this group of carp alone and let me do it. I hope to solve the problem with the method of eating goods empire.

For carp, it's like "in a word". Now, they are really sent to China.

From May 24th to 26th, a well-known domestic e-commerce platform held an activity to welcome Asian carp back to China. Asian carp also went on sale on May 24th. In order to build momentum, e-commerce companies even slogan "Save America". From the whole publicity page, the statement that the wild freshwater fish in the United States is "pure natural, wild, pure water, pollution-free, and does not contain any chemical additives" occupies the whole page.

First of all, I am not an expert in food quality. But before we are ready to embrace American wild carp, we might as well come up with some questions about the spirit of melamine milk and understand what kind of existence this Asian carp is.

1. How did they come to America across the ocean?

The United States has the largest freshwater lake group in the world-the Great Lakes, and the upper Mississippi River, which originated from Lake Tasca in the north of the United States, is the longest river in the United States. The water system they form covers most of the inland river networks in the United States.

According to public information, with the shift of the world economic growth center from Western Europe to North America in the early 20th century, the Boston-new york-Washington urban agglomeration and the Great Lakes urban agglomeration were formed in the northeastern and central parts of the United States respectively. The prosperity and development of the Great Lakes urban agglomeration not only brought great economic benefits to the local area, but also brought great impact to the original ecological environment system. For example, untreated industrial wastewater in the early stage is directly discharged into the water body; The use of pesticides and fertilizers, including DDT (also known as DDT), has polluted most rivers; Deforestation and agricultural reclamation lead to land exposure and increased soil erosion; The rapid expansion of cities has led to a large reduction of wildlife habitats; Sewage from cities and sewers is directly collected into rivers through groundwater. Chlorine-containing disinfectants and phosphorus-containing detergents in sewage make the problem worse. The water bodies in North America are seriously eutrophic, anoxic, algae multiply and fish die in large numbers.

By the 1940s and 1960s. The local development of organic chemical industry and metallurgical industry has led to a large number of heavy metals and toxic pollutants entering the water body. Heavy metal pollution is extremely harmful to aquatic organisms and human health because of its strong toxicity, accumulation and non-biodegradability. In addition, the popularity of automobiles has led to an increase in the emission of lead-containing waste gas, and the widespread use of fertilizers and pesticides has also aggravated the water pollution in the Great Lakes.

At that time, public health and environmental agencies in the Great Lakes region and Ontario even issued warnings to warn people not to eat certain fish. Because of the high content of PCBs, mercury or other toxic substances in the body, people who often eat fish and wild animals consume more toxic substances than those who don't, especially those indigenous people, fishermen, their families and immigrants who live on fish and wild animals are the most vulnerable groups. According to an epidemiological study of Michigan residents at that time, it was shown that the concentration of PCBs in people who often ate fish with high PCB content was higher than others.

1971119 An overflow accident occurred in the waste water storage tank of the nuclear reactor of North Electric Power Company in Monticello, USA, and more than 50,000 gallons of radioactive waste water flowed into the Mississippi River, causing serious pollution. From 65438 to 0972, the Detroit River in the Great Lakes system caught fire because of long-term oil pollution. This incident finally attracted the attention of Canada and the United States and began to control the Great Lakes.

Therefore, the United States government imported eight kinds of Asian fish from Southeast Asia, including bighead carp, silver carp and grass carp, so-called Asian carp, and put them into some aquaculture lakes in the south to purify the water quality, which is an important part of this governance plan. Asian carp can eat aquatic plants and plankton equivalent to 40% of their own weight every day. Due to the scarcity of natural enemies, Asian carp breed in large numbers. In the 1980s, they even went north along the flood, competing with native fishes in North America for food and space. At present, Asian carp not only flood the Mississippi River, but also pose a serious threat to the primitive fish in the Great Lakes of North America.

It can be seen that the purpose of introducing Asian carp in the United States is to clean and improve the seriously polluted water quality in the United States. Therefore, the living environment of these Asian carp had nothing to do with the pollution-free pure water quality. So after decades of cleaning and treatment, is the water quality of these Asian carp pollution-free? Tmall tip: Puweixin imported from the United States can effectively prevent smog.

2. Current status:

Regrettably, from the public information, the situation in the Great Lakes region is still not optimistic. According to a report on 20 1 1, which was funded by the US Environmental Protection Agency (EPA), more than 170 scientists and researchers participated, and 300,000 sets of relevant data were used to demonstrate that although the mercury level in the Great Lakes region has been completely reduced in the past 40 years, the mercury content still exceeds the critical value acceptable to human beings and ecosystems. In addition, the scientific research cited in the report shows that, contrary to previous understanding, mercury content will have harmful effects on fish and wildlife at very low levels. This report was published in that year's Ecological Toxicology. (Here is the report link)

Today, the pollution in the Great Lakes is still very serious.

James G. Wiener, the research director of the report, said, "We selected six kinds of edible fishing fish as the research object. We found that in the study area of 6 1%, the average mercury content of these fish exceeded the human health standard stipulated by the US Environmental Protection Agency.