In ancient Chinese literature, one of the oldest and most influential pieces of divination text is the I Ching, or Book of Changes. It features the story of Shennong, the first Yan Emperor and the “Divine Husbandman”, who taught the Chinese people agriculture:
“When Pao Hsi’s clan was gone, there sprang up the clan of the Divine Husbandman. He split a piece of wood for a plowshare and bent a piece of wood for the plow handle, and taught the whole world the advantage of laying open the earth with a plow.”
- I Ching, Book II: The Material
It is likely the Divine Husbandman believed China would continue to use his knowledge to cultivate the land indefinitely. Thousands of years later, however, it is beginning to look like this will not be the case. Heavy metal soil contamination, caused mostly by industrial activity, means that the percentage of arable land in China is decreasing. This is increasing health risks of consuming crops grown in this poisonous soil and threatening the stability of the food chain as
The origins of soil contamination
Before the 20th century, China was a completely agrarian society. However, the creation of the People’s Republic of China in 1949 under the Chinese Communist Party (CCP) spurred a new age of industrialization within the country. Development of the country came in several phases. Communist leader Mao Zedong ushered in the first phase with the first Five Year Plan (1953-57), the goal of which was to increase industrial production and output. The subsequent phase, called the Great Leap Forward (1958-1950), intended to continue advancement of industry within China. However, due to imbalances between industrial and agricultural growth and inflexibility of leadership, this plan was largely a failure. In fact, it caused the largest man made famine in history, killing an estimated 45 million people.
In the 1960s the second Five-Year Plan was able to recover some of the devastation of the preceding years, but it wasn’t until Mao Zedong’s death and new leadership was assumed within the CCP that the country completely made up for their losses. Beginning in 1978, the Chinese Communist Party reformed their economic policy. The CCP targeted deficiencies and imbalances in production, with the goal of growing exports. Unlike previously, however, this time was met with success. For about the next 30 years, China’s economy would grow about 10% each year, bringing with it a whole slew of environmental issues.
The uninterrupted expansion of China’s economy has since winded down, but the environmental impacts of that period of unchecked growth have not. One of the most pressing consequences of this has been heavy metal contamination of soil. Heavy metals are naturally present in soil in small quantities, however, certain human activities can introduce higher than normal levels into the soil. In 2013, the Ministry of Environmental Protection produced a book stating that one-sixth of China’s arable land - nearly 50 million acres - was polluted with dangerous metals like arsenic, cadmium, and nickel. This caused nationwide panic as the government had always kept information on the state of the environment tightly under wraps, leaving most people unaware of the true scale of pollution. But these “state secrets” were finally starting to reveal themselves and the true extent of heavy metal contamination was beginning to be uncovered.
Food chain dilemmas
China’s per capita land area is less than half of the world average, meaning that it cannot afford to lose any of that valuable property to pollution. So far, China has been able to utilize this small fraction of the world’ arable land to feed nearly 20% of the world’s population. The country produces ¼ of the world’s grain, reaching a 686.53 million ton output in 2022. In addition, it is the top global producer of cereals, fruit, vegetables, fishery products, meat, poultry, and eggs. However, over the last two decades, China has begun to rely more and more on food imports, indicating that they are no longer able to produce a sufficient harvest to support their population.
Heavy metal soil contamination is known to decrease productivity of cropland. Excess heavy metal in the soil is taken up into plants through their roots, accumulating and causing damage. They decrease seed germination, root elongation, plant biomass, and chlorophyll biosynthesis.
In 2000, China’s food self-sufficiency ratio was at 93.6 percent. In 2022, it was 65.8 percent. The ratio is predicted to decrease about 10% more by 2030, largely in part to reduction of safely cultivable land. Still in the shadow of the famine caused by the Great Leap Forward, China cannot afford another food security crisis. Recent events have already begun to unveil how sensitive China is to food distribution disruptions. Supply chain disruptions during the COVID-19 pandemic caused food shortages and frantic appeals from people starving under lockdown. More recently, the Russian war on Ukraine has again demonstrated China’s food instability. Ukraine is one of the largest corn exporting countries, and China is its biggest buyer. Ukrainian grain production suffered a heavy blow due to the Russia-Ukraine, and China was not left undisturbed by this.
Health risks and “cancer villages”
A 2022 study found the main sources of soil heavy metal pollution in China to be metal mining and smelting, industrial activities, power generation, agricultural activities (e.g. utilization of fertilizer and animal manure), waste disposal, urban development, and transportation. Certain areas of the country constitute heavy metal contamination levels greater than others. Hunan Province in central China, for example, has some of the worst soil in the nation. This is mainly due to the area being a top provider of nonferrous metals. Byproducts associated with production of these metals, including industrial and mining wastewater, as well as dust released during mining and smelting, lead to toxic levels of heavy metals into the soil. This has severe implications as nonferrous metals are not the only major contribution of the region. Hunan Province also makes up around 15% of China’s rice production. In 2021, the region produced 26.83 million metric tons of rice. Grain samples collected and tested for heavy metals from various locations around China revealed that rice originating in Hunan Province contained the highest levels of cadmium and lead. In addition, several other provinces were discovered to have grain samples that contained greater than acceptable levels of multiple heavy metals.
One could imagine the implications of crops being grown in such poisonous soil. Crop production does decrease from heavy metal contamination, but the plants that do survive will contain a dangerous accumulation to toxins. Humans who then consume these plants are exposed to their effects. For example, cadmium is a probable human carcinogen that also causes kidney disease and weakened bone structure after long periods of exposure. When ingested, it causes stomach irritation, vomiting, and diarrhea. Another example, lead, is a probable human carcinogen and that can accumulate over time, wreaking havoc on the body. It is especially detrimental to young children, causing brain and nervous system damage, learning disabilities, delayed growth and development, and hearing and speech problems. For both lead and cadmium poisoning, there are no cures, with the only available option being to manage symptoms as they arise. Other heavy metals cause similarly disastrous effects.
Many studies done in China have suggested higher health risks associated with heavy metal soil pollution in China. Some of the most pressing evidence comes from the so-called “cancer villages”. Various sources claim that there are around 400-500 different cancer villages in China, which are locations in which an unusually high level of cancer cases are recorded, most likely having to do with environmental problems. These villages first started appearing in the 1980s, which coincides with the time when the Chinese Communist Party revamped their economic policy and industrialization really began to take off. The Chinese government has admitted to the existence of these villages, but has continued to keep information about them shielded from the public. A 2015 study attempted to use the limited available data on these villages to create a map of their locations. They concluded that cancer villages tended to cluster around major rivers and their tributaries, almost always densely populated and near industry facilities. In addition, the researchers noted that the highest levels of cancer morbidity came from grain producing regions in China. Hunan Province was one such region where the densest locations of cancer villages were found.
Current efforts and future actions
In February of 2015, the documentary “Under the Dome” went viral in China, revealing shocking portrayals of soil contamination, as well as air and water pollution, within the country. Within one month the Chinese government blocked access to the film. This extreme censorship makes it very difficult to gauge the levels of heavy metal soil contamination in China, let alone solve it. Despite this, it seems like the government is beginning to understand the severity of soil contamination within the country. In 2019, the Chinese government declared a “farmland redline” policy stating that China’s total arable land should never fall below 120 million hectares. In February of 2022, the government announced the first national soil survey in 40 years. The survey will take more than four years to complete, but when finished it should give the country a better understanding of what they are dealing with.
The future of China’s soil in the face of heavy metal soil contamination is largely unknown. We do not know for sure whether the country will fully commit to their pledge of reversing the damage caused by industrialization and heavy agriculture. It remains to be seen whether Shennong, the Father of Agriculture’s, legacy will remain within the soils of China.