Yangtze River Pollution: Understanding The Primary Causes

The Yangtze River, the largest source of fresh water in China, is now dangerously polluted. Nearly half of the 400 million people who depend on it are without safe drinking water. The river's pollution is caused by industrial, domestic, and municipal wastewater discharges, as well as agricultural chemical fertilizer, sediment accumulation, ship garbage, and acid rain. The World Bank has approved loans to enhance ecological protection and reduce water pollution, but the fight against pollution is still ongoing.

Industrial and municipal wastewater discharges

The Yangtze River, the largest source of fresh water in China, has been facing severe pollution, threatening the drinking water safety of nearly half of the 400 million people who depend on it. Industrial and municipal wastewater discharges are a significant contributor to this issue.

Industrial Wastewater Discharges

Industrial wastewater is a major source of pollution in the Yangtze River. The river basin is home to numerous chemical plants, oil refineries, steel mills, and other industrial facilities that continuously discharge untreated sewage and liquid waste into the river. For instance, the Chongqing Municipality at the upper reaches of the river has been plagued by industrial waste from chemical companies.

From 2001 to 2009, there was an overall declining tendency in industrial Chemical Oxygen Demand (COD) and ammonia nitrogen (NH4-N) discharges in China. However, the production effect, which is caused by changes in the scale of economic activity, was a major factor contributing to the increase in these pollutant discharges. The intensity effect, influenced by changes in the technological level of each sector, also played a significant role, with cleaner production contributing to a reduction in COD and NH4-N discharges.

Municipal Wastewater Discharges

Municipal wastewater discharges also contribute to the pollution of the Yangtze River. Rapid population growth and inadequate wastewater infrastructure in cities like Chongqing have led to the discharge of raw domestic sewage into the river. The opening of the Three Gorges Dam further impacted the flushing and assimilative capacity of the river.

Mitigation Efforts

To address the pollution in the Yangtze River, the Chinese government and the World Bank have initiated various projects and policies. The World Bank has provided loans and grants to improve wastewater treatment infrastructure and reduce pollution from plastics and animal manure. The Chinese government has enforced new regulations to prevent and control pollution from ships, including prohibiting the discharge of untreated sewage. Additionally, companies along the river, such as Sinopec Jiujiang, have invested in projects to mitigate pollution and promote green transformation.

Solid trash and plastic waste

The Yangtze River Economic Belt (YREB) is of strategic importance to China, contributing to around 42% of the country's GDP and providing food and energy security. However, the dominance of industries such as agriculture, chemical production, and textile dyeing and finishing has come at a significant environmental cost. Solid waste, primarily plastic, enters the river from these industrial and agricultural activities, as well as from population centres along its banks. In some places, the trash accumulates to form entire islands.

Plastic pollution in the Yangtze River has dire consequences for wildlife in the surrounding areas. Animals have been found with microplastics in their stomachs, leading to their slow deaths. The river is also a major conduit for plastic pollution in the oceans, carrying 333,000 metric tons of plastic to the oceans annually. This contributes to the global plastics crisis and has potential implications for water security and fish stocks in the Asia-Pacific region.

The Chinese government has taken some measures to address plastic pollution in the Yangtze River. They have appointed local party members as river chiefs accountable for water quality, levied fees on single-use plastic bags, and relocated highly polluting chemical factories away from the river. Additionally, the World Bank has approved loans to enhance ecological protection and reduce water pollution, including plastic waste, in the Yangtze River basin.

The ineffectiveness of waste management and pollution prevention in China has exacerbated the problem. Population growth, rapid economic development, and changes in consumer lifestyles have increased plastic consumption and waste. The lack of waste treatment facilities, particularly in rural areas, has resulted in plastic waste being dumped into landfills or directly into the river.

Shipping and transport pollution

The river's status as a "golden waterway" has led to extensive shipping activity, with vessels transporting various goods, including dangerous substances such as oil, toxic chemicals, fuel oil, liquefied gas, gasoline, and alcohol. This activity has resulted in fuel and other hazardous materials ending up in the river, posing a significant ecological risk. The construction of hydropower dams, including the world's largest, the Three Gorges Dam, has also been identified as a potential factor influencing the accumulation and distribution of pollutants in the river.

In addition to the direct discharge of pollutants, shipping and transport activities have indirect effects on the river's ecosystem. For instance, the World Bank has identified the Yangtze River basin as a conveyor of plastic and other pollutants to the world's oceans. This means that the river acts as a pathway for pollutants to reach the oceans, contributing to the broader issue of marine plastic pollution.

Furthermore, the heavy usage of the Yangtze River for shipping and transport has led to concerns about the safety of drinking water. The river provides the main source of water for almost 600 million people, and the high volume of shipping activity increases the risk of water contamination. This issue is exacerbated by the discharge of industrial and municipal wastewater, which contains pollutants such as heavy metals and chemicals from agricultural activities, further compromising the safety of the drinking water sourced from the river.

To address these issues, the Chinese government has implemented various measures, including the Yangtze River Protection Law, which aims to strengthen the management of pollutant reception, transfer, and disposal facilities. Additionally, financial subsidies and policy support are being provided to promote the use of shore power facilities in ports and improve overall water management planning. The World Bank has also approved loans to enhance ecological protection and reduce water pollution, with a focus on improving wastewater treatment and reducing pollution from plastics and animal manure.

Agricultural chemical fertiliser

The river is now so polluted that nearly half of the people who depend on it do not have access to safe drinking water. It is perhaps the most polluted river in the world, with 55% of the material ending up in neighbouring seas and oceans.

An increase in agricultural fertiliser application will exacerbate water pollution, and the worsening water quality in the upper watershed, along with precipitation, will lead to transboundary water pollution in the lower watershed. The amount of fertiliser application and application intensity have a threshold effect on river water quality pollution. When the former exceeds the threshold value of 11.496 tons, and the latter exceeds the threshold value of 7.991 ton/km2, the positive effect is lost. Unreasonable application of fertilisers can result in compacted soil and heavy metal accumulation, with excess nutrients, including nitrogen and phosphorus, entering the water body through soil denudation, direct surface runoff, and leaching loss. This can aggravate the eutrophication of surface water bodies, causing nitrate pollution of groundwater, and seriously threatening the health of the water body.

However, it is important to note that some strategies have proven effective in reducing agricultural non-point source pollution in the Yangtze River basin. For example, the use of organic and controlled-release fertilisers in Yaoqiao County, Zhenjiang City, Jiangsu Province, from 2016 to 2018, reduced the total nitrogen and total phosphorus input for rice and wheat by 20% and 27%, respectively, without any yield loss. The N and P concentrations in the ecological ditches declined by 8%–50.4% for TN and 12%–69.7% for TP compared to the control ditches, and further declined after the purification of eco-ponds. Additionally, the "4R" system, which stands for source reduction, process retention, nutrient reuse, and water restoration, has been successful in improving water quality in other agricultural intensive regions.

Sewage treatment and management

The Yangtze River, the largest source of freshwater in China, has been facing critical levels of pollution due to various factors, including industrial, domestic, and municipal wastewater discharges. To address this issue, several measures have been implemented, and sewage treatment and management play a crucial role in these efforts.

The World Bank's projects have had a positive impact on the water quality in Chongqing, a megacity in China. By providing technical training and upgrading management standards, the projects have helped raise awareness of the unique heritage of the city and improved its liveability during a time of rapid change and urbanisation. The construction of interceptor pipelines, with grants from the Japanese government, has been instrumental in achieving these improvements.

However, the increasing population and industrial growth in the region continue to exert pressure on the river. To keep up with the rising sewage output, additional wastewater treatment plants and landfills are necessary. The World Bank's recent approval of a $200 million loan for ecological protection and pollution reduction in the Hubei Province section of the river is a step in the right direction. This financing is expected to strengthen ecosystem management, reduce water pollution from plastics and animal manure, and enhance wastewater treatment capabilities.

Furthermore, the Chinese government has also committed significant resources to complement the World Bank's financing. The total program financing over a five-year period is projected to be $1.1 billion, with the World Bank contributing $200 million and China providing $874 million. This collaborative effort demonstrates a strong commitment to addressing the sewage treatment and management challenges facing the Yangtze River.

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