For about a month now, durian prices have continuously dropped sharply. The Ri6 variety is currently purchased at the garden for 20,000-30,000 VND per kg, the lowest in many years and only about one-third the price during Tet. Meanwhile, the Monthong variety decreased to 70,000-80,000 VND per kg. Prices plummeted, causing many gardeners to lose money.
In addition to competitive pressure from Thailand, durian prices dropped because many shipments exported to China – the main consumer market – were returned due to cadmium contamination. Currently, China requires testing 100% of shipments, controlling cadmium content within the threshold of 0.05 mg/kg.
Cadmium is a heavy metal, arising from two main groups of causes including natural sources such as volcanic eruptions, mineralization, water sources and industrial production activities such as metallurgy, battery production, mineral exploitation, dyeing, and metal plating.
If waste and wastewater from these activities are not treated properly, cadmium can spread into the environment, seeping into soil and water sources. In addition, this element also exists in some input materials of the farming industry such as inorganic fertilizer (phosphate), manure, and waste sludge from organic fertilizer production.
Broccoli grown around durian roots has the effect of absorbing cadmium, helping to detoxify the soil. Image: Southern Fruit Tree Institute
Dr. Nguyen Thi Ngoc Truc, Southern Fruit Institute (SOFRI), said the cadmium content in agricultural soil is inherently insignificant. However, long-term overuse of chemical fertilizers, over-intensive farming, soil depletion, and poor control of industrial waste cause cadmium to accumulate more and more, causing many consequences for production.
In 2025, SOFRI collected and analyzed 63 durian garden soil samples and recorded that about 60% of the samples had cadmium content exceeding 0.05 mg/kg of soil, but still lower than Vietnam’s current regulations of 4 mg/kg of soil.
Meanwhile, more than 300 durian rice samples tested showed that about 5% of samples exceeded the threshold of 0.05 mg/kg according to China’s National Food Safety Standards.
According to Dr. Truc, controlling cadmium is not too difficult and can be gradually treated with biological and natural solutions. In particular, raising soil pH with lime and organic fertilizer helps plants limit the absorption of cadmium. Microbial preparations have the ability to immobilize, absorb and convert cadmium into a less or non-toxic form.
Additionally, some studies show that adding the right biochar to the soil can retain cadmium for a very long time, up to 100 years.
Purchasing durians at the garden in old Ben Tre, now Vinh Long. Image: Hoang Nam
Soil detoxification is done by intercropping plants that strongly absorb cadmium such as green mustard greens, mint, amaranth, water hyacinth, water spinach, water ferns, everlasting plants… After each crop, these plants need to be collected, burned and treated with ash properly to avoid spreading back into the environment.
According to SOFRI, initial research results show that proper fertilization, planting green mustard around durian roots combined with the use of biological products help reduce cadmium content in durian rice.
In addition to farming solutions, Dr. Vo Huu Thoai, Director of SOFRI, recommends that localities and the agricultural sector need to develop maps of cadmium contaminated areas, strictly control heavy metal content in fertilizers circulating on the market, and strengthen inspection of durian quality right at the garden.
According to the Department of Crop Production and Plant Protection, by 2025 the durian area in the country will exceed 150,000 hectares, double the planning orientation for 2030.