China (Jianxi) – Bioremediation of Farmland at Guixi Smelter

The Problem

A large copper smelter has caused cadmium, arsenic, copper and lead contamination in soil and water.  This  project seeks to remediate rice paddies in the region contaminated by the smelter.  Phase 1 is complete and Phase 2 is underway.

Blacksmith Institute worked with the Jiangxi Academy of Environmental Sciences and the Guixi Environmental Protection Bureau to stop endemic lead poisoning and remove other heavy metals from one of the largest copper smelters in China. This work is conducting a risk assessment and testing soil remediation strategies in one of the most highly affected residential areas – ShuiDuiQuan Village.

The purpose of this project is to demonstrate technically and economically viable methods to remediate agricultural land, in particular rice paddies, contaminated with cadmium, copper, and arsenic in Guixi, Jiangxi Province. The contamination is due to heavy metal releases from a large copper smelter in Guixi. These releases were both to the atmosphere, resulting in deposition on the rice paddies, and into water used for rice paddy irrigation.

The desired goal is to be able to restore the paddies sufficiently that they can return to agricultural use for food crops. The minimum goal is to remediate the land to meet the standard for urban land utilization and eliminate the risk of direct impact to human health and the environment.

Background

The Guixi Smelter is the largest copper-smelting factory in China. It was established at the beginning of the 1980’s and contributes greatly to the local economy. However, it also has discharged significant pollution to the local environment, particularly metals (copper, cadmium, arsenic, lead and others) and acid gases (SO2 and H2SO4). Fifteen villages with a total population of 10,000 people are affected. The affected rice farmland area has been estimated at 132 hectares and vegetable farmland at 6 hectares.

Guixi City is located in the Northeast of Jiangxi province, along the Xinjiang River. The geology is cretaceous red sandstone with little groundwater. The ground water is mainly born in the soil, being perched and phreatic groundwater. The soil in the area and in particular, the project area, is red soil and paddy soil.

The pilot project is locted adjacent to ShuiDuiQuan village, one of the severely polluted areas, southwest and directly downwind (in the prevailing wind direction) of the smelter factory. Water in the area formerly came from the Keshalong reservoir, which serves as a cooling and wastewater discharge point for the smelter, but now discharges from this reservoir are diverted around the project area via a canal and are discharged directly to the Xinjiang River. The project area now receives water from a smaller reservoir constructed below the Keshalong reservoir, which does not receive direct discharges from the smelter, although it may receive contaminated discharges from contaminated soil, surface runoff and several small other industrial sources.

The project area was formerly used for wetland rice, but is now unused, although there are small fields in the area used for vegetables and a few rice paddies are still in use nearby. There are three (3) ditches from the lower reservoir to the village for the purpose of irrigation.

From The Pollution Blog:

Detoxing Polluted Rice Paddies With Lime