Chromium Contamination Accident in China: Viewing Environment Policy of China

Abstract

C (Cr) is the second most abundant inorganic groundwater contaminant at hazardous waste sites. Due to the difference in the toxic nature of both the forms of Cr, the discharge of Cr (VI) into surface water is regulated to below 0.05 mg L 1 by the U.S. Environmental Protection Agency, whereas the total Cr (including Cr(III), Cr(VI) and its other forms) is regulated to below 2mg L . Since Cr(VI) is known to be very mobile and hazardous to human health through inhalation, skin contact, and ingestion, being highly toxic, carcinogenic and mutagenic to living organisms, even when present in very low concentrations in water. Cr compounds released into the environment have been increasing continuously as a result of industrial activities and technological developments, posing a significant threat to the environment and public health because of their toxicity, accumulation in the food chain and persistence in nature. Cr(VI) contaminates through various industrial processes such as electroplating, metal finishing, leather, mining, petroleum refining, wood preservation, corrosion inhibition in power plants and nuclear facilities, manufacturing of pigments, dyes, textiles, carpets, magnetic tapes, jet aircrafts, refractory materials, etc. In spite of the fact that the industry is constantly looking for efficient and innovative routes for chromium recovery or detoxification, large amounts of such soil and wastewater are still released to the environment, throughout the world, every year. China is the largest amount of Cr slag produced country, and there are about 25 enterprises producing Cr salts, of which the annual production capacities reach 329,000 tons and the annual discharges of Cr slag reach 450 000 tons. The storage of untreated Cr slag in past years has exceeded 400 million tons. In China, there are strict environmental regulations on Cr wastes treatment, which require all of Cr wastes must be through harmless treatment before released to environment and every disposal process on Cr wastes must be registered and can be traced. However, on August 13th, 2011, serious Cr slag contamination accident occurred in Qujing in Yunan province. The reason on this accident was due to the amount of 5000 tons of untreated Cr slag, produced by Lvliang Chemical Industry Co., Ltd., was illegally dumped into mountains and Nanpan River located at the source of Zhujian River (Figure 1). The contamination accident lead to the over standard of Cr (VI) concentration detected in Nanpan River was about 2000 times. As government involved in the investigation, they found that there were about 288 400 tons Cr slag piled at the back door of the chemical industry without any other treatment, which there was only one meter distance to Nanpan River. From 1989 to 2005, the storage of Cr slag in the chemical industry has increased to 288400 tons, whereas this industry took no any other detoxification treatment in order to saving treatment cost. Therefore, two drivers were employed by the chemical industry to dump the Cr slag into nearby mountains and reservoirs. With Cr pollution enlarges and media reports, local environment protection department and police arrested the two drivers and close the chemical industry rapidly. However, the effects of Cr slag on ecology, environment and health will last for many years. The Xinrong village is the nearest village to the chemical industry, which is also called “dead village”. According to the villagers’ description, there were at least six to seven people living in this village who died of cancer. Meanwhile, in this village, a total of 77 cows and sheep suddenly died due to drinking Cr polluted water. Although the truths on Cr slag contamination were gradually disclosed, it also leads to a crisis of public confidence. According to the investigation results on the accident, we found that on June 12, 2011, the environmental protection department in Qujing has received an accusation on Cr slag pollution from this chemical industry, whereas the local government opened the processing results on this accident until August 13, 2011. We have enough