Impact of metallurgy on the environment: based on an illegal mining pollution case in Beijing, China

With the great economic benefits that metallurgy can bring to us, serious environmental pollution can occur if metallurgical sewages and tailings are not properly disposed. This study aimed to report a real environmental pollution case that happened in Miyun, Beijing. The suspect components left after mining and the toxicity of the sewage samples were analyzed using a comprehensive forensic approach. Five sewage samples and nine soil samples were collected from the crime scene. The heavy metal and total cyanide contents in these samples were tested using inductively coupled plasma atomic emission spectrometry and ultraviolet–visible spectroscopy, respectively. The soil samples were analyzed by x-ray diffraction. Moreover, the effects of metallurgical sewage on the morphological behavior and activity inhibition rate of Daphnia magna were investigated. The results showed that the sewage samples contained small amounts of Au, large amounts of Cu, and total cyanide. The soil samples contained Mg, Fe, and many other metal elements. The biotoxicity results indicated that all of the five sewage samples caused serious deformation or other problems of D. magna. Furthermore, the study reconstructed the metallurgical process of the case according to the experimental results. In conclusion, the sewage samples contained hazardous waste, and the heavy metal content exceeded the safety standard of China.