Establishment of pre-treatment method on analysis of heavy metal forms in sewer sediments

With the modified BCR sequential extraction method, the ultrasonic vibration and microwave digestion techniques were applied to extract heavy metal forms in sewer sediments. Considering the influence of extraction time, temperature, extractant concentration and the digestion types on the extraction efficiency, the optimal testing conditions of sediments pre-treatment were defined. Compared with the results obtained from the traditional method, the modified extraction procedure demonstrated excellent repeatability, reproducibility. The extraction time of every step could be shortened to about 3h, only 1/5 of the traditional method. Hydrochloric acid concentration increased from 0.5mol/L to 0.8mol/L. Its accuracy is also evaluated by standard samples. The obtained results showed that the extraction method is fut and reliable, and satisfied the requirement of followed quantitative analysis. It could serve as a relatively rapid, accurate and stable pre-treatment method for the research of heavy metal pollution in sewer sediments.