Preliminary Study On The Content And Speciation Of Arsenic In Coal And Soil, And Arsenic Emission From Coal Of A Village In Guizhou Province

Arsenic is one of the largest hazardous trace elements in the environment, which has been listed as the first category of pollutants. Endemic arsenic poisoning (EAP) is widespread and locally seriously in China. It contains water arsenic poisoning and coal-burning arsenic poisoning. The latter one occurred mainly in the southwest of Guizhou.According to the progress of the research for the arsenic in coals, the study is focused on analysis of As content and modes of occurrence in the coal, soil, fly ash and crop from a village, Guizhou, through X-ray Diffraction (XRD), Sequential chemical extraction, ICP-MS analysis. Based on this, we get to research for the migration and transformation of arsenic. Then the local arsenic emission and the arsenic on the local environment are assessed.Based on the study, some conclusions can be drawn:(1)Arsenic content in these coals range between17.83μg/g and 140.64μg/g, and the average mean of Arsenic is 93.31μg/g, whose content is higher than China (6.4μg/g), so as the world (5.0μg/g)and other conturies(24μg/g in the USA).(2)Arsenic occurrence in coal is various in Xingren, Guizhou. The sequence of the average levels of arsenic occurrence in coal is: residual arsenic(56.74%)﹥Fe-Mn oxide arsenic (20.74%)﹥sulfide arsenic (15.20%)﹥organic arsenic (5.07%)﹥carbonate arsenic (1.73%)﹥soluble and exchangeable arsenic (0.52%). Arsenic in coal is mainly residual arsenic, and Fe-Mn oxide arsenic is the second highest. There is a coal sample exception, whose content is lower than other samples relatively, and organ arsenic is the largest in all modes. With previous studies, the result can be inferred: the coal is mainly organic arsenic, but not easy to extract.(3)The average of the arsenic content in soil is 99.62μg/g, and the distribution of the range of 15.71～169.55μg/g, is higher than the world (6.0μg/g) and China (9.2μg/g) average concentration of arsenic in soil. The percentage of each occurrence distributiin soil is as follows: residual arsenic (72.16%)﹥sulfide arsenic (15.45%)﹥Fe-Mn oxide arsenic (5.89%)﹥organic arsenic (3.06%)﹥carbonate arsenic ( 2.51%)﹥soluble and exchangeable arsenic (0.93%). (4)The calculation can be shown, the arsenic emissions from large coal-fired of residents everyday, get to 576.22 mg, and annual emissions to reach 0.21 kg, emission rate is higher. Either arsenic emissions are much different among the three places.(5)Crops'arsenic content is higher among these three sample areas, exceeding allowable value of arsenic in food (0.7μg/g and 0.5μg/g). The higher arsenic emissions from coal-burning areas, the larger arsenic content in crops.