| Chromium salts is an important inorganic chemical products,there are10%typesof products related with chromium in china.Calcium roasting process is most used inChina to produce sodium dichromate,the process including solid, liquid and gas phasereactions, and generates great amount of chromium waste.The chromium saltsenterprise covers a wide range,most of waste of the chromium salts enterprise has notbeen directly stockpiled without treatment.This has resulted chromate enter soil andundergroundwater in a long-term rainfall leaching, causing serious environmentalpollution and threaten human health and life safety.Investigations of surrounding soil of chromate plant show that, surrounding soilof the selected plant has caused serious pollution, urgently needed remediation;Thecontent of chromium changes with the distance;Pollution of chromium slag heap inthe surrounding soil is more serious in downwind of southeast than other directionsand both sides of roads outside the chromate plant have also been polluted seriously.Inthe aquifer a certain point of Cr (Ⅵ) concentrationchanges with the time and extent ofcontamination, does not relate with distance of pollution resource; The variation of Cr(Ⅵ) concentration stabilize gradually with the depth increases.The main process of hexavalent chromium migration and transformation in theaquifer is physical migration,hexavalent chromium flows directly with groundwater,for trivalent chromium the main control process of migration and transformation inthe aquifer is precipitation-dissolution and adsorption-desorption,Hexavalentchromium pollutes the aquifer with the groundwater flow,pollution level varies withchromium concentration,there is a positive correlation between them, the correlationcoefficient is0.9958,but concentration has not effect to the time ofpollution.Hexavalent chromium emergence time, time of reaching equilibriumconcentration and final concentration of hexavalent chromium change with the rate. |
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