WSOC Study The Interaction Between Migration And Cd Tianjin Binhai Plain Alkaline Soil Salinization Vadose Zone Of Heavy Metals

In this paper, The alkaline salinization soil of the the Tianjin Coastal Plain were digested by microwave digestion, using inductively coupled plasma mass spectrometer (ICP-MS) determination of the total amount of Cd in the soil profile of the sampling points, and its distribution characteristics were also analyzed, the results show that:the Cd content of the0-40cm soil in the soil profile of each sampling point is higher and and the change is bigger,40cm below the soil Cd content changed little. According to the soil environmental quality standard of Tianjin, the Cd content in the0-40cm soil of six sampling points, one is in level5belongs to the severe pollution while one is in level4belongs to the moderate pollution, the remaining four are in level3belong to light pollution.Throughout each sampling point,40cm below the Cd content in soil was in the third level Tianjin soil environmental quality standard.WSOC at different depth in soil profiles of the six sampling points has extracted and determined, the results showed that:WSOC content in soil profiles of the six sampling points are concentrated distribution in the soil at the depth of0-40cm, below40cm soil WSOC content showed a trend of obvious gradually reduce. Through the correlation analysis, it found that the Cd content and WSOC content in soil at different depth in the soil profile is positively related, but the relevance is not general.Through indoor simulation experiment, the Cd content and WSOC content of soil under different degrees of salinization of alternating wet and dry condition were determined and analyzed, the experiments showed that:(1) Alternating wet and dry conditions, with increasing alternating wet and dry cycles, the Cd content in the soil of different salinization degree showing a decrease-increase-decrease trend. Which salinization degree of dry and wet alternation, Cd content changed most obviously in the0-60cm soil. It can be seen, the increase of salinity is conducive to the vertical migration of Cd in soil.(2) Alternating wet and dry conditions, with increasing alternating wet and dry cycles, the WSOC content in the soil of different salinization degree showing a first increase and then decrease trend, the trend is most evident particularly in the soil at the depth of0-40cm. WSOC content in soil increased with salinity increasing, and the increase in salinity will aggravate WSOC leaching in the soil at the depth of0-40cm, and the downward migration.By the analysis of the relevant index (R2) between the total amount of Cd and WSOC alternating wet and dry conditions of varying degrees of salinization of soil vadose zone, it found that:with increasing alternating wet and dry cycles, the relevant index has decreased under the control of0mol/L NaCl solution, the relevant index increasing under the control of0.05mol/L NaCl solution, the relevant index declining under the control of0.1mol/L NaCl solution, Three trends all in the third cycle (21d)when it reaches the extremum.