[Environmental geochemical baseline of heavy metals in soils of the Ili river basin and pollution evaluation].

Environmental geochemical baseline models of Cu, Zn, Pb, As, Hg were established by standardized method in the ehernozem, chestnut soil, sierozem and saline soil from the Ili river valley region. The theoretical baseline values were calculated. Baseline factor pollution index evaluation method, environmental background value evaluation method and heavy metal cleanliness evaluation method were used to compare soil pollution degrees. The baseline factor pollution index evaluation showed that As pollution was the most prominent among the four typical types of soils within the river basin, with 7.14%, 9.76%, 7.50% of sampling points in chernozem, chestnut soil and sierozem reached the heavy pollution, respectively. 7.32% of sampling points of chestnut soil reached the permitted heavy metal Pb pollution index in the chestnut soil. The variation extent of As and Pb was the largest, indicating large human disturbance. Environmental background value evaluation showed that As was the main pollution element, followed by Cu, Zn and Pb. Heavy metal cleanliness evaluation showed that Cu, Zn and Pb were better than cleanliness level 2 and Hg was the of cleanliness level 1 in all four types of soils. As showed moderate pollution in sierozem, and it was of cleanliness level 2 or better in chernozem, chestnut soil and saline-alkali soil. Comparing the three evaluation systems, the baseline factor pollution index evaluation more comprehensively reflected the geochemical migration characteristics of elements and the soil formation processes, and the pollution assessment could be specific to the sampling points. The environmental background value evaluation neglected the natural migration of heavy metals and the deposition process in the soil since it was established on the regional background values. The main purpose of the heavy metal cleanliness evaluation was to evaluate the safety degree of soil environment.

Monitoring early toxicity of heavy metals including Hg using a HSE-SEAP reporter gene / 中国中药杂志

<p><b>OBJECTIVE</b>To develop a cellular assay based on heat shock signal pathway and secreted alkaline phosphatase (SEAP) reporter gene for investigating/predicting the early toxicity of heavy metals on HeLa cells in Chinese traditional medicine (TCM).</p><p><b>METHOD</b>The pHSE-SEAP plasmid was transfected into HeLa cells to build a HSE-SEAP-HeLa cell model. For validation of the model, the transfected cells were treated by either heating at 42 degrees C for 1 h or incubated with 5 mol x L(-1) CdCl2 for 4 h. Then the cells were covered in complete DMEM culture medium for 48 h and the activity of SEAP (reflecting the cellular level of heat shock protein) in cultural supernatants was measured; meanwhile, cell viability was determined by MTT assays. In addition, the cells were treated by four mercury compounds, HgCl2, merthilate sodium, HgS and cinnabar at the sub-lethal concentrations (determined by MTT assays). Then the heat shock response was detected likewise.</p><p><b>RESULT</b>Significant level of secreted alkaline phosphatase (SEAP) was found in pHSE-SEAP transfected HeLa cells treated either by heating (42 degrees C) or incubating with CdCl2. The heat shock protein was induced by CdCl2 before decrease of cell viability was observed. All four mercury compounds induced heat shock response in both time and concentration-dependant manner. However, there were big differences among the mercury compounds, suggesting potential differences for early-stage toxicity in vivo.</p><p><b>CONCLUSION</b>The pHSE-SEAP transfected HeLa cells respond effectively to heat shock and metal stresses, and therefore provide a practical and repeatable assay for investigating/predicting the early toxicity of heavy metals and mineral-containing drugs in TCM.</p>