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In order to investigate the effect of long-term (1991—2013) K fertilizer deficiency and surplus on potassium-bearing mineral and K nutrition of purple soil-soil primary, clay mineral composition and potassium (K) nutrition were determined on the long-term experiment of fertility and fertilizer efficiency in neutral purple soil by using X-ray diffraction (XRD) analysis technique. Five soil samples were selected from soil samples library for soil mineral analysis, including original soil, which preserved in 1991 before the experiment carrying out; K deficient treatment for 12 years and 22 years, which means no K fertilizer was applied during 1991—2003 and 1991—2013, respectively; and K surplus treatment for 12 years and 22 years, which means excess K fertilizer was applied during 1991—2003 and 1991—2013, separately. The result showed that, soil potassium-bearing primary mineral, such as mica, potassium feldspar, had apparently weathered and slaked for the K deficient treatment and the weathered extent gradually aggravated following fertilization ages, demonstrating fertilization for 22 years12yearsoriginal soil. However, for K surplus treatment, the content of mica and potassium feldspar only had a little decline. As similar with primary mineral, for soil clay potassium mineral, the content of illite and mica was also seriously reduced for K deficient treatment and a slightly declined for K surplus treatment, representing the disintegration of soil potassium mineral under rice-wheat rotation system, and the deficient input of K fertilizer would obviously accelerate this weathering process. The two treatments all represented raising of vermiculite with the increasing of fertilization ages, and it’s much higher on K surplus treatment than K deficient treatment. In addition, we found that the silica-sequioxide ration of soil clay, which indicated the degree of soil weathering, decreased as the fertilization ages increasing, and after 22 years K deficient input soil clay had the lowest silica-sequioxide ration, showing the greatest weathering extent of soil clay silicate minerals. To further research the changing of soil K nutrition, we analyzed the content of soil available K, slowly available K and total K. The result indicated that, for K deficient treatment, soil available K and slowly available K content all gradually declined with the increasing of fertilization ages, about 62.0% and 37.4% down from 1991 to 2013, respectively. While there had a gain trend of soil available K content after long-term K surplus input, versus slightly dropping of slowly available K content. However, we found that long-term fertilization had no obvious effect on soil total K content. Therefore, long-term K deficiency could have negative effect on soil K, exhausting soil K resource and accelerating soil mineral weathering. It seems to be difficult maintaining soil slowly available K and potassium-bearing mineral content, even excess applied K fertilizer.

A method for the determination of five trace elements, including Pb, Cd, Se, As and Hg concentrations in human whole blood by HNO3-H2O2 digestion under temperature-controllable condition and ICP-MS was described. Under the optimum experimental conditions and instrumental operation parameters, the limit of detection for the five elements were 2-40 ng x L(-1). The system had a good stability with RSDs of the determination of value repeated 3 times less than 3%. The accuracy of the method was evaluated by the results of determination of the Chinese national standard references GBW(E)09034-09036 and GBW09101b, and the analytical results well agreed with the certified values. Using this method, the concentration of the five elements in whole blood of 34 habitants from mercury mining area in western Human province was studied. The result showed that the blood Se and blood As level was at security scope, however, blood Pb, Cd and Hg level was too high and beyond the safety thresholds which should be concerned about. The analytical method mentioned above can be used for determination of trace elements in human blood to achieve a convenient and rapid operation and accurate result.

A method for the determination of Hg, Pb and As concentrations in soil and sediment samples by the BCR and HG-ICP-AES technique was described. Under the optimum experimental conditions and instrumental operation parameters, the detection limits of Hg, Pb and As of the method were 0.6, 1.5 and 0.8 ng x mL(-1) , respectively. Meanwhile, the analytical results of Hg, Pb and As in the Chinese national standard sediment reference samples were in good agreement with the certified values with the RSDs below 8%. Using the BCR and HG-ICP-AES technique, the content of each chemical species of Hg, Pb and As in soils of nonferrous metal mine area in western Hunan province was studied. The result showed that the Hg, Pb and As contents in soils were dominated by residual form, followed by organic and Fe-Mn oxides form, whereas acid-exchangeable form was rather low. The concentrations of the four Hg species in mine soil were 1.2, 3.0, 47 and 272 times higher than those in the control soil. While the concentrations of Pb and As in the same samples were 1.2, 4.6, 8.1 and 4.5 times and 1.5, 2.9, 3.3 and 2.2 times higher than those in the control soil, respectively. The results indicated that the soil in mine area in western Hunan province was co-polluted polluted by Hg, Pb and As.

In the present paper, a method for the determination of trace elements such as Hg and As in biological samples by HG-ICP-AES was presented. Under the optimum experimental conditions and instrumental operation parameters, both the RSDs of Hg and As with the method were below 3%, and the detection limits were 0.6 ng Hg x mL(-1) and 0.8 ng As x mL(-1), respectively, satisfying the demand of detecting trace Hg and As concentration in biological samples. Meanwhile, the analytical results of Hg and As in the national standard reference samples such as human hair (GBW 09101), rice (GBW 08503) and tea leaf (GBW 08505) were in good agreement with the certified values, with RSDs around 5%. Using the HG-ICP-AES method, the concentrations of Hg and As in human hair samples of polymetallic mining area in western Hunan province were determined, and the result shows that human in the mining area was exposed to high levels of Hg and As. The concentrations of Hg and As in the mining area were 1.290 and 1.865 microg x g(-1) respectively, 3.59 and 2.44 times higher than those in the control area, respectively.

Trace elements (Cu, Zn, Fe, Ca, Mg, Mn, Al, K, Ba, P, Sr, Cd, V, Cr, Ni, Pb and Co) concentrations in the drinking water of KBD-affected and non-affected areas were measured using ICP-AES. The RSD of this method was between 0.80% and 2.83%, and the analytical results of the reference samples were consistent with the certified values. The method was simple and accurate. The results indicated that there is an obvious difference in trace elements concentrations between KBD-affected areas and non-afffected areas. The results provided a scientific theoretical basis to improve the conditions of drinking water in KBD-affected areas in Tibet.