Research and Application of Analytical Technique onδ18Op of Inorganic Phosphate in Soil / 分析化学

Analytical technique on oxygen isotope composition of phosphate in soil has important applications in biogeochemical research. As the composition of the soil is complex with multiple oxygen sources, a liable phosphate enrichment and purification technology is important for phosphate oxygen isotope research. Here we presented a protocol on the analysis of the δ18 Op of inorganic phosphate in soil, and phosphate was purified with multiple mineral precipitations and finally precipitated as silver phosphate. The efficiency of NH4 OH purification method was examined and the purity of the product was verified through XRD and element analysis. The result showed that treatment of the Ag3 PO4 sample by recrystallizing with ammonia could remove the impurity efficiently without significantly modifying oxygen isotope compositions. The validity of sample processing and reliability of isotope analyses were confirmed by processing a KH2 PO4 standard in parallel with soil P sample. The analytical result of three soil types indicated that this method provided good precision of 0. 2‰. The differences of δ18 Op between three soils groups are significant ( From 15. 2‰ to 19. 5‰) and can be used to tracing P sources.

Health Risk Assessment of Soil-oral Exposure of Heavy Metal Contaminated Soil by in vitro Method / 环境与健康杂志

Objective To assess the health risk of soil-mouth exposure of soil heavy metal pollution by in vitro method. Methods Collected the soil sampling from the heavy metals contaminated field and roadside. Digested the soil sample by in vitro device and determined the content of Cd, Pb, Zn in the solution in the simulated stomach phase and intestine phase respectively with ICP-MS after centrifuging. Calculated the exposure and assess health risk. Results Bioaccessibility of Cd, Pb and Zn at the stomach phase was 21%-33%, 2%-28%, 33%-43% respectively in the polluted areas, and 27%, 23%, 95% in the control area; At the intestine phase was 16%-19%, 3.4%-4.9%, 8%-14% in polluted areas and 11%,2.6%,18% in control area respectively. The amount of available Cd, Pb and Zn in the stomach phase was 0.04-1.46 ?g/d, 3.09-5.53 ?g/d, 3.86-9.39 ?g/d in polluted areas and 0.01 ?g/d, 0.74 ?g/d ,5.64 ?g/d in control area for children, and 0.01-0.36 ?g/d, 0.77-3.88 ?g/d, 0.97-9.85 ?g/d in polluted areas and 0.00 ?g/d. 0.19 ?g/d, 1.41 ?g/d in the control area for adult ; at intestine phase the amount of available Cd, Pb and Zn was 0.03-0.71 ?g/d, 0.50-9.92 ?g/d, 1.26-9.55 ?g/d in polluted areas and 0.00 ?g/d, 0.08 ?g/d, 1.07 ?g/d in the control area respectively for children, 0.01-0.18 ?g/d, 0.11-2.48 ?g/d, 0.31-2.39 ?g/d in the polluted areas and 0.00 ?g/d,0.02?g/d,0.27 ?g/d in the control area respectively for adult. Conclusion Heavy metals exposure through soil-mouth pathway will increase the total health risk of heavy metal to exposed population.

Advances in in vitro Tests in Evaluating Bioavailability of Heavy Metals in Contaminated Soil via Oral Intake / 环境与健康杂志

As the intake routes and hazards to human health of heavy metals were well recognized,therefore the intake amount of heavy metals through foodchain has been effectively controlled and cut down. In many cases,oral ingested soil has become an important source of heavy metals in human. The traditional approach for estimating the bioavailability of heavy metals in oral ingested soil was animal (in vivo)test. Compared with animal test,in vitro test possesses several advantages including satisfactory replicability,time and cost effectiveness. Also,the results of in vitro tests showed well correlation to those of in vitro tests. The progress of development,current status and the methodology of in vitro tests in evaluating bioavailability of heavy metals in contaminated soil via oral intake were reviewed in this article. In vitro test could be used not only to estimate the bioavailability of heavy metals in soil in order to provide information for establishment of soil quality or clean-up criteria with regard to human health,but also to evaluate the effectiveness of soil remediation technologies. The in vitro test has been employed in many developed countries due to its above mentioned advantages. The use of in vitro test for screening of contaminated soil and evaluating the effectiveness of remediation technology is believed to be promising.