[Enrichment Factors, Health Risk, and Source Identification of Heavy Metals in Agricultural Soils in Semi-arid Region of Hainan Island].

To understand the enrichment factors and pollution levels of heavy metals in agricultural soils in the semi-arid region of Hainan island, 1818 surface soil samples were collected in Gancheng Town and analyzed for their heavy metal contents and physicochemical composition. Correlation analysis was used to determine the heavy metal enrichment factors. The geo-accumulation index (Igeo), comprehensive ecological risk index (RI), and hazard index (HI), as well as carcinogenic risk (CR), were used to assess the degree of pollution and health risk. Positive matrix factorization (PMF) was used to determine the primary sources of pollution and priority sources. The average values of heavy metal contents in the topsoil were 22.7, 0.128, 33.4, 14.5, 0.032, 9.32, 32.5, and 43.3 mg·kg-1 for As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn, respectively. With the exception of Zn, the concentrations of other heavy metals in the topsoil were higher than the soil background values of Hainan, showing different degrees of heavy metal accumulation effect. The Igeo revealed that the major pollutant element in soils was As, followed by Cd and Cu. The RI showed that the proportion of soil samples that were high-risk level or worse was 29.4% of the total number of samples, among which As was the major source of risk. The health risk assessment results indicated that As, Cr, and Ni exposure presented carcinogenic risk for children with high CR values. Based on PMF, four major sources of heavy metals were identified in the study area. Hg was derived mainly from industrial sources, and As was closely associated with agricultural activities. Ni, Cu, Cr, and Zn were related to soil parent materials. Pb and Cd were associated with agricultural activities and traffic emissions. The PMF models combined with correlation analysis were useful for estimating the source apportionment of heavy metals in soils.

[Accumulation and Health Risk of Heavy Metals in Cereals, Vegetables, and Fruits of Intensive Plantations in Hainan Province].

The accumulation of some harmful elements in plants from intensive production systems pose a serious threat to human health. In this study, seven heavy metals(Cu, Pb, Zn, Cr, Cd, As, and Hg) and their distribution characteristics in the crops, vegetables, and fruits were analyzed alongside single factor evaluation and Nemero index analysis. Combined with dietary recommended consumption data from the Chinese Nutrition Society, the dietary exposure of heavy metals were further analyzed, and a consequent safety risk assessment was conducted. A total of 673 crop, vegetable, and fruit samples were collected from typical intensive production systems in Hainan Province. The results showed that the content of Cu, As, and Hg in the 673 plant samples was below the value of the national food standard. The exceed rates of Pb, Zn, Cr, and Cd were 2.67%, 3.71%, 2.53%, and 3.71%, respectively. The heavy metal comprehensive pollution degree of six species of plants showed the trend of leafy vegetables > tuber crops > non-leafy vegetables > legume crops > fruits > cereals. In particular, Cr in leafy vegetables showed significantly higher hazard quotients(HQ) than that in other types, and exceeded 1, suggesting a high potential health risk via the ingestion of heavy metals through leafy vegetables. The relatively lower hazard index(HI) values of tuber crops, non-leafy vegetables, legume crops, fruits, and cereals suggest that these types of plants are more suitable for intensive production systems.

[Comparative proteomics of pancreatic cancer].

OBJECTIVE: To identify differentially expressed proteins between pancreatic tumor tissues and the adjacent noncancerous tissues by comparative proteomics analysis. METHODS: Six pairs pancreatic tumor tissues and the adjacent noncancerous tissues were obtained and selected for two-dimensional polyacrylamide gel electrophoresis (2-DE) analysis. The differentially expressed proteins were identified using the PDQuest 2-D analysis software. After cutting and enzymolysis, the differentially expressed proteins were analysised by ESI-Q-TOF mass spectrometer. The MS/MS data were acquired and searched in the Swiss-Prot database using MASCOT software. Altered expression of representative proteins was validated by immunohistochemical staining. RESULTS: A total of 97 points were identified as differentially expressed by two-dimensional gel electrophoresis, of which 31 were successfully identified by ESI-Q-TOF mass spectrometer. Among the proteins identified by mass spectrometer, 23 were upregulated and the other 8 were downregulated. These proteins were involved in different functional processes and protein families: glucolysis, hyaluronidase, I, II-phase metabolic enzymes, metalloproteinase, cytoskeleton, Ca2+ metabolism and so on. Immunohistochemical staining revealed an overexpression of HYAL1 and low expression of CYP2C8 and GSTM2 in pancreatic tumor. CONCLUSION: The differentially expressed proteins between pancreatic tumor tissues and the adjacent noncancerous tissues can be identified by comparative proteomics approach. The selected proteins will provide a valuable clue and help for further research.