[Health Risk Assessment and Priority Control Factors Analysis of Heavy Metals in Agricultural Soils Based on Source-oriented].

To analyze the source apportionment and health risk of heavy metals in agricultural soils of major producing areas of agricultural products in Chongqing, a positive matrix factorization (PMF) model and health risk assessment (HRA) model based on Monte Carlo simulation were used. Meanwhile, both the PMF and HRA model were combined to explore health risks of heavy metals in agricultural soils by different pollution sources in order to determine the priority control factors. The results showed that the average values of Cd concentration were higher than its corresponding background value; the average values of Cr concentration were lower than its corresponding background value; and the average values of As, Pb, Cu, Ni, and Zn concentration were basically consistent with their corresponding background values. Using PMF model analysis, natural sources, industrial sources, and agricultural sources were identified as the determinants for the accumulation of heavy metals in agricultural soils, with the contribution rates of 35%, 24%, and 41%, respectively. Using the HRA model based on Monte Carlo simulation analysis, carcinogenic risks of adult and children were tolerable (1.00E-6 < TCR ≤ 1.00E-4), whereas non-carcinogenic risks were acceptable (HI ≤ 1). Oral ingestion was the main exposure pathway. The analysis results of the relationship among heavy metals, pollution sources, and health risks showed that industrial pollution and As were identified as priority control factors, and agricultural pollution and Cd were identified as secondary control factors. Our findings provide scientific support for decision makers to control soil pollution and reduce the management costs of soil pollution.

[Health Risk Assessment of Heavy Metals in Agricultural Soils Around the Gangue Heap of Coal Mine Based on Monte Carlo Simulation].

To analyze the pollution characteristics of heavy metals in the soil of farmland surrounding the gangue heap of a coal mine in Chongqing, the Nemerow, Muller, and Hakanson indices were used. Meanwhile, to investigate the health risks of heavy metals in soil, a health risk assessment model was employed using Monte Carlo simulation. The results revealed that the average contents of Cd, Hg, As, Pb, Cr, Cu, Ni, and Zn were higher than their soil background values, and the Muller index (Igeo) from high to low was as follows:Cd>Hg>Cu>As>Ni>Zn>Cr>Pb. The Nemerow index (PN) demonstrated that the results of the assessment indicated mainly light pollution (1Cu>Ni>Cr>Zn>As>Pb>Hg. The Hakanson index (RI) demonstrated that the results of the assessment indicated mainly moderate ecological risk (150 ≤ RI<300). The single ecological risk index (Eri) from high to low was as follows:Cd>Hg>As>Cu>Ni>Pb>Cr>Zn. The health risk assessment of heavy metals revealed that the non-carcinogenic health risks of children and adults could be ignored, but carcinogenic health risks existed, with an average total carcinogenic risk index (TCR) of 1.04E-5 and 3.94E-6, respectively. The major carcinogenic factors were As and Cd. Sensitivity analysis of non-carcinogenic health risks revealed that the ingestion rate of soil (Ringest) was the most sensitive, followed by the contents of As. Meanwhile, sensitivity analysis of carcinogenic health risks indicated that the content of As was the most sensitive, followed by the ingestion rate of soil (Ringest). In general, the health risks of children, including non-carcinogenic and carcinogenic risks, were higher than those of adults.

[Health Risk Assessment and Environmental Benchmark of Cadmium in Farmland Soils around the Gangue Heap of Coal Mine, Chongqing].

To analyze the health risk assessment and environmental benchmark of cadmium in farmland soils surrounding the gangue heap of a coal mine in Chongqing, Hakanson, the ecological risk index and health risk assessment were used. Meanwhile, the soil environmental reference value of the regional cultivated land was inverted based on the species sensitive distribution model (SSD). The results showed that the dryland soil was polluted by Cd, with an over-standard rate of 55.8%, and the paddy field soil was polluted by Cd, with an over-standard rate of 31.6%. The corn was polluted by Cd, with an over-standard rate of 4.4%, and the rice was not polluted by Cd. The Hakanson ecological risk index showed that Cd was mainly characterized in soils by high ecological risk and considerable ecological risk. The health risk assessment indicated that Cd presented low non-carcinogenic risk by corn and rice; however, it showed acceptable carcinogenic risk by corn and unacceptable carcinogenic risk by rice in this study. The sensitivity analysis of health risks showed that the content of Cd was the most sensitive. The SSD inversion showed that the reference values for Cd in dryland soil of pH ≤ 5.5, 5.57.5 had HC5 values of 0.491, 0.382, 0.376, and 0.588 mg·kg-1, respectively, and that for Cd in paddy soil had an HC5 value of 0.807 mg·kg-1. The reverse analysis showed that the HC5 of Cd in dryland soil (pH ≤ 7.5) and paddy soil was relatively relaxed and was higher than the soil risk screening values, which showed that the current standard was relatively loose. However, the HC5 of Cd in dryland soil (pH>7.5) was lower than the soil risk screening values, which showed that the current standard was relatively strict. It is suggested that the current soil standard could be adjusted in this area.

Application of the microarray technique to cell blocks.

OBJECTIVE: To evaluate whether the technique ofmicroarray construction can be applied to paraffin-embedded cell block specinmens. STUDY DESIGN: We used a manual microarray method for construction of a well-aligned cell microarray. First we evaluated the cellularity of the cell block and assigned the cases to the null, low, moderate or high cellularity category. Second, based on the different cellularity, we constructed 25 specimen cylinders into 1 block. We used routine hematoxylin-eosin (H-E) stain and immunocytochemistry (ICC) on the slide. RESULTS: All cell microarray paraffin block shaping and specimen cylinder arraying were finished in 1 step, so the specimen cylinders and the paraffin blocks of the cell microarray could very easily be incorporated. No sample was lost during the H-E staining process. However, a few samples fell off partially during the ICC process. Additionally, we observed that the higher cellularity groups yielded a better outcome as compared to the lower cellularity groups. CONCLUSION: This study introduced a very simple and economical technique for the creation of cell microarrays from cell blocks. This procedure should acquaint cytopathologists with microarray technology and encourage its use.

A simple and economical method for the manual construction of well-aligned tissue arrays.

Tissue array technology has allowed a substantial progression of studies correlating molecular and immunohistochemical findings with clinico-pathological information. Array construction presents technical difficulties and tissue arrayers are expensive, particularly for small and medium sized laboratories. We describe a simple manual method for producing well-aligned tissue arrays using a hand-made paper mold which can successfully perform immunohistochemical staining. All 200 tissue samples were collected and constructed into blocks by the paper mold. The tissue arrays were smoothly sectioned using a standard microtome and performed for a panel of immunohistochemical study with satisfactory results. This alterative method for building custom arrays could be applied in any laboratory and is both simple and economical.