Presence, sources, and risk assessment of heavy metals in the upland soils of northern China using Monte Carlo simulation

The spatial dynamics of heavy metal contamination in the upland soils of northern China are relatively unknown, despite the region's high contribution to the national grain output. In this study, the concentrations of As, Cd, Co, Cr, Cu, Mn, Pb, Sb, Sc, Ti, and Zn and subsequent ecological and human health risks were investigated in three major grain producing areas (Hexi Corridor, L1; Hetao irrigation area, L2; and eastern Inner Mongolia, L3) of northern China. Among the heavy metals, Ti had the highest average concentration of 3.02 g/kg, followed by Mn (470 mg/kg), Cr (56.6 mg/kg), Zn (34.3 mg/kg), Pb (19.4 mg/kg), Cu (17.8 mg/kg), Co (9.66 mg/kg), Sc (7.26 mg/kg), As (5.35 mg/kg), Sb (0.73 mg/kg), and Cd (0.17 mg/kg). Generally, the heavy metal concentrations decreased from west to east (L1 > L2 > L3) across northern China. Moreover, three potential sources of the heavy metal were distinguished, including natural process, anthropogenic activities (industrial development and agricultural cultivation), and atmospheric deposition. Although the contamination of the single metal (including Cd, Cr, Cu, and Pb) was moderate in L1 and L2, the combined contamination was low in the upland soils. It was noted that Cd posed a moderate to considerable ecological risk on the upland soils in northern China. This metal was the most sensitive factor in assessing the combined ecological risk, with a contribution rate of 91.56-94.84%. Considering the ingestion exposure, the current concentrations of the metals posed minimal risks to human health. Furthermore, children experienced higher health risks than adults. Present study analyzed the probabilistic distribution of contamination, ecological, and health risk of heavy metals in upland soils of northern China, providing fundamental information for better agricultural heavy metal pollution assessment in China.

Comparison of two series of non-invasive instruments used for the skin physiological properties measurements: the DermaLab® from Cortex Technology vs. the series of detectors from Courage & Khazaka

BACKGROUND/PURPOSE

The detectors from Courage & Khazaka and DermaLab^® from Cortex Technology were two series of the most commonly used non-invasive instruments for the skin physiological properties measurements. The aim of this study is to reveal the differences and correlations in measuring skin color, hydration, transepidermal water loss (TEWL), sebum and elasticity on the forearm or faces between two commercially available series of instruments.

METHODS

30 subjects were enrolled to be measured by the two series of instruments. The measurements by each series were performed on the left/right side of the body randomly. The hydration, sebum, elasticity and TEWL measurements were performed on different sites.

RESULTS

Positive correlations were found in the values of skin color, hydration, TEWL, sebum and visco-elasticity detected by the two series. The values related to skin firmness measured by the two instruments were statistically negative correlated. Contrary to the results in measuring the skin color, the detectors from Courage & Khazaka presented lower values of variation in measuring skin hydration and TEWL than those from DermaLab^® .

CONCLUSION

The two series have significant correlations.The differences of the two series can be due either to differences in the design of the probe or left/right part of the body.

[Cross-section anatomy of the subphrenic spaces]

The cross-section anatomy of the subphrenic spaces were investigated in 20 Chinese cadavers. On the horizontal sections, the subphrenic spaces consist of the perihepatic and perisplenic spaces. The fissure for ligamentum venosum was separated into two parts by the lesser omentum, the anterior part communicates with gastrohepatic recess, the posterior is the superior recess of the omental bursa into which the caudate lobe of the liver projected. The bare area of the stomach encroaches upon the posterior surface of the gastric fundus between the right and left layers of the gastrophrenic ligament and lies between the superior and splenic recesses of the omental bursa. Left subphrenic retroperitoneal space is between the bare area of the stomach and the diaphragm.