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This paper refers to a survey conducted in Zhengzhou section of the Yellow River for the purpose of investigating heavy metal pollution characteristics and of exploring the pollution sources. Monitoring was thereby carried on August 29-31, 2022 along the riparian zone collecting samples of the river sediments and analyzing the concentrations of nine kinds of heavy metal, including Cd, Pb, Cu, Zn, As, Hg, Cr, Ni and Mn. Then the Tessier five-step sequential extraction method was used for the morphological analysis of the heavy metals; the ground accumulation index (Igeo) was used to evaluate heavy-metal pollution degree, with Nemero pollution index being applied to the comprehensive assessment of the pollution situation; and the principal component analysis (PCA) and absolute factor analysis-multiple linear regression analysis model (APCS-MLR) were used to analyze the source of the pollutants. Consequently, the survey showed that both of the mean concentrations of Pb and Cd in the sediments of the riverine zone of Zhengzhou section of the Yellow River exceeded the soil background value of heavy-metal in Henan Province. Results of the speciation analysis showed that the environmental activities of Mn, Cd, Pb and Hg were relatively high; the evaluation of geo-accumulation index (Igeo) indicated that Cd had resulted in slight to moderate pollution in the sediments of the River; and the evaluation results of the Nemero pollution index showed that all the above-mentioned heavy-metal elements were on the safety level. Result of the source apportionment suggested that tannery industry, agricultural activities and automobile parts production, as well as the natural source were the major heavy-metal pollution sources in the riparian zone of Zhengzhou section of the Yellow River. [ABSTRACT FROM AUTHOR]

Amino sugars (AS) are routinely used as microbial biomarkers to investigate the dynamics of soil carbon (C) and nitrogen (N) under different environments. However, the effect of any AS on soil C and N, or other AS, is not well-defined. In this study, acid soils from Dongbei (D) and Fujian (F) and alkaline soil from Henan (H) were selected to perform an incubation experiment under glucosamine addition for 36 days. In the present study, the dynamics of soil soluble organic C (SOC), NH4+-N, NO3−-N, soluble organic N (SON), and four AS: glucosamine (GluN), mannosamine (ManN), galactosamine (GalN), and muramic acid (MurN), were investigated. The results showed that AS was different among the three soils, but had similar dynamics in the same soil. The higher total C and inorganic N in the D and F relative to the H soil were related to the greater AS in two soils. With incubation, AS decreased in D soil and increased in F soil before 1 week, while after 1 week, the inverse dynamics were observed, which suggest that SOC or SOC combined with inorganic N may be a mechanism to adjust the dynamics of C from AS. Overall, glucosamine addition did not significantly affect AS in D, while the reverse was true for F and H soils. Glucosamine addition decreased AS at day 0 for D soil and at day 3 for F and H soils, and increased SOC. The lowered NH4+-N and AS in D soil, but the higher values of these, were observed in F soil after 1 week of incubation. The increase of SON in D soil with glucosamine addition might be due to the depolymerization of soil organic matter (SOM) into SON. However, the decrease of SON in F soil could be attributed to the mineralization of SON. [ABSTRACT FROM AUTHOR]