Ruiming Han

Spatial patterns and origins of heavy metals in Sheyang River catchment in Jiangsu, China based on geographically weighted regression

Multivariate statistical analyses combined with geographically weighted regression (GWR) were used to identify spatial variations of heavy metals in sediments and to examine relationships between metal pollution and land use practices in watersheds, including urban land, agriculture land, forest and water bodies. Seven metals (Cu, Zn, Pb, Cr, Ni, Mn and Fe) of sediments were measured at 31 sampling sites in Sheyang River. Most metals were under a certain degree enrichment based on the enrichment factors. Cluster analysis grouped all sites into four statistically significant cluster, severely contaminated areas were concentrated in areas with intensive human activities. Correlation analysis and PCA indicated Cu, Zn and Pb were derived from anthropogenic activities, while the sources of Cr and Ni were complicated. However, Fe and Mn originated from natural sources. According to results of GWR, there are stronger association between metal pollution with urban land than agricultural land and forest. Moreover, the relationships between land use and metal concentration were affected by the urbanization level of watersheds. Agricultural land had a weak associated with heavy metal pollution and the relationships might be stronger in less-urbanized. This study provided useful information for the assessment and management of heavy metal hazards in studied area.

Reproduction capacity of Potamogeton crispus fragments and its role in water purification and algae inhibition in eutrophic lakes

The role of fragments in restoring eutrophic lakes remains unclear despite the importance of re-establishing submerged macrophytes via fragments. This study established a manipulative experiment using different biomass fragments of Potamogeton crispus. This approach was adapted to study the reproductive capacity, nutrient removal efficiency, and algae inhibitory effect of fragments. Results showed that fragments could grow throughout a 49-day experiment by maintaining the stable photosynthesis efficiency of leaves and lengthening the stems. These floating fragments could regenerate by producing turions for the maintenance of their species. Moreover, the increasing removal efficiency of TP, TN, NH4+-N, and NO3--N in water with the increase of fragment biomass indicates that the fragments could effectively purify water quality. Floating fragments competed with algae for nutrients, occupied a favorable ecological niche, and reduced algae biomass. They altered the structure of algae community and shifted the dominated green algae to cyanobacteria, the green algae of phytoplankton, and benthic algae. Findings imply that the postponable regulation of fragments is necessary for the ecological restoration of eutrophic lakes.

A century-long trend of metal pollution in the Sheyang River, on the coast of Jiangsu (China), reconstructed from sedimentary record

ABSTRACT In order to reveal the historical context of metal element accumulation under the economic boom during the last decades in eastern China, concentrations of nine metal elements, radionuclides (210Pb), Pb isotope ratios (207Pb/206Pb) and sedimentary characteristics were investigated in two sediment cores collected from the Sheyang River. The sediments have recorded the heavy metal deposition and thus allow establishing a connection between the temporal evolution of the heavy metal pollution and historical changes in industrial and urban discharges. Enrichment factors (EFs) were calculated to estimate the level of contamination in these sediments. A significant anthropogenic enrichment of Cu, Ni, Pb, Cr and Zn was highlighted, which were identified from anthropogenic discharges from cities and industrial sources, according to a cluster analysis. According to the annual variation in GDP growth rate, industrial growth rate, ratio of 207Pb/206Pb and EFs, it was obvious that sedimentary accumulation of metals has a close relationship with anthropogenic activities. In the pre-industrial period, natural inputs prevailed with lower EF and constant 207Pb/206Pb ratios around 0.82. However, during 1980–1995, the rapid industrial development caused a gradual increase in EFs and 207Pb/206Pb (>0.83). Our results disinterred the evolution of anthropogenic metal inputs in the last century into the Sheyang River.

Characterization of Metals in Surface Sediments From Xiaoyang River, Jiangsu, China

ABSTRACT Some metal species and fractions have high affinity to anthropogenic activities, making it feasible to characterize the spatiotemporal characteristics of human-induced degradation of ecosystems. The accumulation of Fe, Mg, Mn, Zn, Cu, Cr, Ni, and Pb, their fractions, physiochemical parameters, and nutrients was evaluated in the surface sediments at 11 sites on the Xiaoyang River in urban and suburban locations in Jiangsu, China for the assessment of pollution. The sediment quality was evaluated based on sediment quality guidelines, enrichment factors, geoaccumulation index, potential ecological risk index, and risk assessment code. Principal component analysis and cluster analysis were used to identify the sources of the metals. The total concentrations of metals, enrichment factors, and geoaccumulation indices demonstrated that all sites were significantly polluted with Zn and significantly to moderately polluted by Cu, Pb, and Ni. Moreover, higher metal enrichment was present downstream through downtown Sheyang due to extensive human activities. However, the potential ecological risk indices and risk assessment codes revealed high bioavailability and toxicity of Pb in this region. These results indicated that the metal fraction showed higher susceptibility. The accuracy of the ecological risk assessment was evaluated in the river, indicating a heavy anthropogenic impact.

Distributions of four taste and odor compounds in the sediment and overlying water at different ecology environment in Taihu Lake

Organic matter-induced black blooms, such as cyanobacterial and vegetation blooms, are a serious ecosystem disasters that have occurred in Taihu Lake. After large-scale outbreaks of blooms in eutrophic water, a large number of cyanobacterial and vegetation residue accumulate in the coastal areas, and rapidly fermented into odorous compounds. In this study, four taste and odor compounds have been analyzed in sediments and overlying water of different ecology environment in Taihu Lake. High concentrations of DMDS (up to 7165.25 ngg−1 dw−1), DMTS (up to 50.93 ngg−1 dw−1), β-cyclocitral (up to 5441.69 ngg−1 dw−1), β-ionone (up to 1669.37 ngg−1 dw−1) were detected in sediments. Also, the spatial distributions of DMDS, DMTS, β-cyclocitral and β-ionone in the sediments were investigated. As the depth of sediment increases, nutrients and odorous compounds are greatly reduced. The results showed that during the degradation of cyanobacterial and vegetation residues, DMDS, DMTS, β-cyclocitral, β-ionone and nutrients are gradually released. In addition, when assessing the source of odorous compounds in overlying water, it should also be considered that it may be released from the sediment. This study shows that odorous compounds are ubiquitous in near-shore zones Taihu Lake, and may take potential hazard to aquatic ecosystems.

Study on the Interaction of Retinoic Acids to Human Serum Albumin byFluorescence and Circular Dichroism Spectroscopy

Retinoic acids (RAs) are considered to be endocrine disruptor chemicals and toxic environmental priority pollutants. In this paper, the interactions between RAs and human serum albumin (HSA) were examined by steady state fluorescence, time-resolved fluorescence and circular dichroism spectroscopy (CD). The RAs quenched the fluorescence of the protein remarkably and the mechanism of quenching was found to be static in nature. Synchronous fluorescence studies suggested that the polarity around the tryptophan(Trp) residues and tyrosine(Tyr) residues was not altered in the presence of RAs. The thermodynamic parameters of the binding reactions (ΔGθ, ΔHθ, ΔSθ) were measured,and they indicated the presences of hydrophobic forces and hydrogen interactions in the RAs–HSA interactions. The alterations of HSA secondary structure in the presence of RAs were confirmed by CD and time resolved fluorescence spectroscopy.