Hongyun Ren

Bio: Hongyun Ren is an academic researcher from Chinese Academy of Sciences. The author has contributed to research in topics: Medicine & Solid phase extraction. The author has an hindex of 3, co-authored 4 publications receiving 91 citations.

Zwitterion-functionalized polymer microspheres as a sorbent for solid phase extraction of trace levels of V(V), Cr(III), As(III), Sn(IV), Sb(III) and Hg(II) prior to their determination by ICP-MS.

Abstract: This paper describes the preparation of zwitterion-functionalized polymer microspheres (ZPMs) and their application to simultaneous enrichment of V(V), Cr(III), As(III), Sn(IV), Sb(III) and Hg(II) from environmental water samples. The ZPMs were prepared by emulsion copolymerization of ethyl methacrylate, 2-diethylaminoethyl methacrylate and triethylene glycol dimethyl acrylate followed by modification with 1,3-propanesultone. The components were analyzed by elemental analyses as well as Fourier transform infrared spectroscopy, and the structures were characterized by scanning electron microscopy and transmission electron microscopy. The ZPMs were packed into a mini-column for on-line solid-phase extraction (SPE) of the above metal ions. Following extraction with 40 mM NH4NO3 and 0.5 M HNO3 solution, the ions were quantified by ICP-MS. Under the optimized conditions, the enrichment factors (from a 40 mL sample) are up to 60 for the ions V(V), As(III), Sb(III) and Hg(II), and 55 for Cr(III) and Sn(IV). The detection limits are 1.2, 3.4, 1.0, 3.7, 2.1 and 1.6 ng L−1 for V(V), Cr(III), As(III), Sn(IV), Sb(III) and Hg(II), respectively, and the relative standard deviations (RSDs) are below 5.2%. The feasibility and accuracy of the method were validated by successfully analyzing six certified reference materials as well as lake, well and river waters.

Interactive effects of microplastics, biochar, and earthworms on CO2 and N2O emissions and microbial functional genes in vegetable-growing soil.

Abstract: Soil carbon dioxide (CO2) and nitrous oxide (N2O) emissions are two main greenhouse gases that play important roles in global warming. Studies have shown that microplastics, biochar, and earthworms can significantly affect soil greenhouse gas emissions. However, few studies have explored how their interactions affect soil CO2 and N2O emissions. A mesocosm experiment was conducted to investigate their interactive effects on soil greenhouse gases and soil microbial functional genes in vegetable-growing soil under different incubation times. Biochar alone or combined with microplastics significantly decreased soil CO2 emissions but had no effect on soil N2O emissions. Microplastics and biochar inhibited CO2 emissions and promoted N2O emissions in the soil with earthworms. The addition of microplastics, biochar, and earthworms had significant effects on soil chemical properties, including dissolved organic carbon, ammonia nitrogen, nitrate nitrogen, total nitrogen, and pH. Microplastics and earthworms selectively influenced microbial abundances and led to a fungi-prevalent soil microbial community, while biochar led to a bacteria-prevalent microbial community. The interactions of microplastics, biochar, and earthworms could alleviate the reduction of the bacteria-to-fungi ratio and the abundance of microbial functional genes caused by microplastics and earthworms alone. Microplastics significantly inhibited microorganisms as well as C and N cycling functional genes in earthworm guts, while biochar obviously stimulated them. The influence of the addition of exogenous material on soil greenhouse gas emissions, soil chemical properties, and functional microbes differed markedly with soil incubation time. Our results indicated that biochar is a promising amendment for soil with microplastics or earthworms to simultaneously mitigate CO2 emissions and regulate soil microbial community composition and function. These findings contribute to a better understanding of the interaction effects of microplastics, biochar, and earthworms on soil carbon and nitrogen cycles, which could be used to help conduct sustainable environmental management of soil.

Trace Elements in Soils of Urban Areas

Abstract: Urban soils are an essential element of the city environment. However, studies on urban soils are scattered in terms of geographical distribution, sampling pattern, analytical dataset, etc. One of the major issues arising from the studies on this ecosystem is the diffusion of its contamination. In cities, in fact, the proximity to humans may cause a serious danger for citizens. In the present study, results from the literature about trace elements in urban soils are presented to compare methodologies and results and to offer a basis for the harmonization of investigation approaches and establishment of remediation thresholds. A total of 153 studies on the urban ecosystem published in the last 10 years were collected and data on trace elements in soils of 94 world cities were compared and discussed. Data highlights the discrepancies among different studies (sampling strategies, analytical procedures) and the extreme variability of urban soils. Most cities are contaminated by one or more trace elements, revealing the environmental relevance of the urban soil system. While Pb is still one of the major concerns in many locations, new contaminants are on the rise and would deserve more attention from the researchers. While in fact some contaminants are almost ubiquitous in world cities and could be used as tracers for urban contamination, some traffic-related elements such as platinum, rhodium, and palladium, whose reactivity and toxicity is still unknown, are becoming of concern. Collation of literature data highlights the need for the harmonization of sampling, analytical, and rendering procedures for regulatory purposes and provides a useful dataset for environmental scientists dealing with the urban ecosystem and for city planners. A sampling design adapted to local urban patterns, a prescribed sampling depth, and a minimum set of elements that deserve to be measured could be the core of a common methodology.

Availability and bioaccessibility of metals in fine particles of some urban soils.

Abstract: Metals in urban soils might be transferred to humans via ingestion, dermal contact, or breathing, especially to children due to the “hand to mouth” activity during outdoor activities in playground and recreational areas. This involuntary soil ingestion depends on soil adherence to skin; it is known that the adhesion process tends to exclude particles greater than 50 μm, so the fraction below this diameter would be the most dangerous for health. The aim of this work was to study the “availability”, estimated by the EDTA extraction, and “oral bioaccessibility”, estimated by the Simple Bioaccessibility Extraction Test (SBET), of several metals in urban soils of two European cities (Sevilla and Torino), as related to the soil particle size distribution. Torino and Sevilla showed different levels of metal contents, availability, and bioaccessibility. In Torino, the finer particles showed metal enrichment of Cu, Zn, and, to a lesser extent, Pb, whereas in Sevilla, all of the studied metals showed this enrichment compared to the whole soils. The whole soil cannot be used as a good general indicator of the bioaccessibility of metals in the finest fractions of the soil. Metal availability was higher in the clay fraction (<2 μm) than in other fractions or whole soils in both cities, and principal component analysis shows that availability is especially due to this fraction. In contrast, Cu and Pb bioaccessibility in the clay fraction seems to be slightly lower than, or comparable to, all of the other fractions and the whole soil. Bioaccessibility of Cr and Ni is clearly greater in the coarser fractions of Sevilla than those of Torino, despite the considerably greater total contents of both metals in the latter city. Adsorbed metal forms are assumed to be preferentially responsible for metals released by EDTA. A different origin is attributed to bioaccessible metal forms. Anthropic influence seems more important in determining metal availability and bioaccessibility in urban soils of both cities than the different geological or industrial characteristics.