Effect of multiple washing operations on the removal of potentially toxic metals from an alkaline farmland soil and the strategy for agricultural reuse

Few studies have carried out soil washing experiments using pot experiments to simulate in situ soil washing operations, particularly for alkaline soils. This study explored the effects of multiple washing operations using pot experiments on the removal efficiencies of potentially toxic metals (PTM) from alkaline farmland soil and the reuse strategy of washed soil for safe agricultural production. The results showed that the removal efficiencies of Cd, Pb, Cu, and Zn after seven washings with a mixed chelator (EDTA, GLDA, and citric acid) were 41.1%, 47.1%, 14.7%, and 26.5%, respectively, which was close to the results of the EDTA treatment. For the alkaline soil studied, the second washing with the mixed chelators most effectively removed PTM owing to the activation of them after the first washing operation. The mixed chelator more effectively increased the proportion of stable fraction of PTM and maintained soil nutrients (e.g., nitrogen content) than EDTA, indicating little disturbance of alkaline soil quality after washing with the mixed chelator. After the amendment of the washed soil, there was no visible difference in the biomass weight of crops from the soils washed with different agents, indicating that the inhibitory effect of both washing agents on plant growth was effectively alleviated. The Cd and Pb contents in Z. mays were below the threshold of Hygienical Standard for Feeds of China (GB 13078–2017) (1 and 30 mg·kg^?1). Moreover, after three cropping operations, the available concentrations of PTM in the soil washed with the mixed chelator were lower than those in the soil washed with EDTA, indicating the value and potential of agricultural reuse of alkaline farmland soil washed with the mixed chelator.

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Effect of composite amendments on physicochemical properties of copper tailings repaired by herbaceous plants

Environmental Science and Pollution Research - Phytoremediation is considered to be the most environmentally friendly green restoration technology for dealing with mine waste. Adding amendments can...     

Determination of 27 pharmaceuticals and personal care products (PPCPs) in water: The benefit of isotope dilution

• Isotope dilution method was developed for the determination of 27 PPCPs in water. • The established method was successfully applied to different types of water samples. • The correction effect of corresponding 27 ILSs over 70 d was investigated. • Benefit of isotopic dilution method was illustrated for three examples. Pharmaceuticals and personal care products (PPCPs) are a unique group of emerging and non-persistent contaminants. In this study, 27 PPCPs in various water samples were extracted by solid phase extraction (SPE), and determined by isotope dilution method using liquid chromatography coupled to tandem triple quadruple mass spectrometer (LC-MS/MS). A total of 27 isotopically labeled standards (ILSs) were applied to correct the concentration of PPCPs in spiked ultrapure water, drinking water, river, effluent and influent sewage. The corrected recoveries were 73%–122% with the relative standard deviation (RSD)<16%, except for acetaminophen. The matrix effect for all kinds of water samples was<22% and the method quantitation limits (MQLs) were 0.45–8.6 ng/L. The developed method was successfully applied on environmental water samples. The SPE extracts of spiked ultrapure water, drinking water, river and wastewater effluent were stored for 70 days, and the ILSs-corrected recoveries of 27 PPCPs were obtained to evaluate the correction ability of ILSs in the presence of variety interferences. The recoveries of 27 PPCPs over 70 days were within the scope of 72%–140% with the recovery variation<37% in all cases. The isotope dilution method seems to be of benefit when the extract has to be stored for long time before the instrument analysis.     

Study on phosphorus loadings in ten natural and agricultural watersheds in subtropical region of China

Water eutrophication in subtropical regions of southern China threatens watershed health and is of major concern. However, annual phosphorus (P) loading and its dominant causes are still unclear, especially at the watershed scale. In this study, we investigated dynamic P loadings and associated factors (e.g., land use, livestock production, and runoff depth) in ten watersheds that varied in area from 9 to 5,212 ha in a hilly area of Hunan Province, China. A flowmeter was installed at the outlet of each watershed, and total P (TP) and soluble P (SP) concentrations were monitored periodically from June 2010 to October 2012. The results showed that annual P loadings (APLs) in the ten watersheds ranged from 22.8 to 247.8 kg P/km² and that P loss primarily occurred from April to June of each year during the main rainfall season in the study area. In addition, the average eutrophication (>0.05 mg P/L) ratio for stream waters was 86.7 % during the study period, which was indicative of a potentially serious condition for the local water environments. Annual P loadings were linearly related to livestock density (LD; R?=?0.92, p?<?0.01), whereas the eutrophication ratio of stream water was significantly (p?<?0.05) correlated with LD (R?=?0.61), percentage cropland (R?=?0.71), and percentage forest cover (R?=??0.68). Thus, it is concluded that the control of livestock production has the greatest potential for reducing P loadings in watersheds in this subtropical area. This will be beneficial to the amelioration and protection of local environment.     

Optimization of bio-drying of kitchen waste: inoculation,initial moisture content and bulking agents

Journal of Material Cycles and Waste Management - Bio-drying has been proved to be a promising method for treatment of MSW (municipal solid waste) and sewage sludge due to its high energy...     

An investigation on pollutant emissions from co-firing of RDF and coal

Pollutant emissions from co-firing of refuse derived fuel (RDF) and coal were investigated in a vortexing fluidized bed combustor (VFBC). RDF-5 was made of common municipal solid waste (MSW). CaCO₃ was injected in the combustor to absorb HCl at 850 °C. The results show that NO_x and HCl emissions increase with RDF-5 co-firing ratio. The NO_x concentration in flue gas at the bottom of the combustor is higher than that at the top. However, the trend of HCl released is reverse compared with NO_x emissions. It was found that the HCl concentration decreases with increasing the molar ratio of Ca/Cl. However, the effect of CaCO₃ addition on HCl retention is not significant when the molar ratio of Ca/Cl is higher than 5. The chlorine content in fly ash increases obviously with the molar ratio of Ca/Cl. PCDD/Fs emissions decrease slightly with an addition of CaCO₃. In this study incomplete combustion is regarded as the main cause for polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) formation.     

Nitrogen removal performance and bacterial communities in zeolite trickling filter under different influent C/N ratios

Environmental Science and Pollution Research - In this study, the degradation performance of nutrients in zeolite trickling filter (ZTF) with different influent C/N ratios and aeration conditions...     

An evolutionary analysis of corruption in the process of collecting environmental tax in China

Environmental Science and Pollution Research - Considering the bargaining power of enterprises, this paper distinguishes between “Offering Bribes Voluntarily” (OBV) and “Offering...     

NABat: A top-down,bottom-up solution to collaborative continental-scale monitoring

Collaborative monitoring over broad scales and levels of ecological organization can inform conservation efforts necessary to address the contemporary biodiversity crisis. An important challenge to collaborative monitoring is motivating local engagement with enough buy-in from stakeholders while providing adequate top-down direction for scientific rigor, quality control, and coordination. Collaborative monitoring must reconcile this inherent tension between top-down control and bottom-up engagement. Highly mobile and cryptic taxa, such as bats, present a particularly acute challenge. Given their scale of movement, complex life histories, and rapidly expanding threats, understanding population trends of bats requires coordinated broad-scale collaborative monitoring. The North American Bat Monitoring Program (NABat) reconciles top-down, bottom-up tension with a hierarchical master sample survey design, integrated data analysis, dynamic data curation, regional monitoring hubs, and knowledge delivery through web-based infrastructure. NABat supports collaborative monitoring across spatial and organizational scales and the full annual lifecycle of bats.