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The background value of cadmium (Cd) in soil and water sediments in the karst area is 0.31 mg kg−1, with a typical high background of cadmium geochemistry. It is well-known that Cd is classified as a highly toxic metal. Therefore, at the Yelang reservoir in Guizhou province, eco-toxicological tests were carried out using Daphnia pulex. The Geo-Accumulation Index and Potential Ecological Risk Index were used to assess the environmental risk of Cd in sediments. The Cd contents in the sediments of Yelang reservoir ranged from 2.51 to 5.23 mg kg−1, while the LC50 values of the acute toxicity test of Daphnia pulex and Cd at 24, 48, 72, and 96 h were 1.17, 0.50, 0.24, and 0.12 mg L−1, respectively, giving a Safe Concentration threshold of Cd of 1.20 × 10−3 mg L−1 in the water body. Based on curve fitting the solid–liquid two-phase distribution model of cadmium in Yelang reservoir was Y = 7.59 × 10−9 × X2.58 (R2 = 0.9995). The safety threshold sediment Cd concentration was 103 mg kg−1, and was much higher than the Cd content in the sediment of the Yelang reservoir. The Geo-Accumulation Index (Igeo 2.432–3.491) results show that the sediments had reached medium-strong or strong risk levels. The Potential Ecological Risk Index (
Faustino Dinis; Hongyan Liu; Qingdong Liu; Xuewen Wang; Meng Xu. Ecological Risk Assessment of Cadmium in Karst Lake Sediments Based on Daphnia pulex Ecotoxicology. Minerals 2021, 11, 650 .
AMA StyleFaustino Dinis, Hongyan Liu, Qingdong Liu, Xuewen Wang, Meng Xu. Ecological Risk Assessment of Cadmium in Karst Lake Sediments Based on Daphnia pulex Ecotoxicology. Minerals. 2021; 11 (6):650.
Chicago/Turabian StyleFaustino Dinis; Hongyan Liu; Qingdong Liu; Xuewen Wang; Meng Xu. 2021. "Ecological Risk Assessment of Cadmium in Karst Lake Sediments Based on Daphnia pulex Ecotoxicology." Minerals 11, no. 6: 650.
Hongfeng Lake is one of the largest artificial freshwater lakes on the Karst plateau of China, and the control of external nutrient input into the lake by a vegetation buffer zone is key to mitigating its eutrophication. Although soil microbial communities play key roles in nitrogen pollutant interception and in maintaining ecosystem stability, few studies have investigated these communities in lake vegetation buffer zone soils. In this study, the effects of seasonal and human disturbances on soil microbial communities of the vegetation buffer zones of Hongfeng Lake were determined by high-throughput sequencing and community profiling. BIOENV analysis revealed that soil redox potential was the primary factor associated with soil microbial community composition during the wet season, while Total nitrogen better explained variation in the dry season microbial communities. The relative abundances of Cyanobacteria were significantly higher in vegetation buffer zone soils that were polluted by upstream livestock and domestic sewage. Further, analysis of microbial community network topological features indicated that the soil microbial communities of the vegetation buffer zone markedly differed between wet and dry seasons. Specifically, wet season community networks suggested that the proliferation of Cyanobacteria, E. coli, and Panaeolus papilionaceus inhibited the growth of microorganisms capable of nitrification and denitrification, thereby contributing to increased risk of nitrogen loss to surface waters. Based on these results, we suggest that discharge of domestic sewage and livestock wastewater should be prohibited along Hongfeng Lake tributaries. Moreover, vegetation should be artificially managed to improve the mitigation of non-point source pollution into the lake via vegetation buffer zones.
Zhu Chen; Hong-Yan Liu; Chen Rao; Chang Jiang; Yue-Chen Tan; Tu Yu; En-Jiang Yu; Pan Wu. Soil microbial community dynamics indicate disruption of nitrogen cycling by pollution in vegetation buffer zones. Pedobiologia 2021, 85-86, 150722 .
AMA StyleZhu Chen, Hong-Yan Liu, Chen Rao, Chang Jiang, Yue-Chen Tan, Tu Yu, En-Jiang Yu, Pan Wu. Soil microbial community dynamics indicate disruption of nitrogen cycling by pollution in vegetation buffer zones. Pedobiologia. 2021; 85-86 ():150722.
Chicago/Turabian StyleZhu Chen; Hong-Yan Liu; Chen Rao; Chang Jiang; Yue-Chen Tan; Tu Yu; En-Jiang Yu; Pan Wu. 2021. "Soil microbial community dynamics indicate disruption of nitrogen cycling by pollution in vegetation buffer zones." Pedobiologia 85-86, no. : 150722.
The deposition and release of heavy metals in sediments often lead to their diffusion in lakes, especially for dispersed elements such as cadmium (Cd), which indirectly introduces pollutants into the food chain. The high rate of deposition or release of heavy metals in sediments is a problem to be solved. Southwest China is most famous in the world for the continuous distribution of karst area, for holding the largest area of bare carbonate rocks and for experiencing the strongest karst development in the world. The trace metals in 15 sites of Yelang Lake were determined by diffusive gradients in thin-films (DGT) method. The distribution and release mechanism of Cr, Ni, Cu, Cd, Zn and Pb under high geochemical backgrounds in the karst area of Guizhou Province in Southwest China were discussed. Based on the DGT concentration and pore water analysis, the distribution order of these heavy metal contents is usually upstream (SC), middle (DCB) and downstream (SW) areas of the lake, which increases during the dry season and decreases during the wet season. There was no significant difference in concentration between 0–4 and 4–8 cm depth (p < 0.05). The R values of heavy metals in the dry and wet seasons were highest with cadmium (Cd) and lowest with chromium (Cr) and lead (Pb). The results of the metal geo-accumulation index (Igeo) and the potential ecological risk index are highest on Cd and lowest on Cr. The mean concentrations of Cr, Cd, Zn, Ni (DCB, SW), Pb (SC, DCB) and Cu (SC) are between the corresponding threshold effect level and the probable effect level, and the average potential ecological risk is ranked in descending order of Cd > Pb > Zn > Cu > Ni > Cr. These three areas are at medium risk levels and the potential ecological risks increases from upstream to downstream. The deposition rate of heavy metals in Yelang Lake sediment was higher than the release rate and the ecological risk from heavy metals was relatively low. Since Cd is the main ecological risk factor in the lake, more attention needs to be given to Cd contamination in the Yelang Lake basin of the karst area.
Kai Luo; Hongyan Liu; Enjiang Yu; Yu Tu; Xiaofeng Gu; Meng Xu. Distribution and release mechanism of heavy metals in sediments of Yelang Lake by DGT. Stochastic Environmental Research and Risk Assessment 2020, 34, 793 -805.
AMA StyleKai Luo, Hongyan Liu, Enjiang Yu, Yu Tu, Xiaofeng Gu, Meng Xu. Distribution and release mechanism of heavy metals in sediments of Yelang Lake by DGT. Stochastic Environmental Research and Risk Assessment. 2020; 34 (6):793-805.
Chicago/Turabian StyleKai Luo; Hongyan Liu; Enjiang Yu; Yu Tu; Xiaofeng Gu; Meng Xu. 2020. "Distribution and release mechanism of heavy metals in sediments of Yelang Lake by DGT." Stochastic Environmental Research and Risk Assessment 34, no. 6: 793-805.
Abscisic acid (ABA) plays a central role in the plant response to water deficit by inducing stomatal closure to conserve water when the soil dries. Exogenous ABA was applied at 45 days after sowing (DAS) as a soil drench, the physiological and seed yield response of soybean to exogenous ABA were examined as the soil was drying. Three experiments were conducted using the drought-tolerant soybean cultivar Jindou 19, grown in pots at the Yuzhong Experimental Station of Lanzhou University, China. In experiment 1, plants were exposed to progressive soil drying and leaf ABA concentration, leaf photosynthesis rate, leaf relative water content (RWC) and osmotic adjustment (OA) were measured. In experiment 2, plants were under progressive soil drying and lethal leaf water potential was measured. In experiment 3, flower production and abortion, and grain yield were measured in plants under well-watered (WW), moderate (MWD) and severe water deficits (SWD). Exogenous ABA application increased ABA accumulation in leaves and reduced the rate of soil drying. It also increased leaf photosynthetic rate, stomatal conductance and transpiration rate at 7–10 days after withholding water. The intrinsic and instantaneous water use efficiency (WUE) was consistently higher with exogenous ABA than without ABA as the soil dried. Exogenous ABA increased OA when the leaf relative water content (RWC) decreased at eight days after withholding water, lowering the lethal leaf water potential by 0.4 MPa. Exogenous ABA reduced water use, increased WUE for grain yield under WW and MWD, and had no effect on flower number, flower abortion or grain yield in any water treatment. We concluded that (1) exogenous ABA induced OA, improved leaf photosynthetic rate, leaf water relations and desiccant tolerance, but did not benefit grain yield in soybean under water deficits; (2) exogenous ABA improved the WUE at the leaf level as soil drying and WUE for grain yield under moderate water deficit.
Jin He; Yi Jin; Jairo A. Palta; Hong-Yan Liu; Zhu Chen; Feng-Min Li. Exogenous ABA Induces Osmotic Adjustment, Improves Leaf Water Relations and Water Use Efficiency, But Not Yield in Soybean under Water Stress. Agronomy 2019, 9, 395 .
AMA StyleJin He, Yi Jin, Jairo A. Palta, Hong-Yan Liu, Zhu Chen, Feng-Min Li. Exogenous ABA Induces Osmotic Adjustment, Improves Leaf Water Relations and Water Use Efficiency, But Not Yield in Soybean under Water Stress. Agronomy. 2019; 9 (7):395.
Chicago/Turabian StyleJin He; Yi Jin; Jairo A. Palta; Hong-Yan Liu; Zhu Chen; Feng-Min Li. 2019. "Exogenous ABA Induces Osmotic Adjustment, Improves Leaf Water Relations and Water Use Efficiency, But Not Yield in Soybean under Water Stress." Agronomy 9, no. 7: 395.