scholarly journals Toxicity Effects of Microplastics and Nanoplastics with Cadmium on the Alga Microcystis Aeruginosa

Author(s):  
Qiongjie Wang ◽  
Jinxiaoxue Wang ◽  
Huijuan Chen ◽  
Yangyang Zhang

Abstract The objective of this paper is to present a thorough analysis of the toxicity of microplastics (MPs) and nanoplastics (NPs) with the heavy metal cadmium (Cd). These components were studied separately and combined to determine how these environmental toxins affect Microcystis aeruginosa (M. aeruginosa) in fresh water. The combined toxicity of MPs or NPs and Cd to M. aeruginosa showed an aggressive and negative effect after 96 h of exposure. Due to the higher adsorption ability of NPs, the accumulation of Cd inside cells with NPs was lower than that found inside the cells with MPs. But the difference in toxicity between the MPs and NPs was not significant. Meanwhile, the more produce of the extracellular polymeric substance (EPS) in the presence of NPs, the more complex effect of EPS bonded to heavy metals, which reduce the toxic effect on the algal cells. Notably, the production of microcystin-LR (MC-LR) under different treatments has demonstrated that the presence of combined MPs/NPs with Cd can potentially raise some of the toxin risks harming the aquatic environment. Our findings highlight the great potential ecological risks of the combined Cd and MPs/NPs in the aquatic system.

2020 ◽  
Vol 9 (1) ◽  
pp. 17
Author(s):  
Zexing Kuang ◽  
Yangguang Gu ◽  
Yiyong Rao ◽  
Honghui Huang

The concentrations of heavy metals in sediments and marine organisms in Daya Bay were investigated, and the Monte Carlo method was used to analyze the uncertainty of the results of geo-accumulation characteristics and ecological and health risks. The mean concentrations of metal elements in sediments were in the following order: Zn > Cr > Cu > As > Cd > Hg, while those in marine organisms were Zn > Cu > As > Cr ≈ Cd > Hg. The geo-accumulation index (Igeo) indicated that the primary pollutant was Hg, with 5.46% moderately polluted, and 39.52% for unpolluted to moderately polluted. Potential ecological risks (RI) were between low and high risks, and the contributions of Hg, Cd, and As to ecological risks were 50.85%, 33.92%, and 11.47%, respectively. The total hazard coefficients (THQ) were less than 1, but on the basis of total carcinogenic risks (TCR), the probability of children and adults exceeded the unacceptable risk threshold of 22.27% and 11.19%, respectively. Sensitivity analysis results showed that the concentrations of carcinogenic elements contributed to risk in the order of As > Cd > Cr. Therefore, in order to effectively control heavy metals contamination in Daya Bay, it is necessary to strengthen the management of Hg, Cd, and As emissions.


2021 ◽  
Vol 33 (1) ◽  
Author(s):  
Dongping Liu ◽  
Jian Wang ◽  
Huibin Yu ◽  
Hongjie Gao ◽  
Weining Xu

Abstract Background Heavy metal pollution of aquatic systems is a global issue that has received considerable attention. Canonical correlation analysis (CCA), principal component analysis (PCA), and potential ecological risk index (PERI) have been applied to heavy metal data to trace potential factors, identify regional differences, and evaluate ecological risks. Sediment cores of 200 cm in depth were taken using a drilling platform at 10 sampling sites along the Xihe River, an urban river located in western Shenyang City, China. Then they were divided into 10 layers (20 cm each layer). The concentrations of the As, Cd, Cr, Cu, Hg, Ni, Pb and Zn were measured for each layer. Eight heavy metals, namely Pb, Zn, As, Cd, Cr, Cu, Ni, and Hg, were measured for each layer in this study. Results The average concentrations of the As, Cd, Cu, Hg, and Zn were significantly higher than their background values in soils in the region, and mainly gathered at 0–120 cm in depth in the upstream, 0–60 cm in the midstream, and 0–20 cm downstream. This indicated that these heavy metals were derived from the upstream areas where a large quantity of effluents from the wastewater treatment plants enter the river. Ni, Pb, and Cr were close or slightly higher than their background values. The decreasing order of the average concentration of Cd was upstream > midstream > downstream, so were Cr, Cu, Ni and Zn. The highest concentration of As was midstream, followed by upstream and then downstream, which was different to Cd. The potential factors of heavy metal pollution were Cd, Cu, Hg, Zn, and As, especially Cd and Hg with the high ecological risks. The ecological risk levels of all heavy metals were much higher in the upstream than the midstream and downstream. Conclusions Industrial discharge was the dominant source for eight heavy metals in the surveyed area, and rural domestic sewage has a stronger influence on the Hg pollution than industrial pollutants. These findings indicate that effective management strategies for sewage discharge should be developed to protect the environmental quality of urban rivers.


2020 ◽  
Vol 9 (1) ◽  
Author(s):  
Deshu Mamo Mekuria ◽  
Alemnew Berhanu Kassegne ◽  
Seyoum Leta Asfaw

Abstract Addis Ababa City’s river ecosystem is under extreme pressure as a result of inappropriate practices of dumping domestic and industrial wastes; thus, threatening its ability to maintain basic ecological, social and economic functions. Little Akaki River which drains through Addis Ababa City receives inorganic and organic pollutants from various anthropogenic sources. Most of inorganic pollutants such as toxic heavy metals released into the river are eventually adsorbed and settle in the sediment. The objective of this study was to evaluate the enrichment levels, pollution load and ecological risks of selected heavy metals (Zn, Cr, Cd and Pb) using various indices. The mean concentrations of heavy metals in Little Akaki River sediment were: Zn (78.96 ± 0.021–235.2 ± 0.001 mg/kg); Cr (2.19 ± 0.014–440.8 ± 0.003 mg/kg); Cd (2.09 ± 0.001–4.16 ± 0.0001 mg/kg) and Pb (30.92 ± 0.018–596.4 ± 0.066 mg/kg). Enrichment factor values indicated that sediments were moderate to significantly enriched with Zn and Cr; moderate to very highly enriched with Pb, and very highly enriched in all sampled sites with Cd. Geo-accumulation index and contamination factor values indicated that the sediments were moderate to very highly contaminated with toxic Cd and Pb. The decreasing order of pollution load index (PLI) in downstream was: (S9) > (S4) > (S8) > (S3) > (S6) > (S10) > (S5) > (S2) > (S7) > (S1). PLI and hierarchical cluster analysis revealed that the highest pollution load occurred in the lower course of the river (S9) which may be due to metals inputs from anthropogenic sources. The ecological risk (RI = 350.62) suggested that the contaminated Little Akaki River sediment can pose considerable ecological risks of pollution. The concentrations of Zn, Cr, Cd and Pb in Little Akaki River sediment surpassed eco-toxicological guideline limits of USEPA (threshold effect concentration) and CCME (Interim Sediment Quality Guidelines). Thus, the contaminated sediments can pose adverse biological effects on sediment dwelling organisms.


PEDIATRICS ◽  
1984 ◽  
Vol 73 (6) ◽  
pp. 799-805 ◽  
Author(s):  
Robert E. Black ◽  
Kenneth H. Brown ◽  
Stan Becker

Village-based surveillance data from longitudinal studies in rural Bangladesh have been used to evaluate the nutritional consequences of infectious diseases, including diarrhea due to specific pathogens. The prevalences of specific illnesses were related to the ponderal and linear growth of young children for 2-month and 1-year periods. Of the common illnesses, only diarrhea had a significant inverse relationship with increments of weight during 2-month periods and of length during 1 year. Diarrhea accounted for 20% of the difference in linear growth between the study children and the international reference population during the first 5 years of life. Diarrhea associated with enterotoxigenic Escherichia coli had a significant negative effect on the bimonthly weight gain of children in this community and shigellosis had the strongest negative effect on bimonthly and annual linear growth. Control of diarrhea due to enterotoxigenic E coli and Shigella would not only substantially diminish diarrheal morbidity but would also improve the growth of children and thereby reduce the prevalence of protein-energy malnutrition.


2021 ◽  
Vol 36 (Supplement_1) ◽  
Author(s):  
Nicholas Chesnaye ◽  
Yvette Meuleman ◽  
Esther De Rooij ◽  
Friedo W Dekker ◽  
Marie Evans ◽  
...  

Abstract Background and Aims Differences between the sexes are apparent in the epidemiology of CKD. Cross-sectional studies show that women consistently report a poorer health-related quality of life (QoL) than men, however, longitudinal studies are lacking. Here we investigate the sex-specific evolution of QoL over time in advanced CKD. As a secondary aim, we explore the sex-specific determinants of QoL. Method EQUAL is an observational prospective cohort study in stages 4 and 5 CKD patients ≥65 years not on dialysis with an incident estimated glomerular filtration rate (eGFR) < 20 ml/min/1.73m². Data on QoL (measured using the RAND-36), clinical and demographic patient characteristics were collected between April 2012 and September 2020. QoL trajectories were modelled by sex using linear mixed models, and joint models were applied to deal with informative censoring. We followed patients until death or dialysis initiation. Results We included 5151 QoL measurements in 1416 patients over a total of 1986 person years of follow-up. Overall, the physical component summary (PCS) declined with 2.0 (95% CI 1.4-2.6) points and the mental component summary (MCS) by 2.4 (95% CI 1.8-3.0) points per year. Although women had overall lower QoL scores, figure 1 demonstrates that PCS and MCS declined more than twice as fast in men (PCS: 2.4 per year, 95% CI 1.7 – 3.1, MCS: 2.9 per year, 95% CI 2.2 – 3.6) compared with women (PCS: 1.1 per year, 95% CI -0.2 – 2.0, MCS: 1.5 per year, 95% CI 0.5 – 2.4). We identified a non-linear interaction effect between sex and eGFR levels on QoL, demonstrating a stronger negative effect of decreased eGFR on both PCS (p=0.02) and MCS (p=0.04) in men compared with women. Subsequent adjustment for renal decline attenuated the difference in rate of QoL decline between men and women (difference after adjustment; PCS: 1.1, 95% CI -0.1 – 2.2, MCS: 1.2, 95% 0.0 – 2.3). In univariable analyses, higher serum haemoglobin was more beneficial to QoL in men compared to women (p-value for interaction; PCS: p=0.03, MCS: p=0.01). Higher serum phosphate had a strong harmful effect on both PCS and MCS in men, but not in women (PCS & MCS: p<0.001). The presence of pre-existing diabetes had a negative effect on PCS and MCS in men, but to a lesser extent in women (PCS: p=0.02, MCS: p=0.01). Conclusion Despite the higher overall QoL reported by men, both their physical and mental QoL declined approximately twice as fast compared with women. The faster decline in men was mediated in part by their lower levels of renal function, which had a stronger impact on their QoL as compared with women. Furthermore, in exploratory analyses we identified that high levels of phosphate, low levels of haemoglobin, and pre-existing diabetes were more detrimental to QoL in men than in women.


2021 ◽  
Vol 11 (2) ◽  
pp. 67-80
Author(s):  
Nguyen Quoc Anh ◽  
Duong Nguyen Thanh Phuong

This study investigates the impact of credit risk on the financial stability of Vietnamese commercial banks. The paper uses the Z-score to proxy the financial stability of banks. We use the data of 27 Vietnamese commercial banks on BankScope, during 2010 - 2019. The paper applied a dynamic panel data approach; the selected method is the difference GMM (DGMM). The key question discussed is which factor impacts on Z-score. Analysis results show the negative effect of non-performing loans on the financial stability of banks. When commercial banks have higher non-performing loans, the lower the financial stability is. Additionally, bank-specific variables such as equity on asset ratio, the return on equity, the size of the bank and set of macroeconomic variables affect the bank’s financial stability. Based on the analysis results, we imply relevant policies for the State Bank of Vietnam and commercial banks.


2018 ◽  
Vol 35 (7) ◽  
pp. 676-687 ◽  
Author(s):  
Ibtissame Abaidi ◽  
Eric Vernette

PurposeThe internet has made it possible to diffuse totally digitized products on a very large scale. The newspaper business is one of the sectors that has been most affected by this technological revolution. Given such products’ uneven commercial success, an analysis of the literature suggests that these mixed results could be explained by the digitized nature of the product combined with a price judged too high. Both these elements reduce the perceived global value of the digital support compared with the print version on paper. To test this proposition, the authors have constructed an experimental design, manipulating the format (digital newspaper vs. print newspaper) and the price (high vs low). The results show that newspaper digitization significantly reduces perceived global value for the consumer compared with the print format. The authors also show that the perceived intangibility of the product exerts a more complex effect on perceived global value: this effect depends on both the nature of the intangibility (mental vs physical) and the cost and benefit analysis.Design/methodology/approachAn experimental study was conducted with two factors: digitalization (print vs digital format) and price (low vs high). The authors carried out a mixed-factor variance analysis and follow Preacher and Hayes procedure to test the hypothesis. A sample of 387 undergraduate students was interviewed in laboratory.FindingsThe results show that newspaper digitization significantly reduces (i.e. destroys) perceived global value for the consumer (i.e. it destroys value), compared to the print format. The reuslts also show that the perceived intangibility of the product exerts a more complex effect on perceived global value: this effect depends at the same time on the nature of the intangibility (mental vs physical) and the account taken of costs and benefits.Originality/valueOne major result is the fact that digitizing newspaper strongly destroys its perceived global value for the consumer, compared to the physical alternative. To explain this phenomenon, the product’s perceived intangibility had been considered, as well as how this is related to the perceived costs and benefits. It appears that it has an overall direct negative effect on perceived value; therefore, the more a newspaper format is perceived as physically intangible, the more its perceived global value decreases. Results shows that this loss of value can be counteracted in two different ways, through the indirect effects of costs and benefits.


RSC Advances ◽  
2017 ◽  
Vol 7 (30) ◽  
pp. 18421-18427 ◽  
Author(s):  
Haiming Wu ◽  
Li Lin ◽  
Guangzhu Shen ◽  
Ming Li

The risk of heavy metals to aquatic ecosystems was paid much attention in recent years, however, the knowledge on effects of heavy metals on dissolved organic matter (DOM) released byMicrocystiswas quite poor, especially in eutrophic lakes.


2020 ◽  
Vol 2 (1) ◽  
pp. 1
Author(s):  
Nanda Alfarina ◽  
Hasdi Aimon

This study aims to determine the effect of monetary policy measured by the central bank’s policy rate (X1) on portfolio investment (Y) in Indonesia and United States in the long run. The data used are secondary data seouced from SEKI BI, FRED The FEd, coinmarketcap.com, and investing.com, with the VECM (Vector Error Correction Mechanism) analysis methode. The study show The study shows the differences between the results that occur in Indonesia and the United States. The policy interest rate has a significant positive effect on portfolio investment in the long run in Indonesia, while in the United States the interest rate in the long run has a significant negative effect on portfolio investment. The difference in research results between the two countries shows the need for different treatment for monetary authorities in encouraging portfolio investment 


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