Assessing ecological risks and probable sources of Cu, Zn, and Mn in River Tana sediments, Kenya

2021 ◽  
pp. 1-16
Author(s):  
Kelvin Githaiga ◽  
Samwel Njuguna ◽  
Janet Onyango ◽  
Xue Yan
Keyword(s):  
Ecological Risks

p-EMA (II): evaluating ecological risks of pesticides for a farm-level risk assessment system

Agronomie ◽  
2003 ◽  
Vol 23 (1) ◽  
pp. 75-84 ◽  
Author(s):  
Andy Hart ◽  
Colin D. Brown ◽  
Kathy A. Lewis ◽  
John Tzilivakis
Keyword(s):  
Risk Assessment ◽  
Assessment System ◽  
Ecological Risks ◽  
Farm Level

Hong Kong University Students’ Normative Beliefs about Aggression toward Police during Social Protests 2019–2020: The Role of Ecological Risks and Future Orientation

2021 ◽  
pp. 001112872110141
Author(s):  
Jian-Bin Li ◽  
Catrin Finkenauer
Keyword(s):  
Hong Kong ◽  
University Students ◽  
Community Violence ◽  
Future Orientation ◽  
Ecological Risks ◽  
Normative Beliefs ◽  
Poor Family ◽  
Social Protests ◽  
Delinquent Peers

We examined the association between normative beliefs about aggression toward police (NBAGG→P) and participation in social protests during 2019–2020 and use of aggression among 1,025 Hong Kong university students. We also investigated the role of ecological risks (i.e., distrust in institutions, exposure to community violence, poor family monitoring, poor university discipline and affiliation with delinquent peers) and future orientation in NBAGG→P. The results showed that NBAGG→P was related to more participation in social protests and use of aggression. Ecological risks (except for poor family monitoring) and a positive future orientation were related to more and less NBAGG→P, respectively. Moreover, the “distrust in institutions and NBAGG→P” link was stronger for students with more, rather than less, positive future orientation.

scholarly journals Dilemma of mining: economic development and ecological risks

2020 ◽  
Vol 575 ◽  
pp. 012245
Author(s):  
Sukri ◽  
Ariana ◽  
Dian Ekawaty ◽  
Febriyanto Syam ◽  
Ahmad Amiruddin
Keyword(s):  
Economic Development ◽  
Ecological Risks

scholarly journals Biological Risk Assessment of Heavy Metals in Sediments and Health Risk Assessment in Marine Organisms from Daya Bay, China

2020 ◽  
Vol 9 (1) ◽  
pp. 17
Author(s):  
Zexing Kuang ◽  
Yangguang Gu ◽  
Yiyong Rao ◽  
Honghui Huang
Keyword(s):  
Heavy Metals ◽  
Risk Assessment ◽  
Marine Organisms ◽  
Daya Bay ◽  
Ecological Risks ◽  
The Monte Carlo Method ◽  
Accumulation Index ◽  
The Mean ◽  
Primary Pollutant ◽  
Geo Accumulation

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.

scholarly journals Evaluating ecological risks and tracking potential factors influencing heavy metals in sediments in an urban river

2021 ◽  
Vol 33 (1) ◽  
Author(s):  
Dongping Liu ◽  
Jian Wang ◽  
Huibin Yu ◽  
Hongjie Gao ◽  
Weining Xu
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Ecological Risk ◽  
Metal Pollution ◽  
Heavy Metal Pollution ◽  
Risk Index ◽  
Urban River ◽  
Ecological Risks ◽  
Background Values ◽  
Potential Factors

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.

scholarly journals Little Akaki River sediment enrichment with heavy metals, pollution load and potential ecological risks in downstream, Central Ethiopia

2020 ◽  
Vol 9 (1) ◽  
Author(s):  
Deshu Mamo Mekuria ◽  
Alemnew Berhanu Kassegne ◽  
Seyoum Leta Asfaw
Keyword(s):  
Heavy Metals ◽  
River Sediment ◽  
Addis Ababa ◽  
Biological Effects ◽  
Sediment Quality ◽  
Contamination Factor ◽  
Anthropogenic Sources ◽  
Ecological Risks ◽  
Pollution Load ◽  
Akaki River

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.

Sign in / Sign up

Export Citation Format

Share Document