scholarly journals ECOLOGICAL RISK ASSESSMENT OF A TROPICAL LAKE SYSTEM

2013 ◽  
pp. 323-329 ◽  
Author(s):  
K. Swarnalatha ◽  
J. Letha ◽  
S. Ayoob
Keyword(s):  
Risk Assessment ◽  
Ecological Risk ◽  
Sediment Quality ◽  
Contamination Factor ◽  
Tropical Lake ◽  
Risk Category ◽  
Sand Mining ◽  
Waste Discharge ◽  
Quality Guidelines ◽  
Risk Indices

Risk analysis of urban aquatic systems due to heavy metals turns significant due to their peculiar properties viz. persistence, non-degradability, toxicity, and accumulation. Akkulam Veli (AV), an urban tropical lake in south India is subjected to various environmental stresses due to multiple waste discharge, sand mining, developmental activities, tourism related activities etc. Hence, a comprehensive approach is adopted for risk assessment using modified degree of contamination factor, toxicity units based on numerical sediment quality guidelines (SQGs), and potentialecological risk indices. The study revealed the presence of toxic metals such as Cr,Cd, Pb and As and the lake is rated under ‘low ecological risk’ category.

Risk Assessment of Organochlorine Compounds in Water and Surface Sediments from Taihu Lake and Nanjing Section of Changjiang, China

2011 ◽  
Vol 356-360 ◽  
pp. 624-629 ◽  
Author(s):  
Xu Yin Yuan ◽  
Quan Liu ◽  
Ji Zhou Li ◽  
Jun Feng Ji ◽  
Chang Ping Mao
Keyword(s):  
Risk Assessment ◽  
Surface Water ◽  
Ecological Risk ◽  
Surface Sediments ◽  
Taihu Lake ◽  
Sediment Quality ◽  
Organochlorine Compounds ◽  
Quality Guidelines ◽  
Water And Sediment ◽  
Low Levels

Samples of surface water and sediment were collected in Taihu Lake and Nanjing section of Changjiang. Organochlorine compounds(OCCs) of samples were detected to investigate the characteristics and ecological risk of them in the lake and river. The concentrations of OCCs in water of Nanjing section of Changjiang were higher than those in Taihu Lake, but the concentrations of OCCs in sediments were higher in Taihu Lake. HCHs of Taihu sediments were relatively enriched, indicating the agricultural source of compounds. PCBs of Changjiang sediments were higher compared to Taihu sediments, denoting a obvious industrial source. Comparing with other compartments in China, HCHs of the study area were higher than most sediment of Chinese rivers, DDTs didn’t show high contents in sediments, PCBs was in relatively low levels. By contrast with the relevant sediment quality guidelines of these compounds, the ecological risk of OCCs in sediments were evaluated. The OCCs of sediments in Taihu Lake and Nanjing section of Changjiang didn’t show high ecological risk.

scholarly journals Hydrocarbon Pollution and Potential Ecological Risk of Heavy Metals in the Sediments of the Oturuba Creek, Niger Delta, Nigeria

2017 ◽  
Vol 10 (1-2) ◽  
pp. 1-10
Author(s):  
Clinton Ifeanyichukwu Ezekwe ◽  
Israel Clinton Utong
Keyword(s):  
Heavy Metals ◽  
Ecological Risk ◽  
Oil Pollution ◽  
Sediment Quality ◽  
Potential Ecological Risk ◽  
Oil Refineries ◽  
Quality Guidelines ◽  
Risk Indices ◽  
Guideline Values ◽  
The Impact

Abstract This study aimed at examining the impact of oil pollution from artisanal oil refineries on the Oturuba river ecosystem using active river bottom sediment. Specific objectives included to determine the level of hydrocarbons and trace metals (Pb, Cd, Zn, Cu, Ni, V and Mg) in the sediments and to relate this with general ecosystem health. The study found elevated concentrations of both hydrocarbons and heavy metals in the range above most sediment quality guidelines exceeding the respective Threshold Effects Level and Probable Effects. Level guideline values and occurring at levels where impairment to biological communities is certain an d where toxicity levels can lead to negative impacts on benthic animals or infaunal communities. Heavy metal geochemical accumulation index and potential ecological risk analysis also returned anomalously high concentrations in the range of very highly polluted sediment environments with very high ecological risk indices, thereby ranking the Oturuba Creek as one of the most polluted coastal river systems in the world.

scholarly journals Reforestation Impacted Soil Heavy Metal Fractionation and Related Risk Assessment in the Karst Area, Southwest China

Forests ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 891
Author(s):  
Qian Zhang ◽  
Guilin Han ◽  
Xingliang Xu
Keyword(s):  
Heavy Metals ◽  
Risk Assessment ◽  
Ecological Risk ◽  
Southwest China ◽  
Risk Index ◽  
Contamination Factor ◽  
Karst Area ◽  
Risk Assessment Code ◽  
Bcr Sequential Extraction ◽  
Soil Heavy Metals

Human agricultural activities have resulted in widespread land degradation and soil contamination in the karst areas. However, the effects of reforestation after agricultural abandonment on the mobility risks and contamination of heavy metals have been rarely reported. In the present study, six soil profiles were selected from cropland and abandoned cropland with reforestation in the Puding karst regions of Southwest China. The Community Bureau of Reference (BCR) sequential extraction method was used to evaluate the compositions of different chemical fractions of soil heavy metals, including Fe, Mn, Cr, Zn, Ni, and Cd. The total contents of Cr, Ni, Zn, Cd, and Mn in the croplands were significantly higher than those in the abandoned croplands. For all soils, Cr, Ni, Zn, and Fe were mainly concentrated in the residual fractions (>85%), whereas Mn and Cd were mostly observed in the non-residual fractions (>65%). The non-residual fractions of Cd, Cr, Ni, and Zn in the croplands were higher than those in the abandoned croplands. These results indicated that the content and mobility of soil heavy metals decreased after reforestation. The individual contamination factor (ICF) and risk assessment code (RAC) showed that Cd contributed to considerable contamination of karst soils. The global contamination factor (GCF) and potential ecological risk index (RI) suggested low contamination and ecological risk of the investigated heavy metals in the croplands, moreover they can be further reduced after reforestation.

scholarly journals Contamination and ecological risk assessment of trace elements in sediments of the Anzali Wetland, Northern Iran

2021 ◽  
Author(s):  
Marjan Esmaeilzadeh ◽  
Elham Mahmoudpuor ◽  
Somayeh Haghighat Ziabari ◽  
Sara Esmaeilzadeh ◽  
Hamideh Aliani ◽  
...  
Keyword(s):  
Ecological Risk ◽  
Risk Index ◽  
Sediment Quality ◽  
Aquatic Organisms ◽  
Pollution Load Index ◽  
Pollution Indices ◽  
Anzali Wetland ◽  
Northern Iran ◽  
Pollution Levels ◽  
Quality Guidelines

Abstract In this paper, concentrations of some heavy metals in surficial sediments of the International Anzali Wetland were measured, this wetland is located in northern part of Iran. Sediment pollution levels were examined and analyzed using reliable pollution indices including Pollution Load Index (PLI), Geoaccumulation Index (Igeo) and Enrichment Factor (CF), and finally it was revealed that heavy metal pollution ranged from low to moderated loads in the wetland. According to Sediment Quality Guidelines (SQGs) and Ecological Risk Index (ERI), it was concluded that As and Ni may have significant toxic impacts on aquatic organisms and also according to Effect Range Median (ERM), the toxicity probability of sediments in the Anzali wetland was estimated at 21%.

scholarly journals An Assessment of Metal Contamination Risk in Sediments of the Mohammad Abad River, Northern Iran

2021 ◽  
Vol 2 (8) ◽  
pp. 696-704
Author(s):  
Hassan Malvandi
Keyword(s):  
Heavy Metals ◽  
Biological Effects ◽  
Sediment Quality ◽  
Contamination Factor ◽  
Anthropogenic Source ◽  
Degree Of Contamination ◽  
Northern Iran ◽  
Pollution Levels ◽  
Quality Guidelines ◽  
Very High

Background: Sediments in the aquatic ecosystems can be used as suitable indicators for monitoring contaminants. Then, objectives of this study were to evaluate the concentration of heavy metals in the surface sediments of the Mohammad Abad River, to determine the degree of pollution of heavy metals in sediments using some major contamination indices; to identify the major sources (anthropogenic or natural sources) of the studied metals; and to evaluate the “reference river” of the river under study for ecotoxicology studies. Methods: Samples of sediment were taken from six sites of the river. The present study, eleven heavy metals (chromium, manganese, iron, cobalt, nickel, zinc, selenium, magnesium, silver, aluminum and arsenic) were studied. Results: Comparison of metal concentrations with those of Sediment Quality Guidelines (SQGs) showed no association with harmful biological effects for the heavy metals studied except for Se and As. The results of the contamination factor index showed low pollution levels for most metals (Cr, Mn, Fe, Co, Ni, Zn and Al), moderate pollution levels for As, and very high pollution levels for Se. The degree of contamination (Cd) and modified degree of contamination (mCd), showing the total contamination of elements, demonstrated very high degree contamination status in the study area. According to the index of quantification of contamination, the values of Cr, Mn, Fe, Ni, Zn and Al were derived mainly from geogenic sources of enrichment, while the values for Se and As were enriched by anthropogenic source of enrichment. Conclusion: These findings suggest that continuous monitoring of Se and As in sediment and organisms of the Mohammad Abad River should be directed to evaluate the threat of these elements to the public health and to the ecology of the river under study.

scholarly journals Ecological risk by potentially toxic elements in surface sediments of the Lake Maracaibo (Venezuela)

2021 ◽  
Vol 27 (4) ◽  
pp. 210232-0
Author(s):  
Julio Marín ◽  
Marinela Colina ◽  
Hilda Ledo ◽  
P.H.E. Gardiner
Keyword(s):  
Ecological Risk ◽  
Toxic Elements ◽  
Sediment Quality ◽  
Potential Ecological Risk ◽  
Potentially Toxic Elements ◽  
Lake Area ◽  
Risk Assessment Code ◽  
Quality Guidelines ◽  
Lake Maracaibo ◽  
Superficial Sediments

The evaluation of potential ecological risk of aquatic sediments associated with the presence of potentially toxic elements (PTE) determines its degree of danger on native biota. In this work, the potential ecological risk of V, Ti, Cr, Ni, Cu, Zn, As, Se, Cd, Sn, Hg and Pb in superficial sediments is explained in three different areas of Lake Maracaibo: El Tablazo Bay, Strait of Maracaibo and the lake itself, through a multi-guideline approach (elemental enrichment (enrichment factor, contamination degree, pollutant load index and geo-accumulation index), sediment quality guidelines and risk assessment code). The PTE levels ranged from < 0.025 to 176.722 mg·kg−1 DW, with an overall proportion of V > Ti > Pb > Zn > Cr > Cu > Ni > As > Cd > Se > Hg > Sn. The PTE concurrent effect on biota was El Tablazo Bay > lake > Strait of Maracaibo. The superficial sediments of Lake Maracaibo constitute a medium with a high potential ecological risk on estuarine biota. This is mainly due to the levels of As in El Tablazo Bay, Cd in the Strait of Maracaibo and Pb in the lake area. This represents a latent toxicity hazard for native biological communities and other associated organisms.

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