Current status of knowledge of the biological effects of heavy metals in the Chesapeake Bay

1972 ◽  
Vol 13 (1) ◽  
pp. 149S-153S
Author(s):  
John M. Frazier
Keyword(s):  
Heavy Metals ◽  
Chesapeake Bay ◽  
Biological Effects ◽  
Current Status

Current Status of Research on the Biological Effects of Pesticides in Chesapeake Bay

1972 ◽  
Vol 13 ◽  
pp. S154
Author(s):  
Thomas O. Munson ◽  
Robert J. Huggett
Keyword(s):  
Chesapeake Bay ◽  
Biological Effects ◽  
Current Status

Current status of research on the biological effects of pesticides in Chesapeake Bay

1972 ◽  
Vol 13 (1) ◽  
pp. 154S-156S
Author(s):  
Thomas O. Munson ◽  
Robert J. Huggett
Keyword(s):  
Chesapeake Bay ◽  
Biological Effects ◽  
Current Status

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.

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.

Biological Effects of Spoil Disposal in Chesapeake Bay

1968 ◽  
Vol 94 (4) ◽  
pp. 683-706
Author(s):  
David A. Flemer ◽  
W. L. Dovel ◽  
H. T. Pfitzenmeyer ◽  
D. E. Ritchie
Keyword(s):  
Chesapeake Bay ◽  
Biological Effects
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