scholarly journals State of trace element contamination of sediments from the Nangbéto hydroelectric dam lake (Togo)

2021 ◽  
Vol Unlabeled volume ◽  
Author(s):  
Koudjo Adje ◽  
Kamilou Ouro-Sama ◽  
Hodabalo Dheoulaba SOLITOKE ◽  
Gnon Tanouayi ◽  
Sadikou AGBERE ◽  
...  

The Nangbéto hydroelectric dam lake, which is a spillway for agricultural input residues, urban and industrial effluents present in the Mono basin, is exposed to all forms of pollution. The aim of this work is to estimate the content of seven trace elements present in the sediments of the aforementioned lake in order to assess the ecological risk incurred by the aquatic biocenosis and therefore by man. Forty-two sediment samples (21 per season) are realized in different areas of the Lake. Cd, Pb, Ni, Cu, Cr, As and Hg are measured out in the sediments by the flame atomic absorption spectrophotometer in these pre-mineralized samples. The results show average contents varying from the lowest level 0.04 mg / kg for Hg to the highest 12.15 mg / kg for Cu in the rainy season and from 0.03 mg / kg for Hg and for As to 9.14 mg/kg for Cu in the dry season. All of these values are below Canadian sediment quality standards. The strongest average geoaccumulation indices (Igeo) are obtained for Pb with values less than 2. The mean values of the contamination factor (FC) are less than 1. The mean indices of contamination (Im) are less than 2, threshold d 'an onset of polymetallic contamination. The ecological risk (Ri) in relation to the contamination of the sediments of the Lake with trace elements is low in any season (Ri <40) and this implies a low risk of contamination of the biocenosis. However, the present study only deals with metallic trace elements. It does not take into account other pollutants, nor the potential "cocktail" effects between them. Additional work should therefore be continued in this direction to consolidate the low risk recorded for the biocenosis. Le Lac du barrage hydroélectrique de Nangbéto qui constitue un déversoir des résidus des intrants agricoles, des effluents urbains et industriels présent dans le bassin du Mono est exposé à toutes formes de pollution. Le but de ce travail est de quantifier les teneurs de sept (7) éléments traces dans les sédiments dudit Lac afin d’évaluer le risque écologique encouru par la biocénose aquatique et partant par l’homme.Quarante-deux (42) échantillons de sédiments (21 par saison) sont échantillonnés dans différentes zones du Lac. Le Cd, Pb, Ni, Cu, Cr, As et Hg sont dosés dans les sédiments par le spectrophotomètre d’absorption atomique à flamme dans ces échantillons minéralisés. Les résultats montrent des teneurs moyennes variant de la plus faible teneur 0,04mg/kg pour le Hg à la plus forte (12,15mg/kg) pour le Cu en saison pluvieuse et de 0,03 mg/kg pour le Hg et pour l’As à la plus forte (9,14 mg/kg) pour le Cu en saison sèche. Toutes ces valeurs sont inférieures aux normes canadiennes de qualité des sédiments. Les plus forts indices de géoaccumulation (Igeo) moyens sont obtenus chez le Pb avec des valeurs inférieures à 2. Les valeurs moyennes de facteur de contamination (FC) sont inférieures à 1. Les indices moyens de contamination (Im) sont inférieurs à 2, seuil d’un début de contamination polymétallique. Le risque écologique (Ri) par rapport à la contamination des sédiments du Lac en éléments traces est faible en toute saison (Ri < 40) et cela implique un faible risque de contamination de la biocénose. La présente étude ne porte toutefois que sur les éléments traces métalliques. Elle ne tient compte ni des autres polluants, ni des effets "cocktail" potentiels entre eux. Un travail complémentaire devra donc être poursuivi dans ce sens pour consolider le faible risque enregistré pour la biocénose.

2021 ◽  
Vol 8 ◽  
Author(s):  
Jéssica C. E. Vilhena ◽  
Ana Amorim ◽  
Lourenço Ribeiro ◽  
Bernardo Duarte ◽  
Maíra Pombo

Analyzing the presence and quantifying trace elements is of paramount importance to understand natural environmental processes and monitor the degree of anthropogenic disturbance to mitigate impacts already caused. Here, we aimed to establish a baseline of the trace elements profile and concentrations in sandy sediments of intertidal areas of three Amazonian beaches (Brazil). For each beach, sediments were collected from three different sectors (south, center, and north) and five shoreline distance levels (from the high- to the low-water mark), totalizing 15 samples per beach. The concentration of the different trace elements (Mg, Al, P, S, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Br, Rb, Sr, Y, Zr, Cd, Sn, I, Hg, and Pb) was determined by Total reflection X-ray Fluorescence spectrometry. Sediment was also characterized for its grain size, organic matter, and pH. To assess possible enrichment due to anthropogenic activities we compared trace element levels with the values for the Earth’s crust and calculated pollution indexes: geoaccumulation index (Igeo), ecological risk index (RI), contamination factor (CF), pollution load index (PLI), and sediment quality guideline (SQG), threshold effects level (TEL) and probable effects level (PEL). Individual trace metal concentrations did not vary significantly between beaches, sectors, or sample levels, evidencing a homogeneity of trace elements composition and concentrations across this environment. Igeo indicated 62.2% of the sampling stations uncontaminated, 20.0% from uncontaminated to moderately contaminated, and 4.44% (two sampling stations) strongly contaminated, the same two areas classified as high ecological risk by RI. Most of the sampling points presented low CF. Cadmium and Hg were the only elements that showed moderate to very high values of CF. According to the SQGs, 77.7 and 8.8% of the sampling points presented values above the moderate threshold effect level (SQG-TEL) and probable effect level (SQG-PEL), respectively. All points were classified as non-polluted according to the PLI. Our results show that the three beaches present safe levels of almost of the elements demonstrating the good state of preservation. Most of the indexes classified the sampling points as non-polluted, except for Cd and Hg in a few specific sampling points.


Diversity ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 51
Author(s):  
Bouchra Oujidi ◽  
Mohammed El Bouch ◽  
Mounia Tahri ◽  
Mostafa Layachi ◽  
Soilam Boutoumit ◽  
...  

Marchica Lagoon, a Ramsar site on the Mediterranean coast of Morocco, is experiencing the impacts of watershed pollution, which includes pollutants from the domestic, agricultural, industrial, and mining sectors. Restoration actions were undertaken around this lagoon during the last decade in order to protect its ecological value and to develop tourist activity. To conserve the biodiversity in the lagoon, it is important to assess the environmental state of this ecosystem. This study aims to evaluate the ecotoxicological state of sediments through the post restoration characterization of the trace elements Pb, Cu, Zn, Cr, Co, and Ba, as well as their correlation to the major elements, grain size, and total organic carbon, sampled during two campaigns (the wet and dry seasons of 2018) across a sampling network of thirteen stations. Multivariate analysis and ecotoxicological risk assessment of the trace elements using the sediment quality guidelines and five pollution indices (geoaccumulation index (Igeo), enrichment factor (EF), contamination factor (CF), pollution-load index (PLI), and mean effect range median quotient (m-ERM-Q)) revealed contamination of the lagoon by Pb, Zn, and Cu, and minimal pollution by Cr, Co, and Ba. The distribution of the biological-risk index reveals that four zones of the lagoon may present a high probability of toxicity, thus constituting potential risk areas for aquatic organisms: during the wet season, the area in the northwestern sandbar border, the southwest eutrophication zone, and the mouth of the stream valley conveying industrial discharges; and during dry season, the northwestern eutrophication zone. Despite the restoration actions achieved around the lagoon, the lead, zinc, and copper concentrations increased, and their variation was significant between group stations. The biodiversity conservation of Marchica Lagoon requires continuous monitoring and assessment, as well as the implementation of an integrated management plan with restoration actions, not only around the lagoon, but also at its watershed level.


1987 ◽  
Vol 33 (11) ◽  
pp. 2004-2007 ◽  
Author(s):  
S Nomoto ◽  
S Shoji

Abstract We sought to establish optimum conditions for measuring calcium in erythrocytes by atomic absorption spectrophotometry. The conditions we selected are as follows. Wash one volume of fresh heparin-treated packed cells once with 30 volumes of isotonic buffered saline (pH 7.4) at a temperature somewhat exceeding 25 degrees C. Dilute the washed packed cells 10-fold with 12 mmol/L hydrochloric acid, and analyze the supernate for calcium. Measure the hematocrit of the washed packed cells, then analyze an aliquot of them for calcium, using a computer-readout type of flame or a non-flame atomic absorption spectrophotometer equipped with a pyrocoated graphite tube. The temperature program is 1000 degrees C for ashing [corrected] and 1800 degrees C for the atomizing cycle. Intraday and day-to-day reproducibility of the assay was 6.55% and 8.19%, respectively, at the mean concentration of calcium in the erythrocytes of healthy adults, which is 4.30 mumol/L.


2020 ◽  
Author(s):  
K. Y. Lim ◽  
N. A. Zakaria ◽  
K. Y. Foo

Abstract The present work is aimed at assessing the aftermath effects of the 2014 flood tragedy on the distribution, pollution status and ecological risks of the heavy metals deposited in the surface river sediment. A series of environmental pollution indexes, specifically the enrichment factor (EF), geo-accumulation index (Igeo), contamination factor (CF), modified degree of contamination (mCd), pollution load index (PLI), potential ecological risk index (PERI) and sediment quality guidelines (SQGs) have been adopted. Results revealed that the freshly deposited sediments collected soon after the flood event were dominated by Cu, Fe, Pb, Ni, Zn, Cr and Cd, with the average concentrations of 38.74, 16,892, 17.71, 4.65, 29.22, 42.36 and 0.29 mg/kg, respectively. According to the heavy metal pollution indexes, Pahang River sediments were moderately to severely contaminated with Pb, Ni, Cu, Zn and Cr, while Cd with the highest risk of 91.09 was the predominant element that illustrated an aesthetic ecological risk to the water body after the tragic flood event. The findings highlighted a critical deterioration of the heavy metals content, driven by the catastrophic flood event, which has drastically altered their geochemical cycles, sedimentary pollution status and biochemical balance of the river's environment.


2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
M. Z. H. Khan ◽  
M. R. Hasan ◽  
M. Khan ◽  
S. Aktar ◽  
K. Fatema

The concentrations of major (Si, Al, Ca, Fe, and K) and minor (Cd, Mn, Ni, Pb, U, Zn, Co, Cr, As, Cu, Rb, Sr, and Zr,) elements in the surficial sediments were studied in an attempt to establish their concentration in the Bengal coast. It was revealed that the majority of the trace elements have been introduced into the Bengal marine from the riverine inflows that are also affected by the impact of industrial, ship breaking yard, gas production plant, and urban wastes. The concentration of heavy metals was measured using Atomic Absorption Spectroscopy and Energy Dispersive X-ray fluorescence instruments. The highest concentrations for several trace elements were thus recorded which generally decrease with distance from the coast. It was observed that the heavy metal concentrations in the sediments generally met the criteria of international marine sediment quality. However, both the contamination factor and pollution load index values suggested the elevation of some metals’ concentrations in the region. Constant monitoring of the Bengal coast water quality needs to be recorded with a view to minimizing the risk of health of the population and the detrimental impacts on the aquatic ecosystem.


1996 ◽  
Vol 76 (2) ◽  
pp. 165-171 ◽  
Author(s):  
Z. Q. Lin ◽  
W. H. Hendershot ◽  
P. H. Schuepp ◽  
G. G. Kennedy ◽  
P. Dutilleul

Major and trace elements (Al, As, Ba, Ca, Cd Co, Cr Cs, Cu Eu Fe, Hf, K, La, Lu, Mg, Mn, Na, Ni, Pb, Rb, Sb, Sc, Si, Sm, Sr, Ta, Tb, Th, Ti, U, V, Yb and Zn) in forest soils from three acid-deposition-affected locations in southern Quebec were investigated. Total element concentrations in the surface layer (0–20 cm) of the Podzolic soils were mostly well within the range of element concentrations in Podzols reported worldwide but showed higher mean values for most elements. The mean concentrations of elements (except Zn, at 124 μg g−1) were also generally comparable to the respective elemental baseline data established for Canadian soils. Element concentrations (μg g−1) of Cs (6.2) Sc (19 8) V (106) Rb (194) K (26 500) and Al (76 900) in the surface soils were significantly higher at the 940-m elevation than the concentrations from the sites at 650 and 770 m along the Roundtop Mountain slope, but Ca (1120) and Ni (4.4) were lowest at the 940-m elevation A similar trend with elevation was not observed at the other mountain location (White Peak). Enrichment-factor (EF) analysis showed significant element enrichment (EF ≥ 10) for Cd, Rb and Sb but impoverishment (EF ≤ 0.1) for Ca, Cu and Ni in topsoils. Key words: Major and trace elements, surface soils, acid deposition


Author(s):  
G. E. Sebiawu ◽  
N. J. Mensah ◽  
E. Amankwah ◽  
S. Antwi-Akomeah

The study was to analyze and determine the toxic metal contamination level of locally produced tobacco sold in the Tamale Metropolis of Northern region. The study was carried out at the Tamale Metropolis of Northern region of Ghana within a period of 12 months. The study focused on the analyses of five (5) toxic metal contaminants in twelve (12) variant locally produced tobacco sold in various spots within the Tamale Metropolis of Ghana. Toxic metals including As, Cd, Hg, Pb and Cr were analyzed using Flame Atomic Absorption Spectrophotometer. The mean recorded concentrations of As, Cd, Hg, Pb and Cr were respectively in the ranges of 0.184 ± 0.011 to 0.515 ± 0.015 µg/kg, 0.0420 ± 0.010 to 3.100 ± 0.000 µg/kg, 0.176 ± 0.016 to 0.291 ± 0.009 µg/kg, 1.169 ± 0.019 to 3.195 ± 0.019 µg/kg and 1.600 ± 0.116 to 3.880 ± 0.369 µg/kg. The mean concentrations of As and Pb measured in all samples tested were below their respective WHO permissible limits of 4.00 ppm and 10.00 ppm. In the case of Cd, mean concentrations measured for all locally produced tobacco tested were above the WHO permissible limits of 0.30 ppm. For the metal Hg, levels measured in 75% of tested locally produced tobacco were slightly above the WHO permissible limit of 0.20 µg/kg. Cr levels measured in 30% of tested locally produced tobacco were below the WHO permissible limits of 2.00 µg/kg. The very presence of these metals typically raises health concerns on consumption in the instances where their levels exceeded permissible guideline limits. The study revealed that Cd, Hg and Cr levels in the locally produced tobacco studied were found to exceed the WHO permissible limits for human consumption by plant uptake with As and Pb levels well below their permissible thresholds. The analyzed locally produced tobacco essentially poses a threat of heavy metal toxicity to consumers via bioaccumulation and bio-concentration in human tissues.


2021 ◽  
Vol 6 (1) ◽  
pp. 146-152
Author(s):  
M. Z. Karkana ◽  
◽  
Mujahid Ajah Matazu

The research was conducted to assess the level of heavy metals contamination using single and integrated pollution indices in soils around municipal solid waste dumpsites of Kano Metropolis, Kano State, Nigeria. Forty two soil samples were collected from seven municipal solid waste dumpsites of Kano metropolis using circular plot method. A stainless hand auger at a depth of (0 to 15) top soils and sub-surface soils (15-30cm) depth were collected and analyzed with Flame atomic absorption spectrophotometer to determine the heavy metal concentration. The mean concentration (mg/kg) of heavy metals from the depth of (15-30 cm) were observed to follow a decreasing order Pb (7.71)>Zn (0.50) > Ni (0.45) > Cr (0.31) > Cd (0.025) while for surface soils (0- 15cm) the mean concentration were in the following order: Pb (1.77) > Ni (0.49) > Zn (0.30) > Cr (0.27) > Cd (0.012).The results showed that calculated CF and Er recorded that investigated soil samples are uncontaminated with Zn, Pb, Cd, Cr and Pb and Ni. The pollution load index (PLI) was less than unity showing that there was minimum pollution in the studied dumpsite. The potential ecological risk showed that soil samples were in the class of low contaminated with the studied heavy metals. The results showed that concentrations of heavy metals of soil samples from dumpsites location at waste dumpsites of Kano Metropolis were within limits of European Union (2002) standards. Keywords: Heavy metals, single and integrated pollution indices Kano, Municipal dumpsites


Author(s):  
K. O. Ondoo ◽  
J. K. Kiptoo ◽  
A. O. Onditi ◽  
S. M. Shivaji ◽  
J. K. Ogilo

Agricultural activities, discharge of raw sewage into farms and the rise in urbanization have greatly contributed to soil pollution. During the rainy season, surface runoff from farms find their way into water bodies and deposits these contaminants into Rivers and Lakes which poses a threat to both aquatic and terrestrial organisms that depend on that water source. The objective of this research was to determine the level of anions and heavy metals from sediments in River Sio, Busia County, Kenya. Five sediment samples were taken from five sampling points and the levels of anions and heavy metals in them determined. Anions were determined using Shimadzu 1800 UV/visible spectrophotometer while heavy metals were determined using Shimadzu 6200 flame atomic absorption spectrophotometer (AAS). Copper, lead and nickel were above the allowed WHO limits while cadmium was below detection limit. The levels of nitrates, phosphates and chlorides were higher during the wet season due to surface runoff that carried these nutrients from the farms and deposited them on the bottom of the River. The levels of heavy metals were high during the dry season due to evaporation of water from the River, leading to an increase in the analyte concentration during the dry season. High levels of copper and nickel in the sediments points to the use of herbicides and pesticides in farming and washing of vehicles and motorcycles on the banks of the River. According to Igeo nickel showed moderate pollution during the dry season. The contamination factor for lead was very high during the dry season, while pollution load index confirmed pollution due to anthropogenic activities in sampling sites 1 – 4 during the dry season and no pollution due to anthropogenic activities during the wet season.  The study recommends reduced use of inorganic fertilizers in order to save the River from the danger of eutrophication. Excessive use of agrochemicals such as herbicides and pesticides should be discouraged. In addition, pesticide leaching and the level of microbes in soil and sediments should be considered for further research


2017 ◽  
Vol 64 (2) ◽  
pp. 111-126
Author(s):  
Abdul-Rahman Dirisu ◽  
John Ovie Olomukoro ◽  
Ifeanyi Maxwell Ezenwa

AbstractThis study assessed the physico-chemical status of sediments in the Agbede Wetlands with the aim to create a reference archive for the Edo North catchment and to further identify the characteristics mostly influenced by the natural and anthropogenic activities going on at the watershed. Nutrients, zinc, nickel and lead were identified to be mostly of anthropogenic origin, while alkali metals and alkaline earth metals were from both anthropogenic and natural sources. The clustering of stations 1 and 4 indicates that the sediment quality in the lentic systems was not completely excluded from the lotic system, suggesting that principal component analysis (PCA) and cluster analysis (CA) techniques are invaluable tools for identifying factors influencing the sediment quality. The mean values of the particle size distribution were in the following order across the ecosystems: sand (61.86–80.53%) > silt (9.75–30.34%) > clay (7.83–13.89%). The contamination of the water bodies was primarily derived from agricultural run-offs and through geochemical weathering of the top soils. Therefore, our analysis indicates that the concentrations of cations, anions and nutrients in the sediments of the lotic and lentic ecosystems in Agbede Wetlands are not at an alarming level.


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