Pollution des eaux à usages domestiques par les éléments traces métalliques des activités anthropiques : cas du sous bassin versant du fleuve Sassandra en amont du barrage de Buyo, Côte d'Ivoire

Pour résoudre les problèmes d'approvisionnement en eau potable des centres urbains, le gouvernement ivoirien a décidé d'utiliser les ressources pérennes telles que le fleuve Sassandra. Ainsi, le sous bassin du fleuve Sassandra en amont du barrage de Buyo est pressenti pour alimenter les villes de la région du Haut Sassandra et du département de Duekoué. Cependant, les intrants agricoles, les activités d'orpaillage et les déchets ménagers entrainent une forte contamination des eaux de ce fleuve en éléments traces métalliques (ETM). Ainsi, les tendances spatiales et temporelles de la pollution métallique ont été évaluées par le calcul des facteurs d'enrichissement, des indices de géo-accumulation, de l'indice de charge polluante, de l'indice de pollution sédimentaire et de l'indice de risque écologique individuel sur vingt-huit (28) échantillons provenant de sédiments de surface de ce fleuve. Les résultats montrent que des pollutions modérées à modérément sévères sont enregistrées au niveau du mercure (Hg) et du cuivre (Cu). Le Pb, l'As et le Cd connaissent un enrichissement modéré, avec des facteurs d'enrichissement respectifs de 1,77; 1,60 et 1,79 suggérant l'existence d'autres sources de métaux autres que la source naturelle terrigène. L'indice de pollution sédimentaire estimé à 5,95 (<10) montre que les sédiments sont moyennement pollués. Le risque écologique moyen lié aux Cd, As, Pb, Cu et Zn est largement inférieur à 40 traduisant un risque bas en référence à ces métaux avec le risque écologique moyen lié au Hg (160) largement supérieur à 40. L'analyse temporelle couplée au test SEQ-Eau montre également que le stockage des éléments traces métalliques au niveau des sédiments n'est pas définitif. Les risques de relargage, de remobilisation, de biodisponibilité et donc de toxicité, sont à craindre et constituent ainsi un danger permanent pour toute la chaîne trophique. Des mesures de prévention doivent donc être prises pour anticiper sur les difficultés que pourrait rencontrer le traitement de ces eaux pour les usages domestiques.

Contamination Evaluation of Heavy Metals in a Sediment Core from the Al-Salam Lagoon, Jeddah Coast, Saudi Arabia

The Al-Salam Lagoon is one of the recreational sites along the Jeddah coast, showing the environmental impacts of urbanization along the coast. A sediment core (220 cm) was collected from the intertidal zone to evaluate the heavy metals (Fe, Mn, Cr, Ni, Cu, Zn, and Pb) and geochemical indices (contamination factor, geo-accumulation index, and pollution load index). In the organ-ic-rich muddy sediments (0–100 cm), there is a high metals content and a pollution load index of ~3, indicting anthropogenic impacts with high Cu contamination (CF:12) and moderate Fe, Mn, Cr, Ni, Zn, and Pb contamination (CF: <3). The organic matter and heavy metals washed through surface run-off from the land and deposited as urban waste. Down the core, consistent metals concentration, CF, and Igeo trends indicate a common pollutant source and pollution load variations over time. In the sediment section (70–40 cm), a high organic matter, metal concentration, CF, Igeo, and PLI value (≥5) suggest an uncontrolled pollution load. The decreased and stable trends of environmental indicators toward surface sediments suggest measures taken to control the pollution along the Jeddah coast. Below 110 cm, the carbonate-rich sediments have low organic matter and metals, showing an unpolluted depositional environment. The negative geo-accumulation index implies a geogenic source and indicates no anthropogenic impacts as inferred from low (~1.0) CF and PLI.

Assessment of Radiation Levels and Geochemical Factors in Iraqi Soil

Radiation exposure related human hazards and environmental pollution caused by the natural and manmade radioactive materials needs inhibition. An accurate evaluation of the radiation levels and geochemical factors of soil play a vital role. In this perception, γ-ray spectroscopy with NaI (Tl) luminescence detector was used to assess the natural radioactivity level and associated radiological risk due to contaminated surface soil (33 samples) collected from the Waist province of Iraq. Compared to the stipulated global average, about 64% and 15% of the samples showed higher radioactivity concentration of 226Ra and 40K, respectively, whereas for 232Th it was lower. Furthermore, the statistical guides of the geo-accumulation and contamination factors were used to calculate the pollution levels in the soil samples. The geochemical factors for some polluting heavy metals (Ge, Se, Ag, Sn, Sb, Te, I, Ce, Hf, W, Hg, Ti, and Bi) in the samples revealed wide variation. The contamination factor and I-Geo-accumulation catalogues of the samples exhibited the pollution level fluctuations from very high (Hg of 1.88 ppm) to very low (W of 1.33 ppm, U of 1.87 ppm, Sn of 3.8 ppm, Sb of 2.99 ppm, Ti of 0.66 ppm and Ag of 1.92 ppm, Bi of 1 ppm) to moderate Se of 0.53 ppm, Hf of 1.81 ppm and I of 3.19 ppm). It was asserted that the observed intense adsorption of some specific metals on the surface soils was due to the natural sources in the clays and heavy minerals originated from the carbonates. Such heavy elements could move into the minerals structure of the surface soils from the anthropogenic urban wastes, agricultural and industrial activities.

Pollution, Ecological Risk and Source Identification of Heavy Metals in Sediments from the Huafei River in the Eastern Suburbso Kaifeng, China

Rivers in urban environments are significant components of their ecosystems but remain under threat of pollution from unchecked discharges of industrial sewage and domestic wastewater. Such river pollution, particularly over the longer term involving heavy metals, is an issue of worldwide concern regarding risks to the ecological environment and human health. In this study, we investigate the long-term pollution characteristics of the Huafei River, an important urban river in Kaifeng, China. River sedimentary samples were analyzed, assessing the degree and ecological risk of heavy metal pollution using the geo-accumulation index and potential ecological risk index methods; whilst Pearson’s correlation, principal component, and cluster analyses were used to identify the sources of pollution. The results show that heavy metal concentrations are significantly higher than their corresponding fluvo-aquic soil background values in China, and the geo-accumulation indexes indicate, that of the 8 heavy metals identified, Hg is most prevalent, followed in sequence by Cd > Zn > Cu > Pb > Ni > As > Cr. The potential ecological risk index of the Huafei river is very high, with the potential ecological risk intensity highest in the midstream and downstream sections where it is recommended that pollution control is carried out, especially concerning Hg and Cd. Long-term sequence analysis indicates that Cu and Pb dropped sharply from 1998 to 2017, but rebounded in 2019, and that Zn shows a continuous decreasing trend. Four main sources for the heavy metal contaminants were identified: Cr, Cu, Ni, Pb, Zn and Hg derived mainly from industrial activities, traffic sources and natural sources; Cd originated mainly from industrial and agricultural activities; whilst As was mainly associated with industrial activities. It is anticipated that the findings of this study will provide theoretical references for the effective control and scientific management of heavy metal pollution in the Huafei River and its surrounding areas.

Comparative assessment of wellbeing of Chrysichthys filamentosus, Kribia nana and Pegusa lascaris from Tomaro, Ajegunle and Badagry Creeks in Lagos, Nigeria

An investigation was made from April to September 2018 to detect some metals (cadmium, chromium, copper, iron, lead and zinc) in the fishes like Kribia nana, Chrysichthys filamentosus and Pegusa lascaris, as well as in water and sediment from three creeks i.e. Badagry (Station 1), Tomaro (Station 2) and Ajegunle (Station 3) in Lagos, Nigeria. Samples were collected and analyzed according to standard methods. Most of the water quality parameters are within standard recommended limits. Iron content in C. filamentosus (11.57±2.50mg/kg) from station 3 was higher (p<0.05) than iron content from station 2 (6.54±2.88mg/kg), while iron content in K. nana (8.34±1.10mg/kg) from station 3 was higher (p<0.05) than that from station 1 (6.12±1.04mg/kg) and station 2 (3.62±1.14mg/kg) respectively. Zinc (5.54±1.12mg/kg) recorded from station 3 was significantly (p<0.05) higher than that from station 2 (2.45±0.96mg/kg) and station 1 (3.84±0.86mg/kg). Iron content in all the fishes, cadmium in C. filamentosus and lead, chromium, copper in K. nana in stations 1 and 3 exceeded permissible limits. Condition factor (K) of most fish species was greater than 1. The Hazardous Index (HI) content in C. filamentosus from the three creeks and K. nana from stations 1 and 3 was above 1. Ecological risk factor(Er), enrichment factors (EF) and Index of geo-accumulation indicated moderate contamination of the sediment with cadmium. In conclusion, the three creeks are moderately polluted with metals but consumption of large quantity of the fish species could have high health risk. Hence, discharge of untreated metals into the water should be precluded.

Ecological Risk Assessment of Cadmium in Karst Lake Sediments Based on Daphnia pulex Ecotoxicology

The background value of cadmium (Cd) in soil and water sediments in the karst area is 0.31 mg kg−1, with a typical high background of cadmium geochemistry. It is well-known that Cd is classified as a highly toxic metal. Therefore, at the Yelang reservoir in Guizhou province, eco-toxicological tests were carried out using Daphnia pulex. The Geo-Accumulation Index and Potential Ecological Risk Index were used to assess the environmental risk of Cd in sediments. The Cd contents in the sediments of Yelang reservoir ranged from 2.51 to 5.23 mg kg−1, while the LC50 values of the acute toxicity test of Daphnia pulex and Cd at 24, 48, 72, and 96 h were 1.17, 0.50, 0.24, and 0.12 mg L−1, respectively, giving a Safe Concentration threshold of Cd of 1.20 × 10−3 mg L−1 in the water body. Based on curve fitting the solid–liquid two-phase distribution model of cadmium in Yelang reservoir was Y = 7.59 × 10−9 × X2.58 (R2 = 0.9995). The safety threshold sediment Cd concentration was 103 mg kg−1, and was much higher than the Cd content in the sediment of the Yelang reservoir. The Geo-Accumulation Index (Igeo 2.432–3.491) results show that the sediments had reached medium-strong or strong risk levels. The Potential Ecological Risk Index (Eri 242.8–505.9) reached a very high or extremely high-risk level. However, due to high concentrations of Ca2+ and Mg2+, and the pH being in the neutral–alkaline range of water body in karst areas, the Daphnia ecotoxicology evaluation method showed slight ecological risk, quite different from other assessment results, thus this method could be considered to use in such areas.

Monitoring Heavy Metal Contamination in the Pineapple (Ananas comosus) Cultivated tracts of Kerala, India

Agriculture plays an important role in the sustainable development of the country. Use of chemical fertilizers escalate certain components in excess quantity thereby deteriorate the productivity and leads to unpredicted outcome. This study makes an effort to reckon the accumulation of some selected heavy metals [Lead (Pb), Nickel (Ni) and Cadmium(Cd)] and related indices [bio concentration factor(BCF) and translocation factor (TF)] from roots, leaves and fruits of pineapple plantations in Ernakulam district. Contamination factor(CF), enrichment factor(EF) and geo accumulation index (Igeo) disclose the extent of soil contamination in the pineapple cultivated regions of Ernakulam district. Root to shoot TF derived for Pb, Ni, and Cd were 0.25, 0.733 and 0.6731. TF of Pb, Ni and Cd from root to fruit was 0, 0.5 and 0.195 respectively. Values obtained for BCF of Pb, Ni and Cd in root of the pineapple plant were 0.2013,0.5758 and 0.3288. In pineapple leaves BCF showed the values 0.0503, 0.4222 and 0.2214 by Pb, Ni and Cd. Pineapple fruit showed BCF values Zero, 0.2879 and 0.0641 for Pb, Ni and Cd. Enrichment factor for Pb, Ni and Cd in pineapple cultivated areas comes under the value 4.2, 3.7 and 2.8 respectively. Furthermore, the contamination factor of Pb, Ni and Cd was 9.93, 8.26 and 6.23, respectively. The values of geo accumulation index obtained for different heavy metals pass on that the degree of pollution with respect to Pb (6.621) was very strong and extremely contaminated, heavily to extremely contaminated for Ni (5.513) and Cd (4.15).

Pollution, Ecological Risk and Source Identification of Heavy Metals in Sediments From the Huafei River in the Eastern Suburbs of Kaifeng, China

Rivers in urban environments are significant components of their ecosystems, but remain under threat of pollution from unchecked discharges of industrial sewage and domestic waste water. Such river pollution, particularly over the longer term involving heavy metals, is an issue of worldwide concern regarding risks to the ecological environment and human health. In this study, we investigate the long-term pollution characteristics of the Huafei River, an important urban river in Kaifeng, China. River sedimentary samples were analyzed, assessing the degree and ecological risk of heavy metal pollution using the geo-accumulation index and potential ecological risk index methods; whilst Pearson’s correlation, principal component, and cluster analyses were used to identify the sources of pollution. The results show that heavy metal concentrations are significantly higher than their corresponding fluvo-aquic soil background values in China, and the geo-accumulation indexes indicate that of the 8 heavy metals identified, Hg is most prevalent, followed in sequence by Cd>Zn>Cu>Pb>Ni>As>Cr. The potential ecological risk index of the Huafei river is extremely strong, with the potential ecological risk intensity highest in the midstream and downstream sections where it is recommended that pollution control is carried out, especially concerning Hg and Cd. Long-term sequence analysis indicates that Cu and Pb dropped sharply from 1998 to 2017, but rebounded in 2019, and that Zn shows a continuous decreasing trend. Four main sources for the heavy metal contaminants were identified: Cr, Cu, Ni, Pb, Zn and Hg derived mainly from industrial activities, traffic sources and natural sources; Cd originated mainly from industrial and agricultural activities; whilst As was mainly associated with industrial activities. It is anticipated that the findings of this study will provide theoretical references for the effective control and scientific management of heavy metal pollution in Huafei River and its surrounding areas.

Multielement Contamination of Land in the Margin of Highways

The spatial distribution of potentially toxic elements in land near a heavily loaded highway in the West Attica region (Greece) is discussed. This study aimed to investigate the extent of soil contamination with trace elements on land in the margin of highways. The concentration of thirty-five elements in topsoil, car ash, and road sediment bulk samples was determined. Statistical and spatial analysis was applied for evaluating the geochemical dispersion of the examined elements. Geo-accumulation index was estimated. Elements content were compared to criteria and screening values established by the literature. The concentration of As, Cu, Mn, Ni, P, Pb, and Zn in topsoil appeared to be influenced by traffic emissions. It is found that engine exhaust, tyre wear, and brake lining contribute to the As, Ba, Cu, Mn, Ni, P, Pb, and Zn content recorded in topsoil in the margin of highways. The bulk sample of road sediment is moderately contaminated to extremely contaminated with Cu, Mn, Ni, P, Pb, and Zn. Comparison of elements content in topsoil with screening values revealed that Al, As, B, Ba, Cd, Co, Cr, Cu, Fe, Mn, Ni, Sb, V, and Zn pose a potential risk for plants.