Metal Concentrations In Water Research Articles

Effect of biochar addition on sludge aerobic composting and greenbelt utilization

Biochar (B) addition is considered to be an effective optimization method for accelerating the composting process and improving the quality of the final compost. Many studies have focused on the use of B in sludge compost as additives. However, the optimal level of B in the composting process and the effect of greenbelts utilization after composting have not been explained yet. In this study, autocontrol composting reactors were constructed and the effects of different B concentrations on nutrient transformation and morphological changes of heavy metals in sewage sludge–corn cob (C) aerobic composting were carried out. The feasibility of lawn grass ( Festuca arundinacea ) planting in soil composed of garden soil and different concentrations of composting sludge (40%, 60%, and 80%) was analyzed. The results revealed that a longer high temperature period can be maintained when the ratio of sludge:C:B is 10:6:1 (v/v). The detection result of TN, TP and TK indicated that B plays a positive role in nutrient retention in sludge. The addition of B has a positive effect on the passivation of Cu, Zn, Pb, Ni, and Cr in sludge. After composting, the residual fraction of heavy metals increased and exchangeable fraction decreased. The bacterial community diversity and richness showed dynamic changes during composting process. The enriched microbial groups of different treatments were analyzed. The linear discriminant analysis effect size (LEFSe) results showed that enriched microbial groups were totally different between different treatments and more bacterial clades were enriched at treatment S2. The heavy metal concentrations in the leached water were safe for plant and groundwater. The best growth conditions for F. arundinacea was the addition of composting sludge with a ratio of sludge:C:B of 10:6:1 (v/v) under an addition rate of 40%. • 10:6:1 (v/v) (Sludge: corn cob: biochar) is the best composting treatment. • Biochar has a positive effect on the passivation of heavy metals in sludge. • Bacterial community diversity and richness dynamically change during composting. • 40% of composting sludge addition is the best growth condition for F. arundinacea .

Accumulation Of Heavy Metal Lead (Pb) And Cadmium (Cd) In Halophila ovalis And Thalassia hemprichii As Agents Of Phytoremediation In South Serangan

Seagrass ecosystem is part of the marine ecosystem that has quite important ecological role. Halophila ovalis and Thalassia hemprichii are seagrass species have the potential to become an agent of phytoremediation by determining the concentration of heavy metals Pb and Cd that have accumulated in them. This study was conducted in January 2018 in Southern Serangan Beach. The purpose of investigating the concentration of heavy metals in water, sediments, roots and leaves of seagrass and determine the bioaccumulation, translocation character and can be made as an agent for phytoremediation. The method used is purposive random sampling method, determined by 3 point. The point is determined from the condition closest to the port Benoa to the outermost point the bay mouth. Determination of station points is considering the presence of the most seagrasses. Results obtained in this study obtained average Pb concentration in water 0.0521 ppm, average metal Cd 0.1652 ppm, the average sediment Pb 75.8574 ppm, Cd 15.33593 ppm, concentration of Pb and Cd in roots and leaves of H. ovalis and T. hemprichii respectively Pb 42.4940 ppm, 45.5334 ppm, and 35.6207 ppm, 38.3931 ppm. Metal Cd 12.9708 ppm 14.8581 ppm Bioaccumulation value of seagrass is accumulator plants. Value of Pb and Cd translocation factors in seagrass H. ovalis (phyto-extraction) seagrass T. hemprichii Pb (phyto-extraction) and Cd (fitostabilization) phytoremediation values by both types of seagrass are greater in remediating heavy metal cadmium, meaning that both types of seagrass are better used for phytoremediation agents of heavy metal cadmium.

Changes of heavy metal concentrations in Shitalakhya river water of Bangladesh with seasons

Heavy metal concentrations in water and fish of the Shitalakhya river was measured to find out the suitability of its water for drinking and irrigation purposes. The concentrations of Pb, Cu, Cr, Zn, Cd and Hg in water were 0.0065; 0.0240; 0.0069; 0.8170; 0.0044; and 0.0057 mg/L, respectively in pre-monsoon, 0.0029; 0.0151; 0.0019; 0.4270; 0.0015; and 0.0020 mg/L, respectively in monsoon, and 0.0040; 0.0212; 0.0039; 0.6520; 0.0029; and 0.0031 mg/L, respectively in post-monsoon season. The heavy metal concentrations were found higher in pre-monsoon followed by post-monsoon and monsoon. The results also depicted that over the three seasons heavy metal pollution index and heavy metal evaluation index for all metals were lower than the critical pollution index value and low heavy metal contamination, respectively, and the degree of contamination in pre-monsoon season stated medium level pollution, followed by post-monsoon and monsoon season. The concentrations of Pb, Cu, and Cr in fish were found less than the lower detection limit, while the Zn were found 25.42; 18.30; and 29.34 mg/kg during the pre-monsoon, monsoon and post-monsoon, respectively. The study concluded that the Shitalakhya river water was not safe for the aquatic environment, especially for aquatic biota.

Impact of Flooding and Urbanisation on the Content of Heavy Metals in the Water and Bottom Sediments of the Amur River

The impact of floods on the migration activity of elements coming from urbanized territories to the Amur river was assessed. The influence of large cities on pollution of water and floodplain ecosystems is revealed. The content of heavy metals in water, bottom sediments, and small watercourses draining urban areas is characterized. The processes of sediment accumulation in the floodplain, their influence on the redistribution of elements and geochemical transformations in the soil space of floodplain soils are studied. Conditions for the accumulation of heavy metals in soils are described, their concentration levels and migration activity are determined. The role of organic matter in swamps and silts on water pollution and bottom sediments of the Amur river is shown. It was found that the main mass transfer of soluble substances and pollutants dispersed fractions of nailc is carried out by water flow during floods.

Water-Soluble Carbon Quantum Dots Modified by Amino Groups for Polarization Fluorescence Detection of Copper (II) Ion in Aqueous Media

Industrialization is serious for changing the environment and natural water composition, especially near cities and manufacturing areas. Logically, the new ultrasensitive technology for precise control of the quality and quantity of water sources is needed. Herein, an innovative method of polarization fluorescence analysis (FPA) was developed to measure the concentration of heavy metals in water. The approach was successfully applied for precise tests with reduced analysis time and increased measurement efficiency among laboratory methods. Based on this work, the investigations established the new type of carbon quantum dots (CQDs) with controllable fluorescence properties and functionalized amino—groups, which is appropriate for FPA. The parameters of one and two-step microwave synthesis routes are adjusted wavelength and fluorescence intensity of CQDs. Finally, under optimized conditions, the FPA is showed the detection of copper (2+) cations in water samples below European Union standard (2 mg/L). Moreover, in comparison with fluorescence quenching, polarization fluorescence is proved as a convenient, simple, and rapid test method for effective water safety analysis.

Critical Shifts in Trace Metal Transport and Remediation Performance under Future Low River Flows.

Exceptionally low river flows are predicted to become more frequent and more severe across many global regions as a consequence of climate change. Investigations of trace metal transport dynamics across streamflows reveal stark changes in water chemistry, metal transformation processes, and remediation effectiveness under exceptionally low-flow conditions. High spatial resolution hydrological and water quality datasets indicate that metal-rich groundwater will exert a greater control on stream water chemistry and metal concentrations because of climate change. This is because the proportion of stream water sourced from mined areas and mineralized strata will increase under predicted future low-flow scenarios (from 25% under Q45 flow to 66% under Q99 flow in this study). However, mineral speciation modelling indicates that changes in stream pH and hydraulic conditions at low flow will decrease aqueous metal transport and increase sediment metal concentrations by enhancing metal sorption directly to streambed sediments. Solute transport modelling further demonstrates how increases in the importance of metal-rich diffuse groundwater sources at low flow could minimize the benefits of point source metal contamination treatment. Understanding metal transport dynamics under exceptionally low flows, as well as under high flows, is crucial to evaluate ecosystem service provision and remediation effectiveness in watersheds under future climate change scenarios.

Assessment of Copper and Iron Concentration in Water of Yamuna River, Delhi, India

The concentration of Copper (Cu) and Iron (Fe) in water from River Yamuna, Delhi, India, were determined by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Heavy metals are potentially toxic and are transferred to the surrounding environment through different pathways. Heavy metals are considered one of the most dangerous groups since they are non-degradable due to their persistent nature, toxicity, and tendency to accumulate in organisms and alters the food chain cycle and still more. Yamuna river water may become contaminated by the accumulation of trace metals and metalloids through emissions from the rapidly expanding industrial areas, disposal of high metal wastes, leaded gasoline and paints, land application of fertilizers, animal manures, sewage sludge, pesticides, wastewater irrigation, and Electronic waste. Trace element toxicity has proven to be a major threat, and there are several health risks associated with it. Even though they do not have any biological role, these metals' toxic effects remain present in some of the other forms harmful for the human body and its proper functioning. On comparison of these heavy metals concentration in water, it was found that Fe, Cu were higher than the permissible limits of WHO, which gives an indication of hazardous risk to human health.

Removal of Contaminants from Water by Bacterial Activity

High concentration of sulphates and metals in waters is often as a consequence of anthropogenic activity and industry. The principlesof the biological-chemical methods for pollution removal include various processes. The most widely metabolic pathway of sulphate-reducing bacteria - overall dissimilatory reduction - is the complete reduction of sulphate to hydrogen sulphide. Two major metabolicgroups are known, depending on whether or not they can oxidize acetate. One group utilizes lactate, fumarate, propionate, butyrate,pyruvate, and aromatic compounds, which they typically oxidize to acetate, while the other group oxidizes acetate to CO₂ and H₂O.Sulphate is reduced to H₂S through a series of intermediate reactions. The end product of this reaction, hydrogen sulphide, can reactwith metal ions to form insoluble metal sulphides or reduce soluble toxic metals, often to less toxic or less soluble forms. This way,sulphate-reducing bacteria are utilizable in bio-elimination of sulphate and metal from water.

Source identification and human health risk assessment of heavy metals in water sources around bitumen field in Ondo State, Nigeria

The concentrations of Cr, Cu, Fe, Mn, Pb, Ni, V and Zn in sediment, surface and groundwater were determined in a total of 180 samples acquired bi-monthly for one year to evaluate the impact of bitumen spills. Principal component analysis (PCA) and cluster analysis (CA) were also used to identify the possible sources of contamination. The concentrations of heavy metals in groundwater, surface water and sediment as follows: Fe > Mn > Zn > Cu > Pb > Ni > V > Cr, Mn > Fe > Zn > Cu > Pb > Ni > V > Cr and Mn > Fe > Zn > Pb > Ni > V > Cu > Cr respectively. The average concentrations of Fe, Pb and Mn in groundwater were found to be above the World Health Organization (WHO) drinking-water quality standard of 0.1, 0.003 and 0.4 mg L−1 respectively. Multivariate analysis suggests significant intrusions of two diagnostic heavy metals (Ni and V) into groundwater samples indicating the migration of these trace metals from bitumen into the water sources. Data from this study showed that the child hazard quotient (HQ) for Pb and Mn were all ≥1, contributing up to 55.5% towards the Hazard Index (HI). Furthermore, Cr, Pb and Ni in groundwater were the predominant contributors towards carcinogenic risks with Ni contributing an average of 81.7% towards the aggregate cancer risk. These results showed significant petroleum contamination that could lead to heavy metal bioaccumulation in residents with a potential threat to public health. Conclusively, these results provide a useful reference for water system management of metals in Agbabu environment.

Evaluating the Performance of a Diffusive Gradient in Thin Film Embedded with Montmorillonite for the Determination of Labile Cd, Pb, Mn, and Zn in Natural River Water

Montmorillonite (MMT), a natural clay mineral with high ion-exchange capacity and trace metal adsorbability, has been demonstrated to be a suitable binding phase in the diffusive gradient in thin film (DGT) technique for the determination of labile trace metals in synthetic water samples. However, in situ working performance of DGT-MMT with natural river water has not yet been investigated. The present study examined the performance of a DGT containing montmorillonite (MMT) for the in situ isolation and determination of labile Cd, Pb, Mn, and Zn fractions in Lach Tray River water, North Vietnam. The repeatability and accuracy of the DGT-MMT probe were assessed on the basis of seven measurement replicates performed on Cd2+, Pb2+, Mn2+, and Zn2+ standard solutions. Then, the DGT-MMT probes were deployed in Lach Tray River water at different sampling sites to determine the labile metal fractions present in river water. By comparing the total and dissolved metal concentrations in the river water, the distributions of the four tested trace metals were constructed. The proportions of the dissolved fractions of Cd, Pb, Mn, and Zn were 46.7–73.7%, 38.5–63.9%, 36.4–41.6%, and 49.8–67.7%, respectively. The results also showed that the high accuracy and reproducibility of the DGT-MMT data were comparable with measurements obtained by the commonly used DGT-Chelex-100 method. In comparison with the data obtained from anodic stripping voltammetry (ASV), a traditional technique for the determination of non-in situ speciation of trace metals, labile metal concentrations measured by DGT-MMT were in similar ranges. These findings indicate that naturally available montmorillonite can be used as an alternative binding material in DGT probes for the in situ determination of labile metal concentrations in natural watercourses.

Trace metal biogeochemical responses following wood ash addition in a northern hardwood forest

Wood ash may be useful as a forest soil amendment in Canada, but trace metals can have detrimental effects if they accumulate in, or are transported from, forest ecosystems. Metal concentrations in soil water and sugar maple (Acer saccharum Marsh.) seedling tissue chemistry were measured in a north temperate hardwood forest over 4 years following a biomass boiler ash addition field trial. Twenty plots (3 m × 3 m) were established in Haliburton Forest with both fly and bottom ash treatments of 0, 4, and 8 Mg·ha−1 with four replicates, and tension lysimeters were positioned in each plot at 30, 50, and 100 cm depths. Over the 4 years, soil water metal concentrations in treated plots were not significantly different from those of the control plots. No differences in metal concentrations in foliage of sugar maple seedlings could be detected, but there were significantly higher concentrations of some metals (Al, Fe, Zn, Pb, Ni, and Sr) in roots of treated plots. Simulated drought mobilized several metals in upper mineral soil, but this mobilization occurred similarly in controls and ash-treated soils. These results suggest that doses below 8 Mg·ha−1 industrial wood ash with trace metal concentrations below Canadian regulatory limits do not cause an increase in trace metal mobility or availability in northern hardwood forests with acidic soils during the first 5 years after application.

Metal Distributions and Human Health Risk Assessments on Waters in the Huixian Karst Wetland, China

The concentrations of nine metals (As, Cr, Al, Cu, Pb, Zn, Ni, Mn, and Hg), in 23 water samples collected from four main types of water (well, surface river, subterranean stream and blue hole), in the Huixian karst wetland were determined and analyzed to investigate their distributions and health risks. A multivariate statistical analysis was used to study the distribution characteristics of the metals. A human health risk assessment model was developed to assess the health risks. The results found that the mean concentrations of metals in water from the Huixian karst wetland were in the order:Al > Mn > Zn > Cr > Ni > As > Hg > Cu > Pb. The maximum concentrations of Hg (1.08 μg·L-1) in the well water, Hg (0.78 μg·L-1) and Mn (259.00 μg·L-1) in the surface river water, and Hg (0.47 μg·L-1) and Al (300.00 μg·L-1) in the blue hole water all exceeded the corresponding standard limits. The metal concentrations in the subterranean stream samples were all within the regulated limits. For the nine metals, the well water and the subterranean stream water qualities were better than those of the surface river and the blue hole. The results of the multivariate statistical analysis showed that the concentrations of Cr, Ni, Cu, and Zn in the well water were mainly related to the regional geological background, while the concentrations of Al and Pb in the blue hole water were mainly affected by pyrite mining and residential activities. The concentrations of As and Mn in rivers may be affected by tourism activity, aquaculture and river sediments. The results of the health risk assessment on water through the drinking and skin penetration pathway indicated that the total health risks order was:well > subterranean stream > blue hole > surface river. The total health risks values of well water as drinking water for adults (6.11×10-5 a-1) and children (6.67×10-5 a-1) exceeded the maximum allowance level (5.0×10-5 a-1). Cr was the main metal element that causes carcinogenic risks. For drinking water safety, the concentrations of Hg and Cr in well water should be controlled before drinking.

Effect of pyrolysis temperature of rice husks and corncobs on the concentration of heavy metals in leachate water

Biochar has the potential to remove heavy metal ions through the adsorption process. Corncobs and rice husks are agricultural waste that has the potential to be biochar. This research was aimed to decrease the concentration of lead metal from leachate liquid. The sample is taken from the Supit Urang landfills Malang City. The used method is an experimental method applying a completely randomized design. The method used in the collection of leachate wastes using a grab sampling method. Biochar is made from rice husk and corncobs with a high temperature of 600 °C, 700 °C while the low temperature is 300 °C, 400 °C, dried in an oven to determine the moisture content. The running process is carried out by entering biochar charcoal weighing 10 g in 100 ml of water leachate. When observing heavy metals, lead is carried out for 1 day at the 6th hours. After being separated, lead concentration was measured using atomic absorption spectrophotometer. As well as producing that the treatment of corncobs with a temperature of 400 °C can absorb the best Fe compared to the other treatments, the concentration of lead metal in wastewater has decreased significantly, because the carbon content of corncob is greater than that of rice husks.

An assessment of heavy metals concentration in water around quarries and barite mine sites in part of central Cross River State, Southeastern Nigeria

The assessment of the level of heavy metal concentrations in water sources around quarries and barite mine sites in central Cross River State, Southeastern Nigeria, was carried out to evaluate the degree of contamination due to mining and quarrying activity in the area. The investigation involved the collection of twelve water samples from ponds, streams, river and boreholes around the area. The water samples were passed through 0.45 µm filter paper and preserved with a drop of 0.1M HNO3 acid. The preserved samples were analyzed for their heavy metal (Ba, Cr, Cu, Fe, Mn, Pb and Zn) content, using inductively coupled plasma-mass spectrometry (ICP-MS). The results show that the average concentration of Ba, Cu, MN, Pb and Zn were above WHO guideline value for drinking water quality, hence not suitable for drinking. The average concentration of the metals is in the order Ba>Mn>Cu>Fe>Pb>Zn>Cr. Computed values of contamination index show that the samples from four locations were contaminated. Single factor pollution index computation indicates that the waters are not contaminated with Cr, but slightly polluted with Fe and Zn, moderately polluted with Ba and severely polluted with Cu, Mn and Pb. Further, Nemerow comprehensive pollution index indicates that samples from four locations were severely contaminated. The study revealed that the water sources around the barite mines had elevated level of heavy metal concentration compared to location around the quarries. It is recommended therefore, that the water be treated before use for drinking purpose.
 Keywords: heavy metals, contamination index, pollution index, barite mine, quarry

Metal Accumulation Using a Bacterium (K-142) Identified from Environmental Microorganisms by the Screening of Au Nanoparticles Synthesis.

The use of technology that uses organisms to synthesize metal nanoparticles is necessary to maintain a sustainable society. In this study, we investigated and screened the microorganisms isolated from environmental water by quantifying the reproducibility of synthetic Au nanoparticles and the ability of large amount synthesis. The microorganism (K-142) of the Bacillus genus showed the best activity in the investigation. K-142 can also synthesize Ag, CdS and PbS nanoparticles, and the deposition efficiency of Ag, Al, Cd, Cu, and Pb was about 64.8–99.2%. According to the observation results under the microscope after fluorescent staining, K-142 could survive after being treated with 0.5 mM metal solution for 24 h. Therefore, it is expected that K-142, which is easy to cultivate, would also have a high ability to reduce and deposit metal substances. K-142 can be applied to the concentration and recovery of heavy metals in environmental water, thereby opening up channels for biological water purification.

Enhanced removal of heavy metals using sorbent and Phragmites australis

Water pollution by heavy metals has currently been an increasing worldwide concern. This study was conducted to assess the removal efficiency of a treatment system using sorbent and common reed (Phragmites australis). Approximately 1400 g of sorbent that was modified from Ban Cuon iron mine drainage sludge by adding 10% sodium silicate solution and heating at 400 °C was put in a column of 1.8l. The initial concentrations of As and Cd in inflow water were 1.0 mg/l, those of Pb, Mn, and Zn were 6.0 mg/l. During 30 days of the laboratory experiment, aqueous solution of constant flow rate (50 l/day) was pumped through the sorbent column before flowing into surface and horizontal subsurface constructed wetlands using P. australis. The results showed that the removal efficiency of As, Cd, Mn, Pb and Zn by sorbent – surface constructed wetland were 83.0 – 89.5, 89.3 – 93.3, 69.7 – 98.0, 94.8 – 95.4, and 69.2 – 92.3%, respectively; those by sorbent – subsurface constructed wetland were 85.3 – 89.1, 98.5 – 98.7, 92.8 – 98.7, 95.5 – 96.0, and 93.1 – 96.2%. The concentrations of heavy metals in the outlet water met the National Technical Regulation on Industrial Wastewater of Vietnam (QCVN 40:2011–BTNMT) with the exception of As, which indicates the effectiveness of combined sorbent and P. australis for simultaneous removal of these metals from contaminated water.

Heavy metal concentrations in sediment, water and fish in two major rivers (Ankobra and Tano) in major farming and artisanal gold mining areas in Ghana

Heavy metal concentrations in sediment, water and fish in two major rivers (Ankobra and Tano) in major farming and artisanal gold mining areas in Ghana1University of Ghana, Accra, Ghana, 2University of Michigan, Ann Arbor, USABackground: Arsenic (As), mercury (Hg) and lead (Pb) are toxic heavy metals that occur naturally in the environment. However, their levels are on the rise due to anthropogenic activities, including artisanal gold mining thus polluting fresh water bodies and posing a threat to aquatic wildlife, animals and humans.Objective: The aim of the study was to assess As, Hg and Pb concentrations in sediment, water and fishes from the Ankobra and Tano Rivers in the Western Region of Ghana, where human activities; especially artisanal gold mining are suspected of grossly polluting river bodies..Methods: Levels of As, Hg and Pb in different fish species and aquatic media (water and sediment) from the Tano and Ankobra River basins were analysed using the Atomic Absorption Spectrophotometer (AAS) Pinnacle 900T (Perkin Elmer, USA). Statistical analysis was done using Microsoft version 10 excel spread sheet and STATA software version 13 (StataCorps LP, Chicago, USA).Results: Overall, levels of heavy metals were in the order, Hg>As>Pb across study sites. Mean concentrations of Hg and As were highest in fish (2.09±1.29 mg/Kg) and (2.80±1.52 mg/Kg), followed by sediment (1.40±1.78 mg/Kg) and (0.61±0.40 mg/Kg), and water (0.09±0.36 mg/L) and (0.06±0.05mg/L) respectively. Pb levels were highest in sediment (1.46±4.26 mg/Kg), followed by water (0.14±0.10 mg/L), and then fish (0.11±0.11 mg/Kg) respectively. Conclusion: As and Hg levels in both Tano and Ankobra were above the WHO recommended levels for pristine freshwater ecosystems and may therefore pose a threat to aquatic wildlife and human health. Keywords: Tano, Ankobra, Heavy metals, artisanal

The geological setting of arsenic enrichment in groundwater of the shallow aquifers of the Tista Floodplain, Rangpur, Bangladesh

Arsenic is present in water samples within the studied active floodplain areas of the Tista river, Rangpur Division, Bangladesh. All the water samples contain less arsenic than the WHO prescribed limit of 10 μg/L. 93.33% groundwater samples have higher Mn content than the permissible limit of 0.01 mg/L of WHO. The heavy metal concentrations of water can be expressed as Fe>Mn>Zn>As on the basis of their mean content. The heavy metals are negatively correlated with the well depth which is indicative of the influence of the anthropogenic activities on the concentrations of heavy metals. The arsenic concentration in water samples is higher in the central part of the study area. The coarser grain size, dominance of physical weathering, elevated topography and the effective flushing of groundwater resulted low concentration of arsenic in the groundwater. The EDS study reveals that arsenic occurs as coating materials of the silicate minerals. The river waters also have arsenic content lower than WHOs permissible limit. The factor analysis reveals that the iron and arsenic is released by the chemical weathering of arsenic bearing minerals like pyrite and arsenopyrite. The Fe and Mn derived in the groundwater by the chemical weathering of iron and manganese bearing minerals such as iron rich clay, silicate minerals and iron sulfides. Â

Health risk indices and zooplankton-based assessment of a tropical rainforest river contaminated with iron, lead, cadmium, and chromium

Oil exploration’s devastation on health and the environment may far outweigh its economic benefits. An oil spill occurred at Egbokodo River in Delta State, Nigeria, thereby polluting the land and water bodies. The study was therefore aimed at evaluating the impacts of iron, lead, cadmium, and chromium on the zooplankton community structure of Egbokodo River and the potential health risks. Zooplankton and surface water samples were collected to investigate the concentrations of trace metals and zooplankton abundance. The associated carcinogenic and non-carcinogenic effects of the metals in the water were analyzed. Trace metal concentrations in the surface water were determined using atomic absorption spectroscopy (Philips model PU 9100) and zooplankton samples were collected using a hydrobios plankton net (mesh size 25 µm). Total petroleum hydrocarbons (TPH) and oil and grease (OG) were determined using Agilent 7890B gas chromatography coupled to flame ionization detector (GC-FID) and volumetric analysis respectively. The trend of the abundance of zooplanktons cross the river was 18 individuals (Station A) < 100 individuals (Station B) < 155 individuals (Station C). Cyclopoida proved to be the most resilient to the impacts of the oil spill. On a taxa basis, the order of abundance among Calanoida, Cyclopoida, Cladoceran, and Harpacticoida was Station C > Station B > Station A, except in Amphipoda where Station B > Station C > Station A was observed. Iron and lead posed significant carcinogenic risks that are liable to be inflicted by the ingestion of the water. The cumulative non-carcinogenic health risk in the male was the only significant (> 1) among the age groups. Total petroleum hydrocarbons (TPH), oil and grease (OG), iron, and lead had notable impacts on the general abundance of zooplankton in the aquatic habitat. The dominance of the Cyclopoida in the river buttressed the impact of the oil spill which warrants a prompt remediation measure. The pollution had notable ecological impacts on the zooplankton community structure of the aquatic habitat. The adults in the nearby human populations are liable to elicit carcinogenic health challenges associated with lead and iron ingestion. The males are at risk of non-carcinogenic illnesses which are associated with the combined toxicity effects of all the metals. The study suggests that the pollution in Egbokodo River was validated by the dominance of the Cyclopoida in the aquatic habitat. The study confers bioindicator reputation on the Cyclopoida for future biomonitoring studies.

Preliminary investigation of lower Danube pollution caused by potentially toxic metals

The current study aims to assess the pollution status of the European river-sea system lower Danube River-Danube Delta-North West Black Sea, through an integrated analysis of metal concentrations in water, sediments and fish community. The Danube flows through numerous industrial cities and receives a significant amount of pollutants due to the reception of urban and industrial emissaries, as well as agricultural land runoff. Samples of water, sediments and fish (10 species) were collected from 7 representative sites along Danube River, Danube Delta and Black Sea shore. For the analysed fish species, potentially toxic and essential elements (Pb, Cd, As, Cu, Fe, Zn, Mg, Ca, Na, K) from muscle and liver samples were measured and discussed. Measurement of elements and other environmental quality parameters were determined for water and sediments. The Black Sea area, represented by S6 and S7, received sediments from Danube with the lowest concentrations of Cd (0.05 ± 0.01 μg g−1, respectively 0.01 ± 0.001 μg g−1), Pb (3 ± 0.03 μg g−1, respectively 2 ± 0.03 μg g−1), As (2 ± 0.02 μg g−1, respectively 1.4 ± 0.3 μg g−1), Ni (8.9 ± 0.1 μg g−1, respectively 5.2 ± 0.2 μg g−1), Cr (8 ± 0.7 μg g−1, respectively 5 ± 0.2 μg g−1), Cu (3 ± 0.1 μg g−1, respectively 2 ± 0.04 μg g−1), Fe(6 ± 0.3 μg g−1, respectively 3 ± 0.1 μg g−1) and Zn (0.03 ± 0.003 μg g−1, respectively 0.017 ± 0.001 μg g−1). These results suggest that the Danube Delta system plays an important role in filtering the pollutants. Based on the biota and water analysis, there was no correlation observed between Cd, respectively Pb concentration in the environment and fish body (Person Coef. = −0.02 in muscle tissue and −0.01 in liver tissue, respectively Pearson Coeff. = −0.06 in muscle tissue and 0.1 in liver tissue). Cadmium remained an active element in the pollution of the Danube area (S1 and S2), with high concentration in the water matrix (0.14 ± 0.02 μg L−1, respectively 0.05 ± 0.01 μg L−1) and fish muscle (0.15 ± 0.03 μg g−1f.w. in C. carpio – S2). This fact was confirmed by several other studies.