Metal Concentrations In Water Samples Research Articles

Potential risk assessment and occurrence characteristic of heavy metals based on artificial neural network model along the Yangtze River Estuary, China.

Pollution from heavy metals in estuaries poses potential risks to the aquatic environment and public health. The complexity of the estuarine water environment limits the accurate understanding of its pollution prediction. Field observations were conducted at seven sampling sites along the Yangtze River Estuary (YRE) during summer, autumn, and winter 2021 to analyze the concentrations of seven heavy metals (As, Cd, Cr, Pb, Cu, Ni, Zn) in water and surface sediments. The order of heavy metal concentrations in water samples from highest to lowest was Zn > As > Cu > Ni > Cr > Pb > Cd, while that in surface sediments samples was Zn > Cr > As > Ni > Pb > Cu > Cd. Human health risk assessment of the heavy metals in water samples indicated a chronic and carcinogenic risk associated with As. The risks of heavy metals in surface sediments were evaluated using the geo-accumulation index (Igeo) and potential ecological risk index (RI). Among the seven heavy metals, As and Cd were highly polluted, with Cd being the main contributor to potential ecological risks. Principal component analysis (PCA) was employed to identify the sources of the different heavy metals, revealing that As originated primarily from anthropogenic emissions, while Cd was primarily from atmospheric deposition. To further analyze the influence of water quality indicators on heavy metal pollution, an artificial neural network (ANN) model was utilized. A modified model was proposed, incorporating biochemical parameters to predict the level of heavy metal pollution, achieving an accuracy of 95.1%. This accuracy was 22.5% higher than that of the traditional model and particularly effective in predicting the maximum 20% of values. Results in this paper highlight the pollution of As and Cd along the YRE, and the proposed model provides valuable information for estimating heavy metal pollution in estuarine water environments, facilitating pollution prevention efforts.

Heavy metal concentrations in water from Bakkhali River estuary, Cox’s Bazar, Bangladesh

Heavy metals contamination of water is considered as severe global issues for developing countries like Bangladesh. Because heavy metal pollution ruined aquatic ecosystem especially fish diversity which contribute important share on economy of a country. The present study designed to investigate the contamination level of lead (Pb), chromium (Cr), cadmium (Cd), copper (Cu) and zinc (Zn) in surface water of Bakkhali river estuary in Bangladesh. The decreasing order of metals concentration was Cu>Zn >Cr>Pb>Cd with the mean value of 2.6> 0.825 > 0.355 > 0.056 >0.003 mg/L, respectively. The results showed a significant seasonal variation of heavy metals concentration in water. Higher contamination occurred during post monsoon, while lower during the monsoon season. Among the all studied heavy metals Cu concentration was higher (2.6 mg/L) and lower (0.003 mg/L) concentration was Cd. Metal concentrations in water samples exceeded the safe limits of drinking water which indicated that the water from this estuarine river is not fully safe for using/drinking. The study area was not entirely polluted in terms of all metal concentrations. But level of metal concentration in polluted sites supposed risk to ecological health. The findings of present study recommended that continuous monitoring of water should be aimed to evaluate the risk which could help to maintain healthy coastal ecosystem and improve management strategy of this estuarine river.

Bioremediation of Selected Heavy Metals from Industrial Influent Collected at Wupa Wastewater Treatment Plant, Abuja

One of the primary issues brought about by the industrialization's rapid development is aquatic pollution. Utilizing microorganisms to remediate industrial wastewater (IWW) is a sustainable approach. This study was conducted to assess pollution load in Wupa wastewater treatment plant and to use introduced microbes (Bacillus subtillis and Aspergillus niger) individually and in a consortium for bioremediation. The Wupa wastewater treatment plant in Abuja provided the wastewater samples, which were then analysed for heavy metal content and other physicochemical characteristics. Measurements were made of the pH, colour, temperature, turbidity, electrical conductivity (EC), total suspended solids (TSS), chemical oxygen demand (COD), biological oxygen demand (BOD), and total dissolved solids (TDS). Wastewaters samples were subjected to heavy metal analysis using Atomic absorption spectrometry (AAS). For eight days, a container experiment was conducted to assess the effectiveness of the chosen species. Selected species were used to remediate the wastewater samples both alone and collectively. Following treatment, turbidity (41.2%), BOD (95.2%), COD (96%), TSS (87-99%), TDS (27-8%), and EC (45-8%) all showed significant decreases. Following the experiment, atomic absorption spectrophotometry was used to determine the metal concentrations in water samples. 98.4% of Zn, 92.4% of Fe, and 92.4% of Mn were eliminated by the chosen species. Heavy metal removal percentage from Wupa wastewater using Aspergillus niger and Bacillus subtillis. Zinc significantly (p>0.05) record high removal efficiency as compared to Mangane and Iron in the waste water treated with Bacillus subtilis, A. Niger and the combination of both organisms.The bioremoval efficiency of Aspergillus niger and Bacillus subtillis for heavy metals in Wupa wastewater. The control treatment significantly (p<0.05) has lower bioremoval efficiency of the heavy metals (Manganese, Iron and Zinc) when compared to the waste water treated with Bacillus subtilis, A. Niger and the combination of both organisms. Based on the findings of this study, it can be concluded that the Bacillus subtillis and Aspergillus niger and other ingineous wastewater isolsates had the capacity to resist and grow on heavy metals and thus contributes in the removal of heavy metals present in the wastewater by absorbing them which also increased the biomass of the microbes.

Contamination and ecological risk assessment of Cr, As, Cd and Pb in water and sediment of the southeastern Bay of Bengal coast in a developing country

Safe levels of heavy metals in the surface water and sediment of the eastern Bay of Bengal coast have not been universally established. Current study characterized heavy metals such as arsenic (As), chromium (Cr), cadmium (Cd) and lead (Pb) in surface water and sediments of the most important fishing resource at the eastern Bay of Bengal coast, Bangladesh. Both water and sediment samples were analyzed using inductively coupled plasma mass spectrometer. Considering both of the seasons, the mean concentrations of Cr, As, Cd, and Pb in water samples were 33.25, 8.14, 0.48, and 21.14 μg/L, respectively and in sediment were 30.47, 4.48, 0.20, and 19.98 mg/kg, respectively. Heavy metals concentration in water samples surpassed the acceptable limits of usable water quality, indicating that water from this water resource is not safe for drinking, cooking, bathing, and any other uses. Enrichment factors also directed minor enrichment of heavy metals in sediment of the coast. Other indexes for ecological risk assessment such as pollution load index (PLI), contamination factor (CF), geoaccumulation index (Igeo), modified contamination degree (mCd), and potential ecological risk index (PERI) also indicated that sediment of the coastal watershed was low contamination. In-depth inventorying of heavy metals in both water and sediment of the study area are required to determine ecosystem health for holistic risk assessment and management.

Persistence of Heavy Metals in River Sirsa Around Industrial Hub Baddi, India.

The Indian riverine system has become dumping site for toxic industrial pollutants. For assessing the flow of pollutants at various trophic levels, it is primarily important to do elemental profiling first so as to detect their load in Sirsa tributary of river Sutlej flowing through foothills of Shivalik in Himachal Pradesh, around the industrial hub Baddi, Solan. The study area includes three observation sites (S1, S2, and S3) on river Sirsa and drainage system of Baddi industrial units; the Effluent Nallah as demarcated in figure1. Heavy metal concentrations in water samples were detected using inductively coupled plasma mass spectroscopy of elements (Ti, V, Cr, Co, Ni, As, Li, Cd, Cs, Pt, Pb, Hg) as these were found to be very common in effluents of chemical, cement, textile dyeing, electronics and pharmaceutical industries. Statistical analysis showed that the concentrations (ppb) of elements found to be within permissible limits of WHO at sites under study for seven metals (Hg, Li, Ti, V, Co, Cs, Pt) but it was higher for five toxic heavy metals (Cr, Ni, Pb, As, Cd) at S2 only, streamlined in order Cr >Ni > Pb> As >Cd >Hg >Li >Ti >V >Co > Cs > Pt. It may be due to improper installation of common effluent treatment plant (CETP) on the bank of river Sirsa or due to leakage by tanker carrying waste water from various industrial set ups as these units were not directly linked to CETP. These sites were committed to act as ultimate gutter to receive all types of industrial pollutants as part of mismanagement. The load of Arsenic and Lead is increasing in lotic region and its impact on aquatic ecosystem at trophic level can be explored to combat toxicant pollution.

Assessment of environmental and toxicity impacts and potential health hazards of heavy metals pollution of agricultural drainage adjacent to industrial zones in Egypt

The objectives of this study were to assess the environmental impact of industrial wastewater disposal in the El-Khadrawiya agricultural drain, Menoufia Governorate, Egypt, as well as the effect on water, soil, and plant qualities in the drain's extension area, which was primarily adjacent to the industrial zone. The analyses results of wastewater at El-Khadrawiya drain revealed that heavy metal concentrations in water samples exceeded WHO permitted limits. Heavy metal levels followed the following pattern: (Pb > Zn > Cr > Cd > Ni > As), where Heavy metal levels average were: (1.8492 > 1.7857 > 0.1815 > 0.1578 > 0.059 > 0.0048. Wastewater, soil and plant samples were analyzed using (PerkinElmer AAnalyst 400 Atomic Absorption Spectrometer A Analyst 400), Heavy metal pollution evaluation indicators: Target hazard quotient (THQ), Hazard index (HI), Chronic daily intake (CDI), Carcinogenic risk (CR), and Heavy metals pollution index (HPI)) showed that a majority of samples discovered values referring to carcinogenic health risks for the population. In contrast, the soil contamination indices followed the same trend, with the contamination factor (CF) indicating that the majority of samples exposed low to medium levels of pollution for (Ni, Cd, and Zn), while Pb and Cr were between high and very high, and the contamination degree (Cd) and modified degree of contamination (mCd) indicating that the majority of samples revealed the medium level of pollution, with the exception of one site with a high level of contamination. The bioaccumulation factor (BAF) revealed that heavy metal accumulation in plants exceeds the critical range. This study should be expanded to include additional agricultural regions with comparable conditions in order to provide environmental monitoring of present challenges and work toward solutions.

Potential Health Risk Assessment of Bioaccumulation of Heavy Metals in Freshwater Organisms from Ojo River, Lagos, Nigeria

This study investigated potential health risk associated with heavy metal bioaccumulation in freshwater organisms in Ojo River, Lagos, Nigeria. Liver, gills and muscle from fish samples and muscle and exoskeleton from crab samples were analysed for concentration of Cd, Cr, Zn, Pb, Ni and Cu using Atomic Absorption Spectrophotometer after digestion of samples. Generally, heavy metal concentration in water samples from different locations in Ojo River did not exceed WHO limits. Concentration of Pb, Cu, Zn and Cr in tissues of M. niger and L. campechanus shows high bioaccumulation of heavy metals. Heavy metals bioaccumulated more in liver > muscle > gills in both fish samples. Ni and Cd were not detected in the two fish species. Similarly, Pb, Cu and Ni were found in muscles and exoskeleton of C. pagurus and S. serrate at quantities higher than WHO limits. Zinc was detected only in muscle and not exoskeleton of both crab samples, while Cr was found only in exoskeleton of C. pagurus and Ni was not detected in all crab species. Estimated daily intake (EDIs) for Pb, Cu, Zn and Cr in M. niger and L. campechanus and for Pb, Cu and Ni in C. pagurus and S. serrate were higher than the oral reference doses. Target Hazard Quotient (THQ) for heavy metals were also extremely high. Significantly high bioaccumulation of heavy metals in freshwater organisms from Ojo River calls for serious actions because it is a major source of freshwater foods for residents of Lagos.

Heavy Metal Contamination Status and Risk Assessment in Surface Sediments of Köyceğiz Lagoon Estuary System (KLES) (South-West Anatolia)

This study reports the presence of heavy metals (Cr, Ni, Cu, Cd, Pb) in the sediment and water column in the Köyceğiz Lagoon Estuary System (KLES) (South-West Anatolia). The mean heavy metal concentrations (µg L-1) in the water were found as Cr: 3.72-8.36, Ni: 6.51-9.48, Cu: 1.29-11.88, Cd: ND-0.08, Pb: ND-0.34. The heavy metal concentrations in water samples were found to be below the internationally acceptable limits. The mean heavy metal concentrations (mg kg-1) in the sediment were found as Cr: 1.75-4.25, Ni: 5.24-12.69, Cu: 0.25-0.51, Cd: <0.01, Pb: 0.04-0.13. As a result of the analyses conducted concerning contamination factor (CF), geo-accumulation index (Igeo), pollution load index (PLI), monomial potential ecological risk index (ER), and total potential ecological risk index (RI) for heavy metals in the sediment, it was deduced that there was not any pollution and moderate or high ecological risks.

Analiza uticaja rudarskih aktivnosti na sadržaj teških metala u podzemnoj vodi i vodi za piće u zavisnosti od klimatskih parametara

The purpose of this analysis is to show whether mining activities have an impact on the grondwater and drinking water quality. Water samples were analyzed in three unfavorable climatic periods during the winter of 2018-2019. The obtained results show that the heavy metal concentrations in water samples do not have values higher than the allowable according to the current statutory regulations. Also, the heavy metal concentration did not change with changes in climate parameters. However, a higher concentration of molybdenum than statutory by the law was found in the period of snow melting. This has shown that in extremely unfavorable climatic conditions, the karst groundwater can contain certain metals that can origin either from the surrounding field or as a result of mining activities, considering that there are two open pits s in the immediate vicinity of the "Surdup" source.

Assessing the environmental risk and pollution status of soil and water resources in the vicinity of municipal solid waste dumpsites.

Municipal solid waste management remains a major challenge for many developing countries where unsanitary and environmentally damaging practices, such as open dumping and burning of wastes, are consistently utilized as means of waste disposal. This study aimed to assess the impact of local dumpsites in a region in Southern Lebanon and to assess/determine the level of pollution they cause on local ecosystems and the concomitant risks to public health. Accordingly, soil and water samples were collected from the seven dumpsites that were investigated over the course of two seasons. Several biological, chemical, and physical parameters were examined, with the results being utilized to calculate a number of environmental indices. Results indicated that several soil parameters including TN (700-2400mg/kg), pH (8.3-8.7), COD (39-1995mg/kg), and sulfate levels (17.8-301.6mg/kg) were altered by the dumpsites. Heavy metal concentrations varied between dumpsites; however, the most commonly prevalent metals across all dumps were Fe (992-41,500mg/kg), Cr (17.4-139.5mg/kg), Zn (24.1-177.4mg/kg), Cu (9.42-148.2mg/kg), and Mn (25.2-776.5mg/kg), though recorded concentrations exceeded permissible limits only in certain instances. Evidently, soil samples collected at dumpsites had higher concentrations compared to the samples collected away from dumpsites reaching 27 times more in certain locations. The altered parameters have a direct effect on soil fertility and, if biomagnified, could disrupt crop yields and impact human health. Physiochemical properties and heavy metal concentrations in water samples were not significantly altered and were found to be within permissible limits. However, it is crucial to develop a monitoring and remediation plan to decrease the percolation of leachate to water resources.

Concentration of heavy metals in the drinking water of Kut city - Iraq and their impact on health

The quality of drinking water is related to the state of the water supply networks, pollution, and contamination of drinking water with contaminants of both anthropogenic and natural origin. Water samples were collected from 22 different waterworks in Kut, Iraq, and heavy metal concentrations (Pb, Ni, and Zn) were analyzed. In various parts of the city, 22 sampling sites were pre-defined. The results indicated that heavy metal concentrations in water samples did not surpass WHO guidelines (World Health Organization).

Heavy Metal Concentrations in Water Samples from Lake Kivu, Rwanda

Heavy metals are among the pollutants threatening the living organisms including human beings. The presence of heavy metals in water is of great concern due to their toxicity to aquatic organisms, humans and ability to accumulate in food chains. Thus, there is a need to regularly monitor heavy metal levels in aquatic medium. The present study was conducted to assess heavy metal concentrations in Lake Kivu water. Water samples from Lake Kivu were taken from three sites, namely: Rusizi, Karongi and Rubavu. Heavy metals in the samples were analyzed using Atomic Absorption spectro-photometer (SHIMADZU AAS-6800) and Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES).Copper, lead, cadmium, chromium, manganese, mercury and arsenic concentrations were determined. Copper ranged from 3.24 to 10.01 μg/l, lead varied from 8.81 to 37.44 μg/l, cadmium ranged from 5.01 to 14.01 μg/l,chromium was between 139.5 and 226.6 μg/l, manganese varied from 598.3 to 795.7 μg/l, mercury ranged from 0 to 0.047 μg/l, while arsenic was not detected in any of the analyzed water samples. Except for arsenic, all the other heavy metals exceeded the EPA (US Environment Protection Agency) maximum permissible limit for class III surface water intended for fish consumption and recreation. Thus, there is a need to establish the sources of lake water pollution by heavy metals in order to design further strategies limiting the amounts of heavy metals entering Lake Kivu.
 Keywords: Cadmium, chromium, copper, lead, manganese, mercury

Local and landscape factors affecting tadpole diversity in subtropical Atlantic Forest streams

AbstractAnalysing which environmental features influence structure of communities is important to establish management and conservation priorities for regional biodiversity. In this study, we analysed the structure of amphibian larval assemblages in southern Brazilian streams and their relationships with local and landscape factors. We sampled tadpoles in 18 streams between November 2014 and February 2015. We collected pH, electric conductivity, temperature and dissolved oxygen in streams, and performed laboratory analyses to estimate metal concentrations in water samples. We collected metrics describing landscape factors, such as the land cover classification of a set of buffers around the streams. We found eight amphibian species in total. Tadpole richness was higher in streams with greater cover of agriculture in the 50 and 100 m buffers, but it was also lower in streams with greater cover of buildings in the 100 m buffer. Highest abundance was also found in streams with greater dissolved oxygen and larger areas of dams in the 250 m buffer, but it was lower in streams with larger areas of forests in the 500 m buffer. The presence of agriculture in the immediate surroundings of streams can increase richness of amphibians due to the occupation by open‐habitat species. On the other hand, the low number of rheophilic species suggests that soil use may restrict permanence of these species.Abstract in Portuguese is available with online material.

Seasonal assessment of some heavy metal pollution and Metallothionein gene expression in cultured Oreochromis niloticus

BackgroundThe present study was planned to estimate the heavy metal concentrations in water samples and fish tissue residue (liver and muscle) of cultured Oreochromis niloticus as well as metallothionein (MT) gene expression in fish liver. Fish samples were collected from different private fish cultures in Kafr El-Sheikh governorate during April 2018–April 2019 in order to assess the public health risks associated with consuming cultured fish. Therefore, we investigated the concentrations of four metal elements (cadmium [Cd], copper [Cu], lead [Pb], and zinc [Zn]) in both fish tissues (muscle and liver) and water samples during the four seasons. Other water parameters (pH value, chemical oxygen demand, dissolved oxygen, alkalinity, total hardness, ammonia, and nitrite) were also determined.ResultsNH3 values were above recommended limits mostly along the year. The trend of metal mean contents found in the fish were in decreasing order of Zn > Cu > Pb > Cd, and the liver showed greater accumulation than muscle. The highest amounts of metals accumulated in fish liver and muscle were recorded in winter and autumn, respectively, while the lowest amount was recorded in summer. Regarding fish muscle which is the edible part consumed by human, the concentration of studied metals was within the safe limits for seafood except for Pb. MT showed a significant high level in response to metals accumulated in fish liver. A positive correlation occurred between MT levels and Cu and Pb concentrations across different seasons.ConclusionIn conclusion, MT expression levels seem to be sensitive to the heavy metals in natural habitats making it a powerful biomarker of heavy metals pollution in fish cultures. In addition, cultured fish in this study could be unfit for human consumption due to a high level of Pb in the edible part of fish. Therefore, greater attention should be set to Pb sources accumulated in cultured fish in Kafr El-Sheikh governorate.

Trace Metal Accumulation in Trigonella foenum-graecum Irrigated with Wastewater and Human Health Risk of Metal Access Through the Consumption.

The aim of the present research was to determine the trace metal accumulations in Trigonella foenum-graecum irrigated with three different water regimes (ground water, canal water and sugar mill water). Also, transfer factors, pollution load indices, and health risk indices were assessed to evaluate metal transport and accumulation through the food chain. The analysis was conducted by Atomic Absorption Spectrophotometer (Shimadzu model AA-6300) to evaluate the concentration of metals in water, soil and vegetables. Trace metal concentrations in water samples ranged from 0.84 to 1.67, 0.42 to 0.72, 0.45 to 0.85, 2.51 to 9.99, 1.21 to 1.92, 1.82 to 9.98 and 0.64 to 0.91mg/kg for Cd, Cr, Cu, Fe, Ni, Zn and Mn, respectively. The mean metal concentrations in soil samples were determined as 0.25, 0.86, 0.96, 3.37, 0.4, 0.44 and 2.31mg/kg for Cd, Cr, Cu, Fe, Ni, Zn and Mn, respectively. Trace metal accumulations in T. foenum-graecum samples gathered from where soil samples were taken are as follows: The contents of Cd, Cr, Cu, Fe, Ni, Zn and Mn ranged from 0.48 to 1.06, 0.11 to 0.35, 0.15 to 0.29, 1.43 to 8.39, 0.39 to 0.54, 2.1 to 3.05 and 0.42 to 0.47mg/kg, respectively. Statistical analyses showed that the treatments have non-significant effect (p > 0.05) on concentrations of metals in T. foenum-graecum samples collected from three sites for Ni, Cr, Cu, Zn and Mn and significant effect on Fe and Cd.

Determination of Some Selected Heavy Metals in Water, Oreochromis niloticus and Labeobarbus intermedius Samples from Abaya and Chamo Lakes

The fish organs and water was collected from three sampling sites of Lakes Chamo and Abaya. A procedure consuming 12 mL mixture of HNO 3 -H 2 O 2 for gill, kidney, liver and 1:2.5 mL mixture of HNO 3 -HCl for water samples for digestion of was developed. Concentrations of six metals in water and their accumulation in the edible tissue of Tilapia (Oreochromis niloticus) and Barbus (Labeobarbus intermedius) fish species were determined using Flame Atomic Absorption Spectroscopy. The results revealed that the average heavy metal concentrations in water samples were; Zn 0.017, Cu 0.077, Fe 7.50, Cr 0.033, Cd 0.264 and Pb 1.731 mg/L respectivelty. The highest concentrations of iron (Fe) and lead (Pb) were observed at Chamo Park and Sile sites, respectively. The average contents of heavy metals in fish samples were; Zn 0.062, Cu 0.047, Fe 2.270, Cr 0.041, Cd 0.045 and Pb1.78 mg/Kg in both fish species. The highest accumulations of iron (Fe) and lead (Pb) concentration were observed in liver and gill of Tilapia fish from Chamo Lake. There was no significant difference between the two lakes in accumulating trace metals. Keywords : Fish variety, Heavy metals, Lakes, ANOVA DOI : 10.7176/FSQM/83-05

Molecular Characterization of Vibrio Harveyi and Vibrio alginolyticus with the Impact of Stressful Environment on Some Naturally Infected Marine Fish

Cultured seabass (Dicentrarchus labrax L.) and seabream (Sparus aurata L.) are marine species of high economic important especially in Mediterranean aquaculture. Among bacterial diseases of marine cultured and wild fish, vibriosis caused by Vibrio species is one of the most prevalent diseases. In the present work, we report the isolation and identification of the V. harveyi and V. alginolyticus, based on biochemical and molecular characterization, from cultured seabass and seabream native to private fish farms at Mathalath-El Diba region, Domitte City at Domitte Governorate, Egypt during summer season. The most prominent clinical signs of diseased fish were hemorrhagic ulceration on the dorsal musculature and caudal peduncle area as well as sever protrusion of the eye outside the orbital cavity. Histological examination of seabass revealed haemorrhage on the liver and nodular formation on different organs especially in kidney and liver. While, diseased seabream showed marbling appearance of gill with nodular formation and necrotic area distributed over the liver. Physico-chemical characteristics of water samples collected parallel to fish samples indicated that pH and organic matter of the water sample was within the permissible limits. However, the unionized ammonia, nitrate, and hydrogen sulphate concentrations were higher than the acceptable limits. Moreover, the heavy metals (copper, zinc, cadmium, lead, mercury, nickel, and iron) contained of water samples were higher than permissible limits. In regards to the haematological parameters associated with diseased and apparently healthy seabream and seabass. The total protein, albumin, and globulin were lower in diseased seabass and seabream than apparently healthy fish. Serum lysozyme and bactericidal activity was lower in the diseased fish than apparently healthy seabass and seabream. Levels of aspartate amino-transferase (S.AST) and alanine amino transferase (S.ALT) in plasma of diseased seabass and seabream were higher than apparent healthy seabass and seabream. Altogether, higher level of heavy metal concentrations in water samples than the permissible limits act as chemical stressors that help in increase the prevalence of V. harveyi and V. alginolyticus species in seabass and seabream.

Assessment of toxic metal contamination with ecological risk of surface water and sediment of Korotoa River in Bangladesh

Toxic metal contamination is a major problem globally, especially in developing countries. In this study, the levels of toxic metals such as Cr, Ni, Cu, As, Cd and Pb in surface water and sediment of Korotoa River of Bogra City, Bangladesh were investigated. The average concentration of Cr, Ni, Cu, As, Cd and Pb in studied sediment were 1.01, 0.89, 1.98, 6.02, 0.0054 and 0.469 mg/kg, respectively. In the water sample, the mean concentration of Cr, Ni, Cu, As, Cd and Pb were 1.13, 1.33, 3.02, 2.62, 0.75 and 0.81 mg/kg, respectively. A huge amount of municipal wastes, industrial effluents and agricultural runoff from the periphery of Bogra City notably are dumped to this river. Most of the effluents channeled into these rivers are not treated. Considering the sampling sites, the decreasing order of total metal concentration in water samples were Cu > As > Ni > Cr > Pb > Cd and in sediment were As > Cu > Cr> Ni > Pb > Cd. Total average concentrations of Cr, Ni, Cu, As, Cd and Pb in the water samples were higher than WHO guidelines for drinking water quality. This contamination level implied that the condition is much frightening and probably severely affecting the aquatic ecology of the river.

Flow of toxic metals in food-web components of tropical mangrove ecosystem, Southern India

ABSTRACTThe concentration of heavy metals in water, sediment, and various food-web components like plankton, shrimp, bivalve, and fishes were collected from Muthupet mangrove ecosystem. Heavy metal concentration in water samples was relatively lesser than the biological and sediment samples. Among the heavy metals studied, zinc showed highest concentration ranged from 1.81 to 81.5 mg/kg or mg/L, whereas Cd (0–26.06 mg/kg or mg/L) was found to be lesser in all the samples except a few organisms viz. Anadara sp. (26.06 mg/kg), Coilia sp. (10.09 mg/kg), Anguila sp. (9.14 mg/kg), and Tachysurus maculates (6.95 mg/kg) observed during this study. Pb and Cu were ranged from 10.29 to 14.99 mg/kg and 0.59 to 16.06 mg/kg, respectively. The reported values of heavy metals were several folds higher than permissible levels of international regulatory agencies like WHO, FAO, and USEPA. The order of accumulation of heavy metals in biological samples are as follows: Pb > Cu > Zn > Cd. All the biota showed a higher degree of bioconcentration factor for Zn, in the range of 3.90–34.39. Principal component analysis concluded that Muthupet was contaminated by lithogenic as well as anthropogenic activities.Therefore, field observation and sample analysis clearly indicated that sampling sites were polluted with both point and nonpoint source of pollution.

Studies on seasonal pollution of heavy metals in water, sediment, fish and oyster from the Meiliang Bay of Taihu Lake in China

The present study, seasonal pollution of heavy metals (Pb, Cd, Cr and Cu) in water, sediment, tissues of fish Carassius carassius and oyster Crassostrea gigas were determined at seven sampling sites from Meiliang Bay, Taihu Lake during one year calendar, 2016. The total heavy metal concentrations in water samples were higher in winter and summer than in spring and autumn season, whereas in sediment they were higher in winter and summer seasons, respectively. The trend of metal mean contents found in the fish and oyster were in decreasing order of Pb > Cu > Cr > Cd and Pb > Cu > Cr > Cd, respectively. The tissues of fish and oyster captured during winter and summer accumulated a higher significant different amount of metals relative to other season, which was attributed to a higher influx of agricultural waste, sewage and sludge by heavy rainfall and floods. In addition, the pollution load index (PLI) values were above one (>1), indicating an advanced decline of the sediment quality, and contamination factor (CF) confirmed that the sediment samples were moderate to high contamination by Pb and Cr. Thus, comparative studies with seasonal pollution of heavy metals in Meiliang Bay of Lake Taihu regions indicate considerable heavy metal enrichment in water, sediments as well as in various organs of fish and oyster. Finally, our results indicated that the metal concentration values increased statistically significant different related to season (p < 0.001). The determination of heavy metal stress biomarkers in fish along with seasonal variations may serve as a convenient approach during pollution bio-monitoring programme.