Heavy Metals In Tissues Research Articles

Bioaccumulation of heavy metals in tissues of Indian anchovy (Stolephorus indicus) from the UAE coast, Arabian Gulf

Pollution in the Arabian Gulf has risen in recent decades due to rapid development in the region. We studied 21 elements in the liver, gastrointestinal (GI) tract and muscles of the Indian anchovy (Stolephorus indicus) to characterize bioaccumulation in this abundant forage fish. Mean concentrations (μg/g wet weight) of elements ranged as follows: Cd: 0.1–8.0; Cr: 0.1–24.0; Cu: 1.2–24.0; Ni: 0.3–76.5; Ca: 1237.0–15,270.0; S: 2966.0–7467.0; Zn: 7.1–247.0; V: 0.1–27.0; Hg: 0.04–0.18 and Sr: 8.1–191.0. Zn, Cu, Cr, and Cd in the tissues exceeded the maximum permissible limit recommended by FAO, WHO and EC. We suggest that bioaccumulation in fish could be a hazard for human consumption. Therefore, further monitoring is needed to better characterize pollutant levels in fish of higher trophic levels in the Arabian Gulf.

Heavy Metals in Tissues of Blue Crabs Callinectes danae from a Subtropical Protected Estuary Influenced by Mining Residues.

This short note aims to report in detail a preliminary assessment of the concentrations of Cd, Hg and Pb in tissues of blue crabs Callinectes danae collected from the Cananéia-Iguape-Peruíbe estuarine complex (CIP), in the South of São Paulo State coast, Brazil. In October 2014, blue crabs were collected from CIP. Tissues were removed by dissection and metal determination was performed by GF-AAS and CV-AAS. According to statistical analysis, Pb and Cd concentrations in gills were significantly higher than those found in muscles and hepatopancreas, respectively. There were no significant differences in Hg concentrations between samples. Cd, Hg and Pb concentrations in gills and hepatopancreas were lower than those reported in a previous study performed at CIP. However, Cd concentration in hepatopancreas was higher than the Brazilian limit for consumption and new efforts to monitor Cd concentrations in C. danae tissues must be performed.

Comprehensive assessments of ecological states of Songhua River using chemical analysis and bivalves as bioindicators.

The aim of this study was to compare environmental pollution and ecological states of two different areas of the Songhua River areas: near Harbin City and Tongjiang City, located at a distance of about 500km downstream. The anthropogenic pollution concentrations of heavy metals (HM) were determined. The results showed that concentrations of eight metals (Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) in the water were in the range of 0.001-0.588mg/L for Tongjiang and 0.001-0.508mg/L for Harbin, while that in sediments were in the range of 0.67-1575.37mg/kg for Tongjiang and 0.07-5617.13mg/kg for Harbin, respectively. Bivalves from tested sites exposed to environmental pollution exhibited significantly different physiological states. The latter was assessed using the method of physiological loading, based on measuring the recovery time (Trec) of heart rate (HR) after removal of the load. Trec in mussels from Harbin was recorded in the range of 151 to 234min, while that from Tongjiang was only 115min. Cd, Cu, Pb, and Zn in mollusk soft tissues were also determined for Harbin and Tongjiang, respectively. The metal pollution index (MPI) and bioconcentration factor (BCF) in the mollusks were calculated for each metal. BCF in the mussels from the Tongjiang area was lower than that from the Harbin area. Physiological testing, as well as the concentration of HM in water, and sediment, and also the bioaccumulation of HM in tissue showed that the ecological state of the Tongjiang area was better than that of Harbin. Apparently, after more extensive studies, a methodological approach of assessing the ecological state of water areas, based on physiological state testing of aboriginal mollusks, could be used in the monitoring of pollution effects in water bodies and streams.

Accumulation and health risk assessment of heavy metals in tissues of the shrimp and fish species from the Yumurtalik coast of Iskenderun Gulf, Turkey

In this study, concentrations of heavy metals were determined in the tissues of fish species (S. solea and S. aurata) and shrimp (P. semiculatus) from the Yumurtalık zone of the Iskenderun Gulf, Turkey. The aim of of our study is to evaluate potential risks to human health associated with fish and shrimp consumption. Metals concentrations varied significantly depending on the tissues and species. The concentrations of Cu, Fe, Pb and Zn in fish and shrimp tissues were high, while Cd levels were relatively low. In comparing with the permissible limits set by the European Union and Food and Agricultural Organization for fish and shrimp, mean values of Cu, Fe, and Zn were within acceptable limits, but the mean values of Cd and Pb exceeded the limits.From the standpoint of human health, this study suggests that the observed Pb and Cd accumulation may pose a possible health risk to excessive S. solea and P. Semiculatus consumers in Turkey.

Химический состав и накопление тяжелых металлов в тканях и органах цыплят - бройлеров при введении в рацион кормовой добавки «Гумэл Люкс»

Химический состав и накопление тяжелых металлов в тканях и органах цыплят - бройлеров при введении в рацион кормовой добавки «Гумэл Люкс»

Concentrations and Risk Assessment of Heavy Metals in Tissues of Walleye Pollock (Gadus chalcogrammus) Captured from the Northeastern Coast of Korea

All heavy metals, except Hg, were well accumulated in liver compared with muscle and gonads. Estimated daily intakes of heavy metals were within 2% of the provisional maximum tolerable daily intakes, Hazard quotients of heavy metals were less than 1.0. Appropriate intake control of G. chalcogrammus is necessary to protect human health in the future.

Intake of Heated Leaf Extract of Coriandrum sativum Contributes to Resistance to Oxidative Stress via Decreases in Heavy Metal Concentrations in the Kidney.

Coriandrum sativum (coriander) is an annual herb of the Apiaceae family and has been used as a traditional remedy. Here we examined whether heated leaf extract of coriander decreases the concentrations of heavy metals in tissues. Male ddY mice were given a drinking water containing 0.25% of heated leaf extract of coriander for 8weeks. Eight weeks after the intake, the concentrations of zinc, iron, copper, arsenic, and cadmium were measured in the liver and kidney. The intake of coriander did not modify the concentrations of all heavy metals tested in the liver, but decreased the concentrations of iron, arsenic, and cadmium in the kidney. Because heavy metals can induce oxidative stress, the effect of coriander intake on hydrogen peroxide-induced oxidative stress was compared between slices from the kidney and liver. The slices were immersed in Ringer solution containing 100μM hydrogen peroxide and aminophenyl fluorescein (APF), a probe for detecting reactive oxygen species (ROS). APF fluorescence was markedly increased in the control kidney slices, while the increase was completely blocked in kidney slices from coriander intake group. In contrast, APF fluorescence was also markedly increased in the control liver slices, while the increase was not blocked by coriander intake. The present study indicates that intake of coriander leaf extract contributes to powerful resistance to oxidative stress in the kidney, probably via decreased concentrations in heavy metals. It is likely that decrease in arsenic concentration to the detection limit is a major factor for the resistance.

Coal mine effluent-led bioaccumulation of heavy metals and histopathological changes in some tissues of the catfish Clarias batrachus.

Coal mining generates huge quantity of toxic effluent which consistently pollutes the neighboring wetlands where the local inhabitants regularly cultivate edible fishes. In the present study the concentration of heavy metals Fe, Zn, Cu, Mn, Ni, Cd, Pb and Cr were analyzed in the water and various tissues of edible catfish Clarias batrachus reared in a pond receiving effluents from Rajrappa coal mine, Jharkhand, India. The metal concentrations in the pond water were dramatically higher (Fe 350%, Zn 423%, Cu 12%, Mn 7029%, Ni 713%, Cd 1700%, Pb 4333% and Cr 588%) than the safe limit of Environmental Pollution Agency (2003) as well as the control tap water. Excessive amounts of metals in effluent caused their substantial transfer to the different tissues of the catfish reared in such ponds. Results showed that accumulation of metals in fish tissues were in the following order: liver > kidney > air breathing organ (ABO) > gills > skin > brain > muscles. Among the various tissues the highest accumulation of most of the metals was recorded in the liver (2.05-271.28mg/kg dry weight) and lowest in the muscles (1.39-30.27mg/kg dry weight), while the concentration of metals in other tissues ranged in between. The accumulation of heavy metals in tissues appears to cause remarkable histopathological alterations in skin, gills, ABO, liver and kidney that might be leading to deleterious effect on fish physiology and consequently impact the consumers of such fishes.

Evaluation of heavy metals in tissue of Tympanotonus fuscatus sold in some markets in port harcourt metropolis, Nigeria

Evaluation of heavy metals in tissue of Tympanotonus fuscatus sold in some markets in port harcourt metropolis, Nigeria

Marine pollution by some heavy metals and physiological response of Ruditapes decussatus

Bivalves can accumulate toxicants such as heavy metals in their tissues, for this reason, they are considered as good bio-indicators for water quality. The risk is increased due to eating these clams raw or lightly cooked. This study aims to determine the concentration of some selected metals (Cu, Zn, Mn, Cd, and Pb) in the soft tissue of Ruditapes decussatus collected in the summer of 2017, from three locations at Alexandrian coasts, Egypt, Abo Quir, (loc.#1), Sedi Beshr (loc.#2) and (loc.#3), El-Max) and to find out whether pollution alters the clam physiological functions or not. The present data showed that the highest mean value of salinity was reported in water samples collected from Abo Quir (loc.#1) and the highest level of dissolved oxygen was reported in water samples collected from Sedi Beshr (loc.#2). The present results showed that the studied heavy metals concentrations are highly significant in samples of water and soft tissue of Ruditapes decussatus collocated from Abo Quir bay. From the above-cited results, it is concluded that loc.#1(Abo Quir bay) represents the most polluted site in the present study. Statistical analysis showed a significant increase of MDA and a significant decrease of SOD and GPx in the soft tissue of Ruditapes decussatus collected from Abo-Quir Bay (loc.#1). There was a highly significant difference between the concentration of MDA, SOD, and GPx in the tissue of clams collected from the three locations (p < 0.001). The correlation coefficient of heavy metals in tissue, heavy metals in water, and oxidative stress biomarkers showed that the concentration of MDA in the tissue of calm collected from Abo Quir Bay (loc.#1), Sedi Beshr (loc.#2), and El-Max (loc.# 3) were positively correlated with the mean activity level of SOD and the concentration of SOD in the clam's tissue collected from Abo Quir Bay (loc.#1) and Sedi Beshr (loc.#2) were negatively correlated with the activity level of GPx. The present work also showed that the correlations between different heavy metals in the tissues of R. decussatus collected from three locations indicated that different rates and mechanisms of metal accumulation were taking place.

Measurement of some heavy metals in tissues infect by intestinal worms of two kind of fishes in Al-Qadisiyah Province

Measurement of some heavy metals in tissues infect by intestinal worms of two kind of fishes in Al-Qadisiyah Province

ТЯЖЕЛЫЕ МЕТАЛЛЫ В ТКАНЯХ И ОРГАНАХ PОPULUS PYRAMIDАLIS

The data on the accumulation of heavy metals in tissues and organs of poplar pyramidal in industrial and residential functional areas of Kursk are presented. It was found that the leaves of the poplar pyramidal, vegetating in the industrial zone have the maximum depositing capacity and accumulate 1.1 - 5.06 times more heavy metals than the leaves of the studied rock in the residential zone. Concentrations of Pb and Cd in the tissues of the Lombardy poplar depends on their content in the environment. It is noted that they either exceed the norm by 1-27 times, or they grate with normal values of concentrations of heavy metals in plants. Zn, Cu and Ni concentrations in poplar tree tissues in the studied areas did not exceed MAC. It is noted that the content of heavy metals in the tissues of above-ground and underground bodies of the pyramidal poplar varies greatly. The limit of variation of lead concentrations in the studied plants reaches 241.2 units. Such fluctuations are due to physiological and anatomical features of poplar tissues, the nature of soil pollution, as well as the intensity of human impact on the environment. In the polluted areas of the city the affinity of elements to accumulation in the depositing bodies of plants sharply changes. In the industrial zone of Kursk in the wood of poplar pyramidal mainly compartmentalized Pb, Cd and Ni, in the residential zone-Zn, Cu.

The Chemical Composition of the Lionfish (Pterois miles, Bennett 1828), the New Invasive Species of the Mediterranean Sea

In this study, the proximate composition of muscle tissue was investigated in lion fish (P. miles), which has a high invasion potency in the Mediterranean. At the same time, the potentials of accumulation of essential and toxic metals in brain, gill, muscle and liver tissues have been examined. The study was carried out with 4 lion fish individuals (1st individual 278 g, 28 cm, 2nd individual 55 g, 19 cm, 3rd individual 68 g, 20 cm, 4th individual 92 g, 22 cm) caught from the Yeşilovacık Bay in 2016. Water, crude protein, total lipid, total mineral substance (TMS) percentages were found to be 75.68-77.62%, 20.05-21.08%, 1.11-1.84%, 1.22-1.54 in P. miles, respectively. The percentage of fatty acids in lionfish ranged from 34.26% to 37.57% saturated fatty acids (SFAs), from 24.99% to 27.99 % monounsaturated fatty acids (MUFAs), and from 20.49% to 49.31% polyunsaturated fatty acids (PUFAs). Dominant fatty acids are palmitic acid and stearic acid from SFAs, palmitoleic acid, oleic acid, cetoleic acid from MUFAs, EPA and DHA from PUFAs. The accumulation levels of heavy metals in the tissues were found as Fe&amp;gt; Zn&amp;gt; As&amp;gt; Cu&amp;gt; Cr&amp;gt; Pb, respectively. The accumulation levels of each metal in the tissues were determined as follows: liver&amp;gt;gill&amp;gt;brain&amp;gt;muscle (29.19-384.43 μg g-1dw) for Fe, gill&amp;gt;brain&amp;gt;liver&amp;gt;muscle (16.08-56.68 μg g-1dw) for Zn, muscle&amp;gt;brain&amp;gt;gill&amp;gt;liver (2.69-7.88 μg g-1dw) for As, liver&amp;gt; brain&amp;gt;gill&amp;gt;muscle (0.74-7.05 μg g-1dw) for Cu, brain&amp;gt;gill&amp;gt;muscle&amp;gt;liver (0.35-2.67 μg g-1dw) for Cr, brain&amp;gt;gill&amp;gt;muscle&amp;gt;liver (0.26-2.11 μg g-1dw) for Pb. As a result; while lionfish muscle tissue contains high levels of protein, unsaturated fatty acids, minerals and trace elements, it has been determined that levels of heavy metals in this consumable tissue are not at levels that could threaten human health.

Metal contamination in quail meat: residues, sources, molecular biomarkers, and human health risk assessment.

Quail meat is an emerging source of high-quality animal protein. Quails are exposed to a wide range of xenobiotics such as heavy metals. In this study, residual concentrations of four toxic metals, of significant public health importance, including cadmium (Cd), lead (Pb), arsenic (As), and nickel (Ni), were determined in edible tissues of quails. In addition, metal loads were measured in water, feed, and litter samples collected from same quail farms as possible sources for quail exposure to heavy metals. The possible use of metallothionein (MT) and heat shock protein 70 (Hsp70) as molecular biomarkers of exposure to heavy metals was further investigated. Furthermore, the dietary intake and the potential risk assessment of the examined heavy metals among children and adults were calculated. The edible tissues of quails contained high concentrations of four heavy metals (contents (ppm/ww) ranging from 0.02 to 0.32 in Cd, 0.05 to 1.96 in Pb, 0.002 to 0.32 in As, and 1.17 to 3.94 in Ni), which corresponded to the high contents of these metals in the feeds, water, and litter. MT and Hsp70 mRNA expressions showed positive correlations with the concentrations of heavy metals in tissues indicating the possibility to use these proteins as biomarkers for quail's exposure to toxic metals. Dietary intake of quail meat and risk assessment revealed potential risks especially for children after prolonged exposure to the examined metals. Thus, legislations should be established and continuous screening of metal residues should be adopted in order to reduce the toxic metal concentrations in feeds and drinking water for quails. Reduction of exposure to heavy metals subsequently would lead to minimization of exposure of such toxicants through consumption of quail meat.

Bioaccumulation of heavy metals in tissues of selected fish species from Ganga river, India, and risk assessment for human health

ABSTRACTThe study measured the concentration of Cd, Cr, Pb, Cu, and Zn in various fish tissues (muscle, gills, and liver) of 18 fish species (C. gachua, C. marulius, C. punctatus, C. nama, C. ranga, H. fossilis, C. batrachus, P. ticto, P. phutunio, L. rohita, L. calbasu, L. gonius, T. putitora, T. tor, R. rita, G. chapra, H. ilisa, and N. botia) collected from Ganga river. It is the survey regarding metal concentration in fish tissues increasing day by day. The metal concentration in different fish tissues varied on the following range: Cu (0.45–8.54 µg/g wet wt), Zn (0.07–2.2 µg/g wet wt), Pb (0.20–2.62 µg/g wet wt), Cd (0.07–2.32 µg/g wet wt), and Cr (0.09–1.74 µg/g wet wt). The results show the concentration of Pb, Cd, and Cr metals to be higher than internationally recommended standard limits (as determined by the WHO and FAO) and other similar studies. Generally, higher concentrations of metals were found in liver and gills than muscles. Despite lower estimated daily intake (EDI) of fish in the area (per recommended daily allowance guidelines), values of daily average consumption were lower than the recommended values by FAO/WHO/EFSA, and in fish samples these were below the provisional permissible levels for human consumption. The continuous exposure to heavy metals has been linked to the development of mental retardation, kidney damage, various cancers, and even death in instances of very high exposure in human body.

Heavy metal contamination status in seven fish species from reservoirs of Polonnaruwa district, Sri Lanka

Heavy metal contamination in aquatic ecosystems has become an emerging environmental issue. The stable physico-chemical properties of heavy metals could result in bioconcentration and bioaccumulation in different organs of freshwater fishes. The present study records the accumulation of Lead (Pb), Cadmium (Cd), Chromium (Cr), Copper (Cu) and Zinc (Zn) in the head, muscle and skin regions of seven fish species namely, Labeo rohita , Oreochromis mossambicus, Oreochromis niloticus, Etroplus suratensis , Heteropneustes fossilis , Oligolepsis acutipennis and Puntius dorsalis collected from Minnerya, Parakrama Samudraya and Kaudulla reservoirs in Polonnaruwa district, Sri Lanka. The results showed that both Pb and Cd accumulated in high concentrations in the head region compared to the skin and muscles of the fish samples. The highest amounts of Pb (22.44±5.48 mg/Kg) and Cd (4.98±0.86mg/Kg) were recorded from the head parts of the H. fossilis in Minneriya and O. niloticus in Kaudulla respectively, whereas the highest amount of Cr (30.87±4.51mg/Kg) was detected in head part of the O. acutipennis in Minneriya. The Cu concentration was the highest (2.92±0.001 mg/Kg) in head regions of H. fossilis from Minneriya. Zn was the most abundant heavy metal detected in the head, muscle and skin regions of fish in all three reservoirs. The highest amount of Zn (118.93±10.55mg/Kg) was detected in the head part of O . acutipennis from Minneriya. The Pb, Cd, Cr, Cu and Zn concentrations detected in the head part of popular edible freshwater species, O. mossambicus, O. niloticus and E. suratensis were higher than the provisional tolerable weekly intake (PTWI) of Pb (0.025 mg/Kg), Cd (0.007 mg/Kg), Cr (0.1 mg/Kg), Cu (3.5 mg/Kg) and Zn (7 mg/Kg) specified by the FAO/WHO. Therefore, long-term consumption of these fish species especially the head parts may lead to accumulation of these heavy metals in tissues and lead to chronic diseases which may risk the health of consumers especially in the north-central province of Sri Lanka.

Tropidurus torquatus (Squamata: Tropiduridae) as a bioindicator of heavy metal (aluminum and zinc) pollution in Vila Velha, Brazil.

Urbanization is responsible for numerous environmental changes including pollution. Information on the susceptibility of reptiles to environmental contaminants is relatively scarce. Tropidurus torquatus represents a potential bioindicator of heavy metal pollution. Levels of heavy metals in tissues from T. torquatus depend on bioavailability and vary among different populations. The aim of this study was to determine the heavy metal concentration in liver and fat tissue of T. torquatus from three distinct populations in the state of Espírito Santo, Brazil. The study areas included coastal rocky outcrops, dunes, and mountain rocky outcrops; each area had a different climate, vegetation, and level of anthropogenic influence. Fifty-one individuals were captured. Biometrics and sexes were determined, and stomach contents were identified. The tissue samples were digested with nitric acid and analyzed via inductively coupled plasma optical emission spectrometry (ICP-OES) for aluminum (Al), arsenic (As), barium (Ba), cadmium (Cd), chromium (Cr), copper (Cu), lithium (Li), manganese (Mn), molybdenum (Mo), nickel (Ni), lead (Pb), strontium (Sr), titanium (Ti), vanadium (V), and zinc (Zn) contents. The concentration of zinc in Tropidurus torquatus was higher in liver than in fat tissue (432±1380mgkg-1), and that of aluminum was higher in fat tissue (765±1455mg.kg-1). The animals' diet may be related to heavy metal contamination. The study suggests that T. torquatus could be used for soil biomonitoring with liver as a bioindicator for aluminum contamination and fat tissue as a bioindicator for zinc contamination. Graphical abstract ᅟ.

Use of the sea hare (Aplysia fasciata) in marine pollution biomonitoring of harbors and bays

Our study evaluated heavy metal concentrations in soft tissues of sea hare, Aplysia fasciata, from the Lower Laguna Madre, Texas. Heavy metals in tissues followed Se>As>Pb>Cd. Concentrations ranged As (BDL-28.08), Cd (BDL-5.50), Pb (BDL-12.85) and Se (4.25–93.43ppm). Median As, Cd, Pb, and Se tissue levels exceeded exposure levels. Significant relationships occurred in metal-metal (AsCd, AsPb, CdPb, CdSe, and PbSe), metal-tissue (significant Se uptake by inhalant and exhalant siphons and As in the hepatopancreas), and metal-metal within tissue (AsPb in the hepatopancreas and CdPb in the digestive cecum) analyses (p<0.05). Bioaccumulation factors (BAF) suggested the inhalant siphon, hepatopancreas, and digestive cecum function as macroconcentrators of Cd, hepatopancreas and digestive cecum as macroconcentrators of Pb, and all tissues were deconcentrators for As and Se. As a bioaccumulator of heavy metals, Aplysia was evaluated as a bioindicator of marine pollution in harbors and bays.

Bioaccumulation of heavy metals in some tissues of croaker fish from oil spilled rivers of Niger Delta region, Nigeria

ObjectiveTo investigate the level of heavy metals (Cu, Zn, Fe Mn Ni, Pb and Cd) in muscles, gills and liver tissue of Croaker fish from oil spilled rivers of Bonny and Finima, Niger Delta region, Nigeria. MethodsTwenty four Croacker fishes (Genyonemus lineatus) weighing between 250 and 260 g and 24–26 cm length were collected from each sampling sites (Bonny and finima rivers). The frozen fishes were thawed and dried at 105 °C until they reach a constant weight. The dried samples were homogenized and digested with 10 ml tri-acid mixture (HNO3: HClO4:H2SO4), and then the digested samples were diluted to 100 ml with deionized water. Heavy metals (Cu, Ni, Zn, Pb, Mn, Iron Fe, and Cd) concentrations were determined by atomic absorption spectrophotometer. ResultsOur results revealed that concentrations and distribution patterns of all heavy metals studied varied significantly (P < 0.05) amongst the fish tissues analyzed and sampling sites. Moreover, liver tissue of fish caught from Finima creek accumulated the highest concentrations of Cu (52.64 ± 3.01 μg/g dry wt), Zn (166.50 ± 6.45 μg/g dry wt) and Fe (801.50 ± 14.15 μg/g dry wt) in comparison to the liver of fish caught from Bonny river in which the levels of Cu, Zn and Fe were (45.00 ± 2.79), (49.90 ± 2.91) and (216 ± 6.11 μg/g dry wt), respectively. In addition, Mn, Ni, Pb and Cd exhibited their highest concentrations in gills from both locations. As expected, muscle tissue contained the least concentrations of all metals investigated from both sampling sites. Furthermore, all the metals investigated exhibited highest concentration in fish collected from Finima creek. These abnormal high level heavy metals accumulation observed in this location could be linked to the frequent crude oil spills as well as industrial activity around the area which might get discharged into Finima creek. In general, the mean concentrations of some toxic heavy metals investigated exceed the recommended maximum permissible limits set by the Joint FAO/WHO committee. However, some metals are within the acceptable limits. ConclusionsIn conclusion, our data showed the abnormal higher concentration of these metals and this might be toxic to the fish and other aquatic organisms directly or by extension to humans that frequently consumed such contaminated fishes.

Heavy metal accumulation in organs of Oreochromis niloticus (Linnaeus, 1758) from industrial effluent-polluted aquatic ecosystem in Lagos, Nigeria.

The concentrations of four heavy metals (Zn, Fe, Cu, and Pb) in water, sediment, and tissues (gill, muscle, brain, and intestine) of Oreochromis niloticus from a segment of the Lagos Lagoon complex were monitored for 10months (July 2012-April 2013) spanning wet and dry seasons. Three sampling stations were selected: Ologe Lagoon, the nearest to the point where effluent is discharged from Agbara Industrial Estate, the Owo River is upstream before the point of discharge of industrial effluent, and Etegbin is downstream. In most cases, the highest concentrations of heavy metal in fish tissues were recorded in samples obtained from Ologe Lagoon. The ranges of concentrations of heavy metals in the tissues of the fish were 4.06±2.45-49.94±13.11, 81.27±28.52-2044.64±554.77, 10.90±7.69-41.10±11.24, and 0.12±0.07-1.81±3.12mg/kg for Zn, Fe, Cu, and Pb, respectively. There were significant negative correlations (lowest; r=-0.24, p<0.01, n=30; highest; r=-0.58, p<0.01, n=30) between fish tissue metal concentrations and size of fish from Ologe Lagoon. Also, significant positive correlations (lowest; r=0.48, p<0.05, n=30; highest; r=0.93, p<0.01, n=30) between concentrations of Cu in sediment and tissues of O. niloticus were observed. The concentrations of the metals in the tissues of O. niloticus have exceeded the limits recommended by WHO. The maximum safe daily consumption (MSDC) value of Fe in Ologe Lagoon was lower than the recommended average daily intake of fish for humans. This indicated that O. niloticus from Ologe Lagoon may not be safe for human consumption. Therefore, there is a need for regular monitoring of heavy metal in these water bodies and enforcement of existing laws on the treatment of effluent before they are discharged into aquatic ecosystems.