Bioaccumulation of heavy metals in living organisms

Biosorption is a physico-chemical and metabolically-independent process based on a variety of mechanisms including absorption, adsorption, ion exchange, surface complexation and precipitation. Biosorption processes are highly important in the environment and conventional biotreatment processes. As a branch of biotechnology, biosorption has been aimed at the removal or recovery of organic and inorganic substances from solution by biological material which can include living or dead microorganisms and their components, seaweeds, plant materials, industrial and agricultural wastes and natural residues. For decades biosorption has been heralded as a promising cost-effective clean-up biotechnology. Despite significant progress in our understanding of this complex phenomenon and a dramatic increase in publications in this research area, commercialization of biosorption technologies has been limited so far. This article summarizes existing knowledge on various aspects of the fundamentals and applications of biosorption and critically reviews the obstacles to commercial success and future perspectives.

Seedlings of Sinapis alba L. species (white/yellow mustard) were grown in nutrient solution containing different concentrations 50, 100, 250 and 500 mg/kg Cu for 10 days. Seedlings were measured and weighed at the end of the experiment. Leaf pigment concentration (chlorophylls a and b and carotenoids), tissular copper concentration and Biological Accumulation Coefficients (BAC) were determined. Copper content in Sinapis alba L. tissues reached 74.54-171.20 mg/kg dry mass, with highest values at high ambient concentration. BAC reached 1.49 at 50 mg/kg and was subunitary at higher concentrations, between 0.75-0.34. Shoot length and biomass emphasize a significant decrease at high ambient copper levels, while photosynthetic pigment concentrations did not decrease. These results indicate a limited tolerance of white mustard to high copper concentrations and a limited bioaccumulation potential of this metal.

A. altissima [(M ill.) Swingle] is a hardy, fast-growing, invasive species, common in all temperate areas. The Cu, M n and Zn content was determined in A. altissima individuals growing in the coastal area in Constanța, Romania, as part of a wider screening for local plant species capable of high heavy metal bioaccumulation-with possible application in soil bioremediation. Determination was done through atomic absorption spectrometry of aboveground organ samples, together to corresponding soil samples. The Biological Accumulation Coefficients (BAC)-ratio of metal content in plant organs and soil-were also calculated for each metal. Average metal content was 14.15 mg/kg Cu (above the average value found in normal vegetation), 47.09 mg/kg M n and 36.06 mg/kg Zn (both below average), compared to 42.93 mg/kg Cu, 396.87 mg/kg M n and 166.38 mg/kg Zn average concentrations in adjacent soils. Notable differences were found among different individuals. All tissular metal concentration values were all below accepted thresholds for hyperaccumulation. Average BAC values were 0.43 for Cu, 0.13 for M n and 0.37 for Zn. Higher metal concentration in soils led to lower BAC for all three metals. In conclusion, A. altissima cannot be considered as an accumulating species for selected metals. However, there is a possible potential for copper phytostabilization.

This study aim to estimate bioaccumulation of some metals (Cr, Mn, Fe, Cu, Zn and Pb) in different fish tissue (skin, Muscle, liver and gills) of Dicentrarchus punctatus. The samples were collected from local supermarket in Misurata city, Libya in summer, 2017. Tissue of this study was analyzed by atomic absorption spectrophotometer (AAS) to find the concentration of heavy metal (mg/kg). The results showed that the mean concentration of Zn was higher than Pb in skin, gills. Furthermore, Fe, Zn and Mn were higher in muscle than liver, except Cu and Zn their concentrations were higher in liver. While low concentration of Pb in all study organs.The order of metals in liver, gills, skin and muscle samples were found to be Cu > Fe > Mn >Zn >Cr = Pb; Fe > Zn > Cr >Mn >Cu >Pb; Fe >Zn >Mn >Cr = Cu >Pb respectively. Some levels of metals (Cr and Fe) in this study were higher than the maximum permissible limits of FAO and WHO for human consumption.

As a result of a peculiar practice of agriculture, widespread of intensive methods of agriculture, land pollution by industrial waste and transport in China there is a situation of significant contamination of cultivated area, water sources and feed by heavy metals. In its turn, through feed heavy metlas pass to meat, eggs and milk and pose a significant danger to humans.
Despite apparent effectiveness of all  approaches to treatment of heavy poisoning, all these approaches are aimed at elimination of consequences from toxicants, already entered into organism. In this sense, a tactic of sorption of heavy metals in gastrointestinal tract, binding and rapid elimination from the body regardless of their ingestion, must be much more effective. As a result of a peculiar practice of agriculture, widespread of intensive methods of agriculture, land pollution by industrial waste and transport in China there is a situation of significant contamination of cultivated area, water sources and feed by heavy metals. In its turn, through feed HM pass to meat, eggs and milk and pose a significant danger to humans.
Despite apparent effectiveness of all the above approaches to treatment of HM poisoning, all these approaches are aimed at elimination of consequences from toxicants, already entered into organism. In this sense, a tactic of sorption of heavy metals in gastrointestinal tract, binding and rapid elimination from the body regardless of their ingestion, must be much more effective. BIFEGE drug, created on the basis of ferrocyanide of iron-potassium, not only selectively binding heavy metals, but due to a high content of bioavailable iron, competitive inhibiting absorption of heavy metals in intestine, can be the best preparation for animal treatment and breakage of vicious cycle of heavy metals accumulation in the environment.

Heavy metal pollution is a major environmental problem, especially around highways with high traffic density.
This study investigates the levels of Pb, Cd, Zn and Cu in roadside soils of Wukari section of the Wukari-Jalingo
highway, Taraba state, Nigeria. Samples were randomly collected and analyzed using standard methods. The
mean concentrations (μg/g) of Pb, Cd, Zn and Cu from all sample sites ranged: 89.6-247.0, 0.15-5.3, 26.8-163.0
and 7.1-61.2 respectively. The extent of the heavy metals contamination was assessed, as analytical data were
subjected to pollution calculation methods. The contamination factors (CF) reveal extreme contamination of the
sites and an increasing trend in the heavy metals concentrations was observed in sites with more human
activities. The pollution load index (PLI) showed that the sites are severely polluted as the PLI of the metals from
each sample site exceeded the PLI of the background (control) sample (0.7). Spearman’s rank correlation
analysis showed clear correlations (p<0.001) amongst the metals suggesting a common source. It can be
concluded that the study sites pollution is mostly due to automobile emissions. This study provides awareness
for residents to avoid activities such as farming, trading etc very close to the highway due to exposures to these
toxic metals.

Fish Bioaccumulation Monitoring a b s t r a c t The concentrations of heavy metals (Cu, Zn, Pb, Cd, Fe and Mn) were measured in the liver, gills and muscles of fourteen benthic and pelagic fish species collected from three main landing areas (Shalateen, Hurghada and Suez) in the Egyptian Red Sea. The levels of heavy metals varied significantly among fish species and organs. As expected, muscles always possessed the lowest concentrations of all metals. In most studied fish, the liver was the target organ for Cu, Zn and Fe accumulation. Pb and Mn, however, exhibited their highest concentrations in the gills. Different species of fish showed inter-specific variation of metals, as well as variations between fish from the same species. These differences were discussed for the contribution of potential factors that affected metals' uptake, like age, geographical distribution and species' specific factors. Generally, recorded metal concentrations were within the range or below the levels in similar species from global studies. The concentration of metals in the present fish muscles were accepted by the international legislation limits and are safe for human consumption.

The levels of lead (Pb), copper (Cu), cadmium (Cd), iron (Fe), zinc (Zn) and manganese (Mn) were measured in water samples and in tissues (liver, kidney, gill, spleen and muscle) of Nile tilapia collected from two locations along the River Nile basin at Greater Cairo in Egypt. We investigated the impact of these traces of heavy metals on the physiology, immune responses, genotoxicity and histology of Nile tilapia. The concentrations of heavy metals in water samples from polluted area (El-Tebeen, Area 2) were significantly higher than reference area (El-Zamalek, Area 1) for all investigated metals. The prevalence of each element in various fish tissues was variable between the two sampling areas. The level of plasma total proteins was significantly (P< 0.001) elevated in Area 2 compared to Area 1. Lysozyme levels were insignificantly declined in plasma of fish from Area 2 while phagocytosis percentage was markedly reduced (P< 0.001) in Area 2 compared to Area 1. DNA damage (comet assay) in blood elevated statistically in tilapia collected from Area 2 compared to Area 1. Additionally, numerous histopathological alterations were observed in Area 2.Thus,
innate immune responses of tilapia could be sensitive to environmental contamination.

Five trace metals in Leptodius exarata, epipellic sediments and surface water from an intertidal ecosystem in the Niger Delta (Nigeria) were studied to evaluate their spatial distributions, degrees of contamination, and associated ecological and health risks. The results show that the Cd (cadmium), Cr (chromium), Ni (nickel), Pb (lead) and Zn (zinc) concentrations in sediment range from 0.550–1.142, 9.57–15.95, 9.15–13.96, 2.00–8.90 and 91.5–121.6 mg kg −1 dw, respectively, while the L. exarata tissue metal content varies from 0.162–0.931, 3.81–8.62, 4.45–17.15, 1.90–7.35, and 125.55–269.75 mg kg −1 dw, respectively. The bioconcentration factor ranking for trace metals was found to follow the Zn > Ni > Pb > Cr > Cd sequence. The high biota to sediment accumulation factor (BSAF) found for L. exarata reveals a sentinel metal bioindicator. Sediments from most sites were found to be uncontaminated to moderately contaminated (geoaccumulation, I geo > 0), with Cd and Zn associated with anthropogenic intrusions. Low mean-ERM (effect range-median) and mean-PEL (probable effect level) quotients of sediments were found, indicating low–moderate degrees of contamination with 30% and 21% probabilities of toxicity. The multi-metal potential ecological risk index (R I) for the intertidal ecosystem denotes low–moderate risk. Health risks associated with crab (L. exarata) consumption are more significant for children than for adults.

Hexavalent chromium [Cr(VI)] is a toxic oxidation state of the heavy metal Cr, which has a wide range of industrial applications. Cr-based mining and industrial activities release Cr(VI) as a pollutant into the soil, which is responsible for pollution. Restoration of soil quality in these mining and industrial areas is highly essential for sustainable development and healthy living. The application of plant systems as a sink for the remediation of soil rich in Cr(VI) is a cost-effective technique to control soil pollution. The present study targets Pongamia pinnata (L.) Pierre as a biological sink for the remediation of Cr(VI)-contaminated soil. The analytical study on Cr(VI) accumulation in plant parts of P. pinnata (L.) Pierre and the status of Cr(VI) present in its rhizospheric soil were carried out following the standard methodologies of the American Public Health Association. The results of the analysis are in favor of the steady increase in Cr(VI) accumulation in plant parts of the targeted plant with the increase in its concentration in rhizospheric soil. The novelty of this study focuses on the survival of P. pinnata (L.) Pierre on soil under high Cr(VI) stress conditions and the differential accumulation of Cr(VI) in its vital vegetative parts with the uptake of the toxic metal from the soil to reduce pollution. It is supported by the higher value coefficient of correlation during the uptake of Cr(VI) from polluted rhizospheric soil with its concentration in soils up to 200 µg/g soil. The order of accumulation of Cr(VI) in root > leaf > stem is significant at p = 0.05 and p = 0.01. Further work on this plant species, P. pinnata (L.) Pierre, can make it an elite species for remediation of Cr(VI)-polluted soil.

Harmful substances like metals ultimately end in the seafloor and contaminate marine ecosystems. These substances are of particular concern due to their bioavailability and toxicity to marine organisms. In this study, metals (Pb, Cd, Cr, Zn, and Cu) were determined in the body wall of common sea star L. laevigata, and A. planci collected from Carmen, Agusan del Norte, Philippines. The metal content in terms of concentration of L. laevigata follows the order Pb > Cu > Cd > Cr > Zn while for A. planci is Pb > Cu > Cr > Zn > Cd. Both species were found to consistently contain the most lead and copper, which could suggest bioaccumulation of these elements from the environment. It is believed that these metals were sourced from the sediments or their food and are accumulated in their body wall. The differences in metal content for Pb and Cd were believed to be due to the difference in the diet for the two species. Comparable metal content was found in Cd, Cr, and Zn. It is recommended that further studies are conducted, especially in monitoring the metal content in the sediment and bioaccumulation of these metals in different trophic levels.

The chromium bioaccumulation potential in Sinapis alba L. was studied in experimental hydroponic conditions. Mustard seedlings were grown in nutrient solution containing 50, 100, 250 and 500 ppm Cr. After 10 days, seedlings were analyzed for shoot length, biomass, leaf pigment (chlorophylls and carotenoids) and tissular Cr concentration. The Biological Accumulation Coefficients (BAC) were also determined. Cr content in S. alba dry mass reached 415-2,064 ppm, depending on ambient Cr concentration. BAC ranged between 8.30 to 4.13, with a peak at 100 ppm and lowest values at higher concentrations. Shoot length, biomass and pigment concentration values showed an average decrease at high Cr concentrations (mostly, at 500 ppm), without a definite statistical significance. Results indicate that S. alba is tolerant to high Cr levels and has hyperaccumulative abilities.

Chromium concentration was determined, through HR-CS-AAS, in tissular and rhizospheric soil samples from three Poaceae species growing in Romanian ruderal and coastal areas: Hordeum murinum L., Leymus racemosus ssp. sabulosus (M. Bieb.) Tzvelev and Lolium perenne L. Biological Accumulation Coefficients (BAC) were calculated. The highest average concentration was found in L. racemosus (22.21 mg/kg) higher than the 1.5 mg/kg "standard reference" levels, but below the hyperaccumulation threshold (1,000/300 mg/kg) With 0.11-0.54 average BAC, all selected species can be considered as moderate accumulators, with the highest values in L. racemosus. Results show that L. racemosus, although not an accumulator under natural conditions, has a potential for Cr phytostabilization, or enhanced phytoextraction experiments.

In the recent past, the Indian Sundarbans is constantly exposed to various anthropogenic activities including urbanization, tourism and fishing. This study presents the concentrations of Fe, Zn, Cu, and Pb in the vegetative parts of Avicennia marina, Avicennia alba, Avicennia officinalis, Excoecaria agallocha and Heritiera fomes collected from Western Indian Sundarbans during July, 2015. Metals accumulated as per the order Fe > Zn > Cu > Pb. In the vegetative parts, the order of accumulation of metals is root > stem > leaf. A long-term data on ambient soil, water and vegetative parts is required to identify the indicator species in context to heavy metal pollution in the Indian Sundarban deltaic complex.

The Hooghly-Matla estuarine complex of West Bengal is under severe stress due to heavy metals discharged from urban sectors, industries, tourism units etc. in recent decades. The bioaccumulation of heavy metals in Ipomoea pes-caprae is considerable in the present study area and hence the bioaccumulation factor has been studied with respect to dissolved heavy metals and bioaccumulation of heavy metals in sediments. The study reports considerable level of bioaccumulation factor in the vegetative parts of the species.

The aim of this study was comparing the toxic effects of zinc oxide nanoparticles (ZnO NPs) versus zinc ions (Zn2+) at a high non-lethal (500µg/L) and a low environmental relevant (0.05µg/L) concentrations on gills of rainbow trout (Oncorhynchus mykiss) following 14 days of waterborne exposure. Structural alterations, histopathological anomalies, and zinc bioaccumulation were investigated in the gills using field emission scanning electron microscopy (FESEM), hematoxylin and eosin staining (H&E), and graphite furnace atomic absorption spectrophotometry (GFAAS) respectively. Some damages such as shortening and fusion of secondary lamellae, surface epithelium hypertrophy, and hyperplasia of the primary lamellae were observed in the gill tissue. Histopathological alterations of gills were minimum in both none exposed (control) fish and fish exposed to 0.05µg/L Zn2+. The severity of gill damages were higher in fish exposed to 500µg/L ZnO NPs compared to 500µg/L Zn2+ and 0.05µg/L ZnO NPs. The Zn accumulation in the gills was concentration-dependent such that bioaccumulation order was as 500µg/L Zn2+> 500µg/L ZnO NPs ≈ 0.05µg/L Zn2+> 0.05µg/L ZnO NPs> control. In summary, the results of present study showed that although the accumulation capability of Zn2+ was higher than ZnO NPs, but NPs cause more structural damages to gills compare to ions.

http://www.trjfas.org/abstract.php?lang=en&id=1215

Heavy metals concentrations in bivalve Psammotaea elongata from five sampling sites in Semerak Lagoon were determined by ICP-MS. The mean concentrations of Cd, Cu, Pb, Fe and Zn were 0.18, 4.42, 1.15, 1.47 and 46.35 μg/g in total soft tissue; 0.68, 20.08, 5.29, 85.5 and 9.06 μg/ g in stomach; 0.7, 17.05, 4.39, 84.15 and 8.62 μg/g in leg; 0.74, 15.19, 4.4, 80.69 and 8.6 μg/g in ligament, respectively. The statistical ANOVA showed a significant difference between metals. Generally, metal concentrations in P. elongata were lower than the permissible limit suggests it is safe to be consumed by human.

Objective: To determine the quality of water, heavy metal content of edible muscles of a piscivorous fish (Protopterus annectens) and assess the health risks associated with using water and consumption of P. annectens from Nyabarongo and Nyabugogo rivers of Rwanda. Results: All the water quality parameters were within World Health Organization's acceptable limits except total nitrogen, iron, manganese and lead levels. Edible muscles of Protopterus annectens contained 272.8 ± 0.36, 292.2 ± 0.25, 8.8 ± 0.36, 135.2 ± 0.15, 148.0 ± 0.21 and 432. 0 ± 0.50 mg/kg of iron, manganese, copper, zinc, chromium and lead at Ruliba station and 336.0 ± 0.70, 302.6 ± 1.22, 6.4 ± 0.26, 44.7 ± 0.20, 138.2 ± 0.17 and 302.4 ± 1.50 mg/kg of iron, manganese, copper, zinc, chromium and lead at Kirinda bridge of Nyabarongo river. Health risk assessments indicated that though ingestion and dermal contact with heavy metals in water from the rivers may not cause obvious health effects, consumption of Protopterus annectens from Nyabarongo river may lead to deleterious health effects.

Knowledge on initial bioadhesion and composition of micro and macro nutrients within
the biofilm matrix are recognised as essential for understanding the formation of biofilms.
This communication highlights the heavy metal accumulation pattern in biofilms, influenced
by the substrate and seasons. Natural biofilms were simultaneously grown on aluminium
and steel panels for 72 hours by exposing them in the aquatic environment. Accumulation
of toxic and nutrient metals in biofilms on different substrates and its seasonal variation were
studied. Biofilms grown within 24 hours had shown significantly (p < 0.05) higher
concentrations of trace metals in both the metal substrates. Trace metals accumulated over
the substrates varied in different seasons. Among the metals, the accumulation of zinc was
more during all the seasons. Biofilms grown on steel, concentrated more metals than on
aluminium.

The studywas conducted to evaluate the accumulation of heavymetals in barnacle shells and tissues
in different seasons of the year. Heavy metal concentration was monitored in barnacle tissues and
shells on a long term and short term (monthly) basis by exposing glass panels in Cochin estuary.
Short term panels gave a clear idea of the dynamics of heavy metal accumulation in barnacles.
Accumulation of chromium and cadmiumwasmaximum in the tissues and shell during themonsoon
season whereas lead and nickel was maximum in pre monsoon period. Selenium varied irregularly
and arsenicwas detected only in one sample. Higher levels of copper andmanganese were observed
in shells during both high and low salinity season (pre monsoon and monsoon). Manganese and
iron uptake was significantly higher in the initial stages of growth and is mainly utilized for shell
formation. Zinc was maximum during monsoon in short term panels whereas in soft tissues of long
term panels it was detected during monsoon and pre monsoon seasons. Fouling settlement on
exposed glass panels was highest during November, the transition period from monsoon to post
monsoon season.

The chromium bioaccumulation potential in Sinapis alba L. was studied in experimental hydroponic conditions. Mustard seedlings were grown in nutrient solution containing 50, 100, 250 and 500 ppm Cr. After 10 days, seedlings were analyzed for shoot length, biomass, leaf pigment (chlorophylls and carotenoids) and tissular Cr concentration. The Biological Accumulation Coefficients (BAC) were also determined. Cr content in S. alba dry mass reached 415-2,064 ppm, depending on ambient Cr concentration. BAC ranged between 8.30 to 4.13, with a peak at 100 ppm and lowest values at higher concentrations. Shoot length, biomass and pigment concentration values showed an average decrease at high Cr concentrations (mostly, at 500 ppm), without a definite statistical significance. Results indicate that S. alba is tolerant to high Cr levels and has hyperaccumulative abilities.

Copper, manganese and zinc bioaccumulation potential was screened for three common Poaceae species, Hordeum murinum ssp. murinum L., Leymus racemosus ssp. sabulosus (M. Bieb.) Tzvelev and Lollium perenne L., abundantly growing along the Romanian Black Sea Coastal area, Constanta County. The concentration of the selected heavy metals was analyzed though atomic absorption spectrometry in samples of aboveground plant organs and soils. To assess the potential for phytoaccumulation, the Biological Accumulation Coefficients (BAC) were calculated. Considering the minimal thresholds widely accepted in literature for Cu, Mn and Zn hyperaccumulators, none of the selected species can fit in this category. The highest average copper concentration was found in Hordeum murinum ssp. murinum L. (5.45 mg/kg). For manganese, the highest value was found in Lollium perenne L. (104.08 mg/kg), while for zinc, the maximum was reached in Leymus racemosus ssp. sabulosus (M. Bieb.) Tzvelev, tissue (62.95 mg/...

The absence or presence of particular plant species indicates specific level of pollution. It was hypothesized that the marble waste polluted ecosystem also host specific plant indicators that can grow, survive and tolerate more successfully than others and can be utilized in better managements of such systems. The current research work was therefore, conducted to determine the indicators of marble polluted region of Buner, Pakistan. Ecological techniques using varying sized quadrats i.e., 1 Â 1 m 2 , 5 Â 2 m 2 and 10 Â 2 m 2 for herbs, shrubs and tree species were used respectively. Standard protocols were used to prepare soil samples and plant parts (root, leaf and shoot) for Atomic Absorption Spectrophotometry. Indicator i.e., Populus alba L., Arundo donax L., Erigeron canadensis L and Morus alba L. were identified via Indicator Species Analyses (ISA) in various polluted zones. All the collected data were put in MS Excel for analyses in PCORD through Cluster Analysis (CA), Two Way Cluster Analysis (TWCA) and ISA. CANOCO software was used to examine the impact of miscellaneous environmental variables in zonation via both direct and indirect gradient techniques i.e., Detrended Correspondence Analysis (DCA) and Canonical Correspondence Analysis (CCA). A total of 102 plant species belonging to 95 genera and 48 families were recorded in the marble waste polluted ecosystem. CA and TWCA through Jaccard Distance measurements and Wards Linkage methods gave rise to 3 major polluted zones. These zones were i) Heavily Polluted Zone (HPZ), ii) Moderate Polluted Zone (MPZ) and iii) Less Polluted Zone (LPZ). The recorded values of Biological Concentration Factor (BCF), Translocation Factor (TF) and Bioaccumulation Coefficient (BAC) for analyzed heavy metals i.e. Fe, Mg, Ca, Na and Cu in root and shoot of P. alba L., A. donax L., and M. alba L. showed that these species were significant phytostabilizers and E. canadensis L. was phytoextracters and hence best indicandum of marble waste polluted ecosystems. It was concluded that among all the measured environmental variables, higher phosphorus level, higher pH, moderate potassium and lower electrical conductivity (EC) had significant effects (p < 0.05) on the functions of these indicators as phytoremediaters. It is recommended to develop green belts of these indicators around the marble industrial areas for the better management and hazardous free environment.

We analyzed concentrations of zinc, copper, lead and cadmium in the crab species of the lower stretch of the River Ganga in April, 2015 using a Perkin-Elmer Sciex ELAN 5000 ICP mass spectrometer and expressed as mg kg-1 dry weight. The concentrations ranged from 10.40 ±0.88-239.00 ±2.80 for Zn, 30.09 ±0.81-189.44 ±1.81 for Cu, BDL-28.09 ±0.80 for Pb and BDL-8.89 ±0.80 for Cd in ppm dry wt. Heavy metals in the edible parts of the investigated crab species were compared with the permissible safety levels for human uses.

The aim of this study is to determine the heavy metals (Zn, Cu, Pb and Cd) in edible finfish species (Polynemus paradiseus, Tenualosa ilisha, Liza parsia, Liza tade and Stolephorus commersonii) and compare the level of heavy metals determined in the Gangetic delta region earlier. Finfish species were sampled from 4 different stations. Levels of four selected heavy metals were determined in the muscle of edible finfish species in the Gangetic delta region using a Perkin-Elmer Sciex ELAN 5000 ICP mass spectrometer and expressed as mg kg-1 dry weight. To determine whether heavy metal concentrations varied significantly between sites and species, analysis of variance (ANOVA) was performed. In addition to, heavy metal concentrations were compared with WHO and FAO's permited levels. In finfish species the concentrations of Zn, Cu, Pb and Cd ranged from 12. respectively. For Zn and Cu, accumulated metal concentrations in Stn. 4 were significantly higher than accumulated metal concentration in Stn 1 and Stn 2. For Pb, significantly stational difference between stations was not found. Between all studies fish species, lowest metal acculation values was found for S. commersonii (p<0.05). The selected heavy metals in finfish muscle (except Zn in Liza parsia in station 1) were also within the permissible limits for human consumption as indicated by the Food and Agricultural Organization.

Heavy metal pollution is a major environmental problem, especially around highways with high traffic density. This study investigates the levels of Pb, Cd, Zn and Cu in roadside soils of Wukari section of the Wukari-Jalingo highway, Taraba state, Nigeria. Samples were randomly collected and analyzed using standard methods. The mean concentrations (µg/g) of Pb, Cd, Zn and Cu from all sample sites ranged: 89.6-247.0, 0.15-5.3, 26.8-163.0 and 7.1-61.2 respectively. The extent of the heavy metals contamination was assessed, as analytical data were subjected to pollution calculation methods. The contamination factors (CF) reveal extreme contamination of the sites and an increasing trend in the heavy metals concentrations was observed in sites with more human activities. The pollution load index (PLI) showed that the sites are severely polluted as the PLI of the metals from each sample site exceeded the PLI of the background (control) sample (0.7). Spearman’s rank correlation analysis sho...

Copper, manganese and zinc bioaccumulation potential was screened for three common Poaceae species, Hordeum murinum ssp. murinum L., Leymus racemosus ssp. sabulosus (M. Bieb.) Tzvelev and Lollium perenne L., abundantly growing along the Romanian Black Sea Coastal area, Constanta County. The concentration of the selected heavy metals was analyzed though atomic absorption spectrometry in samples of aboveground plant organs and soils. To assess the potential for phytoaccumulation, the Biological Accumulation Coefficients (BAC) were calculated. Considering the minimal thresholds widely accepted in literature for Cu, Mn and Zn hyperaccumulators, none of the selected species can fit in this category. The highest average copper concentration was found in Hordeum murinum ssp. murinum L. (5.45 mg/kg). For manganese, the highest value was found in Lollium perenne L. (104.08 mg/kg), while for zinc, the maximum was reached in Leymus racemosus ssp. sabulosus (M. Bieb.) Tzvelev, tissue (62.95 mg/...

Accumulation of heavy metals in some commercially important fish and crustacean species in the Gulf of Khambhat reveals that Pb and Cd are relatively higher than the standards prescribed in countries other than India. However, the concentrations were comparatively lower than the Marine Product Export Developmental Authority of India standards. The greater bioaccumulation of these metals may be due to anthropogenic activities, unusual physical oceanographic conditions and effluent discharges from the industries located in the vicinity. The conspicuous metal accumulation pattern among the fishes collected near oil rigs
and ship braking yard indicates the presence of bioavailable toxic metals from these industries.

Bioaccumulation of heavy metals is a burning problem of current times. Considerable studies on heavy metal toxicity at various trophic levels of the ecosystem indicate the serious and far reaching implications of the issue at a global scale. The current paper investigates the bioaccumulation pattern of heavy metals such as Copper, Zinc, Lead in commonly consumed vegetables such as cauliflower, radish and brinjal collected from selected areas in and around the metropolitan city of Kolkata. The bioaccumulation trend shows that Zn>Cu>Pb irrespective of the study areas; Swarupnagar Community Development Block and East Kolkata Wetlands. The pattern of accumulation in vegetables also shows the order Radish>Cauliflower>Brinjal irrespective of the selected areas. A long term survey on the bioaccumulation pattern of heavy metals through seasons may prove the potential of the species to be used as indicator of heavy metal pollution. Such studies are to be repeated with rigorous monitoring of the commonly consumed vegetables in and around Kolkata to prevent the long term effects of such toxic consumption.

Coal mining generates large quantities of complex effluent, and this often contains high levels of dissolved solids, suspended solids, metals, hydrocarbons, salts and other compounds. Substantial volumes of mine wastewater are periodically discharged into the environment, through both planned and accidental releases, and this raises concerns about the potential for adverse impacts on aquatic wildlife. There have been few attempts to explore sub-lethal effects of coal mine wastewater on amphibians compared to other organisms, and this is particularly true for Australian species. To address existing knowledge gaps, we exposed striped marsh frog (Limnodynastes peronii) tadpoles to 25, 50 and 100% coal mine wastewater collected from two holding dams (CMW1 and CMW2) located at an open cut mine in Central Queensland, Australia. The exposure lasted for four weeks, after which survival, growth and development , swimming behaviour, and concentrations of metals and metalloids in tail and liver tissues were assessed. Physico-chemical parameters varied considerably between sites, with higher turbidity, nutrients , total and dissolved organic carbon, alkalinity and arsenic (As) concentrations at CMW1, and higher conductivity, salinity, dissolved solids, hardness and sulfate levels at CMW2. There was no mortality in controls and less than 5% mortality in CMW1 treatments, whereas survival was significantly decreased in tadpoles exposed to CMW2 with 40 and 55% mortality in the 50 and 100% treatments, respectively. Development was significantly delayed in 100% CMW1 wastewater, but tadpole size (growth) was not influenced by the exposure. Hepatosomatic indices were significantly increased in tadpoles exposed to 25 and 50% CMW1 but not the 100% treatment group. Exposed tadpoles (predominantly those exposed to CMW1) exhibited increased activity after very short-term exposure (24 h), but this did not persist as animals approached metamorphic climax. At the end of the experiment, tadpoles exposed to both wastewaters had elevated levels of selenium (Se), cobalt (Co) and As in tail and liver tissue compared to controls. Manganese (Mn) levels were also elevated in livers and tails of CMW2 exposed tadpoles. Hepatic tissue accumulated 8–9 times higher concentrations of Co, Mn and Se compared to tail tissue, irrespective of treatments. Future research is warranted to explore possible relationships between metal bioaccumu-lation, morpho-physiological effects during development, and subsequent higher-level outcomes related to individual performance and population fitness.

In the San Francisco Estuary, management actions including tidal marsh restoration could change fish mercury (Hg) concentrations. From 2005 to 2007, small forage fish were collected and analyzed to identify spatial and interannual variation in biotic methylmercury (MeHg) exposure. The average whole body total Hg concentration was 0.052 μg g−1 (wet-weight) for 457 composite samples representing 13 fish species. MeHg constituted 94% of total Hg. At a given length, Hg concentrations were higher in nearshore mudflat and wetland species (Clevelandia ios, Menidia audens, and Ilypnus gilberti), compared to species that move offshore (e.g., Atherinops affinis and Lepidogobius lepidus). Gut content analysis indicated similar diets between Atherinops affinis and Menidia audens, when sampled at the same locations. Hg concentrations were higher in sites closest to the Guadalupe River, which drains a watershed impacted by historic Hg mining. Results demonstrate that despite differences among years and fish species, nearshore forage fish exhibit consistent Hg spatial gradients.