Concentration of four heavy metals (cadmium, lead, mercury, and arsenic) in organs of two cyprinid fish (Cyprinus carpio and Capoeta sp.) from the Kor River (Iran)

Effects of Cadmium and Nickel Mixtures on Multiple Endpoints of the Microalga Raphidocelis subcapitata

It is crucial to investigate the effects of mixtures of contaminants on aquatic organisms, because they reflect what occurs in the environment. Cadmium (Cd) and nickel (Ni) are metals that co-occur in aquatic ecosystems, and information is scarce on their joint toxicity to Chlorophyceae using multiple endpoints. We evaluated the effects of isolated and combined Cd and Ni metals on multiple endpoints of the chlorophycean Raphidocelis subcapitata. The results showed that Cd inhibited cell density, increased reactive oxygen species (ROS) production (up to 308% at 0.075 mg L-1 of Cd), chlorophyll a (Chl a) fluorescence (0.050-0.100 mg L-1 of Cd), cell size (0.025-0.100 mg L-1 of Cd), and cell complexity in all concentrations evaluated. Nickel exposure decreased ROS production by up to 25% at 0.25 mg L-1 of Ni and Chl a fluorescence in all concentrations assessed. Cell density and oxygen-evolving complex (initial fluorescence/variable fluorescence [F0/Fv]) were only affected at 0.5 mg L-1 of Ni. In terms of algal growth, mixture toxicity showed antagonism at low doses and synergism at high doses, with a dose level change greater than the median inhibitory concentration. The independent action model and dose-level-dependent deviation best fit our data. Cadmium and Ni mixtures resulted in a significant increase in cell size and cell complexity, as well as changes in ROS production and Chl a fluorescence, and they did not affect the photosynthetic parameters. Environ Toxicol Chem 2024;00:1-15. © 2024 SETAC.

Arsenic, lead and cadmium concentration in food and estimated daily intake in the Cuban population and the health risks using a Total Diet Study

This study estimates the intake of arsenic, lead and cadmium by the adult population (aged 18-91) of Cuba. The food consumption indices were obtained through 24-h dietary recall surveys applied to 450 people between October 2020 and March 2021. The Estimated Dietary Intake (EDI) of t-As (54.6 μg/day), Pb (118.5 μg/day) and Cd (35.1 μg/day) complied with Cuban legislation but was higher than the EDI for Cd established by the CONTAM Panel. The Target Hazard Quotients for the three contaminants were: iAs (0.220), Pb (0.409) and Cd (0.424), making the value of the Total Target Hazard Quotient 1.05, which indicates potential health risks for the population. Additionally, associated carcinogenic risks were: iAs (1.0·10-4), Pb (7.2·10-4) and Cd (25.9·10-4). Therefore, 10, 72 and 259 persons per 100,000 inhabitants are likely prone to developing cancer due to the ingestion of iAs, Pb and Cd, respectively.

Assessment of Environmental Water Requirement Allocation in Anthropogenic Rivers with a Hydropower Dam Using Hydrologically Based Methods—Case Study

Anthropogenic activities such as damming have caused an alteration in the natural flow regime in many rivers around the world. In this study, the role of constructing a hydroelectric dam on the natural flow regime of the Kor River, Iran, is investigated. Nine different methods, which fall into the category of hydrological methods, were used to determine the environmental water requirement (EWR) of the Kor River. In addition, two indices are introduced to evaluate the environmental flow allocation in anthropogenic rivers. The results show that although the supply of environmental flow in some months is in relatively acceptable conditions on average, there is a deficiency in the allocation of EWR in the range of 1.92–30.2% in the spawning period of the dominant fish species. The proposed indicators can provide a comprehensive picture of the status of environmental flow allocation in rivers where little ecological data is available and the hydrological regime has changed due to human activities, particularly in rivers with hydropower plants. Moreover, after the construction of the dam, no major floods have occurred in the river, which has led to the loss of the morpho-ecological balance in the river and disruption of the natural state of habitats. Therefore, the negative impact of dam construction on the environmental conditions of the river should be considered in the active management of the dam outlets.

Effects of cadmium and cobalt mixtures on growth and photosynthesis of Raphidocelis subcapitata (Chlorophyceae)

Metals occur simultaneously in the environment, and therefore it is important to know their toxicity and mechanism of action when associated with another metal. Furthermore, anthropogenic actions increase their concentrations in the environment where they can interact and undergo transformations that can even increase their toxicity. This study aimed to evaluate the effects of cadmium (Cd) and cobalt (Co), isolated and combined, on the microalgae Raphidocelis subcapitata. Regarding the toxicity of isolated metals, the IC₅₀96 h was 0.08 mg L^-1 of Cd and 0.16 mg L^-1 of Co. Cell density decreased at all concentrations of the Cd tested. The parameters related to cell size, cell complexity and mean cell chlorophyll a (Chl a) fluorescence were significantly affected by both metals. According to species sensitivity curves (SSD), the microalgae R. subcapitata was the second most sensitive organism to Co exposure and the tenth concerning Cd. Metal mixture data were best fitted to the concentration addition (CA) model and dose-ratio dependence (DR) deviation, showing synergism at high concentrations of Co and low concentrations of Cd. Besides that, antagonism was observed at low concentrations of Co and high concentrations of Cd. Photosynthetic performance, assessed by maximum quantum yield (Φ_M) and oxygen evolving complex (OEC), presented antagonism effects for both analyzed parameters. Thus, the mixture of Cd and Co showed synergistic and antagonistic interactions for the parameters analyzed in R. Subcapitata, indicating the importance of understanding the mechanisms of toxicity of metal mixtures in phytoplankton.

Bioaccumulation of heavy metals in fish species of Iran: a review

Accumulation of heavy metals (HMs) in fish tissues is an important factor in monitoring the health and safety of aquatic ecosystems. Furthermore, fish are important parts of aquatic food chains and play a significant role in human health. Considering the significant role of fish in the diet of humans and their ability to transfer and biomagnify HMs, it is necessary to determine and study these contaminants in fish tissues, especially in the edible parts of the fish. In addition to the other ecological and economic services of aquatic ecosystems, water bodies, especially the Persian Gulf in the south and the Caspian Sea in the north of Iran, are the main sources of seafood for people in nearby areas, as well as people living farther away who have gained access to seafood due to the extensive trade of aquatic organisms. This study provides an overview of the health conditions of the aquatic ecosystems in Iran by monitoring HM bioaccumulation in fish species. For this purpose, we reviewed, summarized, and evaluated papers published on HM concentrations in fish species from different aquatic ecosystems, including the Persian Gulf, the Caspian Sea, wetlands, rivers, qanats, water reservoirs, lakes, and dams, with emphasis on species habitats, feeding habits, and target organs in accumulation of HMs. Generally, the highest concentrations of HMs were observed in fishes collected from the Persian Gulf, followed by species from the Caspian Sea. Species inhabiting the lower zone of the water column and carnivorous and/or omnivorous species showed the highest levels of HMs. Moreover, liver was the main accumulator organ for HMs.

Using multiple endpoints to assess the toxicity of cadmium and cobalt for chlorophycean Raphidocelis subcapitata

Metals may cause damage to the biota of contaminated environments. Moreover, using multiple endpoints in ecotoxicological studies is useful to better elucidate the mechanisms of toxicity of these compounds. Therefore, this study aimed to evaluate the effects of cadmium (Cd) and cobalt (Co) on growth, biochemical and photosynthetic parameters of the microalgae Raphidocelis subcapitata, through quantification of lipid classes composition, chlorophyll a (Chl a) content, maximum (Φ_M) and effective (Φ'_M) quantum yields and efficiency of the oxygen-evolving complex (OEC). Both metals affected the algal population growth, with an IC_50-96h of 0.67 and 1.53 μM of Cd and Co, respectively. Moreover, the metals led to an increase in the total lipid content and reduced efficiency of OEC and Φ_M. Cell density was the most sensitive endpoint to detect Cd toxicity after 96 h of treatment. Regarding Co, the photosynthetic parameters were the most affected and the total lipid content was the most sensitive endpoint as it was altered by the exposure to this metal in all concentrations. Cd led to increased contents of the lipid class wax esters (0.89 μM) and phospholipids (PL - at 0.89 and 1.11 μM) and decreased values of triglycerides (at 0.22 μM) and acetone-mobile polar lipids (AMPL - at 0.44 and 1.11 μM). The percentage of free fatty acids (FFA) and PL of microalgae exposed to Co increased, whereas AMPL decreased in all concentrations tested. We were able to detect differences between the toxicity mechanisms of each metal, especially how Co interferes in the microalgae at a biochemical level. Furthermore, to the best of our knowledge, this is the first study reporting Co effects in lipid classes of a freshwater Chlorophyceae. The damage caused by Cd and Co may reach higher trophic levels, causing potential damage to the aquatic communities as microalgae are primary producers and the base of the food chain.

Oxidative Damage of Mussels Living in Seawater Enriched with Trace Metals, from the Viewpoint of Proteins Expression and Modification

The impact of metals bioaccumulation in marine organisms is a subject of intense investigation. This study was designed to determine the association between oxidative stress induced by seawater enriched with trace metals and protein synthesis using as a model the mussels Mytilus galloprovincialis. Mussels were exposed to 40 μg/L Cu, 30 μg/L Hg, or 100 μg/L Cd for 5 and 15 days, and the pollution effect was evaluated by measuring established oxidative biomarkers. The results showed damage on the protein synthesis machine integrity and specifically on translation factors and ribosomal proteins expression and modifications. The exposure of mussels to all metals caused oxidative damage that was milder in the cases of Cu and Hg and more pronounced for Cd. However, after prolonged exposure of mussels to Cd (15 days), the effects receded. These changes that perturb protein biosynthesis can serve as a great tool for elucidating the mechanisms of toxicity and could be integrated in biomonitoring programs.

Mining waste as a cause of increased bioaccumulation of highly toxic metals in liver and gills of Vardar chub (Squalius vardarensis Karaman, 1928)

Freshwater contamination with mining waste can result with high concentrations of toxic metals in the water and in fish organs. In North-Eastern Macedonia, several rivers (e.g., Zletovska, Kriva) are exposed to acid mine drainage from active Pb/Zn mines. Previous studies confirmed high concentrations of dissolved metals in their water. This study was performed in liver and gills of Vardar chub (Squalius vardarensis Karaman, 1928) from three Macedonian rivers (Bregalnica, Kriva and Zletovska) in spring and autumn 2012. The aim was to establish if increased exposure to certain metals have resulted with their increased bioaccumulation. The concentrations of 19 elements were measured in cytosolic tissue fractions, to obtain information on metabolically available metal species. The following ranges of cytosolic concentrations of highly toxic elements were measured in the Vardar chub liver (in μg/L): Cd, 1.18-184; Cs, 0.25-25.4; Tl, 0.02-5.80; Pb, 0.70-61.1. Their ranges measured in the gills (in μg/L) were the following: Cd, 0.24-59.2; Cs, 0.39-24.4; Tl, 0.01-1.00; Pb, 0.65-87.2. Although the water of the mining impacted Zletovska River was highly contaminated with several essential metals, especially with Mn and Zn, the majority of essential elements (Na, K, Ca, Mg, Co, Cu, Fe, Mn, Mo, and Zn) did not reflect the exposure level. In contrast, seven nonessential elements reflected the level of exposure in the water. Significantly increased hepatic and gill concentrations of Cs, Rb, Sr, and Tl were detected in Vardar chub from the Zletovska River compared to the other two rivers, of Cd and Pb in the Zletovska and Kriva River compared to Bregalnica, and of V in the Bregalnica River compared to Zletovska and Kriva rivers. Observed significant metal bioaccumulation, in particular of highly toxic elements, as a consequence of exposure to water contaminated with mining waste points to necessity of intensified supervision of mining impacted rivers.

Changes in Histopathology, Enzyme Activities, and the Expression of Relevant Genes in Zebrafish (Danio rerio) Following Long-Term Exposure to Environmental Levels of Thallium

Thallium is a rare-earth element, but widely distributed in water environments, posing a potential risk to our health. This study was designed to investigate the chronic effects of thallium based on physiological responses, gene expression, and changes in the activity of relevant enzymes in adult zebra fish exposed to thallium at low doses. The endpoints assessed include mRNA expression of metallothionein (MT)2 and heat shock protein HSP70; enzymatic activities of superoxide dismutase (SOD) and Na⁺/K⁺-ATPase; and the histopathology of gill, gonad, and liver tissues. The results showed significant increases in HSP70 mRNA expression following exposure to 100 ng/L thallium and in MT2 expression following exposure to 500 ng/L thallium. Significantly higher activities were observed for SOD in liver and Na⁺/K⁺-ATPase activity in gill in zebra fish exposed to thallium (20 and 100 ng/L, respectively) in comparison to control fish. Gill, liver, and gonad tissues displayed different degrees of damage. The overall results imply that thallium may cause toxicity to zebra fish at environmentally relevant aqueous concentrations.

Tissue Contaminant Burdens in San Francisco Estuary White Sturgeon (Acipenser transmontanus): Implications for Population Recovery

The San Francisco Estuary (SFE) is heavily influenced by anthropogenic activities, including historic and chronic contaminant inputs. These contaminants can adversely affect SFE fish populations, particularly white sturgeon, because they are a benthic dwelling, long-lived species. We measured a suite of metals and organic contaminants in liver and gonad tissues of 25 male and 32 female white sturgeon as well as several physiological indicators of sturgeon health. Most sturgeon (68% of males and 83% of females) were estimated to be between 13 and 17 years of age. Sturgeon tissues had elevated concentrations of several metals, including As, Ba, Cd, Cu, Cr, Pb, Hg, Ni, Se, and Zn. The most frequently detected organic contaminants in sturgeon livers and gonads were DDE, PCBs, PBDEs, and galaxolide. Selenium was detected at levels similar to those shown to cause impaired liver physiology and reproductive success in white sturgeon. Observed Hg levels were higher than those shown to result in lower condition factor and gonadosomatic indices in white sturgeon. Liver galaxolide levels correlated with decreased plasma estradiol levels in female sturgeon. The Cd, As, and Cu warrant further investigation, because they were detected at levels known to impair fish health. Our results suggest contaminants are negatively affecting SFE white sturgeon health and fitness. Future SFE white sturgeon contaminant research is suggested.

Concentrations of Arsenic and Boron in Water, Sediment and the Tissues of Fish in Emet Stream (Turkey)

In this study, the concentrations of arsenic and boron were determined in the water and the sediment, as well as in the muscle tissues of Squalius cephalus, Alburnoides bipunctatus, Barbus plebejus and Capoeta tinca from Emet Stream. The fish samples were caught in May 2011 and September 2012. The metal concentrations in the water samples were as follows: arsenic was 137.1-1002 µg L^-1, and boron was 2421-14490 µg L^-1. The metal concentrations in the sediment samples were as follows: arsenic was 14.51-3317.1 mg kg^-1, and boron was 14.22-1014.01 mg kg^-1. The mean tissue concentration of arsenic was lower than the TFC and WHO limits. Boron has been identified in fish tissues at concentrations between 0.26 and 2.96 mg kg^-1. The bioaccumulation in the muscle tissues of all fish species caught from Emet Stream did not exceed the limit values.

Human exposure to trace metals and arsenic via consumption of fish from river Chenab, Pakistan and associated health risks

This study provided the first hand data of trace elements into fish muscles (N = 65) collected from river Chenab in Pakistan during 2013, using inductively coupled plasma mass spectrometry (ICP-MS). We monitored the health risk associated with consumption of contaminated fish of river Chenab, by the local population. The mean concentrations (μg/g, wet weight), in descending order were: Zn (35.5-54.4), Cu (1.38-4.57), Mn (2.43-4.5), As (0.23-1.21), Cr (0.21-0.67), Ni (0.14-0.34), Pb (0.14-0.31), Co (0.09-0.12), Cd (0.07-0.12) with higher concentration to be observed in the herbivore fish species (i.e., Cirrhinus reba and Catla catla). The levels of trace elements in different fish species found in this study were compared with similar data worldwide, and with the international standards for consumption. The concentration (μg/g) of arsenic in many cases (>65%) exceeded the FAO/WHO expert committee on food additives permissible limits. From the human health point of view, this study highlights that the local inhabitants, (i.e., fisher folk communities and population frequently consuming fish at about 100 g/day) along the river Chenab are exposed chronically to arsenic pollution with carcinogenic (10^-4 to 10^-6) and non-carcinogenic (THQ>1) risks, especially from the intake of Cirrhinus reba.

Acanthocephalan Parasites (Acanthogyrus sp.) of Nile Tilapia (Oreochromis niloticus) as Biosink of Lead (Pb) Contamination in a Philippine Freshwater Lake

The potential use of acanthocephalans as bioindicators of Lead (Pb) pollution in Sampaloc Lake, Laguna, Philippines was investigated. Nile tilapias (Oreochromis niloticus) were collected and Pb concentrations were determined in fish tissues and in their acanthocephalan parasites, Acanthogyrus sp. Significantly higher levels of Pb were detected in the parasites relative to the fish host tissues (p = 0.001). Bioaccumulation capacity of the parasites against fish tissues were 102, 119, and 147 times higher than the fish intestine, liver, and muscles, respectively. Pb sensitivity of the parasites was quantified by exact logistic analysis showing higher odds of Pb detection ranging from 18 to 45 folds (p = 0.001-0.009). Interestingly, infected fish showed significantly lower Pb concentration in their tissues compared to uninfected fish (p = 0.001), suggesting parasites were able to sequester Pb and served as active biosinks. The Pb levels in the parasites were also hundred folds higher (988 times) relative to the ambient waters, indicating a potential role of fish parasites as metal biosinks in aquatic ecosystems.

Sex-related mercury bioaccumulation in fish from the Madeira River, Amazon

Sex plays an important role in the kinetics and dynamics of methylmercury in some animals. Although fish is the main source of mercury exposure to consumers, the role of sex in fish-Hg bioaccumulation is less known. We studied total Hg (THg) concentrations in 2538 samples (males=1052, females=1486) of fish from different trophic levels (herbivorous, planctivorous, detritivorous, omnivorous, carnivorous, piscivorous); for each species we made a post hoc estimation of the minimum number of samples required to detect variance-based differences between sexes. Only five of the 41 studied species showed significant difference between sexes; but, no consistent dominant pattern of THg concentrations favored either sex. When grouped by trophic levels, overall mean difference in THg concentrations between males and females were not statistically significant. Correlation analysis showed sex-dependent THg bio-accumulation as a function of condition factor was statistically significant and negative for all trophic levels (detritivorous, herviborous, omnivorous, planctivorous, carnivorous, and piscivorous).

CONCLUSIONS

Sex is not the main driver of Hg bioaccumulation in most Amazonian fish species; however, studies have to consider the minimum number of samples required to ascertain sex effects on THg bioaccumulation. Therefore, neither the surveillance of environmental pollution nor the current food advisories based on muscle THg need to change because of fish sex.

Differential GFP expression patterns induced by different heavy metals in Tg(hsp70:gfp) transgenic medaka (Oryzias latipes)

Heat shock protein 70 (Hsp70) is one of the most widely used biomarker for monitoring environment perturbations in biological systems. To facilitate the analysis of hsp70 expression as a biomarker, we generated a Tg(hsp70:gfp) transgenic medaka line in which green fluorescence protein (GFP) reporter gene was driven by the medaka hsp70 promoter. Here, we characterized Tg(hsp70:gfp) medaka for inducible GFP expression by seven environment-relevant heavy metals, including mercury, arsenic, lead, cadmium, copper, chromium, and zinc. We found that four of them (mercury, arsenic, lead, and cadmium) induced GFP expression in multiple and different organs. In general, the liver, kidney, gut, and skin are among the most frequent organs to show induced GFP expression. In contrast, no detectable GFP induction was observed to copper, chromium, or zinc, indicating that the transgenic line was not responsive to all heavy metals. RT-qPCR determination of hsp70 mRNA showed similar induction and non-induction by these metals, which also correlated with the levels of metal uptake in medaka exposed to these metals. Our observations suggested that these heavy metals have different mechanisms of toxicity and/or differential bioaccumulation in various organs; different patterns of GFP expression induced by different metals may be used to determine or exclude metals in water samples tested. Furthermore, we also tested several non-metal toxicants such as bisphenol A, 2,3,7,8-tetrachlorodibenzo-p-dioxin, 4-introphenol, and lindane; none of them induced significant GFP expression in Tg(hsp70:gfp) medaka, further suggesting that the inducibility of Tg(hsp70:gfp) for GFP expression is specific to a subset of heavy metals.

Daily dietary intakes of zinc, copper, lead, and cadmium as determined by duplicate portion sampling combined with either instrumental analysis or the use of food composition tables, Shiraz, Iran

Estimation of essential and toxic element intakes is crucial to evaluate the risks of deficiency or toxicity. The purpose of this study was to investigate and also to compare the dietary intakes of zinc (Zn) and copper (Cu) by adults living in Shiraz, Iran, determined by two procedures: duplicate portion sampling of 21 hospital meals combined with either instrumental analysis (voltammetric measurement) or the use of food composition tables (FCTs). The level of exposure to lead (Pb) and cadmium (Cd) was evaluated as well. The daily Zn intakes of both methods were not significantly different and were higher than the RDA values except the value measured by the instrumental analysis which was lower than the RDA established for a male adult. Daily intake of Cu determined by instrumental analysis was significantly lower and closer to RDA for adults compared with the value estimated by FCTs. The dietary intakes of Pb and Cd were 313 and 61% of the respective provisional tolerable weekly intakes (PTWIs), respectively. The accuracy of two methods used for estimation of Zn intake was similar. In the case of Cu, the use of FCTs, in which the influence of environmental conditions and dietary habits of meal preparation is not taken into account, overestimated dietary intake. The risk of zinc deficiency was found in adult males. Moreover, the estimated intake of Pb, but not Cd, could be a cause of concern for Shiraz population. Thus, conducting regular periodic studies to assess the dietary intake of mentioned elements are recommended.

Mercury contamination in Khramulia (Capoeta capoeta) from the Cheshme Kile and Zarrin Gol Rivers in Iran and human health risk assessment

Total mercury concentrations were determined in muscle tissue of Khramulia (Capoeta capoeta) captured in the Cheshme Kile and Zarrin Gol Rivers, Iran. In Cheshme Kile River, 49 fish samples were collected. The mean total mercury concentration in the muscles of C. capoeta from this area was 249 ng g(-1) dw. In Zarrin Gol River, where 62 fish samples were collected, the total mercury in muscles averaged 164 ng g(-1) dw. A significant difference was found between means of mercury in the rivers (p < 0.001). All samples from the two rivers had mean mercury concentrations below the maximum allowable limits for mercury set by the Food and Agriculture Organization, World Health Organization, Standardization Administration of China and Environmental Protection Agency. The results of this study indicate that the values of hazard target quotient and estimated weekly intake are low and represent a negligible risk for human health.

Changes of polyamine pattern in digestive glands of mussel Mytilus galloprovincialis under exposure to cadmium

Polyamines, in particular spermidine and spermine, have been identified as important antioxidants, highly induced by oxidative stress in a variety of organisms. However, little is known about changes in polyamine content of metal-stressed marine organisms. In the present study, mussels (Mytilus galloprovincialis) were experimentally exposed to 25 μg/L Cd(2+) or 100 μg/L Cd(2+) for up to 15 days. Cd(2+) was progressively accumulated in mussel tissues, leading to a characteristic oxidative-stress status. Free putrescine (PUT) production was noticeably induced in response to Cd(2+) at day 5 and then declined. In contrast, free spermidine (SPD) content was gradually reduced, whereas the concentration of free spermine (SPM) increased. In combination, these changes led to a 69% or 88% reduction in the ratio of (SPD+SPM)/PUT at day 5, dependent on the Cd(2+) concentration used, which subsequently followed an upward trend in values, albeit not reaching those of controls. Conjugated polyamines constantly increased, in particular conjugated spermidine and spermine, tagging along with metallothionein production. Acetylated polyamines showed a diverse profile of changes, but their content was generally kept at low levels throughout the exposure period. Collectively, our results suggest that certain polyamine compounds could play a significant role in the tolerance of mussels against Cd(2+)-mediated stress, and that the ratio (SPD+SPM)/PUT could be a good indicator of the metal-stress status.

The effect of zinc deficiency and zinc supplementation on element levels in the bone tissue of ovariectomized rats: histopathologic changes

OBJECTIVE

Study aimed to determine the effects of zinc supplementation/deficiency on the histological structure and elements levels in bone tissue in ovariectomized rats.

METHODS

The study included 40 Sprague-Dawley type adult female rats, divided as follows: Control, ovariectomized, ovariectomized + zinc supplemented, ovariectomized + zinc deficient groups. At the end of the study bone tissues (femur) were collected to determine the levels of calcium, phosphorus, magnesium, zinc, iron, aluminium, chrome, lithium, lead, nickel, and manganese. The bone tissue was examined for histopathology.

RESULTS

Ovariectomy leaded to significant decrease in magnesium. Zinc supplementation to ovariectomized rats restored the reduced calcium, phosphorus, zinc. However, zinc deficiency in ovariectomized rats further reduced calcium, phosphorus, zinc, and manganese levels. Zinc deficiency in ovariectomized significantly increased Al, Cr, Li, Pb, and Ni levels. Tissue integrity was impaired due to ovariectomy and zinc deficiency.

CONCLUSION

Ovariectomy and zinc deficiency leads significant decreases elements of the bone.

Status of heavy metal residues in fish species of Pakistan

In this review, we evaluate and summarize the available data that addresses the levels of HM that exist in aquatic species, mainly fish, of Pakistan. Data on this topic were collected from the literature of the last two decades (1990-2012). Results revealed that the highest number (>50%) of studies addressing HM-contaminated fish have occurred in the Punjab province, followed by the Sindh and Khyber Pakhtunkhwa provinces. Our review disclosed that the HM concentrations in Pakistani fish species varied considerably with location. Generally, the level of HM residues detected in fish species had the following descending order: Fe>Zn>Pb>Cd>Hg>Ni>Cu>Ag>Cr>Mn>As. Fish samples collected from the Kabul River near the Nowshera district, Stretch of Ravi River, Indus River near Mainwali district, and Arabian Sea at Karachi revealed extremely high HM concentrations (range: 0.34-8,381.30 jlg/g), compared to other fresh water bodies, such as the Llyold Barrage, Guddu Barrage, Jinnah Barrage, and Chashma Barrage (0.01-2.13 jlg/g). As a reference point, we also reviewed selected data on HM fish residues that exist in countries that neighbor Pakistan. With the exception of fish collected in India, the majority of fish analyzed for HM residues in neighboring countries displayed lower residues than did fish from Pakistan. We concluded from reviewing the available published data that the most probable sources for the HM contaminants found in Pakistani water and fish were release of domestic sewage, agricultural runoff, and industrial effluents. We strongly recommend that action be taken to better control the discharges of unregulated waste that enters the Pakistani aquatic environment, with the intent to mitigate any continuing future damage to the aquatic ecosystem. We also recommend intensifying research programs that address the toxicity of HM to the aquatic environment, so that a better understanding of metal effects on fish can be achieved that will lead to a sustainable ecological harmony in Pakistan.

Toxicity of environmental contaminants to fish spermatozoa function in vitro--a review

In vitro techniques for investigating the toxic effects of environmental contaminants (EC) on fish spermatozoa motility kinetics and fertilizing ability are valuable tools to understand toxicity mechanisms and sites of action. In vitro techniques may also be well-suited to studies of endocrine disruption in male fertility in vivo. This review shows ECs to decrease or suppress spermatozoa motility kinetics and fertilizing ability in a dose-dependent manner, with toxic concentrations being much higher than those reported in the aquatic environment. Sites of action depend on EC concentration and duration of exposure. Both instant (immediate) and incubated exposure of spermatozoa to ECs results in damage to the plasma membrane and the axoneme, while disruption of energy metabolism appears only during incubated exposure. Spermatozoa lose fertilizing ability following exposure to ECs in vitro, not only due to inhibition or suppression of the initiation of motility, but also through damage to DNA. This review highlights the significant lack of information about disruption of spermatozoa function associated with exposure to water from polluted areas as well as combined effects of ECs. Specifics of alterations in intracellular signaling cascades involved in the initiation of spermatozoa motility following exposure to sublethal concentrations of ECs remain unknown. Further studies are also needed to elucidate in vitro EC effects during spermatozoa maturation, when spermatozoa acquire the potential for motility.

Determination of metal (Cu, Zn, Se, Cr and Cd) levels in tissues of the cyprinid fish, Capoeta trutta (Heckel, 1843) from different regions of Keban Dam Lake (Euphrates-Turkey)

The aim of this study was to evaluate Copper (Cu), Zinc (Zn), Selenium (Se), Chromium (Cr) and Cadmium (Cd) concentrations in liver, muscle, gills and kidney tissues of Capoeta trutta collected from four sites of Keban Dam Lake, Turkey. The highest heavy metal level in all tissues was for Zn, while Cd was the lowest. The lowest heavy metal levels were generally found at Station 4 (Agin) for all tissues (p < 0.05). There were statistically significant differences among stations for Cu, Zn, Cr and Se in gills; for Cu, Zn, Se and Cr in liver and kidney; and Cu, Zn and Cr in muscle (p < 0.05). Cadmium concentrations did not differ between sites for any of the tissues. Turkish Food Codex sets the maximum limits of Zn, Cu and Cd as, 50, 20 and 0.05 mg kg(-1) dry weight, respectively, in the muscle of fish used for human consumption. In our study, the level of Zn was higher than Turkish permissible limits only at Station 3 (Guluskur). Cadmium levels were much higher than permissible limits at three stations [S1 (Pertek), S2 (Kockale) and S3], whereas Cu levels were within permissible limits in all stations.

A systematic review on status of lead pollution and toxicity in Iran; Guidance for preventive measures

Lead is an old environmental metal which is presented everywhere and lead poisoning is an important health issue in many countries in the world including Iran. It is known as a silent environmental disease which can have life-long adverse health effects. In children, the most vulnerable population, mental development of children health effects is of the greatest influence. Low level lead exposure can significantly induce motor dysfunctions and cognitive impairment in children. The sources of lead exposure vary among countries. Occupational lead exposure is an important health issue in Iran and mine workers, employees of paint factories, workers of copying centers, drivers, and tile making factories are in higher risk of lead toxicity. Moreover lead processing industry has always been a major of concern which affects surface water, drinking waters, and ground waters, even water of Caspian Sea, Persian Gulf and rivers due to increasing the number of industries in vicinity of rivers that release their waste discharges into river or sea. In addition, lead contamination of soil and air especially in vicinity of polluted and industrialized cities is another health problem in Iran. Even foods such as rice and fishes, raw milk, and vegetables which are the most common food of Iranian population are polluted to lead in some area of Iran. Adding lead to the opium is a recently health hazard in Iran that has been observed among opium addicts. There are few studies evaluated current status of lead exposure and toxicity in the Iranian children and pregnant women which should be taken into account of authorities. We recommend to identify sources, eliminate or control sources, and monitor environmental exposures and hazards to prevent lead poisoning.

Comparative study of mercury accumulation in two fish species, (Cyprinus carpio and Sander lucioperca) from Anzali and Gomishan wetlands in the southern coast of the Caspian Sea

Anzali and Gomishan wetlands are considered as two of the most important wetlands in southern coast of Caspian Sea. To investigate mercury accumulation in these ecosystems, total mercury concentrations were measured in the muscle tissue of two fish species. Higher mercury concentrations were detected in C. carpio, an omnivorous benthic/pelagic species (Anzali wetland: 0.2 μg g(-1) wet weight; Gomishan wetland: 0.2 μg g(-1) wet weight), than in S. lucioperca, a carnivorous pelagic species (Anzali: 0.06 μg g(-1) wet weight; Gomishan: 0.15 μg g(-1) wet weight).

Developmental lead exposure causes startle response deficits in zebrafish

Lead (Pb(2+)) exposure continues to be an important concern for fish populations. Research is required to assess the long-term behavioral effects of low-level concentrations of Pb(2+) and the physiological mechanisms that control those behaviors. Newly fertilized zebrafish embryos (<2h post fertilization; hpf) were exposed to one of three concentrations of lead (as PbCl(2)): 0, 10, or 30 nM until 24 hpf. (1) Response to a mechanosensory stimulus: Individual larvae (168 hpf) were tested for response to a directional, mechanical stimulus. The tap frequency was adjusted to either 1 or 4 taps/s. Startle response was recorded at 1000 fps. Larvae responded in a concentration-dependent pattern for latency to reaction, maximum turn velocity, time to reach V(max) and escape time. With increasing exposure concentrations, a larger number of larvae failed to respond to even the initial tap and, for those that did respond, ceased responding earlier than control larvae. These differences were more pronounced at a frequency of 4 taps/s. (2) Response to a visual stimulus: Fish, exposed as embryos (2-24 hpf) to Pb(2+) (0-10 μM) were tested as adults under low light conditions (≈ 60 μW/m(2)) for visual responses to a rotating black bar. Visual responses were significantly degraded at Pb(2+) concentrations of 30 nM. These data suggest that zebrafish are viable models for short- and long-term sensorimotor deficits induced by acute, low-level developmental Pb(2+) exposures.