Cadmium, lead, mercury and copper in fish from the Marmara Sea, Turkey

Distribution and bioaccumulation of trace elements in two Cyprinidae fish species in the Indus river, Pakistan, including the impact of hydraulic structure on macroinvertebrates' biodiversity

The concentration of trace elements (chromium, lead, zinc, copper, manganese, and iron) was determined in water, sediment and tissues of two Cyprinidae fish species - Labeo rohita and Tor putitora - collected from the eight sampling stations of Indus River in 2022 for four successive seasons (autumn, winter, spring, summer), and also study the present condition of macroinvertebrates after the construction of hydraulic structure. The obtained results of trace element concentrations in the Indus River were higher than the acceptable drinking water standards by WHO. The nitrate concentration ranges from 5.2 to 59.6 mg l-1, turbidity ranges from 3.00 to 63.9 NTU, total suspended solids and ammonium ions are below the detection limit (<0.05). In the liver, highest dry wt trace elements (μg/g) such as Cr (4.32), Pb (7.07), Zn (58.26), Cu (8.38), Mn (50.27), and Fe (83.9) for the Labeo rohita; and Tor Putitora has significantly greater accumulated concentration (Cr, Pb, Zn, Cu, Mn, Fe) in muscle and liver than did Labeo rohita species. Additionally, lower number of macroinvertebrates were recorded during the monsoonal season than pre-monsoon and post-monsoon. Local communities surrounded by polluted environments are more probably to consume more fish and expose them to higher concentrations of toxic trace elements (lead and copper). The findings also provide a basis for broader ecological management of the Indus River, which significantly influenced human beings and socioeconomic disasters, particularly in the local community.

Global mercury concentrations in biota: their use as a basis for a global biomonitoring framework

An important provision of the Minamata Convention on Mercury is to monitor and evaluate the effectiveness of the adopted measures and its implementation. Here, we describe for the first time currently available biotic mercury (Hg) data on a global scale to improve the understanding of global efforts to reduce the impact of Hg pollution on people and the environment. Data from the peer-reviewed literature were compiled in the Global Biotic Mercury Synthesis (GBMS) database (>550,000 data points). These data provide a foundation for establishing a biomonitoring framework needed to track Hg concentrations in biota globally. We describe Hg exposure in the taxa identified by the Minamata Convention: fish, sea turtles, birds, and marine mammals. Based on the GBMS database, Hg concentrations are presented at relevant geographic scales for continents and oceanic basins. We identify some effective regional templates for monitoring methylmercury (MeHg) availability in the environment, but overall illustrate that there is a general lack of regional biomonitoring initiatives around the world, especially in Africa, Australia, Indo-Pacific, Middle East, and South Atlantic and Pacific Oceans. Temporal trend data for Hg in biota are generally limited. Ecologically sensitive sites (where biota have above average MeHg tissue concentrations) have been identified throughout the world. Efforts to model and quantify ecosystem sensitivity locally, regionally, and globally could help establish effective and efficient biomonitoring programs. We present a framework for a global Hg biomonitoring network that includes a three-step continental and oceanic approach to integrate existing biomonitoring efforts and prioritize filling regional data gaps linked with key Hg sources. We describe a standardized approach that builds on an evidence-based evaluation to assess the Minamata Convention's progress to reduce the impact of global Hg pollution on people and the environment.

Monitoring Hg2+ ions in food and environmental matrices using a novel ratiometric NIR fluorescent sensor via carbonothioate-deprotection reaction

Mercury toxicity and its environmental impact are significant concerns for public health and environmental protection. Therefore, the development of effective, rapid, and reliable detection methods for trace levels of Hg2+ is crucial. Herein, a cyanine dye bearing a carbonothioate group is reported as a potential NIR fluorescent probe for Hg2+ detection. The spectral properties of the free probe have been characterized by the presence and absence of a series of analytes. The addition of Hg2+ leads to significant changes in the fluorescence signal with distinct red coloration compared to other competing analytes, indicating that the probe is highly selective for Hg2+. The fluorescence quantum yield increases from 0.073 to 0.315. The detection limit is 0.10 μM, indicating the high sensitivity of the probe to low Hg2+ levels. The most prominent sensing features of the probe include NIR fluorescence, low cytotoxicity, ratiometric fluorescence response, and fast response compared to most of the currently available fluorescent probes. In addition, the probe can detect Hg2+ in actual samples such as foodstuff, soil, water, and live cells. Bioimaging studies have demonstrated that the present probe is highly efficient in targeting mitochondria and possesses good imaging abilities for detecting Hg2+ in cells. Therefore, these results suggest that it can be proposed as a powerful NIR fluorescent probe for the highly sensitive detection of Hg2+.

Heavy Metal and Trace Element Levels in Hair Samples from Fishermen in Turkey: The Fish/Ermen Heavy Metal Study (FHMS)

Toxic chemicals from polluted seas can enter the human body through seafood consumption and cause health problems. The aim of this study was to evaluate the levels of selected heavy metals and trace elements among fishermen who frequently consumed seafood and controls who consumed seafood less frequently in four provinces on the shores of the Sea of Marmara, which is heavily polluted by industrial activities. Fourteen elements (antimony, arsenic, cadmium, chromium, copper, iron, lead, manganese, mercury, nickel, selenium, strontium, vanadium, and zinc) were analyzed in hair samples using the inductively coupled plasma-mass spectrometer method. Levels of arsenic (0.147 ± 0.067 µg/g vs. 0.129 ± 0.070 µg/g, p = 0.025), chromium (0.327 ± 0.096 µg/g vs. 0.269 ± 0.116 µg/g, p < 0.01), nickel (0.469 ± 0.339 µg/g vs. 0.403 ± 0.368 µg/g, p = 0.015), strontium (1.987 ± 1.241 µg/g vs. 1.468 ± 1.190 µg/g, p < 0.01), and zinc (103.3 ± 43.1 µg/g vs. 92.7 ± 37.4 µg/g, p = 0.047) were higher in the fisherman group than in the control group. No difference was found between the groups in terms of other elements. The findings suggest that heavy metal-trace element contamination in the Sea of Marmara may increase the exposure levels of individuals to some chemicals through seafood consumption.

Interdecadal variations of the mercury content in Scomber colias in Canary Islands

Mercury is a very dangerous toxic metal that bioaccumulates very easily in organisms, and it migrates through the food web. The specimens studied in this study were Scomber colias. In the results obtained for the years 1973, 1992, and 2021, the concentration of mercury has been decreasing considerably over the decades, starting with 0.23 ± 0.04 mg/kg in 1973, and having less than half in 2021 with 0.11 ± 0.01 mg/kg. This may be due to the laws imposed by the countries against pollution and to a greater extent in the elimination of mercury; thanks to these measures it has been possible to reduce the concentration of mercury by half in S. colias. Otherwise, the conservation and availability of historical collections of living beings should be considered an unvalued source of information which could help to monitor legislation measures launched to ameliorate the human impact on the natural environment.

Effect of steaming on chemical composition of Mediterranean mussel (Mytilus galloprovincialis): Evaluation of potential risk associated with human consumption

Steaming process is the most popular method for cooking mussels worldwide. The effect of this cooking process on some toxic (Cd, Ni, Pb), essential (Cr, Cu, Fe, Mn, Zn) elements, minerals (Na, K, Ca, Mg), total lipids, and fatty acid profiles in the Mediterranean mussels (Mytilus galloprovincialis) harvested from the Black Sea was studied. Different approaches to assess the benefits and risks (n-6/n-3, PUFA/SFA, AI, TI, h/H, EDI, THQ, HI, TR, and HQEFA) were employed. In general, steaming process significantly modified some essential elements and minerals concentrations as well as the fatty acid profiles. Compared to the raw samples, this culinary practice resulted in an increased concentration of Na, Mg, Zn, and saturated fatty acids and a decrease of polyunsaturated fatty acids. Significant changes in the lipid quality indices (PUFA/SFA, AI, TI, and h/H) from the raw samples were observed. No effect on the DHA content was found. However, the significant increase in the absolute content of EPA + DHA indicates that steaming does not compromise the nutritional quality of mussels. Target hazard quotients (THQs) and hazard index (HI) from elemental intake were below 1, indicating that the steamed M. galloprovincialis pose no hazard for the consumers. The target risk (TR) values for Pb, Cr, and Ni were calculated, evaluated, and showed acceptable or negligible levels. In addition, the benefit-risk ratio indicated that the steamed M. galloprovincialis are safe for human consumption.

A switch-on xanthene-triphenylamine based fluorescent and colorimetric sensor for the detection of ultra-trace Hg2+ in food samples and living cells

A novel colorimetric and fluorescent "switch-on" probe based on xanthene-triphenylamine was developed for detection of Hg2+, which threatens public health, food safety and the environment. The probe displayed superior colorimetric and fluorescent selectivity/sensitivity toward Hg2+ over a series of metal ions via Hg2+-triggered deprotection reaction. Hg2+ induced a ∼18-fold enhancement in emission intensity of probe TXS with yellow fluorescence (λem = 558 nm) and led to distinct color transition from light yellow to blue or yellow under daylight depending on solvent mixture. Detection parameters were optimized and examined for the influence that they exerted on the detection which involved the usage of the Box-Behnken design methodology. The sensing pathway was also examined theoretically by DFT and TD-DFT calculations. The probe was successfully utilized for the detection of Hg2+ in several food and water samples with good recoveries. Cell imaging studies demonstrated that the probe was suitable for Hg2+ detection in live cells.

A review of chemical and microbial contamination in food: What are the threats to a circular food system?

A circular food system is one in which food waste is processed to recover plant nutrients and returned to the soil to enable the production of more food, rather than being diverted to landfill or incineration. The approach may be used to reduce energy and water use in food production and contribute to the sustainability of the system. Anaerobic digestion and composting are common food waste treatment technologies used to stabilize waste and produce residual materials that can replenish the soil, thus contributing to a circular food system. This approach can only be deemed safe and feasible, however, if food waste is uncontaminated or any contaminants are destroyed during treatment. This review brings together information on several contaminant classes at different stages of the food supply chain, their possible sources, and their fates during composting and digestion. The main aim is to identify factors that could impede the transition towards a safe, reliable and efficient circular food system. We investigated heavy metals, halogenated organic compounds, foodborne pathogens and antibiotic resistance genes (ARGs) in the food system and their fates during digestion and composting. Production and processing stages were identified as major entry points for these classes of contaminants. Heavy metals and foodborne pathogens pose less risk in a circular system than halogenated organics or antibiotic resistance. Given the diversity of properties among halogenated organic compounds, there is conflicting evidence about their fate during treatment. There are relatively few studies on the fate of ARGs during treatment, and these have produced variable results, indicating a need for more research to clarify their fate in the final products. Repeated land application of contaminated food waste residuals can increase the risk of accumulation and jeopardize the safety of a circular food system. Thus, careful management of the system and research into the fate of the contaminants during treatment is needed.

Heavy Metals and Trace Elements in Whole-Blood Samples of the Fishermen in Turkey: The Fish/Ermen Heavy Metal Study (FHMS)

Selected heavy metal-trace element (Ag, As, Ba, Cd, Cu, Hg, Pb, Sb, Se, Sr, and V) levels were determined by the ICP-MS method in whole-blood samples of fishermen and control group who accommodate in four provinces of the Marmara Sea. Mercury (1.267 ± 1.061 µg/L to 0.796 ± 0.853 µg/L) and lead (17.8 ± 9.0 µg/L to 12.0 ± 6.83 µg/L) levels were higher in the fishermen group than that of control group (p < 0.001 for both). There was no difference between the fishermen group and the control group in terms of whole-blood levels of other elements. Total monthly fish consumption was 9340.4 gr in the fishermen group and 326.4 gr in the control group, and the difference between the groups was significant (p < 0.001). There was no difference between the groups in terms of having amalgam dental filling (p > 0.05). The results suggest that consuming high amounts of sea products caught from the Marmara Sea is a source for some heavy metals such as mercury and lead, which poses a public health risk. Unlike the control group, the positive correlation between arsenic, copper, and strontium levels and age in fishermen can also be evaluated as an indicator of chronic exposure.

Heavy Metal Concentrations in Trachurus Mediterraneus and Merlangius Merlangus Captured from Marmara Sea, Turkey and Associated Health Risks

Rapid industrialization and excessive human population growth may cause deterioration in marine water quality and biodiversity. Heavy metals are one of the most common pollutants in the seas and marine organisms, including demersal and pelagic fish, can accumulate them from the environment. Assessment of the ecological risk of heavy metals from fish has an important role in public health. In this study, some heavy metal (Pb, Cd, As, Cr, Hg, Cu, Zn, and Fe) concentrations were determined in the muscle tissues of two commonly consumed fish species, Trachurus mediterraneus (Mediterranean horse mackerel) and Merlangius merlangus (Whiting), which are the fifth (14,222 tons/year) and sixth (6814 tons/year) highest commercial catches of marine fish species in Turkey, respectively. Heavy metal concentrations of samples collected from four sites (Adalar, İzmit Bay, Yalova, and Tekirdağ) in the Marmara Sea were determined using ICP-MS. Fish samples caught at Yalova station were found to have the highest heavy metal concentrations. According to the World Health Organization (WHO), in terms of the mean values, only As, and Cr were higher than permissible limits in T. mediterraneus, while Pb, Cd, As, and Cr were higher in M. merlangus. Arsenic concentrations were higher than maximum limits in both T. mediterraneus and M. merlangus. The estimated weekly intake (EWI) was calculated to assess the potential health impact. The EWI for arsenic, cadmium, lead, and mercury for some sites was above the provisional tolerable weekly intake.

Heavy metal concentrations and associated health risks in edible tissues of marine nekton from the outer Pearl River Estuary, South China Sea

Seven heavy metals including Hg, Cu, Pb, Cd, Zn, Cr, and As were examined in seventeen marine nekton species from the outer Pearl River Estuary (PRE), South China Sea. On the wet weight basis, the metal concentration ranges were 0.016-0.157 μg/g for Hg, 0.18-14.3 μg/g for Cu, 0.26-1.48 μg/g for Pb, 0.021-0.873 μg/g for Cd, 1.35-57.15 μg/g for Zn, 0.15-0.53 μg/g for Cr, and 0.42-7.83 μg/g for As, respectively. The levels of tested metals except for Pb in crustaceans were found to be higher than those in fish and cephalopods, suggesting that the diet and habitat played important roles on heavy metal accumulation ability of marine organism. Except for Cd in Champsodon capensis, Calappa lophos, and Portunus argentatus, all the left metal concentrations of investigated nekton species were below their permissible upper limits, indicating that consumption of examined marine nekton should be considered as safe for human health. The values of single target hazard quotient (THQ) and total THQ were all less than 1 and also suggested that there was no health risk for consumption. Even so, the local people should control their daily intake of crustacean foods from the outer PRE, since there might be potential As and Cd cumulative risks.

Ontogenic and seasonal variations of metal content in a small pelagic fish (Trachurus picturatus) in northwestern African waters

Marine organisms are exposed to great changes induced by human beings due, among others, to discharges into the oceans, increasing marine pollution. For this study, 294 specimens of Trachurus picturatus from the Canary Islands were analyzed during a period of 2 years. The concentration of 11 anthropic metals and trace elements was determined in each individual using the Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) technique. Statistical analyses were carried out considering the following factors: oceanographic season, maturity of the gonads, size of the specimens, season. Immature specimens had higher concentration in more metals than the mature specimens. This fact may be due to the fact that these specimens require a much higher metabolic rate due to their growth and do not detoxify like mature specimens.

Baseline evaluation of metal contamination in teleost fishes of the Gulf of Tigullio (north-western Italy): Histopathology and chemical analysis

Metals, whether essential (Cu, Zn, Cr, Fe, Mn) or non-essential (Al, As, Cd, Ni, Pb, Hg) for organism metabolism, occur naturally in the marine environment and their abundance can increase due to the presence of human activities. In this study, fish were used as bio-indicators, to determine a correlation between the bio-accumulation of metals in muscle and gill tissues and the health status of fish. The study area was the Gulf of Tigullio (north-western Italy), which is impacted by various sources of metal contamination. Histopathology served as a significant tool to investigate possible alterations in gills, one of the main organs involved in fish physiology. Results highlighted some correlations between certain metals (e.g. Pb, Ni) and gill alterations (e.g. epithelial hyperplasia, epithelial lifting), providing baseline data from a pool of different fish species, which can be used for comparison purposes in further studies.

Marine pollution in the Libyan coastal area: Environmental and risk assessment

A comprehensive assessment of the potential adverse effects on environment and human health generated by the inputs of chemicals from the most important Libyan petrochemical plant is presented. Ecotoxicological risk associated with the presence of As, Hg, Ni, Zn and PAHs in marine sediments is low or moderate, with a probability of toxicity for ecosystem <9% and <20% for heavy metals and PAHs respectively. However, surface sediments result strongly enriched in Hg and As of anthropogenic origin. Investigation of metals in fish allowed to assess potential risks for human populations via fish intake. Target hazard quotients values indicate potential risk associated to toxic metals exposure by fish consumption and lifetime cancer risk (TR) values highlight a potential carcinogen risk associated to As intake. Noteworthy, the presented results provide an unprecedented environmental dataset in an area where the availability of field data is very scant, for a better understanding of anthropogenic impacts at Mediterranean scale.

Toxicities and risk assessment of heavy metals of the six most consumed fish from the Marmara Sea

Bream, anchovy, horse mackerel, sea bass, sardine, and whiting that are commonly consumed by the Turkish community were collected from the Marmara Sea in September and March and were analyzed for trace elements and for fat content. The total concentrations of some metals in these fish were determined using ICP-MS in acid extracts obtained after microwave digestion. The seasonal fat contents of the fish samples were determined gravimetrically following a Soxhlet extraction method. Experimental results were evaluated statistically using t tests and principal component analyses. This enabled the comparison of the elements' contents in the fish samples in March and September and also led to an investigation into whether or not there is a relationship between the elements' contents and the fat amount. The results of this work showed that a significant temporal difference was observed. This difference was not related to the seasonal variation in fat concentrations.

Metals and metalloids in Little Penguin (Eudyptula minor) prey, blood and faeces

Piscivorous species like the Little Penguin (Eudyptula minor) are particularly at risk of being negatively impacted by pollution due to their heightened exposure through aquatic food chains. Therefore, determining the concentration of heavy metals in the fish prey of seabirds is an essential component of assessing such risk. In this study, we report on arsenic, cadmium, mercury, lead and selenium concentrations in three fish species, which are known to comprise a substantial part of the diet of Little Penguins at the urban colony of St Kilda, Melbourne, Australia. Metal concentrations in the fish sampled were generally within the expected limits, however, arsenic and mercury were higher than reported elsewhere. Anchovy (Engraulis australis) and sandy sprat (Hyperlophus vittatus) contained higher Hg concentrations than pilchard (Sardinops sagax), while sandy sprat and pilchard contained more selenium. We present these findings together with metal concentrations in Little Penguin blood and faeces, sampled within weeks of the fish collection. Mercury concentrations were highest in the blood, while faeces and fish prey species contained similar concentrations of arsenic and lead, suggesting faeces as a primary route of detoxification for these elements. We also investigated paired blood - faecal samples and found a correlation for selenium only. Preliminary data from stable isotope ratios in penguin blood indicate that changes in penguin blood mercury concentrations cannot be explained by trophic changes in their diet alone, suggesting a variation of bioavailable Hg within this semi-enclosed bay.

Heavy metals in tissues of scorpionfish (Scorpaena porcus) caught from Black Sea (Turkey) and potential risks to human health

Scorpionfish (Scorpaena porcus) is a demersal fish species commercially important for its of which meat is tough and delicious. The aim of this study was to determine heavy metal (Al, Cu, Ni, As, Cd, Hg, Pb, U) concentrations in this fish species which is traditionally consumed in the Black Sea Area and, to compare the concentrations of various toxic elements in different organs of the fish specimens (muscle, liver, gill, and skin). Within this scope, the mineralization was performed using microwave digestion system. Thirty-two scorpionfish caught from Sinop Inland Port during 2010 were analyzed. The heavy metal concentrations were determined with the method of inductively coupled plasma mass spectroscopy (ICP-MS). Verification of the method was demonstrated by analysis of standard reference material (NRCC-TORT-2 lobster hepatopancreas). After evaluation of the results, it was determined that the highest heavy metal accumulation was generally found in the liver. The maximum aluminum level and the minimum uranium level were found in the analyzed tissues. In terms of heavy metals, Al, Cu, Cd, and Hg showed a statistically significant difference between tissues (p < 0.05). It was determined that heavy metal concentrations obtained from the muscle tissues did not exceed the national and international recommended limits; and also it was found that daily intake amounts did not exceed tolerable daily intake amounts. Furthermore, in THQ based risk evaluation, the value 1 which is crucial for children and adults was not surpassed. In terms of public health, it was found out that there was not any risk in consumption of scorpionfish in the study area.

Toxicological assessment of fish (Clarias gariepinus) from bitumen-polluted River Oluwa, Nigeria

Toxicological evaluation of Clarias gariepinus from bitumen-polluted River Oluwa, Nigeria, was carried out in furtherance of studies on the environmental impacts of the bitumen exploration in Ondo State, Nigeria. Samples were taken from three different (two polluted and one as control) sites. The effect of changes in monthly seasonal flow rate was assessed for the sites of study. Blood plasma clinical-chemical parameters (BCCPs) and histological changes/lesions in various organs were evaluated as markers of pollution in the fish blood using standard methods. The result of the physicochemical properties of water from the sampling points revealed some of the values conforming to approved standards while others showed deviation. Significant differences were found in the blood and histological endpoints between the control and the polluted sites as well as between the two seasons evaluated across the sites. The public health implications of consuming this fish are fully discussed.

Influence of the water quality improvement on fish population in the Seine River (Paris, France) over the 1990-2013 period

Over the past 20 years, rules concerning wastewater treatment and quality of water discharged into the environment have changed considerably. Huge investments have been made in Paris conurbation to improve waste water treatment processes in accordance with the European Water Framework Directive. The interdepartmental association for sewage disposal in Paris conurbation (SIAAP) carried out a monitoring of both fish assemblages and water quality in the Seine River around the Paris conurbation (France) since the early 90's. The main goal of this study was to estimate the influence of the water quality improvement on fish. On one hand, the study confirmed the improvement of the water quality (dissolved oxygen, ammonia nitrogen, organic matter) in the Seine River, mostly focused downstream of Paris conurbation. On the other hand, an increase of the number of species occurred from 1990 (14) to 2013 (21). Moreover, changes in the river Seine assemblages happened over that 23-year period with emergence of sensitive species (ruffe, scalpin and pike-perch). The improvement of the water quality was also reported with respect to the Index of Biotic Integrity (IBI). However, no variation of pollutant concentrations in roach, eel and chub muscles has been observed. An exceedance of the environmental quality standards have even been reported all over this period as regards mercury and organochlorine.

Review on the Risk Assessment of Heavy Metals in Malaysian Clams

The current review discusses the levels of six heavy metals in different clam species from 34 sites of Malaysian coasts. The concentrations (µg/g dry weight) of these heavy metals ranged around 0.18-8.51, 0.13-17.20, 2.17-7.80, 0.84-36.00, 24.13-368.00, and 177.82-1912.00 for Cd, Pb, Ni, Cu, Zn, and Fe, respectively. It was observed that the concentrations of metals slightly depend on different clam species but mostly depend on site locations. According to Malaysian Food Regulation (1985), about 30% and more than 50% sites are safe from Cd and Pb contamination, respectively, and also the clam species from the other populations studied were safe for consumption.

Determination of heavy metal contents in water, sediments, and fish tissues of Shizothorax plagiostomus in river Panjkora at Lower Dir, Khyber Pakhtunkhwa, Pakistan

The present study was conducted to investigate the contamination of water, sediments, and fish tissues with heavy metals in river Panjkora at Lower Dir, Khyber Pakhtunkhwa, Pakistan. Water, sediments, and fish (Shizothorax plagiostomus) samples were collected from September 2012 to January 2013 at three different sites (upstream site at Sharigut, sewage site at Timergara, and downstream site at Sadoo) of river Panjkora. The concentrations of heavy metals in water were in the order Zn > Cu ≈ Pb > Ni ≈ Cd with mean values of 0.30, 0.01, 0.01, 0.0 and 0.0 mg/l, respectively, which were below the maximum permissible limits of WHO for drinking water. In sediments, heavy metals were found in the order Cu > Zn > Ni > Pb > Cd with mean concentrations of 50.6, 38.7, 9.3, 8, and 0.4 mg/kg, respectively. Ni and Cd were not found in any fish tissues, but Zn, Cu, and Pb were detected with the mean concentration ranges of 0.04-1.19, 0.03-0.12, and 0.01-0.09 μg/g, respectively. The present study demonstrates that disposal of waste effluents causes a slight increase in the concentration of heavy metals in river Panjkora as revealed by variation in metal concentrations from upstream to downstream site. Sewage disposal was also found to change physicochemical characteristics of Panjkora water. At present, water and fish of river Panjkora are safe for human consumption, but the continuous sewage disposal may create problems in the future.

Levels of heavy metals in tissues of shingi fish (Heteropneustes fossilis) from Buriganga River, Bangladesh

Heavy metal pollution was reported in commercially valuable freshwater edible fish in the Buriganga River, Bangladesh. The concentrations of As, Pb, Cd, Cr, Zn, and Cu were investigated in the muscle, gill, stomach, intestine, and liver of Heteropneustes fossilis caught at three stations to assess the degree of fish pollution by heavy metals. Significant differences in concentrations of analyzed elements were observed among different tissues, but not among the stations. The ranges of the measured concentrations (μg/g dry weight) in the tissues of H. fossilis were as follows: arsenic concentration was (0.2-0.4), (0.82-0.90), (3.29-3.99), (2.20-2.80), and (2.41-2.90), that of lead was (1.79-2.20), (4.95-6.55), (10.36-13.38), (5.74-9.70), and (18.20-18.79), that of cadmium was (0.3-0.4), (2.87-4.27), (1.03-1.63), (1.55-4.59), and (2.25-5.50), that of chromium was (1.40-1.70), (3.52-3.72), (2.28-5.29), (2.77-3.79), and (4.25-8.65), that of zinc was (24.47-28.82), (16.82-18.80), (20.22-22.20), (22.86-26.68), and (60.82-67.80), and that of copper was (7.80-8.50), (6.22-6.81), (38.21-44.25), (17.07-21.03), and (43.24-47.30) in the muscle, gill, stomach, intestine, and liver, respectively. This research showed that the liver appeared to be the main heavy metal storage tissue, while the muscle had the lowest levels of analyzed metals. The concentrations of metal in the muscles not exceeded the acceptable levels for a food source for human consumption.

Monitoring programme on toxic metal in bluefish (Pomatomus saltatrix), anchovy (Engraulis encrasicolus) and sardine (Sardina pilchardus) from Istanbul, Turkey: levels and estimated weekly intake

Toxic metal (Hg, Cd, Pb, Cu and Zn) concentrations of small-medium bluefish, anchovy and sardine in Istanbul, Turkey, were determined using inductively coupled plasma-mass spectrometry (ICP-MS) throughout 1 year. The concentrations of pollutants were found to vary according to season and species. Estimates of weekly intake levels of the metals were calculated and compared to recommended safe limits for fish consumption by humans. The levels of Cd, Pb, Cu and Zn in the fillets of all species resulted in estimates of weekly intake levels that were lower than the recommended safe limits. The concentrations of Hg of small bluefish in September, of medium bluefish in June and September, of anchovy in March, and of sardine in August and September resulted in estimates of weekly intake levels that were higher than the recommended safe limits for human consumption.

Heavy metals in raw, fried and grilled Mediterranean finfish and shellfish

The effect of domestic pan-frying and grilling on Cd, Cr, Cu, Fe, Hg, Ni, Pb and Zn content of popular small Mediterranean finfish and shellfish was studied. The species selected -namely anchovy, bogue, hake, picarel, sardine, sand smelt, stripped mullet, Mediterranean mussel, shrimp and squid- are among the most commonly marketed and consumed in Greece and most of the Mediterranean countries. Both culinary practices examined resulted in increased metals concentrations compared to those of raw samples, the increment being inversely related to fish size and -in most cases- being more extended in pan-frying. The consumption of cooked seafood is expected to provide significant amounts of Fe and Zn followed, in decreasing order, by Cr, Cu and Ni. In addition, the estimation of (a) weekly intakes and (b) target hazard quotients for the toxic elements Cd, Hg and Pb revealed that the cooked fish and shellfish do not pose any health risk for the consumers.

Determination of metal levels in thirteen fish species from Lakshadweep Sea

A bio-monitoring study was performed to investigate the concentration of certain metals (cadmium, cobalt, copper, iron, magnesium, manganese, nickel, lead and zinc) in gill, skin and muscle of thirteen demersal fish species of Agatti Coast of Lakshadweep Sea. All the metal concentrations in gill are higher than skin and muscle. Concentrations of toxic metals such as Cd (0.61 ± 0.67 μg g(-1) in Gerres longirostris), Mn (0.83 ± 1.21 μg g(-1) in Lutjanus fulvus) and Ni (0.56 ± 0.83 μg g(-1) in L. bengalensis) were well above the permissible limits suggested by World Health Organization and Food and Agricultural Organizations.

Baseline of the spatial and temporal metal contamination in Dilek National Park, Turkey

Dilek National Park in Western Turkey is a protected habitat for several endangered and threatened species. In an attempt to protect the endangered species, the park was classified as a World Heritage Preserve. Even with this change, the animal and flora variety are still at risk from previous metal contamination. Water samples were collected 10 cm below the water surface and sediment from 0-30 and 30-60 cm depth. Inorganic elements were found in all sediment samples. Sodium had the highest aqueous concentration (10,312 mg/L), while Cu, Fe, Mn, and Zn were present at levels significantly lower than the chronic exposure criteria. Zn was the least prevalent (0.4 mg/kg) compound found in the sediment. The highest toxic contaminant concentration was Mg at an average of 1,100 mg/kg. The main contamination source of that seems to be Great Meandrous River. More studies are needed to develop a protection and remediation strategy for Dilek National Park.

Determination of mineral composition in three commercial fish species (Solea solea, Mullus surmuletus, and Merlangius merlangus)

This study was monitored to determine the changes in the micromineral and macromineral composition of common sole (Solea solea), striped red mullet (Mullus surmuletus), and whiting (Merlangius merlangus) throughout the year. Macromineral concentrations in edible parts of fish species were 444-1,559 mg/kg for Na, 1,975-5,130 mg/kg for K, 228-658 mg/kg for Mg, 187-1,105 mg/kg for Ca, and 2,341-7,341 for P, respectively. The highest mercury contents were found in the autumn months. While the highest protein and lowest fat values were found in the summer, the highest ash contents were found in the spring. Mercury content was found to be over the legislative limits in autumn samples for common sole and in summer for striped red mullet. Lead and cadmium contents of striped red mullet were found to be over the legislative limits throughout year.

Difference of mercury bioaccumulation in red mullets from the north-western Mediterranean and Black seas

The relationships between total mercury (Hg) concentration and stable nitrogen isotope ratio (delta(15)N) were evaluated in Mullus barbatus barbatus and M. surmuletus from the Mediterranean Sea and M. barbatus ponticus from the Black Sea. Mercury concentration in fish muscle was six times higher in the two Mediterranean species than in the Black Sea one for similar sized animals. A positive correlation between Hg concentration and delta(15)N occurred in all species. Increase in Hg concentration with delta(15)N was high and similar in the two Mediterranean fishes and much lower in the Black Sea species. Since this was neither related to trophic level difference between species nor to methylmercury (MeHg) concentration differences between the north-western Mediterranean and the Black Sea waters, we suggested that the higher primary production of the Black Sea induced a dilution of MeHg concentration at the base of the food webs.

Carbon and nitrogen stable isotopes and metal concentration in food webs from a mining-impacted coastal lagoon

Two food webs from the Mar Menor coastal lagoon, differing in the distance from the desert-stream through which mining wastes were discharged, were examined by reference to essential (Zn and Cu) and non-essential (Pb and Cd) metal concentrations and stable isotopes content (C and N). The partial extraction technique applied, which reflects the availability of metals to organisms after sediment ingestion, showed higher bioavailable metal concentrations in sediments from the station influenced by the mining discharges, in agreement with the higher metal concentrations observed in organisms, which in many cases exceeded the regulatory limits established in Spanish legislation concerning seafood. Spatial differences in essential metal concentrations in the fauna suggest that several organisms are exposed to metal levels above their regulation capacity. Differences in isotopic composition were found between both food webs, the wadi-influenced station showing higher delta(15)N values and lower delta(13)C levels, due to the discharge of urban waste waters and by the entrance of freshwater and allochthonous marsh plants. The linear-regressions between trophic levels (as indicated by delta(15)N) and the metal content indicated that biomagnification does not occur. In the case of invertebrates, since the "handle strategy" of the species and the physiological requirements of the organisms, among other factors, determine the final concentration of a specific element, no clear relationships between trophic level and the metal content are to be expected. For their part, fish communities did not show clear patterns in the case of any of the analyzed metals, probably because most fish species have similar metal requirements, and because biological factors also intervened. Finally, since the study deals with metals, assumptions concerning trophic transfer factors calculation may not be suitable since the metal burden originates not only from the prey but also from adsorption over the body surfaces and seawater ingestion.