Metals and metalloids in a first order stream of the Atlantic rainforest: abiotic matrices,bioaccumulation in fishes and human health risk assessment

Background and aimMetals and metalloids have been found in several streams and rivers from the Atlantic Rainforest (ARF), one of the world´s leading biodiversity hotspot, which may represent a risk for environmental and human health. The aims of this study were: 1) to evaluate the accumulation and distribution of 24 trace elements in water, sediments and fish tissues (muscle and gills) of sixteen species from the Atlantic Rainforest, 2) to explore bioaccumulation patterns in fish tissues and abiotic matrices, and 3) to assess the impact of metal and metalloids on the human health from water and fish consumption.MethodsWater, sediments and fish samples were collected from Ramos Stream (Misiones Province, Argentina). The concentrations of Ag, Al, As, Ba, Be, Cd, Co, Cr, Cs, Cu, Fe, Ga, Hg, Li, Mg, Mn, Ni, Pb, Se, Sr, Ti, U, V and Zn were determined by Quadrupole Inductively Coupled Plasma Mass Spectrometry. Bioaccumulation factors (BAFs) were used to evaluate bioaccumulation of metals and metalloids in relation to water and sediment. The Hazard Quotient (HQ), Hazard Index (HI) and Target Hazard Quotient (THQ, general and fisherman populations) were calculated to assess the non-carcinogenic human health risk from water and fish consumption.ResultsThe concentrations of several elements in water and sediment were higher than the international guidelines for aquatic biota protection. Levels of As, Pb and Zn in muscle and gills were above national and international guidelines for human consumption. The bioaccumulation factors ranged from 749 to 13,029 being higher in gills than in muscle. The HQ and HI ranged from 0.001 to 0.015. The THQ for each element and total THQ values were lower than 0.1.ConclusionBioaccumulation factor suggests that several species have a moderate capacity to incorporate some metals and metalloids from the abiotic matrices. According to the HI and THQ values found, there is no risk to human health from consumption of water and fish.     

Mercury in Scalp Hair Near the Mid-Atlantic Ridge (MAR) in Relation to High Fish Consumption

The aim of this study was to evaluate the potential risk of mercury contamination near the Mid-Atlantic Ridge relating total mercury (THg) concentrations in the human scalp hair (n?=?110) and high fish consumption levels. THg was quantified in human scalp hair, and volunteers were questioned about age, gender, and smoking habits being subsequently grouped in categories based on the individual average intake of fish meals per week. THg concentrations ([THg]) in hair samples ranged from 0.05 to 2.24 μg g^?1, and significant differences were found according to age (p?<?0.05) and also among volunteers presenting different fish consumption rates (p?<?0.001) being the highest [THg] observed on the adult population and also on volunteers that indicated consuming five or more meals of fish per week. Results indicate a pattern of increased mercury accumulation with increasing fish consumption. Despite mercury availability and a potential mercury intake of up to seven times, the WHO provisional tolerable weekly intake of mercury value, in consequence of high fish consumption, mercury concentrations in scalp hair are comparatively low regarding recommended levels by WHO.     

Human Exposure to Dioxin-Like Compounds in Fish and Shellfish Consumed in South Korea

Dietary intake is the most important source of exposure to dioxins for the general population. This pathway contributes more than 90% of the daily intake for the general population of Korea. The objective of this study was to assess current exposure to dioxin-like compounds in fish and shellfish consumed by the general population in Korea. Residues of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs), and dioxin-like, non-, and mono-substituted polychlorinated biphenyls (co-planar PCBs) were quantified in 32 fish and shellfish collected from domestic fisheries markets. The contributions of individual DL-PCB congeners to the total 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) equivalents (TEQ) were greater than 50%. Concentrations of 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents based on the TCDD equivalency factors (TEFs) developed by the World Health Organization (TEQ_WHO) were compared to guidelines suggested for the protection of human health by the World Health Organization (WHO). The greatest TEQ concentration was observed in herring, followed by that in dried anchovy and Sailfin sandfish. The exposure to dioxin-like compounds from current fish consumption patterns was estimated to be 72 pg TEQ_WHO/day, which is equal to 1.2 pg TEQ_WHO/kg, bw/d, a value that is less than the current tolerable daily intake (TDI) guideline in Korea, which is 4 pg TEQ_WHO/kg, bw/d. The relatively great exposure was determined to be due to greater fish consumption rate in Korea, rather than greater concentrations of residues in food.     

Biomonitoring of metal(oid)s in mining-affected Borcka Dam Lake coupled with public health outcomes

Due to increased anthropogenic activities, the aquatic environment is exposed to pollutants much more than ever. These pollutants go into the food chain and can pose a health risk to human. Correlatively, Borcka Dam Lake, Turkey has been affected by mining activities since decades. In the present study, therefore, Cu, Pb, As, Zn, Mn, Cd, Cr, and Se concentrations in water, sediment, and different tissues (muscle, gill, liver) of 11 fish species sampled from the lake were analyzed regarding metal(oid)s pollution and potential human health risk through fish consumption. The metal(oid) concentrations in the water were below the limit values recommended by USEPA for aquatic life criteria but sediments were heavily polluted by As, Cu, Pb, and Zn based on Sediment Quality Guideline. The lowest metal(oid) values among tissues for all fish species were determined in muscle (p < 0.05) which was lower than the limits for human consumption declared by European Union Regulation. Target Hazard Quotient and Hazard Index used non-cancer risk estimate which was lower than 1. In the view of these results, the consumption of fish caught from the Borcka Dam Lake may not pose a potential risk to human.     

珠江三角洲池塘养殖中多氯联苯的环境归趋

对珠江三角洲4个不同地方的养殖池塘中水样,泥样和不同种类的鱼样分析,结果表明水产养殖中多氯联苯的分布和归趋在不同分配相中有很大差别,水相中含量较低(8.0～2 4 .0 3ng·L- 1 ) ,沉积相中较高(7.32～36 .2 3ng·g- 1 ,干重) ,特别是工业活动频繁的地方,而乡村相对较低。鱼类不同食性对多氯联苯的积累及其同分异构体的分布有很大影响,肉食性鱼类比草食性鱼类积累更多的多氯联苯.其中代表性同分异构体有IUPAC 118,138,81/ 87,15 3,180 ,5 2 ,4 9,99,4 4。珠江三角洲水产养殖中多氯联苯对生态环境的影响相对较低。     

Aquatic macroinvertebrate assemblages in mitigated and natural wetlands

Many wetlands have been constructed in West Virginia as mitigation for a variety of human disturbances, but no comprehensive evaluation on their success has been conducted. Macroinvertebrates are extremely valuable components of functioning wetland ecosystems. As such, benthic and water column invertebrate communities were chosen as surrogates for wetland function in the evaluation of 11 mitigation and 4 reference wetlands in West Virginia. Mitigation wetlands ranged in age from 4 to 21 years old. Overall familial richness, diversity, density and biomass were similar between mitigation and reference wetlands (p > 0.05). Within open water habitats, total benthic invertebrate density was higher in reference wetlands, but mass of common taxa from water column samples was higher in mitigation wetlands (p < 0.05) Planorbidae density from benthic samples in emergent habitats was higher in reference than mitigated wetlands. Benthic Oligochaeta density was higher across open water habitats in mitigation wetlands. All other benthic taxa were similar between wetland types. Among the most common water column orders, Isopoda density was higher in reference wetlands, but Physidae density was higher in mitigation wetlands. Within mitigation wetlands, emergent areas contained higher richness and diversity than open areas. These data indicate that mitigation and reference wetlands generally support similar invertebrate assemblages, especially among benthic populations. The few observed differences are likely attributable to differences in vegetative community composition and structure. Mitigation wetlands currently support abundant and productive invertebrate communities, and as such, provide quality habitat for wetland dependent wildlife species, especially waterbirds and anurans.     

Distributions and Congener Patterns of PCBs in Fish from Major Aquaculture Areas in the Pearl River Delta,South China

The distribution and concentrations of polychlorinated biphenyls (PCBs) were determined in surface sediments and fish collected from freshwater fishponds in six major aquaculture areas of the Pearl River Delta. The concentrations of total PCBs ranged from 7.32 to 36.2 ng/g (dry weight) in sediments and 5.15 to 226 ng/g (lipid weight) in five species of fish, with higher concentrations in fishponds from two industrialized areas. Feeding habits of fishes played a significant role on the accumulation of PCBs and their homologue patterns in fish tissues, with higher concentrations in muscle and viscera of mandarin fish (Siniperca kneri), and tilapia (Tilapia mossambica) and lower in grass carp (Ctenopharyngodon idellus). In muscle, IUPAC No. 118, 138, 81/87, 153, 180, 52, 49, 99, and 44 congeners were the most dominant out of the 36 congeners measured in the present study. The contents of PCBs in fish cultivated in the Pearl River Delta were rather low when compared with the maximum concentration of total PCBs of 2.0 μg/g (wet weight), imposed by the U.S. Food and Drug Administration edible seafood. However, due to the bioaccumulation and biomagnification nature of PCBs through the food chain, continuous monitoring of PCBs as well as other Persistent Organic Pollutants in this rapidly developed region is encouraged.     

Assessment of potentially toxic heavy metals and health risk in water,sediments, and different fish species of River Kabul,Pakistan

Contamination of freshwater bodies and consequently freshwater fish with toxic heavy metals is a serious environmental issue. The trophic transfer of potentially toxic heavy metals in the human food chains, especially in fish has important implications for human health. The present research study was designed to assess the concentrations of the heavy metals Cr, Ni, Cd, and Pb in the water, sediments, and different freshwater fish species of River Kabul, Pakistan. The heavy metals were quantified in the samples with Atomic Absorption Spectrophotometer. Heavy metal contamination in fish muscles was characterized in terms of metal pollution index and biota-sediments accumulation factor, while human health risk was assessed through calculation of estimated weekly intake. The average concentrations of Cr, Ni, Cd, and Pb in muscle samples of the analyzed fish species at different sampling sites of the river ranged from 12.3 to 33.0, 33.2 to 109.2, 0.98 to 1.5, and 13.9 to 29.6 mg kg^?1 wet weight, respectively. Based on the current study data, consumption of the analyzed freshwater fish species from River Kabul was generally safe in terms of potential risk from Cd and Pb but the observed Ni accumulation may pose a potential health risk to regular/excessive fish consumers.     

Concentrations of Lead,Cadmium, and Mercury in Halfbeaks (Hyporhampus affinis) from the East Java Coast,Indonesia and Human Health Hazard

The objectives of this study were to measure the levels of lead, cadmium, and mercury in the muscle tissues of halfbeaks (Hyporhampus affinis) captured at five stations along the East Java coast, Indonesia. This fish is one of the important species and consumed by local people as a cheap source of protein. We evaluated the hazard level posed by the metals in relation to the maximum residual limit for human consumption and to estimate the weekly intake and compare it with the provisional tolerable weekly intake (PTWI). The Pb, Cd, and Hg concentrations in fish at all stations ranged from 0.006 to 0.023 mg/kg, 0.007 to 0.024 mg/kg, and 0.047 to 0.055 mg/kg wet weight, respectively. All samples of halfbeaks collected from this area appear to be safe for human consumption because their metals’ levels are below the permissible limit for human consumption and the maximum weekly intakes are below the recommended values of PTWI.     

Bioaccumulation of heavy metals in two morphotypes of African large barb Labeobarbus intermedius (Osteichthyes: Cyprinidae) in Lake Hawassa,Ethiopia

Water and muscle tissue samples from two morphotypes of the African large barb Labeobarbus intermedius collected from three sites in Lake Hawassa in 2012–2013 were analysed for eight heavy metals, including Cd, Co, Cr, Cu, Mn, Ni, Pb and Zn. Five metals (Cr, Cu, Mn, Ni and Zn) were detected in fish muscle samples, whereas only Cr, Cu and Ni were detected in water samples. Of the five metals detected in the muscle samples, Cu and Zn were present in higher concentrations in the golden morphotype, whereas Cr, Mn and Ni were found in higher concentrations in the silver morphotype. Bioaccumulation factor (BAF) values indicated that Cr, Cu and Ni have a tendency to accumulate in fish muscle in amounts exceeding those in water. In both morphotypes the highest concentrations of Zn and Mn were detected at the Hospital site, whereas the concentrations of Cr, Cu and Ni were highest at the Tikur Wuha site. Chromium, Cu and Ni concentrations recorded in fish muscle at all sampling sites exceeded the safe limits recommended by FAO/WHO and UNESCO, suggesting that water and fish from Lake Hawassa are contaminated with heavy metals originating from factories, a hospital and agricultural activities in proximity to the lake.     

Heavy metal concentrations in,and human health risk assessment of,three commercially valuable fish species in the lower Niger River,Nigeria

The concentrations of Fe, Mn, Ni, Pb and V in water, sediment and the gill, liver and muscle tissues of Synodontis resupinatus, Heterotis niloticus and Clarias gariepinus, all commercially important fish species of the lower Niger River, were investigated in 2015. Water, sediment and fish samples were collected for six months and heavy metals were determined using an Atomic Absorption Spectrometer. Fe ranked highest in water and sediment, with concentrations of 2.74 mg l^?1 and 61.60 mg kg^?1, respectively. Metals followed the magnitude of Fe > Mn > Ni > V > Pb in the water and Fe > Mn > V > Ni > Pb in the sediments. Metal concentrations were higher in the tissues of S. resupinatus compared with H. niloticus and C. gariepinus. Fe was also highest in the gills, liver and muscle of the three fish species. Its highest concentration of 132.97 mg kg^?1 dry weight was recorded in the gills of S. resupinatus. Bioconcentration factors of metals ranged from 8.79 for Mn in H. niloticus muscle to 67.99 for Ni in S. resupinatus gills. The fish species studied pose no health risk for all metals studied, because the target hazard quotient was less than 1 and the estimated daily intakes of the metals were below the reference doses.     

Mercury Levels in Barbadian Fisher Folk and Commonly Caught Fish Species

Ocean fish are an important staple food for many Caribbean persons. Some species, however, have high Hg concentration levels and represent a significant source of Hg exposure. This study assessed Hg concentrations in fish species commonly caught and consumed in Barbados as well as Hg exposure of those who work in the fishing industry. Total Hg concentrations were measured in 100 fish samples. Human Hg concentrations were determined from hair snippets taken from 46 fisher folk and fish consumption habits evaluated using interview-administered questionnaires. Mercury levels varied by fish species with predatory fish species having the highest concentrations. Low Hg concentrations were found in dolphinfish (Coryphaena hippurus) and flyingfish (Hirundichthys affinis). Reported fish consumption rates were high and varied significantly between men and women, 2675 ± 1600 and 1275 ± 600 (g/week), respectively (p = 0.01). The median hair Hg concentration was 3.1 ± 2.3 μg/g (range: 0.01–15.6 μg/g) and significantly associated with consumption of “high-risk” fish species (p = .02). These results show that it is possible to make informed choices concerning fish consumption habits in order to maximize benefits while minimizing the effect of Hg exposures, especially for sensitive groups such as pregnant women and infants.     

Concentration of toxic metals and potential risk assessment in edible fishes from Congo River in urbanized area of Kinshasa,DR Congo

Abstract

The objective of this research is to determine the concentration and potential health risks of toxic metals in six most consumed freshwater fish species (Auchenoglanis occidentalis, Bagrus ubangensis, Citharinus gibbosus, Distichondus fasciolatus, Marcusenius moorii, and Schilbe mystus). A total of 126 samples of these fish species were collected from seven sites of Congo River in the vicinity of Kinshasa City, Democratic Republic of the Congo. Toxic metals (Cr, Co, Ni, Zn, Se, Ag, Cd, Sn, Sb, and Pb) levels in fish muscle tissues were determined using Inductively Coupled Plasma Mass Spectrometry whereas Hg analysis was carried out using atomic absorption spectrophotometry. The maximum metal concentration (mg kg^?1 wet weight) of Zn (59.72), Sb (5.98), and Pb (4.96) was detected in muscle tissues of M. moorii, C. gibbosus, and D. fasciolatus, respectively. Pb, Zn, and Hg values in many fish samples exceeded the permissible levels set by Food and Agriculture Organization and World Health Organization for human consumption. Given the concentrations of Pb in all fish species and Zn in M. moorii, human health implications are likely to occur on continuous consumption. Addition, the evaluation of potential health risks for fish consumers indicates that there may or not be adverse effects.     

Arsenic in the water,sediment and fish in the Neretva River Delta,Croatia

The Neretva River Delta in Croatia is under constant threat of pollution from various sources along the river watercourse, such as the aluminium industry and bauxite mining, intensive agriculture and untreated sewage from towns. The area is also an important fishing ground and food source for the local residents, whereby the suitability of fish for human consumption is always in question. In this paper the presence of arsenic from six sources was analysed: in water, sediment and fish organs (kidneys, liver, muscles and gonads) of 11 fish species: Lepomis gibbosus, Carassius auratus gibelio, Cyprinus carpio, Anguilla anguilla, Ameiurus nebulosus, Mugil cephalus, Leuciscus svallize, Oncorhynchus mykiss, Salmo trutta, Tinca tinca and Scardinius plotiza. The research showed that arsenic concentrations varied significantly from one source to another in the water, sediment and organs of different fish species. Average concentrations in water and sediment were 18.1 μg L^?1 and 32.7 μg kg^?1, respectively. Average arsenic levels in the fish organs were 115.9, 105.8, 76.1 and 61.9 μg kg^?1 in muscles, kidneys, gonads and livers, respectively. These values are below legally permitted concentrations, although individuals with higher than average concentrations were recorded.     

Assessment of heavy metal in the water,sediment, and two edible fish species of Jamshedpur Urban Agglomeration,India with special emphasis on human health risk

The city of Jamshedpur, nicknamed the “industrial capital of Jharkhand,” is one of the oldest industrial settlements in India, nestled amidst the mineral-rich Chota Nagpur plateau, with its diverse tribal population. Heavy metal contamination from industrialization and urbanization can pose a serious health risk to the resident population of the city. Metal concentrations in water and sediment of various water bodies (rivers, canals, and lakes) were determined using ICP-MS. Pollution indices indicate heavy metal contamination at Jamshedpur Urban Agglomeration, mainly because of Cr (23–1111.6 mg/kg), Hg (0.08–4.11 mg/kg), and Pb (5.2–248 mg/kg). Labeo rohita and Punitus sarara, the two popular edible fishes, also have high concentration of Cr, Hg, and Pb. Health risk to human population due to consumption of metal contaminated edible fishes (L. rohita and P. sarara) was determined by target hazard quotient (THQ) and hazard index (HI). THQ value of fish consumption (most popular protein supplement in the area) was found higher for Cr and Pb when compared with previous literature on fish consumption. Also, HI value ranged from 1.4 to 3.9, suggesting that the children have higher health risks than adults, due to consumption of metal contaminated fishes (especially L. rohita).     

Mercury Pollution from a Chloralkali Source in a Tropical Lake and Its Biomagnification in Aquatic Biota: Link between Chemical Pollution,Biomarkers, and Human Health Concern

Mercury is a highly toxic heavy metal that can cause adverse ecological and toxicological impacts through the mechanism of biomagnification. Hg accumulation in aquatic biota may thus also pose a serious threat to humans and other fish-eating animals. The present work observed the transfer of Hg from abiotic (water and sediments) to biotic (algae, aquatic macrophytes, and fish) components, belonging to different trophic levels in a tropical lake in India. Hg was analyzed in water, sediments, plants, and fish collected from different sampling points, receiving the discharge of chloralkali effluent. Hg concentrations increased significantly from lake water and sediments to algae and aquatic macrophytes. Statistical analysis (Pearson correlation) revealed a significant positive correlation between Hg in water and plants (r = 0.88–0.93; p < .01 and p < .05) as well as for Hg in sediment and plants (r = 0.50–0.83; p < .01 and p < .05). However, the increase in Hg concentration in fish was not significantly correlated with lake ambient water (r = 0.31–0.36), sediments (r = 0.29–0.33), and aquatic plants (r = 0.31–0.36). Results obtained encourage the use of naturally occurring wetland plants in designed systems like constructed wetlands to ameliorate Hg pollution in lakes, rivers, and ponds resulting from the discharge of industrial effluents, especially chloralkali effluent, hence reducing the human health risks associated with Hg.     

Microcystin concentrations in Nile tilapia (<Emphasis Type="Italic">Oreochromis niloticus</Emphasis>) caught from Murchison Bay,Lake Victoria and Lake Mburo: Uganda

Catches of the economically important Nile tilapia (Oreochromis niloticus L.) from two eutrophic tropical lakes in Uganda, Lake Mburo and Murchison Bay, Lake Victoria, were examined to determine the presence of microcystins (MCs) in gut, liver and muscle of the fish. Analysis for MCs (RR, LR and YR) in both fish and water samples was by liquid chromatography coupled with mass spectroscopy (LC-MS) method. Physico-chemical parameters were also measured to establish the status of both lakes. MC-RR was the most prominent MC detected in Lake Mburo and Murchison Bay samples, there was no evidence of significant seasonal variation in the concentration of MCs in fish tissue. MCs were detected in all water samples from both study lakes. The mean concentration of MCs in water was found higher in dry times for Lake Mburo (P < 0.05) and higher in wet times for Murchison Bay (P < 0.05). MC concentrations in the fish guts were positively related with MC concentrations in water samples from Murchison bay (P < 0.05), no such correlation was found in Lake Mburo. In eutrophic tropical lakes, fish seem to have a high tolerance to the toxicity of cyanotoxins including MCs. However, there is a possibility of accumulating these toxins in their tissue with the threat of transferring them higher up in the food chain. Due to a low sample size and short sampling period, the results can only serve to highlight the potential risk of MC accumulation in Nile tilapia in these lakes. Further studies are needed for the purpose of risk assessment.     

Metals (Hg,Pb, Cu,and Zn) Bioaccumulation in Sediment,Fish, and Human Scalp Hair: A Case Study from the City of Mersin Along the Southern Coast of Turkey

This study investigates mercury, lead, copper, and zinc concentrations in six most frequently consumed fish species (120 samples), sediments (20 samples) taken from Karaduvar Fishing Area where fish species live, and Mersin Port as a contrary region, and human scalp hair for people regularly consuming these fish species (50 samples) and non-fish-eaters (15 samples) in Mersin, Turkey. On taking living environment into account, the fish groups include pelagic species of Liza saliens, Liza aurata, and demersal species of Merluccius merluccius, Mullus barbatus, Upeneus moluccensis, and Solea solea. Total Hg (THg) was found to accumulate in muscle tissues at the lowest concentration (0.01 μg/g) in L. saliens and at the highest (2.66 μg/g) in S. solea. Pb was only detected at high concentrations of 1.86 μg/g in M. barbatus and of 2.16 μg/g in M. merluccius. Cu and Zn concentrations were below the detection limit within all fish species. In the sediment samples, Pb and Cu concentrations were persistently below their effect range–median (ERM) value, whereas this limiting value only maintained for 15% of THg concentrations. On the other hand, the effect range–low (ERL) of sediment exceeded at Pb in 15% of samples and Cu in 25% of samples. Zn remained below the detection limit for sediment samples. The metal concentrations at scalp hairs of regular consumers of these fish groups and non-fish eaters vary from the range 0.40–3.28 to 0.14–1.02 μg/g for THg, 11.16–107.84 to 8.00–22.38 μg/g for Pb, and 151.67–645.35 to 144.92–343.50 μg/g for Zn. An important finding of the present study is the significant adverse impact of sedimentary heavy metal bioaccumulation to human through the consumption of demersal fishes in the city of Mersin along the southern coast of Turkey.     

Differences exist in bird communities using restored and natural wetlands in the Parkland region,Alberta, Canada

Wetland restoration is used to compensate for historic and ongoing wetland losses. We compared bird community composition in 24 restored wetlands and 36 natural wetlands in the Parkland region of Alberta. Natural wetlands ranged in exposure to agricultural activity and were binned into three classes (low, medium, and high disturbance). Although the abundance and average species richness of birds were similar between restored and natural wetlands (analysis of variance: p > 0.22), the avian community composition differed significantly among wetland types (multiresponse permutation procedure [MRPP]: A = 0.05, p < 0.001). The avifauna using restored wetlands was distinct from the avifauna using natural wetlands spanning a range of disturbance levels (A = 0.02–0.06; p ≤ 0.006). Notably, restored wetlands were surrounded by less shrub/forest cover and more open water than low‐disturbance, natural wetlands. The majority (58%) of species using the surveyed wetlands were not classified as wetland‐dependent. Interestingly, if only wetland‐dependent species are considered, the avifauna using restored wetlands is no longer distinctive (MRPP: A < 0.01, p = 0.187), although the abundance of wetland‐dependent birds was marginally higher in restored wetlands (n = 24) than in low‐disturbance, natural wetlands (n = 10; Tukey's honestly significant difference test: p = 0.041). Overall, restored wetlands had reduced beta diversity compared to natural wetlands, regardless of whether the avifauna were restricted to wetland‐dependent species or considered comprehensively. This draws into question the legitimacy of the assumption that restoration can fully offset continued losses of natural wetlands.     

210Po Activity and Concentrations of Selected Trace Elements (As, Cd, Cu, Hg, Pb, Zn) in the Muscle Tissue of Tunas Thunnus albacares and Katsuwonus pelamis from the Eastern Pacific Ocean

Daily mineral intake (DMI) of Cu and Zn, percentage weekly intake (PWI) of As, Cd, Hg, Pb, and doses of ²¹⁰Po were estimated by using their elemental concentration in muscle of two tuna species and the average tuna consumption in Mexico. Skipjack tuna Katsuwonus pelamis had significantly (p?<?0.05) higher levels of As (1.38???g?g^?1 dw) and Cu (1.85???g?g^?1 dw) than yellowfin tuna Thunnus albacares, whereas Pb concentrations (0.18???g?g^?1 dw) were significantly (p?<?0.05) higher in T. albacares. The sequence of elemental concentrations in both species was Zn?>?Cu?>?As?>?Hg?>?Pb?>?Cd. In T. albacares, concentrations of Cd and Pb in muscle tissue were positively correlated (p?<?0.05) with weight of specimens, while Cu was negatively correlated. DMI values were below 10?%. PWI figures (<2?%) are not potentially harmful to human health. ²¹⁰Po concentration in T. albacares and K. pelamis accounts for 13.5 to 89.7?% of the median individual annual dose (7.1???Sv) from consumption of marine fish and shellfish for the world population.