Concentrations In Muscle Tissue Research Articles

Human health risks of metalloids and metals in muscle tissue of silver carp Hypophthalmichthys molitrix (Valenciennes, 1844) from Lake Flag Boshielo, South Africa

The Olifants River, a major tributary of the Limpopo River, is one of the most polluted rivers in South Africa. Consequently, concerns regarding the human health impact of long-term consumption of fish from the Olifants River have been raised in recent studies. Nevertheless, Lake Flag Boshielo situated on the main stem of the Olifants River has been proposed as a site for an inland fishery. Planktivorous silver carp Hypophthalmichthys molitrix (Valenciennes, 1844) is among the potential target species for such a fishery. Therefore, a desk-top human health risk assessment was conducted for silver carp from Lake Flag Boshielo. From January to November 2013, muscle samples from 50 specimens were collected and analysed for metals and metalloids. The hazard quotient based on a weekly meal of 150 g exceeded the acceptable level for As, Cd, Cr, Co, Pb, Hg, Se, V and Zn. Compared with previous studies from Lake Flag Boshielo, muscle tissue concentrations of As, Cr, Pb, Hg, Se, V and Zn for H. molitrix were higher. Based on the metal and metalloid concentrations reported in this study, long-term consumption of silver carp from Lake Flag Boshielo might pose a health risk to impoverished rural communities.

Pharmacokinetics and bioavailability of ceftriaxone in brown trout (Salmo trutta fario) after intravenous and intramuscular administration

Ceftriaxone (CTX) is a third-generation cephalosporin that has proven to be effective in the treatment of infections caused by a wide range of gram-positive and gram-negative microorganisms. This study aimed to determine the plasma and muscle pharmacokinetics of CTX after its administration via the intravenous (IV) and intramuscular (IM) routes to brown trout (Salmo trutta fario) at temperatures of 10 °C–13 °C. In total, 140 healthy brown trout (body weight, 245 ± 38 g) were used. The brown trout received single IV and IM injections of CTX at 25 mg/kg. The IV doses were injected into the caudal vein, whereas the IM doses were injected into the right epaxial muscles. The plasma and muscle tissue concentrations of CTX were measured using high-performance liquid chromatography. Pharmacokinetic parameters were calculated using noncompartmental methods. Following the IV administration of CTX, the elimination half-life (t1/2ʎz), volume of distribution at steady state, total body clearance, and area under the concentration–time curve (AUC0–72) in plasma were 5.83 h, 0.09 L/kg, 0.02 L/h/kg, and 1079.46 h*μg/mL, respectively. After the IM administration of CTX, plasma t1/2ʎz, peak plasma concentration (Cmax), time to reach Cmax, and bioavailability were 22.78 h, 87.92 μg/mL, 0.5 h, and 27.19%, respectively. The AUCMuscle/AUCPlasma ratio following the IV administration was 0.02 and that following the IM administration was 0.04. CTX exhibited low bioavailability and prolonged t1/2ʎz after the IM administration. The prolonged t1/2ʎz of CTX could thus be beneficial in brown trout. Nevertheless, future studies that aim to determine the clinical efficacy and pharmacokinetics after repeated administration of CTX are warranted.

Accumulation of Silver in Yellow Perch ( Perca flavescens) and Northern Pike ( Esox lucius) From a Lake Dosed with Nanosilver.

A total of 15 kg of silver nanoparticles (AgNPs) was added continuously over two ice-free field seasons to a boreal lake (i.e., Lake 222) at the IISD Experimental Lakes Area in Canada. We monitored the accumulation of silver (Ag) in the tissues of yellow perch ( Perca flavescens) and northern pike ( Esox lucius) exposed to the AgNPs under environmentally relevant conditions. The greatest accumulation was observed in the liver tissues of pike, and a single pike sampled in the second year of additions had the highest concentration observed in liver of 5.1 micrograms per gram of wet weight. However, the Ag concentrations in gill and muscle tissue of both pike and perch did not exceed 0.35 micrograms per gram of wet weight. Following additions of AgNP, the Ag residues in fish tissues declined, with a half-life of Ag in pike liver of 119 days. Monitoring using passive sampling devices and single-particle inductively coupled plasma mass spectrometry during the AgNP addition phase confirmed that Ag nanoparticles were present in the water column and that estimated mean concentrations of Ag increased over time to a maximum of 11.5 μg/L. These data indicate that both a forage fish and a piscivorous fish accumulated Ag in a natural lake ecosystem dosed with AgNPs, leading to Ag concentrations in some tissues of the piscivorous species that were 3 orders of magnitude greater than the concentrations in the water.

Evaluating the concentration of emamectin benzoate in Atlantic salmon tissues after sea lice treatments

Pharmaceutical treatments are an important part of integrated sea lice control strategies in all major salmon producing countries in the world. Ensuring that in-feed medication is delivered appropriately, and that fish achieve an adequate tissue concentration of the medication is critical to a successful treatment. The muscle tissue concentration of emamectin benzoate was assessed post SLICE® treatment in 867 Atlantic salmon from 147 treatments. Approximately 90% of the muscle samples that included skin had emamectin benzoate levels above 60 ng/g (ppb); however, only 63.8% of muscle samples without skin were at or above this threshold. Further, we found a wide range of tissue concentrations across our samples, with some fish as high as 398 ng/g. The variation in the emamectin benzoate concentration in our samples was associated with the following factors: feeding rate, whether or not the muscle sample contained skin, year of the sample, laboratory analyzing the tissue, prescribed dose, and condition factor, after controlling for temperature, day of the sample post-treatment, and pen effect. Interestingly, the positive relationship between condition factor and the concentration of emamectin benzoate in the tissue sample was dependent on the dose of medication in the feed. In other words, increasing the dose of emamectin benzoate had a greater effect on the concentration of drug in tissues for fish with a high condition factor compared to fish with a low condition factor. Our findings suggest that the feeding rate and fish feeding behavior within a pen may be important factors to consider when applying medicated feed to fish populations to ensure a more even distribution of medication between animals.

Seasonal variation of Cesium-137 concentration in Asian black bear (Ursus thibetanus) and wild boar (Sus scrofa) in Fukushima Prefecture, Japan.

To elucidate and reduce the risk of radionuclide contamination in wildlife caused by the Tokyo Electric Power Company Fukushima Dai-ichi Nuclear Power Station accident, it is important to understand radionuclide variations in the wild animal population. Here, we used environmental monitoring data and muscle samples collected from Asian black bear (Ursus thibetanus) and wild boar (Sus scrofa) from May 2011 to March 2016 to examine seasonal variation in radiocesium (137Cs) concentrations in muscle tissues (hereafter, muscle 137Cs) of these important game species in Fukushima Prefecture. We measured muscle 137Cs of bears and wild boars killed by hunters or in animal control culls. First, using a linear mixed model (LMM), we tested for a positive relationship between muscle 137Cs and 137Cs in the soil at the site of capture (hereafter, soil 137Cs) estimated from a soil 137Cs deposition map produced by the Japan Atomic Energy Agency. In the LMM, muscle 137Cs was positively related to estimated soil 137Cs, which corroborates the results of previous studies. The LMM regression coefficients differed between the two species, with wild boar muscle 137Cs being higher than that of bears sampled at the same locations. We then employed a generalized additive mixed model (GAMM) to estimate seasonal variation in the muscle 137Cs of the target species. GAMM showed that muscle 137Cs varied seasonally and that this seasonal variation also differed between the two species. In bears, muscle 137Cs decreased from spring to early autumn, before increasing in winter. Wild boar muscle 137Cs remained low during spring and summer and was high during autumn and early spring. These patterns are likely influenced by differences in diet, habitat use, and physiology between these two species.

Determination of Heavy Metal Concentrations in Lessepsian Suez Puffer (Lagocephalus suezensis Clark and Gohar, 1953) from North-Eastern Mediterranean

In the present study, the heavy metal concentrations in different organs (skin and muscle tissue)
 were studied in Lessepsian suez puffer (Lagocephalus suezensis Clark and Gohar, 1953)
 collected from Iskenderun Bay, North-eastern Mediterranean. Heavy metals (Cd, Cu, Pb, Co, Cr,
 Fe, Mn, Ni & Zn) were analyzed in different organs for the above mentioned species. The
 maximum heavy metals concentrations in muscle tissues of the species were Cu 1.750 mg/kg, Fe
 18.096 mg/kg, Mn 0.606 mg/kg, Zn 228.571 mg/kg, Cd 2.00 mg/kg, Co 3.571 mg/kg, Cr 0.952
 mg/kg, Ni 1.500 mg/kg and Pb 18.095 mg/kg. Zn was detected higher in all the samples followed
 by Fe, Pb, Co, Cd, Cu, Ni, Cr and Mn. In the present study, heavy metal concentrations were
 found high in muscle tissues when compared to skin. The Pb, Cd and Zn concentration over the
 recommended limits was found in Lagocephalus suezensis. Further, this is the first report on
 distribution of heavy metals and proximate compositions of commercialized important edible
 pufferfishes from Iskenderun Bay, Turkey. 

Facilitating local analysis in northern regions: microwave plasma-atomic emission spectrometry for mercury determination in wild Atlantic salmon

ABSTRACTAn analytical procedure was developed to quantify mercury concentration in wild Atlantic salmon (Salmo salar) muscle tissue by cold-vapour microwave plasma-atomic emission spectrometry (CV-MP-AES) with microwave-assisted acid digestion. Muscle samples were collected from the Atlantic salmon Food, Social, and Ceremonial fisheries in Lake Melville, Labrador (Canada). Muscle samples were digested with nitric acid and hydrogen peroxide, mercury was stabilised with thiourea, reduced with NaBH4, and quantified by CV-MP-AES. Analysis of fish protein certified reference material (CRM, DORM-3) by CV-MP-AES was used to assess the accuracy and precision of the procedure. CRM recovery averaged 88% with a relative standard deviation of less than 8%. The limits of detection were as low as 0.22 µg∙L−1 in solution which translate to 0.02 µg·g−1. Mercury concentrations in salmon muscle tissue quantified by CV-MP-AES were not significantly different from results obtained by cold vapour-atomic fluorescence spectrometry (CV-AFS) from an accredited laboratory. Our results indicated that the CV-MP-AES procedure is appropriate for the quantification of mercury at background levels (range 0.15–0.29 µg∙g−1 dry weight) in wild fish of Labrador.

Assessing concentration of antibiotics in tissue during oral treatments against piscirickettsiosis

The use of antimicrobials in aquaculture is increasingly being scrutinized. In Chile, piscirickettsiosis accounts for approximately 90% of the total volume of antibiotics used in marine aquaculture. Treatment failures are frequently reported, but there is limited information on why this occurs. Fish producers have started assessing the level of antibiotics in fish tissues during and immediately after in-feed treatments to determine if they are adequately medicating their fish. In this study, we evaluated the probability of finding antibiotic concentrations in muscle tissue above the minimum inhibitory concentration for 90% of the P. salmonis isolates (MIC90) recently tested in Chile, for two antibiotics commonly used in aquaculture. We found that the proportion of fish with antibiotic concentrations above the MIC90 varied, depending on the product used, species, day of sample collection, and size category of fish within a cage. The proportion of fish above the MIC90 was lower in fish treated with florfenicol than in fish treated with oxytetracycline. Using a mixed-effects logistic model, we modeled the probability of antibiotic concentrations above MIC90 when fish were treated with florfenicol. Our model suggested lower probabilities of having concentrations above MIC90 in Atlantic salmon than in rainbow trout when samples were collected 14 days after the treatment started compared to 7 days, and in the smaller fish within a cage. We discuss these findings and hypothesize about potential issues with treating large populations of fish with in-feed antimicrobials.

Mercury concentrations in blood, brain and muscle tissues of coastal and pelagic birds from northeastern Canada

Mercury (Hg) is a toxic element which has increased in marine environments for more than a century, due largely to anthropogenic activities, and biomagnifies in food chains to harmful levels in some top predators like waterfowl and seabirds. We analysed total mercury (THg) concentrations in blood, brain and muscle tissue from healthy specimens of 13 coastal and pelagic bird species from eastern and northern Canada to provide a baseline on current concentrations, especially for brain concentrations which are highly underrepresented in the literature. We also examined within and among tissues relationships of THg concentrations within individuals. THg concentrations were generally higher in pelagic species and scavenging gulls, when compared to coastal waterfowl. Brain and muscle tissue had similar concentrations of THg in the birds examined, but both of these tissues had lower concentrations that those found in blood. Our results, and that of a previous study, suggest that body condition has a large influence on blood THg concentrations and should be considered when using blood as a sampling medium. Many of the species we examined had tissue THg above levels known to cause deleterious, sublethal effects in some species.

Assessment of metal concentrations in the SOD1G93A mouse model of amyotrophic lateral sclerosis and its potential role in muscular denervation, with particular focus on muscle tissue

BackgroundAmyotrophic lateral sclerosis (ALS) is among the most common of the motor neuron diseases, and arguably the most devastating. During the course of this fatal neurodegenerative disorder, motor neurons undergo progressive degeneration. The currently best-understood animal models of ALS are based on the over-expression of mutant isoforms of Cu/Zn superoxide dismutase 1 (SOD1); these indicate that there is a perturbation in metal homeostasis with disease progression. Copper metabolism in particular is affected in the central nervous system (CNS) and muscle tissue. MethodsThis present study assessed previously published and newly gathered concentrations of transition metals (Cu, Zn, Fe and Se) in CNS (brain and spinal cord) and non-CNS (liver, intestine, heart and muscle) tissues from transgenic mice over-expressing the G93A mutant SOD1 isoform (SOD1G93A), transgenic mice over-expressing wildtype SOD1 (SOD1WT) and non-transgenic controls. ResultsCu accumulates in non-CNS tissues at pre-symptomatic stages in SOD1G93A tissues. This accumulation represents a potentially pathological feature that cannot solely be explained by the over-expression of mSOD1. As a result of the lack of Cu uptake into the CNS there may be a deficiency of Cu for the over-expressed mutant SOD1 in these tissues. Elevated Cu concentrations in muscle tissue also preceded the onset of symptoms and were found to be pathological and not be the result of SOD1 over-expression. ConclusionsIt is hypothesized that the observed Cu accumulations may represent a pathologic feature of ALS, which may actively contribute to axonal retraction leading to muscular denervation, and possibly significantly contributing to disease pathology. Therefore, it is proposed that the toxic-gain-of-function and dying-back hypotheses to explain the molecular drivers of ALS may not be separate, individual processes; rather our data suggests that they are parallel processes.

Proteomic analysis of the sarcolemma-enriched fraction from dystrophic mdx-4cv skeletal muscle

The highly progressive neuromuscular disorder dystrophinopathy is triggered by primary abnormalities in the Dmd gene, which causes cytoskeletal instability and loss of sarcolemmal integrity. Comparative organellar proteomics was employed to identify sarcolemma-associated proteins with an altered concentration in dystrophic muscle tissue from the mdx-4cv mouse model of dystrophinopathy. A lectin agglutination method was used to prepare a sarcolemma-enriched fraction and resulted in the identification of 190 significantly changed protein species. Proteomics established differential expression patterns for key components of the muscle plasma membrane, cytoskeletal network, extracellular matrix, metabolic pathways, cellular stress response, protein synthesis, immune response and neuromuscular junction. The deficiency in dystrophin and drastic reduction in dystrophin-associated proteins appears to trigger (i) enhanced membrane repair involving myoferlin, dysferlin and annexins, (ii) increased protein synthesis and the compensatory up-regulation of cytoskeletal proteins, (iii) the decrease in the scaffolding protein periaxin and myelin PO involved in myelination of motor neurons, (iv) complex changes in bioenergetic pathways, (v) elevated levels of molecular chaperones to prevent proteotoxic effects, (vi) increased collagen deposition causing reactive myofibrosis, (vii) disturbed ion homeostasis at the sarcolemma and associated membrane systems, and (viii) a robust inflammatory response by the innate immune system in response to chronic muscle damage. SignificanceDuchenne muscular dystrophy is a devastating muscle wasting disease and represents the most frequently inherited neuromuscular disorder in humans. Genetic abnormalities in the Dmd gene cause a loss of sarcolemmal integrity and highly progressive muscle fibre degeneration. Changes in the neuromuscular system are associated with necrosis, fibrosis and inflammation. In order to evaluate secondary changes in the sarcolemma membrane system due to the lack of the membrane cytoskeletal protein dystrophin, comparative organellar proteomics was used to study the mdx-4cv mouse model of dystrophinopathy. Mass spectrometric analyses identified a variety of altered components of the extracellular matrix-sarcolemma-cytoskeleton axis in dystrophic muscles. This included proteins involved in membrane repair, cytoskeletal restoration, calcium homeostasis, cellular signalling, stress response, neuromuscular transmission and reactive myofibrosis, as well as immune cell infiltration. These pathobiochemical alterations agree with the idea of highly complex secondary changes in X-linked muscular dystrophy and support the concept that micro-rupturing of the dystrophin-deficient plasma membrane is at the core of muscle wasting pathology.

Bioaccumulation of heavy metals in maricultured fish, Lates calcarifer (Barramudi), Lutjanus campechanus (red snapper) and Lutjanus griseus (grey snapper)

Mariculture fish contains a rich source of protein, but some species may bioaccumulate high levels of heavy metals, making them unsafe for consumption. This study aims to identify heavy metal concentration in Lates calcarifer (Barramudi), Lutjanus campechanus (Red snapper) and Lutjanus griseus (Grey snapper). Three species of mariculture fish, namely, L. calcarifer, L. campechanus and L. griseus were collected for analyses of heavy metals. The concentration of heavy metal (As, Cd, Cu, Cr, Fe, Pb, Mn, Ni, Se, and Zn) was determined using inductive coupled plasma mass spectrometry (ICP-MS). The distribution of heavy metals mean concentration in muscle is Zn > Fe > As > Se > Cr > Cu > Mn > Pb > Ni > Cd for L. calcarifer, Fe > Zn > Cr > As > Ni > Mn > Se > Cu > Pb > Cd for L. campechanus and Fe > Zn > Cr > Ni > Se > Cu > As > Mn > Pb > Cd for L. griseus. Among all of the species under investigation, the highest concentration of Fe was found in the muscle tissue of L. campechanus (19.985 ± 1.773 mg kg−1) and liver tissue of L. griseus (58.248 ± 8.736 mg kg−1). Meanwhile, L. calcarifer has the lowest concentration of Cd in both muscle (0.007 ± 0.004 mg kg−1) and liver tissue (0.027 ± 0.016 mg kg−1). The heavy metal concentration in muscle tissue is below the permissible limit guidelines stipulated by the Food & Agriculture Organization, 1983 and Malaysia Food Act, 1983. The concentration of heavy metals varies significantly among fish species and tissues. L. campechanus was found to have a higher ability to accumulate heavy metals as compared to the other two species (p < .00). Among all the studied fish, liver tissue has a higher concentration of heavy metals compared to muscle tissue (p < .05). The findings from this study can serve as baseline information for future monitoring and risk assessment studies. Periodic monitoring of heavy metal concentration in mariculture fish must be performed to prevent acute and chronic food intoxication.

Cholinergic alterations by exposure to pesticides used in control vector: Guppies fish (Poecilia reticulta) as biological model

Spinosad and temephos are two of the most used pesticides in Mexico for the control of vector causing disease such as dengue, chikungunya and Zika. The aim of this study was to compare the neurotoxic effects of these two pesticides using guppy fish (Poecilia reticulata) as a model organism. Guppies were exposed for 7 and 21 days to technical grade temephos and spinosad at 1.0 and 0.07 g/L, respectively, (10 and 0.5 mg/L of active substance; concentrations recommended by the Ministery of Health of the State (Secretaría de Salud de Nayarit (SSN) Mexico)). Subsequently, acetylcholinesterase activity (AChE) and acetylcholine concentrations (ACh) in muscle tissue were determined. Temephos exposure decreased AChE activity and increased ACh concentration, whereas exposure to spinosad only increased ACh concentration. Though cholinergic alterations were more severe in fish exposed to temephos, both pesticides were equally lethal during the first seven days after exposure. Nonetheless, temephos was more lethal after 21 days.

Heavy metal contamination in the muscle of Aegean chub (Squalius fellowesii) and potential risk assessment.

Especially after the industrial revolution, the amount of contaminants released in aquatic ecosystems has considerably increased. For this reason, the necessity to carry on research on the existence of contaminants, specifically heavy metals, has emerged. In this study, heavy metal concentrations in muscle tissues of Aegean chub, which was an endemic species of south western part of Turkey, gathered from Tersakan River were examined. Heavy metal concentrations of the samples were analyzed with ICP-MS. Estimated daily intakes (EDI), target hazard quotient (THQ), and carcinogenic risk (CR) of elements were calculated. The heavy metals detected in muscle tissues were Zn > Cu > Cr > Mn > Pb > Cd, consecutively. According to the results of the applied health risk assessment (EDI, THQ and CR) for heavy metal exposure from fish consumption in children and adults, it was determined that there was no any significant threat to human health.

Assessment of zinc and lead concentration in water and muscles of Labeo rohita collected from wild and local fish farms of Pakistan

Reasonable evidences suggest that heavy metal pollutants have been added by factories and other industries to our local water bodies. The present study was conducted to determine the heavy metal (zinc and lead) concentrations in muscle tissues of Labeo rohita inhabiting local water bodies as well as those being raised at farms. Sampling was performed to collect Labeo rohita from two different stations along river Ravi, viz. Lahore Siphon (upstream) and Balloki Headworks (downstream). Additionally, samples were also obtained from the government operated as well as private fish farms located in Lahore District, Pakistan. The fish were dissected; their muscles were digested, filtered, and finally analyzed for concentrations of Zn and Pb. Significant variation of heavy metal ions were observed between two sites along river Ravi as well as government operated and private fish farms. Significantly high mean concentrations of Zn (10.7±1.268) and Pb (0.61±0.082) were observed at Balloki Head-works; whereas, the lowest Zn (1.58±0.235) and Pb (0.16±0.008) heavy metal levels were recorded in the muscle samples collected from private fish farms. It was also observed that the heavy metal concentration in the muscles of Labeo rohita, collected from Balloki Head-works was much higher than the permissible limits laid down by WHO/FAO. Further the recorded highest level of heavy metals in water samples collected from River Ravi indicates that the bioaccumulation of heavy metals is severely affecting the aquatic life of fresh water and industries should not be allowed to release their effluent directly into the river Ravi in their vicinity.

Application of a weight of evidence approach to evaluating risks associated with subsistence caribou consumption near a lead/zinc mine

Overland transport of ore concentrate from the Red Dog lead/zinc mine in northwest Alaska to its seaport has historically raised concerns among local subsistence users regarding the potential impacts of fugitive dust from the operation, including the potential uptake of metals into caribou meat. Caribou are an integral part of life for northern Alaska Natives for both subsistence and cultural reasons. The Western Arctic caribou herd, whose range includes the Red Dog mine, transportation corridor, and port site, sometimes overwinter in the vicinity of mine operations. A weight of evidence approach using multiple lines of evidence was used to evaluate potential risks associated with subsistence consumption of caribou harvested near the road and mine. Data from a long-term caribou monitoring program indicate a lack of consistent trends for either increasing or decreasing metals concentrations in caribou muscle, liver, and kidney tissue. Lead, cadmium, and zinc from all tissues were within the range of reference concentrations reported for caribou elsewhere in Northern Alaska. In addition, a site use study based on data from satellite-collared caribou from the Western Arctic Herd showed that caribou utilize the area near the road, port, and mine approximately 1/20th to 1/90th of the time assumed in a human health risk assessment conducted for the site, implying that risks were significantly overestimated in the risk assessment. The results from multiple lines of evidence consistently indicate that fugitive dust emissions from Red Dog Operations are not a significant source of metals in caribou, and that caribou remain safe for human consumption.

Elimination kinetics of eugenol in grass carp in a simulated transportation setting

BackgroundFish are vulnerable to stress from over-crowding during transportation and eugenol is the most common sedative used to minimize fish injury. The ADI value of 2.5 mg/kg is recommended by the Joint FAO/WHO Expert Committee on Food Additives. The aim of this work was to study the elimination kinetics of eugenol following exposure of grass carp to a eugenol bath in a simulated transportation setting.ResultsGrass carp, Ctenopharyngodon idella (120 fish) were exposed for 24 h to a 10 mg/L eugenol bath. Sampling was performed during a 96 h period after the 24 h bath. Eight fish were sampled at each time point and muscle, plasma and liver concentrations of the drug were determined by ultra-performance liquid chromatography-tandem mass spectrometry. The concentration-time data of eugenol in each tissue were analyzed using non-compartmental methods. The peak concentrations (Cmax) in plasma, muscle and liver were 7.68, 5.30 and 24.63 mg/kg and the elimination half-lives (t1/2β) were 19.79, 10.27 and 55.28 h, respectively. The clearance (CL) values were 0.10, 0.44 and 0.04 L/h/kg and the areas under the concentration-time curve (AUC0-96h) were 91.54, 22.44, and 214.12 mg·h/L in plasma, muscle and liver, respectively. After a eugenol exposure bath, drug concentrations in muscle tissue of grass carp were below 1 mg/kg at 8 h and 0.1 mg/kg at 24 h.ConclusionsThe drug concentrations in muscle tissue at 8 h were lower than the recommended ADI value.

Mercury contamination in bats from the central United States

Mercury (Hg) is a highly toxic metal that has detrimental effects on wildlife. We surveyed Hg concentrations in 10 species of bats collected at wind farms in the central United States and found contamination in all species. Mercury concentration in fur was highly variable both within and between species (range: 1.08-10.52 µg/g). Despite the distance between sites (up to 1200 km), only 2 of the 5 species sampled at multiple locations had fur Hg concentrations that differed between sites. Mercury concentrations observed in the present study all fell within the previously reported ranges for bats collected from the northeastern United States and Canada, although many of the bats we sampled had lower maximum Hg concentrations. Juvenile bats had lower concentrations of Hg in fur compared with adult bats, and we found no significant effect of sex on Hg concentrations in fur. For a subset of 2 species, we also measured Hg concentration in muscle tissue; concentrations were much higher in fur than in muscle, and Hg concentrations in the 2 tissue types were weakly correlated. Abundant wind farms and ongoing postconstruction fatality surveys offer an underutilized opportunity to obtain tissue samples that can be used to assess Hg contamination in bats. Environ Toxicol Chem 2018;37:160-165. © 2018 SETAC.

Total mercury concentrations in liver and muscle of European whitefish (Coregonus lavaretus (L.)) in a subarctic lake - Assessing the factors driving year-round variation

Subarctic lakes are characterised by extreme seasonal variation in light and temperature which influences growth, maturation, condition and resource use of fishes. However, our understanding of how seasonal changes affect mercury concentrations of fishes is limited. We conducted a year-round study (3 ice-covered months, 3 open-water months) with open-water inter-annual aspect (3 years: samples from August/September), focusing on total mercury (THg) concentrations and ecological characteristics of a common freshwater fish, European whitefish (Coregonus lavaretus (L.)) from a subarctic lake. We measured THg concentrations from tissues with fast (liver, n = 164) and moderate (muscle, n = 225) turnover rates, providing information on THg dynamics over different temporal scales. In both tissues, lipid-corrected THg concentrations were highest in winter (liver: 1.70 ± 0.88 μg/g, muscle: 0.24 ± 0.05 μg/g) and lowest in summer (liver: 0.87 ± 0.72 μg/g, muscle: 0.19 ± 0.04 μg/g). THg concentrations increased in winter following the summer-autumn dietary shift to pelagic zooplankton and starvation after spawning. Whitefish THg concentrations decreased towards summer, and were associated with consumption of benthic macroinvertebrates and subsequent growth dilution. Mercury bioaccumulated in both tissues with age, both showing the strongest regression slopes in winter and lowest in summer. THg concentrations in liver and muscle tissue were correlated throughout the year, however the correlation was lowest in summer, indicating high metabolism during somatic growing season in summer and growth dilution. Multiple linear regression models explained 50% and 55% of the THg variation in liver and muscle both models dominated by seasonally-variable factors i.e. sexual maturity, δ13C, and condition factor. Seasonally varying bioaccumulation slopes and the higher level of intra-annual variation (21%) in whitefish THg concentration in muscle than the inter-annual accumulation (8%) highlight the importance of including seasonal factors in future THg studies.

Accumulation and health risk assessment of trace elements in Carassius auratus gibelio from subsidence pools in the Huainan coalfield in China.

Microelement (As, Cd, Cr, Cu, Ni, Pb, and Zn) concentrations were determined in the muscle, skin, gill, and liver tissues of Carassius auratus gibelio collected from subsidence pools at three different coal mines in the Huainan coalfield in China. The concentrations of elements in the water were within the allowable levels for raising fish. However, the higher levels of these metals in sediment may pose potential harm on fish. It was found that the concentrations of Cr, Ni, and Zn in all fish tissues were higher, while As, Cd, and Pb levels were relatively low. Microelement accumulation appeared to be more widespread in subsidence pools than that in natural water. Elements accumulated in fish tissues differently: the highest metal concentrations were generally found in the liver tissues of the fish analyzed, whereas the lowest were recorded in the muscles. The mean element concentrations in muscle tissue from C. auratus gibelio collected from subsidence pools (As, 0.16mg/kg; Cd, 0.06mg/kg; Cr, 6.21mg/kg; Cu, 1.61mg/kg; Ni, 3.88mg/kg; Pb, 1.76mg/kg; and Zn, 12.80mg/kg dry weight) were far below the allowable limit of the hygienic standard in fish proposed by the Ministry of Health in China, suggesting that the fish were safe for human consumption. A health risk assessment also suggested there was no risk from the analyzed elements for inhabitants near the Huainan coalfield that consume fish.