Methylmercury in fish from the southern Baltic Sea and coastal lagoons as a function of species, size, and region

2017 ◽  
Vol 33 (6) ◽  
pp. 503-511 ◽  
Author(s):  
Lucyna Polak-Juszczak

Background: Methylmercury (MeHg) is a highly toxic compound that traverses the blood–brain barrier with deleterious effects to the central nervous system. Exposure is generally through the ingestion of contaminated fish. Fish are a main source of MeHg. Goals and methods: The aim of this study was to determine the dependence of MeHg concentrations on fish species and age, the percentage of MeHg in total mercury (THg) and risk assessment depending on the size of fish. Assays of THg and MeHg were performed on the muscle tissues of 18 species of fish. Results: The investigations indicated there were differences in the mercury concentrations depending on fish size. THg and MeHg concentrations in the muscles of fish species that have a wide length distribution were strongly, positively correlated with fish length. However, concentrations of MeHg were strongly, positively correlated with those of THg in all the fish species investigated. Variation in the percentage share of MeHg in THg in the muscles of fish of large sizes was also noted within species, but this correlation was not noted in small-sized fish. The dose of MeHg in small-sized fish species was estimated and the risk posed to consumer health was assessed using mean MeHg concentrations determined for different fish species. Conclusions: For species of fish that occur within a wide length distribution, the dose of MeHg should be assessed separately in different length classes. Fish consumption of small-sized species poses no health risk.

Author(s):  
Kayode James Balogun ◽  
Kazeem Oladeji Kareem ◽  
Emmanuel Kolawole Ajani

This study aims to examine trace metals (Pb, Cd, Cr, Zn, and Cu) concentration in muscle tissues of four fish species from Five Cowries Creek and assess the safety risks posed by consuming these fish species. For this purpose, fish species such as Cynoglossus senegalensis, Mugil cephalus, Chrysichthys nigrodigitatus and Pseudotolithus typus were procured monthly from anglers in Five Cowries Creek, Lagos, from February to May, 2019. The fish muscle tissues were digested according to the international standards, and the trace metals were measured using an atomic absorption spectrophotometer (AAS). Results revealed that the ranking order of trace element concentrations followed this sequence: Pb > Cr > Zn > Cu > Cd. There were significant differences (P < 0.05) in Pb and Cr among the fish species. Consumer health risk was evaluated using non-carcinogenic and carcinogenic risk indices. The results showed that EDI and target hazard quotient (THQ) of Cr, Zn, Cu and Cd suggested that fish species consumption did not pose risk to consumer health. Nevertheless, the estimated daily intake (EDI) along with THQ of Pb indicated potential health risks to consumers (children and adult) of Chrysichthys nigrodigitatus. The target hazard index (THI) of trace elements in all investigated fish species exceeded the guideline value of 1, indicating an adverse health risk for exposed consumers. However, the carcinogenic risk of Pb was negligible for children and adult consumers of fish species. The results are anticipated to create alertness among the public on the safety risks as a result of consuming metal-contaminated fish. Authorised regulatory agencies should control the unregulated uses of Five Cowries Creek, Lagos and associated water bodies through the enforcement of various regulations, policies and laws.


2006 ◽  
Vol 69 (6) ◽  
pp. 1402-1405 ◽  
Author(s):  
MARIA M. STORELLI ◽  
ROBERTO GIACOMINELLI-STUFFLER ◽  
GIUSEPPE O. MARCOTRIGIANO

Total mercury concentrations were determined in different size classes of two pelagic fish species of great commercial importance, horse mackerel (Trachurus trachurus) and Mediterranean horse mackerel (Trachurus mediterraneus), to evaluate the relationship between total mercury concentration and fish size and to determine whether any differences might affect the quantitative assessment of mercury exposure for consumers. Mercury concentrations in horse mackerel and in Mediterranean horse mackerel were between 0.16 and 2.41 μg g−1 of weight wet (mean, 0.68 μg g−1) and between 0.09 and 1.62 μg g−1 (mean, 0.51 μg g−1), respectively. The regression curves revealed a significant relationship between mercury concentration and fish size (length and weight) for both species. Concentrations exceeding the proposed limit for human consumption were observed in 33.3% of the samples of both species and were associated with larger specimens. The consumption of the larger specimens could lead to an increase in mercury exposure for consumers. Estimated weekly intakes, calculated on the basis of concentrations relative to each size class, revealed a high exposure associated with the consumption of fish larger than 30 cm (horse mackerel, 11.63 to 20.16 μg/kg of body weight; Mediterranean horse mackerel, 5.86 to 13.55 μg/kg of body weight). An understanding of the factors leading to an increase in mercury exposure can help consumers make informed decisions about eating fish.


2015 ◽  
pp. 4754-4765 ◽  
Author(s):  
José Marrugo-Negrete ◽  
Amado Navarro-Frómeta ◽  
Javier Ruiz-Guzmán

ABSTRACTObjective. The aim of this study was to monitor the total mercury (T-Hg) concentrations in fish from the Urrá reservoir, after impoundment. Materials and methods. Five fish species at different trophic levels were sampled from 2004 to 2009 and analyzed by cold-vapor atomic absorption spectroscopy for T-Hg concentrations in muscle tissue. Water quality parameters were evaluated. Results. The highest (1.39±0.69 μg/g ww) and lowest (0.15±0.02 μg/g ww) T-Hg concentrations were detected in Hoplias malabaricus (piscivorous) and Cyphocharax magdalenae (iliophagous/detritivorous) respectively, whereas Leporinus muyscorum (omnivorous) had an intermediate level (0.40±0.11 μg/g ww). The organic matter content in the water increased with time and depth, whereas dissolved oxygen and pH decreased. A covariance analysis (with fish length as a covariate) shows a steady increase of T-Hg levels in all the studied species after impoundment. Conclusions. The T-Hg concentrations in the evaluated fish species, increased after impoundment. The water quality variables showed conditions favoring Hg methylation and its biomagnification, this last was evident in the fish food chain of the reservoir.


Author(s):  
Lara Mitchell ◽  
Ken Newman ◽  
Randall Baxter

Long-term fish survey monitoring programs use a variety of fishing gears to catch fish, and the resulting catches are the basis for status and trends reports on the condition of different fish stocks. These catches can also be part of the data used to set stock assessment models, which establish harvest regulations, and to fit population dynamics models, which are used to analyze population viability. However, most fishing gears are size-selective, and fish size — among other possible covariates, such as environmental conditions — affects the probability that a fish will be caught in the path the gear sweeps. Failing to properly account for selectivity can adversely affect the ability to interpret and use status and trends measures, stock-assessment models, and population-dynamics models. Our side-by-side gear comparison study evaluated the selectivity of multiple open-water trawl surveys that have provided decades worth of information on the imperiled fish species Delta Smelt (Hypomesus transpacificus). We used data from the study to estimate gear selectivity curves for multiple trawls using two methods. The first method examines the total number of fish-at-length caught across all gears, and does not directly use or estimate fish length distribution in the population. The second method examines the total number of fish caught by each gear separately, and explicitly estimates fish length distribution in the population. The results from the two methods were similar, and we found that one trawl was highly efficient at catching larger Delta Smelt. This is the first formal multi-gear evaluation of the relative selectivity of how well survey gear used to monitor Delta Smelt in the San Francisco Estuary selects fish by size, and we plan to incorporate the results into Delta Smelt population models.


2007 ◽  
Vol 67 (3) ◽  
pp. 493-498 ◽  
Author(s):  
LD. Lacerda ◽  
JA. Santos ◽  
RC. Campos ◽  
RA. Gonçalves ◽  
R. Salles

To investigate whether source proximity or bioavailability is the major factor controlling both Hg concentration and Hg speciation in marine fishes, total- and organic-Hg content in muscle and liver tissues from different populations of Cephalopholis fulva (piraúna) from inshore and offshore waters of the Brazilian northeastern coast were analyzed. Average total-Hg in muscle (104 ng.g-1 w.w.) and liver (2,865 ng.g-1 w.w.) tissues, as well as organic-Hg concentrations in muscle (169 ng.g-1 w.w.) and liver (1,038 ng.g-1 w.w.), were much higher in the offshore population of C. fulva than in the inshore ones. In the inshore population total-Hg and organic-Hg average concentrations in muscle tissue were similar and reached only 49 ng.g-1 w.w., while in liver they reached 412 ng.g-1 w.w. for total-Hg and 180 ng.g-1 w.w., for organic-Hg. Concentrations of both Hg species in the two populations were higher in liver than in muscle. The average percentage contribution of organic-Hg to the total Hg content was higher in muscle (98-100%) than in liver (42-53%), but similar between the two populations. Total-Hg and organic-Hg concentrations in muscle and liver from the offshore population showed significant (P < 0.05) positive correlation with fish length. However, in the inshore population only the total-Hg and organic-Hg in muscle tissues correlate significantly with fish size. Although the coastal environments are enriched in total Hg relative to open waters, the significant higher Hg concentrations in the offshore population of C. fulva and the significant correlation found between organic-Hg in liver with fish size suggest higher bioavailability of Hg in offshore waters relative to inshore ones.


2015 ◽  
Vol 17 (1) ◽  
pp. 109-120
Author(s):  
Zahra Khoshnood ◽  
Reza Khoshnood

Abstract In 2009, 36 fish were sampled from two stations in the Karoon River near an industrial site. Two species of fish, Barbus grypus and Hypophthalmichthys molitrix were analyzed for total mercury (Hg) concentration in liver and muscle tissues. The average concentrations of total Hg in liver of B. grypus were 18.92 and 10.19 μg.g-1 in stations 1 and 2 respectively. The corresponding values for total Hg in edible muscle of Barbus grypus were 8.47 and 0.08 μg.g-1. The average concentrations of Hg in the liver of H. molitrix were 25.49 and 12.52 μg.g-1 in stations 1 and 2 respectively. The values for H. molitrix were 11.88 and 3.2 μg.g-1 in station 1 and station 2 respectively. The results showed that the bioavailability of Hg has increased considerably after industrialization and that these values were higher than the standard values as a result of anthropogenic activities in the region.


2006 ◽  
Vol 34 (1) ◽  
pp. 52-61 ◽  
Author(s):  
Atahualpa Sosa-López ◽  
David Mouillot ◽  
Julia Ramos-Miranda ◽  
Domingo Flores-Hernandez ◽  
Thang Do Chi

Author(s):  
Vikas Pathak ◽  
Rinchen N. Bhutia ◽  
Shashi Bhushan ◽  
Geetanjali Deshmukhe ◽  
A.K. Jaiswar

Background: The fishes of family Gobiidae are one of the least studied fishes, especially for otolith structure. The otoliths were possess species specific features. Hence, traits of sagittal otolith of gobid species studied. Methods: Five gobid species Odontamblyopus roseus (Valenciennes, 1837), Trypauchen vagina (Bloch and Schneider, 1801), Glossogobius giuris (Hamilton, 1822), Parachaeturichthys polynema (Bleeker, 1853) and Boleophthalmus dussumieri (Valenciennes, 1837) were investigated by three methods including morphological, shape indices and step wise discriminant function analysis (SDFA). Result: Interrelationship between shape indices investigated, at 95% level of confidence (P less than 0.05), revealed that perimeter of P. polynema and area of T. vagina have isometric growth with their length (b = 3.0071, 2.90, respectively) and otolith area of B. dussumieri have positive allometric growth (b = 4.23077). SDFA, based on otolith morphometry, discriminated species up with 97.18% accuracy. Hence, the results of present investigation can be used for discrimination of the species and as a tool in predicting fish size from the otoliths and in calculating the biomass of these less studied fish species.


2018 ◽  
Vol 25 (14) ◽  
pp. 13894-13905
Author(s):  
Martha Elena Ramírez-Islas ◽  
Alejandro De la Rosa-Pérez ◽  
Fabiola Altuzar-Villatoro ◽  
Patricia Ramírez-Romero

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