Trace elements and metals in farmed sea bass and gilthead bream from Tenerife Island, Spain

Farming Sparus aurata (Teleostei: Sparidae) in marsh ponds: trophic characterization and trace metal accumulation

Considering the overexploitation of fishing on most of the world coasts, the ingestion of fish and shellfish will depend mostly on aquaculture production. Since intensive mariculture usually involves environmental impact, developing sustainable cultures is a priority. In this sense, salt marshes can provide ecosystem services and incorporate both conservation and extensive aquaculture activities. In the present study we compared gilthead seabream Sparus aurata Linnaeus, 1758 cultured in extensive and semi-intensive marsh ponds with wild conspecifics from surrounding coastal areas, using trophic characterization (diet analysis and stable isotopes) and trace metal accumulation. Stomach content analysis revealed different feeding habits among gilthead seabream from different origin. Although wild specimens had the most diverse diet, results of stable isotopes showed that extensive diet had the wider isotopic niche and revealed the highest similarities between wild and extensively cultured gilthead seabream. A similar trace element signature was also measured in wild and extensive culture, whereas the semi-intensive culture showed different concentrations for several elements. Cr, Fe and Mn showed the highest concentrations in semi-intensive cultured fish, while As and Zn showed the lowest values in this group. In any case, average values measured in both extensive and semi-intensive culture were, in general terms, below the hazardous limits provided by the standards recommended for trace metals by national and international regulations. Therefore, marsh ponds provide a suitable environment where the cultured fish, especially extensive, should be promoted.

Evaluation of Iron and Zinc Contents of Some Fish Species

In this study, Fe and Zn contents in the muscle of different fish species (Engraulis encrasicolus, Trachurus trachurus, Mullus barbatus, Mugil cephalus, Pomatomus saltatrix, Dicentrarchus labrax, Scomber scombrus, Sparus aurata) were determined using flame atomic absorption spectrometry (FAAS). The highest Fe and Zn contents among studied fish species were found in Engraulis encrasicolus (7.13 ± 0.19 mg/kg) and Sparus aurata (11.00 ± 0.28 mg/kg). The lowest Fe and Zn contents were determined in Dicentrarchus labrax (3.12 ± 0.09 mg/kg) and Pomatomus saltatrix (5.50 ± 0.05 mg/kg). Moreover, the results were evaluated considering the estimated daily intakes (EDI) of these elements for adults. The estimated daily intakes were varied from 0.0101 to 0.0231 mg/kg bw/day for Fe and 0.0178 to 0.0357 mg/kg bw/day for Zn in fish species. In addition, the hazard quotient (HQ) and the hazard index (HI) values were calculated for risk assessment, and it was determined that these values were below 1 for fish species.

Assessment of Fish Quality Based on the Content of Heavy Metals

The aim of this study was to estimate the fish quality in terms of the Cu, Fe, Mn and Zn contents. The research material was the muscle tissue of the fish crucian carp (Carassius carassius Linnaeus, 1758), flounder (Platichthys flesus Linnaeus, 1758), Gilthead seabream (Sparus aurata Linnaeus, 1758), mackerel (Scomber scombrus Linnaeus, 1758), Blue grenadier (Macruronus novaezelandiae Hector, 1871), rainbow trout (Oncorhynchus mykiss Walbaum, 1792), tench (Tinca tinca Linnaeus, 1758), tilapia (Oreochromis niloticus Linnaeus, 1758), Walleye pollock (Gadus chalcogrammus Pallas, 1814) and perch (Perca fluviatilis Linnaeus, 1758.). Heavy metals were determined with the atomic absorption spectrometry method (AAS). Significantly high concentrations of zinc (19.52 mg/kg wet weight), copper (0.77 mg/kg) and iron (6.95 mg/kg) were found in the muscles of crucian carp (p < 0.05) compared to the other fish studied, whereas Walleye pollock had a higher content of manganese (0.266 mg/kg) (p < 0.05). All studied fish species do not pose a threat to humans from these four metals. This was indicated by quality indexes (THQ and HI) whose values were below one. The values of these metals also did not exceed the maximum allowable concentrations established by the FAO (1983), but monitoring both the aquatic environment and the fish living there is necessary, for example, for the time-changing abiotic and biotic factors that can cause an increase in metals in the organs of fish.

A Limited Survey of Metal Content in Blue Jack Mackerel ( Trachurus picturatus) Obtained from Markets in the Canary Islands

The levels of 20 metals (aluminum, boron, barium, calcium, cadmium, cobalt, chromium, copper, iron, potassium, lithium, magnesium, manganese, molybdenum, sodium, nickel, lead, strontium, vanadium, and zinc) were analyzed in muscle and liver tissue of Trachurus picturatus marketed in the Canary Islands (Spain) by using inductively coupled plasma optical emission spectrometry. In the liver samples, the mean concentrations in milligrams per kilogram wet weight (wt) of Al (14.7), B (0.99), Ba (1.64), Ca (314), Cd (2.52), Co (0.15), Cu (4.07), Fe (106), Li (3.89), Mn (0.85), Mo (0.16), Na (1510), Ni (0.51), Pb (0.36), Sr (3.54), V (0.78), and Zn (23.13) were higher than those detected in the muscle samples in milligrams per killogram wet wt, which were as follows: Al (8.76), B (0.07), Ba (0.30), Ca (210), Cd (0.01), Co (0.01), Cu (1.51 ), Fe (7.33), Li (1.08), Mn (0.12), Mo (0.01), Na (697), Ni (0.11), Pb (0.04), Sr (1.45), V (0.01), and Zn (4.69). The mean concentrations of Cr, K, and Mg (0.14, 1,904, and 243 mg/kg wet wt, respectively) were higher in muscle than in liver (0.05, 1,333 and 236 mg/kg wet wt, respectively). The mean concentrations of Cd and Pb (0.01 and 0.04 mg/kg wet wt) in muscle did not exceed the maximum limits established by a European Commission regulation (0.1 mg of Cd/kg and 0.3 mg of Pb/kg, respectively). Considering a mean daily consumption of fish muscle for the adult population of 31.9 g/day published in the report on food consumption by the Spanish Ministry of Agriculture and Fisheries, Food and Environment, Mg made the highest contributions to the intake (2.58% for adult women of 60 kg and 2.22% for men of 70 kg), and the estimated intakes of Al (0.35 to 0.46 mg/day), Cd (0.55 to 0.74 mg/day) and Pb (1.66 to 5.53 mg/day) were below the respective established tolerable intakes. In conclusion, the results of this study show that the consumption of muscle from this benthopelagic species can be considered safe in terms of maximum legal limits, while consumption of liver is discouraged as a major source of exposure to toxic metals, such as Al, Cd, and Pb.

Influence of waterborne arsenic on nutritive and potentially harmful elements in gilthead seabream (Sparus aurata)

Fish are an important source of nutrients in human nutrition. Although arsenic (As) is considered potentially carcinogenic for human being, very little is known about its toxicity in fish biology. To increase our knowledge of the effect of exposure to waterborne As on fish, gilthead seabream (Sparus aurata) were exposed to 5 μM As₂O₃ and the bioaccumulation of macronutrients (Ca, K, Mg, Na, P), micronutrients (Fe, Mn, Zn) and Potentially Harmful Elements (As, Cd) was determined using spectrometric techniques. All elements were determined in the muscle and liver of non-exposed fish and those exposed to As for 2, 10 or 30 days. The concentrations of K, Na, Mg, Mn and Zn (in muscle) and Fe and Mn (in liver) of control (non-exposed) fish were higher than those determined in exposed fish. Furthermore, neither As nor Cd accumulated in the edible part (muscle) of seabream and were only evident in liver after 30 days of continuous exposure to As, but both concentrations remained below legally established limits.

Metals in Mullus surmuletus and Pseudupeneus prayensis from the Canary Islands (Atlantic Ocean)

A total of 20 metals (Na, K, Ca, Mg, B, Ba, Co, Cr, Cu, Sr, Fe, Li, Mn, Mo, Ni, V, Zn, Al, Cd, and Pb) were analyzed by inductively coupled plasma optical emission spectrometry in muscle and liver tissue from a total of 28 examples of the fishes Mullus surmuletus and Pseudupeneus prayensis marketed in Tenerife, Canary Islands (Spain). Significant differences (P < 0.05) in B, K, Mg, Mn, and Na concentrations were found between muscle and liver. The mean concentrations of K (1,388.04 mg/kg wet weight [wet wt]) and Mg (153.33 mg/kg wet wt) were higher in muscle than in liver (697.49 and 114.21 mg/kg wet wt, respectively). The mean concentrations of B in liver (0.18 mg/kg wet wt), Mn (0.70 mg/kg wet wt), and Na (892.09 mg/kg wet wt) were higher than those in muscle (0.15, 0.11, and 375.55 mg/kg wet wt, respectively). The mean concentrations of Al, Cd, and Pb in muscle tissue were 2.72 mg/kg wet wt and 4.28 and 10.29 μg/kg wet wt, and those in liver tissue were 31.31 mg/kg wet wt and 612.91 and 232.08 μg/kg wet wt, respectively. When comparing the two fish species, the muscle tissue of M. surmuletus has significantly higher concentrations (P < 0.05) of Al, B, Ba, Ca, Co, Cr, Cu, Fe, K, Mg, Mn, Mo, Na, Ni, Sr, and Zn than did P. prayensis muscle, whereas the concentrations of Cd and V were significantly higher (P < 0.05) in P. prayensis muscle. Toxicological assessment of Cd and Pb concentrations was performed using the maximum limits set by the European Commission Regulations 1881/2006 and 629/2008 for muscle tissue (50 and 300 μg/kg wet wt, respectively). The concentrations of Cd and Pb in muscle detected in the present study for all the analyzed examples of M. surmuletus and P. prayensis were lower than the maximums established for muscle tissue by European legislation. Therefore, consumption of the muscle of these fish is considered safe in terms of Al, Cd, and Pb concentrations. However, the consumption of liver tissue should be avoided because of its high levels of metals. Constant monitoring of the concentrations of metals of toxicological concern in fish products available in the market is an essential part of food safety.

Evaluation of content and estimation of daily intake of cadmium and lead in several varieties of potatoes (Solanum tuberosum L.) cultivated in the Canary Islands (Spain)

Monitoring the metal content in foods such as potatoes is an important aspect of food safety and regulation. Samples of nine varieties of potatoes (73 samples of local potatoes and 77 samples of imported potatoes) were randomly obtained from supermarkets, farmers markets, and farmer plots in Tenerife (Canary Islands, Spain). The edible portion (pulp) was the only part considered for analysis because Spaniards traditionally eat only peeled potatoes. Cadmium (Cd) and lead (Pb) were determined using graphite furnace atomic absorption spectrometry. Cd concentrations ranged from 0.006 mg/kg in the Cara and Negra varieties to 0.019 mg/kg in the Bonita variety, and Pb concentrations ranged from 0.007 mg/kg in the Up-to-date variety to 0.023 mg/kg in the Recara variety. The mean concentrations of Cd (0.01 mg/kg) and Pb (0.014 mg/kg) were below the limits established by European regulations for potatoes (0.1 mg/kg of wet weight for each metal). Based on a mean consumption of 143.2 g of potato per person per day for the Canary Islands population, the mean daily intakes of Cd (0.015 mg/day) and Pb (0.023 mg/day) were below the legislated respective tolerable weekly intakes. Thus, the samples analyzed were considered safe to eat with regard to the metal concentrations found.

Accumulation, histopathology and immunotoxicological effects of waterborne cadmium on gilthead seabream (Sparus aurata)

Studies in fish have demonstrated that Cd-exposure produce skeletal deformities and alterations in tissue morphology, enzyme activities, stress response, ion regulation and immune response. In the present work, gilthead seabream (Sparus aurata) specimens were exposed to waterborne Cd (5 μM CdCl2 or 1 mg L(-1)) for 2, 10 or 30 days. Organo-somatic changes, Cd accumulation, liver histology and humoral and cellular immune responses were determined. Results showed that exposure of seabream specimens to Cd induced no alterations on spleen and liver organo-somatic indexes whilst produced progressive deleterious morphological alterations in liver and exocrine pancreas that correlated with the hepatic Cd-accumulation. Regarding the immunotoxicological potential, strikingly, Cd-exposure produced a reduction in the serum complement activity and leucocyte respiratory burst to a significant extent after 10 and 30 days whilst the serum peroxidase activity and leucocyte phagocytosis were increased at different sampling times. On the other hand, serum IgM levels and leucocyte peroxidase activity resulted unaltered. The present results seem to indicate that seabream exposed to Cd in the present conditions suffer toxicity.