Trace and macro elements concentrations in the blood and muscle of loggerhead turtles (Caretta caretta) from the Canary Islands, Spain

Sea turtles can bioaccumulate heavy metals and trace elements over the years, therefore they can be used as bioindicators of pollution in the marine environment. The aim of this study was to analyze seventeen elements in blood and muscle of Caretta caretta from the Canary Islands and compare these concentrations in the two tissues. Thirteen blood samples and six muscle samples were collected from loggerhead turtles admitted to the Rescue Center of La Tahonilla. The samples were processed through microwave digestion and incineration. For the study of the data, a descriptive statistical analysis and a PERMANOVA were performed. All individuals in this study were juveniles (size <70 cm). The results of this study differ from previous studies on loggerhead sea turtles. All the elements analyzed were detected, with Na having the highest concentration in blood (75,379 ± 30,066 mg/kg) and muscle (222,626 ± 156,049 mg/kg). Statistically significant differences were found between the concentration of Al, B, Ba, Ca, Fe, K, Na, Sr, V and Zn in each tissue analyzed. Compared to other studies, a higher Cu concentration was found both in blood (252.9 ± 114.4 mg/kg) and in muscle (416 ± 247.8 mg/kg). This study has provided new data on pollutants in loggerhead sea turtles and increased the information available for different geographic areas, although more studies are needed to understand the effects and impact of these pollutants on sea turtles.

Risk Assessment and Characterization in Tuna Species of the Canary Islands According to Their Metal Content

Bioaccumulation is the process by which living organisms accumulate substances, such as pesticides, heavy metals, and other pollutants, from their environment. These substances can accumulate in the organism’s tissues over time, leading to potential health risks. Bioaccumulation can occur in both aquatic and terrestrial ecosystems, and can have a significant impact on the health of both humans and wildlife. The objective of this study is to find out if the concentrations of metals in the tuna species of the Canary Islands are suitable for human consumption and if they pose a health risk. Fifteen samples of Acanthocybium solandri, Katsuwonus pelamis, Thunnus albacares, Thunnus obesus and Thunnus thynnus present in canaries were analyzed. Ten grams of muscle were taken from each specimen and the metals Al, Cd, Cr, Cu, Fe, Li, Ni, Pb and Zn were determined by Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES). The tuna species that presented more metals with a higher concentration compared to the others was T. thynnus, reaching up to 100 times more than the other studied species in Fe content with 137.8 ± 100.9 mg/Kg, which may be due to the fact that it is the largest species that reaches ages of more than fifteen years. The species Thunnus thynnus should not be suitable for commercialization according to the current legislation on the concentrations of Cd in blue fish, since 75% of the specimens studied exceeded the concentration legislated for Cd. A total of 40% of the studied specimens of this this species exceeded the legislated values for the concentration of Pb in oily fish meat, so this species must be monitored to ensure that it does not pose a risk to human health.

The influence of the degassing phase of the Tagoro submarine volcano (Canary Islands) on the metal content of three species of cephalopods

Underwater volcanic eruptions are a type of natural contamination that affect all marine organisms at a local level. These eruptions usually begin and end a degassing stage of the volcano that, although they do not affect the magnitude of magma emanation, affect organisms to a lesser degree locally, such as cephalopods that due to their metabolism and trophic level, are good bioindicators of contamination. A total of 180 samples of three species of cephalopods were collected for the study: sixty Sepia officinalis, sixty Octopus vulgaris and sixty Loligo vulgaris in the area of the submarine volcano in El Hierro, Tenerife and Lanzarote in the Canary Islands (twenty samples per species in each location), and the metal concentrations (Al, Cd, Cr, Cu, Fe, Li, Ni, Pb and Zn) in each of the samples were analyzed. All species showed significant differences for all metals in El Hierro compared to Tenerife and Lanzarote. All the analyzed species from El Hierro had higher concentrations of the nine studied metals, this is due to the fact that they were caught near the Tagoro submarine volcano, which at the time was in a state of degassing and discharged many metal-rich compounds.

Influence of Biometric and Seasonal Parameters on the Metal Content of Scomber colias in Northwestern African Waters

Studies of the content of heavy metals and trace elements in fish and other marine organisms are of great importance to know the state of the marine ecosystem. This study has been carried out in northwestern African waters, Scomber colias being the target species, sampling a total of 345 specimens over 2 years. For the determination of metals and trace elements (Al, B, Cd, Cr, Cu, Fe, Li, Ni, Pb, V, and Zn) in the muscle, the ICP-OES (inductively coupled plasma optical emission spectrometry) was used. In the statistical study, the factors (oceanographic and maturity in the seasons, size of the specimens) were used. The samples sampled in the cold season that had high concentrations of metals may be due to the influence that African upwelling has on the Canary Islands. The metallic contents of our samples are lower than those found in the studies in Mauritania and Morocco due to the greater influence that upwelling has in these areas.

Development stage and season influence in the metal content of small pelagic fish in the North-West Africa

Marine organisms are exposed to great changes caused by man due to discharges into the oceans, so the study of marine pollution is of great value for each ecosystem. For this study, 963 specimens of pelagic fish have been collected, of which 345 are Scomber colias, 294 are Trachurus picturatus and 324 are Sardina pilchardus, it was wanted to study the development and ontogeny in the three species observing if there were variations in their metallic content. The study covered a total of 2 years, from June 2016 to May 2018.16 samples of each species were studied each month, during the 2 years of sampling, from the samplings carried out by the Canary Islands Oceanographic Center of the Spanish Institute Oceanography (COC-IEO) in the markets of the Island of Tenerife. The concentration of 11 anthropic metals was determined in each sample using the Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) technique. Statistical studies were carried out with factors such as the oceanographic season, and the level of maturity of the gonads. S. colias was the species that presented the highest concentration in a greater number of metals. S. pilchardus presents higher concentration in Cu, Li and Zn, in the warm season. These are metals of a very anthropic character on coasts; This species tends to get closer to the coasts compared to the other two and is the cause of its higher concentration in these metals due to the influence of pollution linked to the coast. The immature specimens of the three species had a higher concentration in more metals than the mature specimens.

[Metal content and trace elements in groundwater supply of the island of El Hierro (Canary Islands, Spain).]

OBJECTIVE

Volcanic eruptions are a natural source of substances potentially dangerous to human health. The island of El Hierro (Canary Islands, Spain) suffered a marine volcanic eruption in 2012, making it necessary to monitor the levels of certain elements that can alter the quality of groundwater supply. The objective of this work was to determine the content of metals and trace elements in the groundwater supply of the Isla del Hierro and to check if they met the quality parameters established in Spanish legislation.

METHODS

The content of metals and trace elements (aluminum, lead, cadmium, calcium, potassium, sodium, magnesium, boron, barium, cobalt, chromium, copper, iron, lithium, manganese, molybdenum, nickel, strontium, vanadium, zinc, fluorine) in a total of 60 samples of groundwater supply and agriculture from six different sampling points on the island. The determination was carried out by inductively coupled plasma optical emission spectrophotometry (ICP-OES) and by fluoride ion selective potentiometry. The data were statistically analyzed applying the Kolmogorov-Smirnov test, Levene's statistic, Kruskal-Wallis, Mann-Whitney U, ANOVA and Tukey's test. Significant differences were those that met p<0.05.

RESULTS

The highest mean concentration of lead was recorded in the Tigaday samples (0.003±0.0005 mg/L), finding statistically significant differences (p<0.05) in the lead levels between the sampling points. The elements analyzed were below the parametric values set in Royal Decree 140/2003.

CONCLUSIONS

The results obtained reflect that, in all the samples analyzed, the quality parameters established in the Spanish legislation (RD 140/2003) are met, being, therefore, waters suitable for human consumption.

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.