Content of toxic heavy metals (mercury, lead, and cadmium) in canned variegated scallops (Chlamys varia)

A highly sensitive ratiometric fluorescent sensor for copper ions and cadmium ions in scallops based on nitrogen doped graphene quantum dots cooperating with gold nanoclusters

Based on the electrostatic interaction, we constructed a ratiometric fluorescence nanomixture of graphene quantum dots-gold nanoclusters (GQDs-AuNCs) for the quantitative detection of Cu²⁺ and Cd²⁺. When Cu²⁺ or Cd²⁺ was added into the reaction system, the fluorescence of GSH-AuNCs at 565 nm can be quenched by Cu²⁺ and enhanced by Cd²⁺ while the intensity of N-GQDs at 403 nm stayed constant. Under the optimized conditions, the fluorescence intensity ratio (I₅₆₅/I₄₀₃) of the GQDs-AuNCs system was proportional to the concentration of Cu²⁺ and Cd²⁺ in the range of 8×10^-8 mol/L-6×10^-6 mol/L and 1×10^-6 mol/L-4×10^-5 mol/L, respectively, with detection limits of 4.12×10^-9 mol/L and 9.43×10^-7 mol/L, respectively. In the presence of Cu²⁺ and Cd²⁺, the paper-based vision sensor would produce visible fluorescent color changes, which can be used for rapid detection on site. The method has been successfully applied to the determination of Cu²⁺ and Cd²⁺ in scallops with satisfactory results.

Determination of metals in Anemonia sulcata (Pennant, 1777) as a pollution bioindicator

Contamination from metals as a result of anthropic action in coastal marine areas is increasing and it is therefore of great importance to have an appropriate follow-up program in these areas. Samples were taken in the intertidal in 6 sites, of which 5 were in the island of Tenerife and one in the island of Lanzarote (Canary Islands, Spain); in all sites, 15 anemone samples were collected. Twenty metals were analyzed by ICP-OES. The results show the highest concentrations of contamination in the area of Los Silos and Puerto del Carmen for the anthropogenic metals Cr, B, Ni, Cu, Pb, Cd, Fe, Li, and V; Los Silos shows Pb 25.264 ± 27.185 mg/kg and Cd 0.058 ± 0.050 mg/kg, which are high compared with the other sites and indicate that the area may be exposed to a high degree of contamination. Compared with other studies, Los Silos has the same or greater concentrations of anthropogenic metals than areas of greater pollution, such as the Mediterranean Sea or the Indian Ocean. For these reasons, Anemonia sulcata can be used as a bioindicator of anthropogenic contamination and it has become a useful organism for environmental pollution monitoring studies.

Influence of the submarine volcanic eruption off El Hierro (Canary Islands) on the mesopelagic cephalopod's metal content

This work investigates whether a submarine volcanic eruption off El Hierro (Canary Islands) in October 2011 influenced the metal contents of two deep water cephalopod species: Abraliopsis morisii and Pyroteuthis margaritifera. This was assessed by comparing metal contents in specimens collected off the island of El Hierro and in the neighbouring islands of La Palma and Tenerife during an experimental deep water fishing trip. The concentration of 20 heavy metals was analyzed in 180 specimens of A. morisii and P. margaritifera collected around the three islands to test for inter-island differences for each species and metal. While both species showed geographical differences in metal concentrations, the main finding was that A. morisii could be a bioindicator species for metals such as Li, Sr and Ca.

Metals in Diplodus sargus cadenati and Sparisoma cretense-a risk assessment for consumers

The increases in urbanization, demography and industrial activity, along with growing human needs which exploit the resources of the planet, have exponentially exacerbated pollution. In particular, the discharge of heavy metals into the marine ecosystem is a problem of global magnitude, as this may damage the diversity of marine species and ecosystems because of their toxicity, long persistence and bioaccumulation. Consequently, it is necessary to carry out an assessment of the risk of human exposure from the consumption of marine species potentially exposed to this type of pollutants. In the present study, the levels of toxic heavy metals (Cd, Pb and Al) as well as trace and essential metals (B, Ba, Co, Cu, Cr, Fe, Li, Mn, Mo, Ni, Sr, V and Zn) and macronutrients (Ca, K, Mg, Na) have been quantified in two species of fish for human consumption. In order to do this, a total of 80 muscle samples and 80 liver samples, belonging to two species of osteichthyes (bony fish), Diplodus sargus cadenati and Sparisoma cretense, were analyzed. The specimens studied were captured on the north coast of Gran Canaria (Canary Islands) using recreational fishing techniques. As they caught from the shore, the data obtained respond to the need to assess the toxic levels in two representative species of artisanal and recreational fishing in the area. The risk assessment indicated that these two fish species are safe for the average consumer; however, if the livers are frequently consumed, there may be potential risks because they exceed the Admissible Daily Intakes for Pb and Cd.

Determination of toxic metals, trace and essentials, and macronutrients in Sarpa salpa and Chelon labrosus: risk assessment for the consumers

Due to increased environmental pollution, monitoring of contaminants in the environment and marine organisms is a fundamental tool for assessing the existence of risk from their consumption to human health. The levels of toxic heavy metals (Cd, Pb, and Al), trace and essential metals (B, Ba, Co, Cu, Cr, Fe, Li, Mn, Mo, Ni, Sr, V, and Zn), and macronutrients (Ca, K, Mg, Na) in two species of fish for human consumption were quantified in the present study. Eighty samples of muscle tissue and 80 samples of liver tissue belonging to two species of Osteichthyes fish; Sarpa salpa and Chelon labrosus were analyzed. The studied specimens were caught on the northern coast of Gran Canaria (Canary Islands) with fishing rods. As they caught from the shore, they are suitable samples for assessing the toxic levels of representative species caught by local amateur fishermen. The results show that both species are fit for human consumption since they have toxic levels of heavy metals (Cd, Pb, and Al) which are below the maximum established levels; however, the toxic levels of the liver samples are several orders of magnitude higher than the muscle samples, so we discourage their regular consumption. The risk assessment indicated that the two species of fish are safe for the average consumer; however, if the livers of these species are consumed, there could be risks because they exceed the PTWI for Pb and the TWI for Cd.

Molecular identification of isolated fungi, microbial and heavy metal contamination of canned meat products sold in Riyadh, Saudi Arabia

Several studies have shown that canned meat products may be contaminated with fungal elements, bacteria and even heavy metals which may occur during the transportation, storage and handling processes. We conducted this study to determine the fungal, microbial and heavy metal contents of canned meats in Saudi Arabia. Of the 13 canned meat samples studied, Aspergillus and Penicillium were found in more than 70% of the total samples. Sequences of Penicillium species isolated from meat samples generated a phylogenetic tree which shows that the studied isolates were clustered in four groups. No bacterial contamination was noted in all of the samples. Nine of the 13 samples had iron concentrations above the permissible limit. All samples had zinc and copper levels below the maximum permissible limit. Four samples had cadmium levels above the maximum permissible level. All samples had levels of lead above the maximum permissible levels. These results indicate that fungal elements and higher levels of heavy metals such as lead and cadmium can be found in canned meat products. This may pose as a real danger to consumers, since canned meat products are readily accessible and convenient in Saudi Arabia.

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.

Dietary intake of aluminum in a Spanish population (Canary Islands)

The aim of this study was to analyze the aluminum content in foods and beverages most commonly consumed by the Canary Island population to determine the dietary intake of this metal throughout the Canary Islands as a whole and in each of the seven islands (Gran Canaria, Lanzarote, Fuerteventura, Tenerife, La Palma, La Gomera, and El Hierro). Four hundred and forty samples were analyzed by ICP-OES. Estimated total intake of aluminum for the Canary population was 10.171 mg/day, slightly higher than the provisional tolerable weekly intake (PTWI; 10 mg/day for a person weighing 70 kg). Aluminum intake by age and sex of the Canary Island population was also determined and compared values from other populations, both national and international.