Potentially toxic elements in commonly consumed fish species from the western Mediterranean Sea (Almería Bay): Bioaccumulation in liver and muscle tissues in relation to biometric parameters.

Marine pollution is one of today's most relevant problems. Public awareness has been raised about the harmful potential of heavy metals (HMs) accumulating in edible fish and possibly ending up in human diet through the food chain. This study aimed to characterize and evaluate As, Cd, Cr, Cu, Ni and Pb contents in four edible fish species from the western Mediterranean Sea. Liver and muscle toxic elements were determined by GF-AAS in Mullus surmuletus, Merluccius merluccius, Auxis rochei and Scomber japonicus from Almería Bay (Spain). Muscular composition, biometrics and trophic levels were also determined. The mean PTE concentration levels (mg kg-1, DW) in fish muscle tissue were: As (2.90-53.74), Cd (0.01-0.18), Cr (0.53-2.01), Cu (0.78-6.93), Ni (0.06-0.24), Pb (0.0-0.32). These concentrations did not exceed the maximum limits set by European legislation (Commission Regulation (EC) No. 1881/2006) for the intake of these marine species. Accumulation of toxic elements tends to be seen in the liver (As (7.31-26.77), Cd (0.11-8.59), Cr (0.21-2.94), Cu (2.64-16.90), Ni (0.16-1.03), Pb (0.0-0.99)). As was the element at highest risk in this Mediterranean region, especially due to red mullet values in muscle. The high As contents with living habits as benthic species that feed near the coast. HMs, especially muscle Cd contents, were associated with higher contents of lipids and organic matter, and bigger specimen size (length and weight), while As was linked to higher fish protein content. However, these relationships between potentially toxic elements (PTE) and biometric indices and body composition parameters depend on species. Finally, the THQ indices indicated that eating fish from Almería Bay poses no human health risk despite pollution from the Almería coastline.

Mercury contents in relation to biometrics and proximal composition and nutritional levels of fish eaten from the Western Mediterranean Sea (Almería bay).

Total liver and muscle mercury, and muscular composition, biometrics and trophic levels, were determined in four species (Mullus surmuletus, Merluccius merluccius, Auxis rochei and Scomber japonicus) of the Mediterranean Sea (Almería Bay, Spain). Mercury levels did not exceed the maximum residue limit, and M. merluccius obtained the highest level in muscle. Considerable variations in Hg content among individuals were observed in non-gregarious species. A positive correlation between Hg and trophic level or length was found in muscle, but not in liver. Organs (liver or muscle) with major Hg accumulation depend on species; muscle in M. merluccius and liver in S. japonicus. The results indicate that Hg levels in fish depend on intra- and interspecies factors that should be taken into account in systems to monitor Hg levels.

Impact of 70 years urban growth associated with heavy metal pollution.

Historical trends in trace element deposition were analyzed using herbaria specimens. We determined Al, Fe, Mg, Mn, Ca, Na, P, K, S, As, Cd, Cr, Cu, Ni, Pb and Zn contents in leaves of eight specimens collected in 1941. To assess changes, we collected the same plants from a botanical garden in 2012. The concentrations of major elements showed large species variability. However, temporal trends were predominately detected for heavy metals. The Cd, Ni and Cr contents in the 2012 leaves were 10, 13 and 16 times higher, respectively, than in 1941. Urban activities have substantially raised the levels of these metals in urban atmospheres due to changes in human activities over 70 years of urban growth. Nevertheless, Pb has decreased (126%) in recent decades thanks to controlled lead fuel combustion. In short, metal deposition trend to increase Cr, Ni and Cd levels.

Biomass nutrient profiles of the microalga Nannochloropsis.

The nutritional composition of the marine eustigmatophyte Nannochloropsis spp. cultured in an indoor chemostat under continuous illumination was analyzed. Proximate composition, (moisture, ash, crude protein, available carbohydrates, fiber, lipids, and energy), nitrate, nucleic acid, mineral element (Na, K, Ca, Mg, Fe, Cu, Zn, Mn, Pb, Cd, Cr, Ni, Co, and S), fatty acid, and pigment (carotenoids and chlorophyll) concentrations were determined. On average, the biomass contained 37.6% (w/w) available carbohydrates, 28.8% crude protein, and 18.4% total lipids. Mineral in 100 g of dry biomass were as follows: Ca (972 mg), K (533 mg), Na (659 mg), Mg (316 mg), Zn (103 mg), Fe (136 mg), Mn (3.4 mg), Cu (35.0 mg), Ni (0.22 mg), and Co (<0.1 mg). Toxic heavy metal contents (Cd and Pb) were negligible. Fatty acid content was as follows (on percent dry weight): 0.6% of 14:0, 5.0% of 16:0; 4.7% of 16:1omega7, 3.8% of 18:1omega9, 0.4% of 18:2omega6; 0.7% of 20:4omega6, and 2.2% of 20:5omega3. Nutrient composition of the biomass was highly influenced by residence time in the photobioreactor. The biomass harvested for short residence times was richer in protein and eicosapentaenoic acid than biomass harvested for high residence time.