Assessment of toxic trace elements (Cd, Pb, As, and Co) in small, medium, and large individuals of Mytilus galloprovincialis and Perna perna mussel species along the Algerian coast.

This research paper focused on the monitoring of marine sites using mussels, which are highly valuable organisms in assessing environmental health. However, a significant challenge arises when determining the appropriate size of mussels for monitoring purposes. The objective of this study was to examine the levels of Cd, Pb, As, and Co in three different size classes of two mussel species, Mytilus galloprovincialis and Perna perna, collected from three sites along the Algerian coast, each exhibiting varying degrees of pollution.At each of the study sites, a total of thirty individuals from small, medium, and large size classes of mussels were collected during four different time periods. The mussels were then dissected, and the concentrations of Cd, Pb, As, and Co were measured in the entire flesh of the mussels using ICP-MS.Across the various study sites, the concentrations of cadmium, lead, arsenic, and cobalt ranged from 0.06 to 1.32 mg/kg, 0.09 to 12.56 mg/kg, 4.23 to 18.31 mg/kg, and 0.11 to 1.85 mg/kg, respectively. Interestingly, the distribution of these metals in the three different size classes of mussels followed a consistent pattern at all the study sites. Large mussels exhibited higher concentrations, while small and medium-sized mussels displayed lower levels. These findings highlight substantial spatial and temporal variations in metal concentrations within the studied sites.

Effects of Pollen Deprivation in Groups of Tellian (Apis mellifera intermissa) and Saharan (Apis mellifera sahariensis) Honey Bees under Controlled Conditions.

Worldwide, honey bees are increasingly faced with periods of pollen scarcity, which can lead to nutritional deficiencies, especially of proteins and amino acids. These are essential for the proper functioning of the single organism and the colony. To understand how bees react to protein deficiency, under controlled conditions, we studied the effect of pollen deficiency on the main physiological parameters in two subspecies endemic of Algeria, Apis mellifera intermissa and Apismellifera sahariensis. Emerging workers of both subspecies were reared with two diets: one was pollen-fed, whereas the other pollen-deprived. Several physiological criteria were measured depending on the type of diet and subspecies: the survival of the bees, the amount of total protein in the hemolymph, hypopharyngeal glands development and the ovary development of workers. These last three parameters were assessed at three different ages (7, 14 and 21 days). At birth, sahariensis workers weighed more than intermissa. With the same protein diet, the average life expectancy of sahariensis was extended by 5.55 days compared to intermissa. Even if deprived of pollen, sahariensis lived longer than intermissa fed with pollen (p < 0.001). In the three age levels, the hypopharyngeal glands were more developed and less affected by pollen deficiency (p < 0.001) in sahariensis than in intermissa (p < 0.001). The total hemolymph protein was higher in intermissa than in sahariensis regardless of the diet, and was also higher in protein-fed than in deprived bees (p < 0.001). The ovaries developed more rapidly with a high proportion in intermissa than in sahariensis (p < 0.05) regardless of the diet, and was also higher in the bees fed with pollen than those deprived (p < 0.05). Pollen deficiency generates physiological alterations and modifications, the amplitude of which varied according to the subspecies of the bee studied.

Partitioning of trace elements in the tissues of Mediterranean mussels (Mytilus galloprovincialis) sampled from industrial sites along the Algerian coast.

This research was aimed at evaluating the seasonal partitioning of Zn, Se, As, Cu, and Co in the tissues of Mytilus galloprovincialis sampled at two industrial sites along the Algerian coast. Adult mussels were seasonally collected from two sites over the course of a whole year. The gills, digestive glands, gonads, and remaining soft tissues were analyzed through ICP-MS. The observations led to identifying metals ranges (µg g-1Dry Weight) of 67.17-395.51 (Zn), 2.18-12.74 (Se), 7.81-28.61 (As), 3.32-155.91 (Cu), and 0.10-3.59 (Co) in the various tissues. The highest concentrations were found in the digestive glands and gills as compared to the gonads and remaining soft tissues. Distinct patterns of metals partitioning were found: indeed, As and Co concentrations were higher in the digestive glands, while Se and Zn concentrations were higher in the gills. Many of the mussels samples resulted contaminated, therefore potentially posing a considerable health risk to consumers.

Seasonal distribution of cadmium, lead, nickel, and magnesium in several tissues of mussels from the Algerian coasts.

This study aims to investigate the distribution of heavy metals (Cd, Pb, Ni, and Mn) in different organs of two marine mussel species, Perna perna collected from Figuier site and Mytilus galloprovincialis sampled from Sercouf and Algiers port sites of the Algerian coast. Thirty individuals (>5 cm length) were seasonally sampled over a 1-year period from each site, and condition index (CI) and gonado somatic index (GSI) of mussels were calculated. The gill, digestive gland, rest of soft tissues, and gonad were accurately isolated and heavy metal contents were analyzed by ICP-MS. Heavy metal results, expressed on µg/g dry weight, ranged from 0.1 to 2.6 Cd, 0.1 to 17.15 Pb, 0.36 to 25.7 Ni, and 3.68 to 74.76 Mn. Thus, typical distribution of studied metals in various organs of mussels was found. In fact, the digestive gland followed by gill revealed significantly high metal concentrations. However, gonad showed low heavy metal contents. Different patterns of heavy metal distribution in various organs of mussels were found at the three sampling sites. High levels of Cd, Pb, Ni, and Mn were detected in mussels of Sercouf, Algiers port, and Figuier sites, respectively. According to the Algerian and European norms, mussels collected from all sites were healthy except those of Algiers port sampled in autumn and winter seasons where lead contamination was found.