The sediments of Saf-Saf river (North eastern of Algeria), were studied in order to evaluate their degree of contamination by trace metal elements. Six heavy trace metals (Cd, Cr, Cu, Fe, Mn and Ni) were researched at the surface sediments of nine study stations. Since these different metallic elements appear as tracers of anthropogenic pollution; various evaluation indices of metallic contamination were studied (Igeo, FC, DC, IPS and PEC). The results of these indices are consistent and reveal a polymetallic sediment contamination by several heavy metals essentially by Fe, Mn and Cd, with an abundance of Fe and Mn. Sediment pollution index, indicates that sediments at all stations are hazardous (IPS ˃ 20). The environmental quality of Saf-Saf river sediments, were realized by comparing the metal contents with the values of the TEC and the PEC has showed that the metals Cd, Cu and Mn present a great danger of toxicity.

Water and sediment samples have been collected from five different stations, located along Djendjen River between February and June, 2016 so that the concentrations of Cd, Ni, Zn, and Cu could be determined. The extent of the sediment pollution has been assessed, using the multiple pollution indices, namely Contamination Factor (CF), Pollution Load Index (PLI), and the geoaccumulation index (Igeo).The distribution of trace elements in water and sediment follows Ni>Zn>Cd>Cu and Zn>Ni>Cu>Cd, respectively. The water sample analysis from Djendjen River shows that the total concentrations of Cu, Ni, Cd, and Zn have been lower according to the references. In comparison, sediment mean metal concentrations with several environmental contamination parameters, like probable effect level (PEC) and background levels, indicates that the concentrations of all investigated elements are lesser than PEC, except for Ni, but higher than the background levels. The Igeo values reveal that Cd has been the most accumulated compared to the other metals.  Contamination Factor (CF) confirms that the sediment samples have been moderate in terms of all studied metals contamination. The Pollution Load Index (PLI) values have been above one (>1), indicating an advanced decline of the sediment quality.

Water and sediment samples were collected from six different stations, located along the Nil River between February and June 2015. Concentrations of cadmium, lead, zinc, and copper were determined. The extent of the sediment pollution was assessed, using the multiple pollution indices, namely contamination factor (CF), pollution load index (PLI), and the geoaccumulation index (Igeo). The results showed that the level of metals in water samples exceeded background concentrations for Cd and Pb, and the average values for those elements were higher than those of Zn and Cu, ranked as the following: Pb (0.58)> Zn (0.38)> Cd (0.32)> Cu (0.061). For sedimentary samples, the results showed that Zn and Pb concentrations were greater than the concentrations of Cu and Cd, exceeding the background values (except for Cu). The concentration of the tested heavy metals decreased to the following order: Zn (96.2)> Pb (61.5)> Cu (38.83)> Cd (2.34). The Igeo values revealed that Cd (2.87) and Pb (1.61) had accumulated significantly in the Nil River. Contamination factor (CF) confirmed that the sedimentary samples were moderate to very high in terms of Cd, Pb, and Zn contamination. The Pollution Load Index (PLI) values were above one (>1), indicating an advanced decline of the sediment quality. Also, the results showed that the stations, located at the middle portion of the river (S3, S4, and S5) have higher levels of metals than the other stations (S1, S2, and S6). The assessment of heavy metals' levels in water and sedimentary samples indicated that river water and the sediments in the study area were strongly impacted by agricultural activities and domestic waste water.

Concentrations of particulate matter less than 1 μm, 2.5 μm, 10 μm and their contents of heavy metals were investigated in two different stations, urban and roadside at Algiers (Algeria). Sampling was conducted during two years by a high volume samplers (HVS) equipped with a cascade impactor at four levels stage, for one year sampling. The characterization of the heavy metals associated to the particulate matter (PM) was carried out by X-Ray Fluorescence analysis (XRF). The annual average concentration of PM1, PM2.5 and PM10 in both stations were 18.24, 32.23 and 60.01 μg m⁻³ respectively. The PM1, PM2.5 and PM10 concentrations in roadside varied from 13.46 to 25.59 μg m⁻³, 20.82–49.85 μg m⁻³ and 45.90–77.23 μg m⁻³ respectively. However in the urban station, the PM1, PM2.5 and PM10 concentrations varied from 10.45 to 26.24 μg m⁻³, 18.53–47.58 μg m⁻³ and 43.8–91.62 μg m⁻³. The heavy metals associated to the PM were confirmed by Scanning Electron Microscopy-Energy Dispersive X-Ray analyses (SEM-EDX). The different spots of PM2.5 analysis by SEM-EDX shows the presence of nineteen elements with anthropogenic and natural origins, within the heavy metal detected, the lead was found with maximum of 5% (weight percent). In order to determine the source contributions of PM levels at the two sampling sites sampling, principal compound analysis (PCA) was applied to the collected data. Statistical analysis confirmed anthropogenic source with traffic being a significant source and high contribution of natural emissions. At both sites, the PM2.5/PM10 ratio is lower than that usually recorded in developed countries. The study of the back-trajectories of the air masses starting from Sahara shows that desert dust influences the concentration and the composition of the PM measured in Algiers.

The breeding parameters and the egg and nestling morphology of Cyanistes caeruleus populations from rural, intermediate, and urban sites in Algeria and the relationships of those variables with lead contamination were studied during three consecutive years. Breeding success was explained only by predation and vandalism rates. Predation was higher in the rural area, whereas vandalism was higher in the urban site. The other measured breeding parameters and egg characteristics were relatively insensitive to study site. The morphology of urban nestlings exhibited a trend toward smaller body size and mass compared to individuals from intermediate and rural sites. Although lead concentrations were higher in the tissues of urban birds than in intermediate and rural individuals, we did not detect a clear influence of this variable on nestling morphology. We conclude that urbanization influenced blue tit breeding parameters through predation and vandalism and nestling morphology through mechanisms other than lead pollution.

The gulf of Annaba, the most important touristic and economic coastal zone located in Northeast Algeria, is contaminated by several pollutants from urban, agricultural, harbor and industrial activities. Elevated levels of heavy metals were detected in a locally prevalent edible mollusk Donax trunculus (Bivalvia, Donacidae) widely used as a sentinel species for the assessment of marine pollution. The present work aims to measure the difference between two localities, one being full of different pollutants (Sidi Salem) and the other being relatively clean (El Battah) and to evaluate the ability of D. trunculus to overcome the environmental stress during a transplantation experiment by a determination of fatty acid profile, the enzymes activities and the level of metallothioneins (MTs), a biomarker of metallic contamination. Adults of D. trunculus were collected at Sidi Salem (contaminated site) and transplanted into El Battah (reference site) for 21 days in cages (60 × 60 × 60 cm with a 2 mm mesh). Biochemical analyzes were conducted at different times (0, 7, 14 and 21 days). At 0-day experiment: the rate of the fatty acids, the enzymes activities and MT levels at the site of Sidi Salem (polluted site) were significantly different from those of El Battah. During the transplantation a gradual restoration of fatty acids rates, enzymes activities and MT levels was observed. At the end of the period of transplantation, the values are comparable to those of El Battah. A two-way ANOVA (time, site) on data revealed significant effects of time and site. Overally, D. trunculus is able to induce its detoxification system and to restore relatively rapidly the status of individuals from the reference site (El Battah).

As part of a larger program aiming at assessing transfer and effects of metals in food webs, this work studied the spatial distribution of Cd, Cr, Cu, Pb, and Zn in 101 sub-surface soils, systematically sampled (1 × 1 km regular grid) over a large area around Annaba, the fourth most-populated city of Algeria. Cd and Cr exhibited only one abnormally high value, with all other concentrations being close to pedogeological background. Some places in the centre of the city were polluted by Pb (up to 823 mg kg-1), probably due to aerial deposition from gasoline exhausts. Zn never exceeded regulatory limits over the whole sampling area. Cu was the only element for which a spatial autocorrelation occurred. A spatial interpolation by cokriging allowed the identification of agricultural activities as the main Cu pollution source. Our approach revealed various anthropogenic pollution sources, more efficiently for large-scale patterns than for local abnormalities.

This study is the first attempt to provide original data on plastics debris occurrence in beach sediments of the Gulf of Skikda in Algeria (southwestern Mediterranean). Sediment samples from seven beaches were collected to extract, quantify and characterize mesoplastics and microplastics. Particles were classified by size into mesoplastics (5–25 mm) and large microplastics (1–5 mm). Overall, microplastics were the most abundant size fraction in terms of number of items. The average mass of mesoplastics was twice that of microplastics, revealing a notable reservoir of plastics that is scarcely ever reported in the literature. The predominant types were fragments and pellets, white/transparent in color. The average concentrations of total plastic were 1067.19 ± 625.62 items/m², 106.98 ± 62.39 items/kg, and 50.65 ± 9.82 g/m², showing variability between beaches and within sampling sites. Thus, the Skikda coast has high levels of pollution compared to other areas of the Mediterranean Sea.

The accumulation of plastic debris in the Algerian coasts is due to inadequate solid waste management and the inhabitants' behavior. To quantify and characterize the plastic pollution, we collected plastic items (≥1 mm) in the sediment of nine beaches covering 124 km of the Algerian western coast. The plastic concentration varied between 7.6 ± 18.8 and 66 ± 107.28 items/m². With 83.27%, fragments were the predominant items as micro- and macro-plastics, whereas pellets were mainly present as microplastics (14.93%); films represented 1.03%. We recorded the highest values for the number of plastic items/m² in beaches located close to coastal villages. Regarding the number and the weight of the plastic debris, we registered significant differences between the locations. Although the plastic pollution is currently moderate in the study area, local authorities are compelled to be aware of its increase. Therefore, the improvement of the solid waste management is urgently needed.

Based on our discussions with fishermen and analysis of catches from professional fishing, this work confirms the presence of the American blue crab Callinectes sapidus in the southwest Mediterranean and highlights its invasion of Mellah lagoon in Algeria. The number and frequency of occurrence of this species in fishing gear (up to 10 individuals per fyke net), the presence of juveniles and ovigerous females as well as its presence in the local market, show that it is well established. The possible impact of C. sapidus on the local environment and native species, and the prospects for its fishing exploitation are discussed in the light of the current knowledge.