Haithem Aib

Over the past 24 years, research on trace metal contamination along the Algerian Mediterranean coast has grown substantially, yet its findings remain fragmented. This review compiles and analyses data from 111 samples reported in 24 independent studies on cadmium (Cd) and lead (Pb) concentrations in the sentinel bivalve Mytilus galloprovincialis. The compiled dataset includes 23 samples from 5 harbour stations and 88 samples from 36 open-coast stations, spanning the three major coastal regions of Algeria. To account for the heterogeneity of the dataset, appropriate non-parametric and multivariate statistical analyses were performed using R version 4.3.2. Results revealed that Western Algeria was the most heavily contaminated region, with significant spatial variability in metal concentrations and a pronounced westward contamination gradient (PERMANOVA, Region R² = 0.27, p < 0.001). These findings identify priority areas for environmental surveillance. Regarding regulatory compliance, Cd concentrations remained below the Codex Alimentarius maximum level for bivalve molluscs at all open sites, whereas Pb exceeded it at 30.3% of stations (10/33), indicating a greater concern with respect to food-safety limits. This synthesis provides the first coherent national assessment of Cd and Pb contamination along the Algerian Mediterranean coast and establishes a scientific foundation for targeted, harmonized biomonitoring strategies.

Wetlands play a critical role in water purification and biodiversity maintenance, yet many are increasingly affected by anthropogenic pollution. This study provides a comparative assessment of physicochemical, microbiological, and heavy metal parameters in six Algerian wetlands spanning coastal, highland, and desert regions over a full annual cycle (November 2021–October 2022). Twenty-five indicators were measured across polluted and non-polluted sites. Polluted wetlands showed significantly higher turbidity (Z = − 3.678, p < 0.001), organic matter (Z = − 2.123, p = 0.04), and heavy metals including Cu (Z = − 4.234, p < 0.001), Fe (Z = − 3.123, p = 0.002), and Pb (Z = − 3.789, p < 0.001). Dissolved oxygen was consistently lower in polluted sites (Z = − 2.345, p = 0.02). Highland wetlands exhibited elevated nutrient loads, with nitrates (Z = − 2.789, p = 0.01) and ammonium (Z = − 3.123, p = 0.002) reflecting agricultural inputs. Microbiological contamination exceeded recommended thresholds at all polluted sites, with fecal coliforms and fecal streptococci surpassing 1000 CFU/100 ml. Seasonal analysis showed higher microbial loads in the wet season and concentration of nutrients in the dry season. Overall, the results demonstrate clear spatial and seasonal variation in water quality, with polluted sites across all regions exceeding national and WHO guideline values for nutrients, heavy metals, and microbiological indicators. These findings underscore the need for strengthened monitoring and pollution-control measures in Algerian wetlands.

The longevity, site fidelity, and trophic position of freshwater turtles have led to their increasing recognition as useful bioindicators of environmental contamination. Mauremys leprosa (n = 25) shells from a Northern African wetland system were examined for trace element concentrations in order to assess shell composition as a non-invasive biomonitoring method. Micro x-ray fluorescence (μXRF) method was used to measure the shell concentrations of 17 elements, including Ca, P, Fe, Zn, Mn, Sr, Pb, Sb, and Al. As would be expected from the structural composition of bony tissues, calcium and phosphorus were the predominant constituents. In addition to bulk concentrations, micro-XRF elemental mapping revealed heterogeneous spatial distributions of essential and toxic elements within the shells, providing visual evidence of bioaccumulation patterns and supporting the use of shells as non-invasive bioindicators. There were statistically significant sex-related differences in the levels of trace elements, with males exhibiting higher concentrations of Mg, Mn, Sb, Pb, and Al (p < 0.05). Spearman correlations revealed strong associations between certain shell elements (e.g., Fe, Mn, Ti, Zn) and morphometric parameters. Comparisons with environmental samples (water and sediment) showed moderate to strong correlations, particularly with sediment metal concentrations, supporting the utility of shell chemistry as an integrative exposure matrix. Nonetheless, there were significant percentages of censored or missing values for certain metals (Cu, Ni, and As). This study emphasizes how viable turtle shells are as non-lethal markers of bioaccumulation and stresses how crucial it is to take environmental matrices, element-specific variability, and sex into account when assessing contamination. Longitudinal monitoring, physiological biomarkers, and isotopic analysis should all be used in future studies to bolster the causal relationships between environmental exposure and turtle health.

Pharmaceuticals and microplastics are persistent emerging contaminants that pose significant risks to aquatic ecosystems and ecological health. Although extensively reviewed individually, a comprehensive, integrated assessment of their environmental pathways, bioaccumulation dynamics, and toxicological impacts remains limited. This review synthesizes current research on the environmental fate and impact of pharmaceuticals and microplastics, emphasizing their combined influence on aquatic organisms and ecosystems. This review provides a thorough and comprehensive examination of their predominant pathways, sources, and distribution, highlighting wastewater disposal, agricultural runoff, and atmospheric deposition. Studies indicate that pharmaceuticals, such as antibiotics and painkillers, are detected in concentrations ranging from ng/L to μg/L in surface waters, while MPs are found in densities up to 106 particles/m³ in some marine and freshwater systems. The toxicological effects of these pollutants on aquatic organisms, particularly fish, are discussed, with emphasis on bioaccumulation and biomagnification in the food chain, physiological effects including effects on growth, reproduction, immune system performance, and behavioral changes. The ecological consequences, including disruptions to trophic dynamics and ecosystem stability, are also addressed. Although valuable efforts, mitigation and remediation strategies remain inadequate, and further research is needed because they do not capture the scale and complexity of these hazards. This review highlights the urgent need to advance treatment technologies, establish comprehensive regulatory frameworks, and organize intensive research on long-term ecological impacts to address the environmental threats posed by pharmaceuticals and microplastics.

Increasing pollution of aquatic ecosystems due to anthropogenic activities underscores the urgent need for effective water quality monitoring. This study evaluates the use of fish scales from chub (Squalius cephalus) and nase (Chondrostoma nasus) as non-invasive bioindicators of trace and macroelement pollution in the Maros/Mureș River. We conducted qualitative and quantitative elemental analyses using X-ray fluorescence (XRF) and inductively coupled plasma optical emission spectrometry (ICP-OES). Scanning electron microscopy (SEM) revealed distinct scale structures among the species studied. Concentrations of Ca, K, Mg, Na, P, S, Al, Ba, Cu, Cr, Fe, Mn, Sr, and Zn were measured by ICP-OES. Our findings indicate significant variability in elemental accumulation in fish scales, supporting their potential use as bioindicators of environmental pollution, with variability depending on the ecological characteristics of the species. This methodology offers promising applications for modern interdisciplinary monitoring programs.

Pharmaceuticals and microplastics are persistent emerging pollutants that pose serious threats to aquatic ecosystems and ecological health. This review provides a thorough and comprehensive examination of their predominant pathways, sources, and distribution, highlighting wastewater disposal, agricultural runoff, and atmospheric deposition. The toxicological effects of these pollutants on aquatic organisms, particularly fish, are discussed, with emphasis on bioaccumulation and biomagnification in the food chain, physiological effects including effects on growth, reproduction, immune system performance and behavioral changes. The ecological consequences, including disruptions to trophic dynamics and ecosystem stability, are also addressed. Although valuable efforts, mitigation and remediation strategies remain inadequate and further research is needed because they do not capture the scale and complexity of these hazards. This review highlights the urgent need to advance treatment technologies, establish comprehensive regulatory frameworks and organize intensive research on long-term ecological impacts to address the environmental threats posed by pharmaceuticals and microplastics.

The discharge of nutrients and organic pollutants is increasing at an alarming rate, driven by the rapid development of human activities. This growing pollution is contributing to significant environmental issues, including eutrophication, making the treatment of wastewater essential before its release into the environment. Prior to being released into water bodies, treated wastewater must undergo rigorous laboratory analysis. For this reason, analysis using standard methods was carried out at the Laboratory Waterworks in Debrecen on multiple samples taken from various wastewater treatment plants in Hungary. The primary objective of this research was to assess the quality of effluents from (14) wastewater treatment plants and investigate their efficiency by measuring various physicochemical and microbiological parameters as indicators. The microbiological indicator monitored was the heterotrophic count (HPC) by estimating its total number. The results revealed that substantial removal efficiencies were demonstrated by parameters including total nitrogen (TN), chemical oxygen demand (COD), and biochemical oxygen demand (BOD₅), with reductions averaging 91%, 92%, and 87%, respectively. However, the reduction in nitrogenous compounds (nitrite NO₂⁻ and nitrate NO₃⁻) was limited, indicating areas for process improvement. Recommendations for enhancing treatment efficiency are proposed to optimize the overall performance of the wastewater treatment plants.

Drought has emerged as a major challenge to global food and water security, and is particularly pronounced for Algeria, which frequently grapples with water shortages. This paper sought to monitor and assess the temporal and spatial distribution of drought severity across northern Algeria (excluding the Sahara) during the growing season from 2011 to 2022, while exploring the relationship between the normalized difference vegetation index (NDVI) anomaly and climate variables (rainfall and temperature). Temporal NDVI data from the Terra moderate resolution imaging spectroradiometer (MODIS) satellite covering the period 2000–2022 and climate data from the European Reanalysis 5th Generation (ERA5) datasets collected during the period 1990–2022 were used. The results showed that a considerable portion of northern Algeria has suffered from droughts of varying degrees of severity during the study period. The years 2022, 2021, 2016, and 2018 were the hardest hit, with 76%, 71%, 66%, and 60% of the area, respectively, experiencing drought conditions. While the relationship between the NDVI anomaly and the climatic factors showed variability across the different years, the steady decrease in vegetation health indicated by the NDVI anomaly corroborates the observed increase in drought intensity during the study period. We conclude that the MODIS-NDVI product offers a cost-efficient approach to monitor drought in data-scarce regions like Algeria, presenting a viable alternative to conventional climate-based drought indices, while serving as an initial step towards formulating drought mitigation plans.