This study reports the biosorption of phenol using dead leaves of Posidonia oceanica (PO), an endemic seagrass in the Mediterranean Sea. The PO dead leaves were pre-treated with sulfuric acid and carbonized at 500°C for 2 h to increase their adsorptive capacity. Leaves were then immobilized in calcium alginate beads to address problems that arise when free particulate biosorbents are used. Response surface methodology (RSM) based on central composite design (CCD) was carried out to optimize key variables, viz., initial phenol concentration (100-500 mg/L), biosorbent dosage (0.05-0.1 g/50 mL), and alginate beads to solution ratio (1/10-2/10). The effect of the operating variables on phenol biosorption capacity was studied in a batch system and a mathematical model showing the influence of each variable and their interactions was obtained. The predicted second-order quadratic model for the response variable was significant (p < 0.01). Further, an adjusted squared correlation coefficient, R² (adj) of 97.7% indicated a satisfactory fit of the model. The results of CCD showed maximum biosorption capacity of about 127 mg/g at 500 mg/L initial phenol concentration, 1 g/L biosorbent dosage, and at 1.85/10 composite beads to solution ratio. This work demonstrates the suitability of using PO dead leaves as an effective low-cost biosorbent for the removal of phenol.

Scorpion stings are a public health problem in the Maghreb region. In Algeria, epidemiological data were collected over the past twenty years by the Algerian health authorities. This study is an analysis of morbidity and mortality data collected from 2001 to 2010. Annual incidence and mortality due to scorpion envenoming were 152 ± 3.6 stings and 0.236 ± 0.041 deaths per 100,000 people (95% CI), respectively. The risk of being stung by a scorpion was dramatically higher in southern areas and central highlands due to environmental conditions. Incidence of envenoming was especially higher in the adult population, and among young males. In contrast, mortality was significantly higher among children under 15 years, particularly ages 1-4. Upper limbs were more often affected than lower limbs. Most stings occurred at night, indoors and during the summer. Data collected since 2001 showed a reduction of mortality by nearly 50%, suggesting that the medical care defined by the national anti-scorpion project is bearing fruit.