ABSTRACT
Pot cultivation experiments were conducted to assess the phytoremediation potential of two local agronomic plants, namely Avena sativa and Vicia sativa. Several soils with long-standing contamination and different levels of Polychlorinated biphenyl (PCB) contamination were used for this study. The soil samples came from different regions of Algeria and had different physico-chemical parameters. We studied the influence of these parameters on remediation potential of the two tested plants. The removal rate of the seven PCBs (PCB 28, 52, 101, 138, 153, 156 and 180) was examined after 40 and 90 days. The results showed that the presence of the plants reduced significantly the overall PCB content, ranging initially from 1.33-127.9 mg kg1. After 90 days, the forage plant Vicia sativa allowed us to reach an excess dissipation rate of 56.7% compared to the unplanted control for the most polluted soil. An average dissipation rate of 50% was obtained in the moderately polluted soil. The less contaminated soil had an excess dissipation rate of about 24% for both plants and a predominant dissipation of the low chlorinated PCBs.
Subject(s)
Polychlorinated Biphenyls , Soil Pollutants , Biodegradation, Environmental , Plants , SoilABSTRACT
BACKGROUND: Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental organic contaminants generated by incomplete combustion of organic materials that are widely distributed in soils. OBJECTIVES: This study represents the first attempt to examine the health toxicity of 16 detected PAHs in contaminated soil, via different exposure pathways to populations in northwestern Algeria. METHODS: The toxicity equivalency quotients (TEQ) of PAHs were evaluated. The carcinogenic risk assessment of incremental lifetime cancer risk (ILCR) from ingestion, inhalation, and dermal exposure pathways to each PAH in soil are described. RESULTS: Incremental lifetime cancer risk values were in the upper limit of the tolerable range (10-6-10-4) for adults and children. The total cancer risk of PAH-contaminated soils for children, adolescents and adults was 2.48×10-5, 2.04×10-5 and 3.12×10-5mg.kg-1d-1, respectively. The highest potential cancer risks were identified for adults and children, with adolescents having the lowest risks. Across exposure pathways, the dermal contact and ingestion pathways had the greatest contributions to the carcinogenic risk of human exposure to PAHs. CONCLUSIONS: Further research and guidelines are needed for risk assessments of PAHs in agricultural, residential/urban, and industrial areas, and further risk assessments should include risks posed by exposure through air. COMPETING INTERESTS: The authors declare no competing financial interests.
ABSTRACT
The main objective of this work was to determinate the optimum conditions for the formation of soluble complexes between sodium caseinate and xanthan in solution at neutral pH, in the presence of the NaCl. The study of the influence of the concentrations of these three substances showed that salt was the most influent factor. It worsens the thermodynamic incompatibility of the two biopolymers in solution, when they are present at large amounts. However, it contributes to soluble complexes formation, when sodium caseinate concentration is below 5.5%. In this case, gels with enhanced rheological properties were obtained. Infrared spectroscopy confirmed that the complexes formation within these gels involves hydrophobic interactions. On the other hand, dynamic light scattering revealed that dilution cause their dissociation. These soluble complexes are promising ingredients to ensure new texturing properties.
