Rami Zurayk

COMMON HYDROPHYTES AS BIOINDICATORS OF NICKEL, CHROMIUM AND CADMIUM POLLUTION

Twelve Mediterranean hydrophyte species collected inLebanon were evaluated for their potential asbioindicator species for heavy metal pollution innutrient cultures enriched with 1 ppm Cr, Ni and Cd.These were: Nasturtium officinale R.Br, Apium nodiflorum L., Veronica beccabunga L., Veronica anagallis aquatica L., Veronicalysimachioides L., Veronica anagalloides L., Mentha longifolia L., Mentha aquatica L., Mentha pulegium L., Potentilla reptansL., Mentha sylvestris L., and Cardamine uliginosa L.. Large variability in responseto exposure to the heavy metals was observed. Growthrates remained high during the experimental period,indicating that the plants were little affected by thepresence of the metal at the experimentalconcentration. Metal accumulation and bioconcentrationvaried within at least one order of magnitude, andranged from less than 10 to over 200. Cr waspreferentially accumulated in the roots. All speciesbut M. pulegium, P. reptans and V. anagallisaquatica accumulated and bioconcentrated sufficientCr to qualify as bioindicator species. Five of thespecies that accumulated Cr also accumulated Ni, withthe same partitioning into the root. These were: N. officinale, C. uliginosa sp., M. longifolia, M. aquatica and M. sylvestris, all of which mayalso be used as bioindicators of Ni pollution. Onlyone species, M. aquatica, accumulated Cdsignificantly, and may, therefore, be used as abioindicator for all three metals.

Using indigenous knowledge in land use investigations: a participatory study in a semi-arid mountainous region of Lebanon

The implementation of land use studies in most developing nations is often faced with the lack of data. Participatory studies offer the possibility of complementing data sets by tapping into indigenous knowledge. They also encourage the adoption of sustainable land management practices by establishing partnership and dialogue among stakeholders. This paper reports on a study in Aarsal, a semi-arid mountainous locality (36,000 ha) in Lebanon where conflicts in land use have recently emerged between pastoralists and growers. The study aimed at supporting sustainable land management in Aarsal by carrying out a land capability classification and a land use analysis. Indigenous knowledge was used as one of the information sources for the land capability classification. Participatory rural appraisal was used to describe the indigenous agroecological zoning and local soil classification. Geographic information system (GIS) technology was used to produce a land capability map and to analyze the current land use. Most of the land area was found to be too marginal for conventional farming, and nearly 5000 ha are in serious danger of land degradation. Moreover, the shrinkage of the grazing lands caused by the expansion of orchards partly explains the reduction in the size of small ruminant flocks. The combination of participatory approach, land capability evaluation and GIS provided a satisfactory understanding of the physical and biological land management constraints in Aarsal, fostered dialogue between the different stakeholders, and created opportunities for the identification of sustainable land management options.

Salinity-heavy metal interactions in four salt-tolerant plant species

The concurrent effect of NaCl salinity and heavy metals [cadmium (Cd), chromium (Cr) and nickel (Ni)] on growth, sodium (Na), and heavy metal accumulation was assessed in four salt tolerant plant species. These were: barley (Hordeum vulgare L.), purslane (Portulaca oleracea L.), Inula crithmoides L., and Plantago coronopus L., all of which have documented potential for use in saline agriculture. Plants were grown in perlite and irrigated with salinized and non-salinized nutrient solutions (9 dS m−1 and 18 dS m−1) containing 2 ppm Cd, 4 ppm Cr, 10 ppm Ni, and a non-metal control. Salinity, Cd, and Ni caused a significant decrease in the dry biomass accumulation of P. oleracea, but had no effects on other plant species. Sodium accumulation was highest in P. coronopus and I. crithmoides, indicating pronounced halophytic properties. The presence of heavy metals reduced Na accumulation in H. vulgare and P. oleracea, but had no effect on P. coronopus and I. crithmoides, indicating that the Na-heavy metal interaction is plant-specific. Metal accumulation in the four plant species was generally enhanced by the 9 dS m−1 treatment, but not by the 18 dS m−1 treatment. This could indicate the presence of an ionic exclusion mechanism operating at high salinity levels that would operate indiscriminately on Na as well as on Cd, Cr, and Ni

Ni Phytoaccumulation in Mentha aquatica L. and Mentha sylvestris L.

Ni phytoaccumulation in Mentha aquatica L. and Menthasylvestris L., two hydrophytes that had shown high Ni accumulation potential in previous screenings, was evaluated forpossible inclusion in aquatic phytoremediation systems. The plants were grown for 14 days in full-strength (FS) and half-strength (HS) Hoaglands solutions spiked with 1, 2, 4, and8 mg L-1 Ni. Roots and shoots were harvested and analysed for Ni. Ni accumulation and bioconcentration factor (BCF) generally increased with increasing external Ni levels, except for shoot Ni in HS solution at 8 mg L-1, which was lower than at 4 mg L-1. We suggest that a mechanism may exist tocontrol Ni entry to the shoot at high external Ni levels in orderto reduce injury. Ni phytoaccumulation and BCF were consistentlylarger in the HS solution, probably resulting from interaction between Ni and other nutrients, and indicating that manipulationof the nutrient concentration is a possible avenue for improvingthe efficiency of aquatic phytoremediation. Due to their large growth rates and biomass, both species accumulated Ni in the roots to levels equal or superior to those of known phytoremediator plants (8327 for M. aquatica and 6762 mg kg-1 for M. sylvestris), indicating their adequacy foruse in phytoremediation systems.

Phosphorus retention in the soil matrix of constructed wetlands

Abstract Constructed wetlands may be described as soil/plant systems for wastewater treatment in which pollutant removal is based on general principles of nutrient transformation in soils. Currently perceived as “black boxes”; by engineers, the design and operation of these systems may be greatly improved based on the knowledge gained from several decades of studying nutrient cycling in soil‐plant systems. This paper reports on an attempt to operate this linkage. Three pilot scale systems planted with reed, cattail, and water hyacinth were used to study the role of the soil matrix in phosphorus (P) removal over a period of five months. Phosphorus removal was superior in the soil‐based systems with a mean P reduction from the influent concentration (24 mg‐mL‐1) of 80% compared with 54% in the soilless bed. Recycling the effluent into the system in order to increase the detention time did not contribute to improving removal, except in the soilless bed. This indicates that P removal in the soil‐based systems...

Chromium Phytoaccumulation from Solution by Selected Hydrophytes

ABSTRACT There is increasing interest in the role of wetland plants in the aquatic phytoremediation of toxic metals. In this experiment, we evaluate the Cr removal capacity of four hydrophyte species (Nasturtium officinale L., Veronica beccabunga L., Mentha longifolia L., R.Br., Cardamine uliginosa L.) under varying nutritional conditions (full-strength and half-strength solution cultures), and over a range of Cr concentration (0, 2, 4, 6, and 8 mg L-1). The results indicate that Cr accumulation is affected by both initial Cr concentration and strength of the nutrient solution. Phytoaccumulation increased with initial Cr concentration and plants grown in the full-strength solution accumulated more Cr at the higher initial solution concentration. Cr was predominantly accumulated in the roots, with minimal shoot translocation, which limits the hazard of Cr entering the food chain through ingestion by animals. Accumulation was large and reached up to 6700 mg Cr Kg-1 in the roots of Veronica beccabunga.

Baseline data of polycyclic aromatic hydrocarbons correlation to size of marine organisms harvested from a war-induced oil spill zone of the Eastern Mediterranean Sea

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Preliminary studies on the salt tolerance and sodium relations of common ornamental plants

Abstract The salinity tolerance of local varieties of five ornamental species Begonia, Chlorophytum, Coleus, Geranium, and Mesembryanthemum was assessed in a medium term pot experiment. The pot grown plants were watered for 50 days with water salinised at 5 dS/m and 15 dS/m and a tap water control. Based on growth parameters and on survival, Begonia was classified as salt sensitive, Coleus, Geranium, and Chlorophtytum as moderately tolerant, and Mesembry‐ anthemum as salt tolerant. Shoot sodium (Na) content was measured at the end of the experiment. It appears that the restriction of Na entry to the shoot is linked to salinity tolerance. Mesembryanthemum seems to be able to control Na entry to the shoot at water salinities above 5 ds/m.

Impact of the Syrian conflict on irrigated agriculture in the Orontes Basin

The impact of conflict on irrigated agriculture and consequently summer crop production within conflict-affected agricultural lands was observed in the Orontes Basin. Water and energy use were reconfigured through a transition from rainfed to irrigated agricultural production over the past 20 years, but have been disrupted as the Syrian war has unfolded since 2011. Remotely sensed vegetation indices were used to determine irrigated summer crop yields during the year 2013. Findings suggest that irrigated agricultural production dropped between 15% and 30% in the Syrian portion of the basin in 2000–2013, with hotspots identifiable in Idleb, Homs, Hama, Daraa and Aleppo. The developed approach demonstrated effectiveness in quantifying and geolocating hotspots where conflicts have the strongest impact on agricultural water use, agricultural production, and eventually support relief and regional agricultural reconstruction in this and other conflict regions.

Effect of nitrogen source and salinity level on salt accumulation of two chickpea genotypes

Abstract This study aimed at investigating mechanisms of salt tolerance and ionic relations of chickpea (Cicer arietinum L.) cultivars with different nitrogen (N) sources. Two resistant genotypes, ILC‐205 and ILC‐1919, were subjected to four levels of salinity (0.5, 3.0, 6.0, and 9.0 dS m‐1). Nitrogen sources consisted of inoculation with two resistant Rhizobium strains, CP‐29 and CP‐32, mineral N additions, and no N application. Data was collected on root and shoot contents of sodium (Na+) chlorine, (Cl‐,) and potassium (K+), and shoot to root Na+ratio, as well as shoot K+ to Na+ ratio. Salinity affected shoot Na+ and Cl‐contents, but nodulating plants had higher shoot Na+ contents than plants supplied with mineral N. Shoot to root Na+ ratios were lower in the mineral N treatment than in nodulating treatments at 3.0 dS m‐1, indicating that root compartmentalization and shoot exclusion were only possible at low salinities. Potassium levels of nodulating plant shoots were lower than those of non‐nodulating plants only at low salinities. N‐source significantly affected shoot K+/Na+ ratio, with nodulating plants having lower ratios than non‐nodulating plants, indicating that rhizobial infection or nodule formation may lead to salt entry curtailing the selective ability of chickpea roots.