Ebrahem M. Eid

Bioaccumulation and translocation of heavy metals by nine native plant species grown at a sewage sludge dump site

ABSTRACT In the present study, nine native plant species were collected to determine their potential to clean up nine heavy metals from soil of a sewage sludge dump site. Almost all nine plant species grown at sewage sludge dump site showed multifold higher concentrations of heavy metals as compared to plants grown at the reference site. All the investigated species were characterized by a bioaccumulation factor (BF) > 1.0 for some heavy metals. BF was generally higher for Cd, followed by Pb, Co, Cr, Cu, Ni, Mn, Zn, and Fe. The translocation factor (TF) varied among plant species, and among heavy metals. For most studied heavy metals, TFs were <1.0. The present study proved that the concentrations of all heavy metals (except Cd, Co, and Pb) in most studied species were positively correlated with those in soil. Such correlations indicate that these species reflect the cumulative effects of environmental pollution from soil, and thereby suggesting their potential use in the biomonitoring of most heavy metals examined. In conclusion, all tissues of nine plant species could act as bioindicators, biomonitors, and remediates of most examined heavy metals. Moreover, Bassia indica, Solanum nigrum, and Pluchea dioscoridis are considered hyperaccumulators of Fe; Amaranthus viridis and Bassia indica are considered hyperaccumulators of Pb; and Portulaca oleracea is considered hyperaccumulator of Mn.

Effects of different sewage sludge applications on heavy metal accumulation, growth and yield of spinach (Spinacia oleracea L.).

ABSTRACT In this study, we present the response of spinach to different amendment rates of sewage sludge (0, 10, 20, 30, 40 and 50 g kg−1) in a greenhouse pot experiment, where plant growth, biomass and heavy metal uptake were measured. The results showed that sewage sludge application increased soil electric conductivity (EC), organic matter, chromium and zinc concentrations and decreased soil pH. All heavy metal concentrations of the sewage sludge were below the permissible limits for land application of sewage sludge recommended by the Council of the European Communities. Biomass and all growth parameters (except the shoot/root ratio) of spinach showed a positive response to sewage sludge applications up to 40 g kg−1 compared to the control soil. Increasing the sewage sludge amendment rate caused an increase in all heavy metal concentrations (except lead) in spinach root and shoot. However, all heavy metal concentrations (except chromium and iron) were in the normal range and did not reach the phytotoxic levels. The spinach was characterized by a bioaccumulation factor <1.0 for all heavy metals. The translocation factor (TF) varied among the heavy metals as well as among the sewage sludge amendment rates. Spinach translocation mechanisms clearly restricted heavy metal transport to the edible parts (shoot) because the TFs for all heavy metals (except zinc) were <1.0. In conclusion, sewage sludge used in the present study can be considered for use as a fertilizer in spinach production systems in Saudi Arabia, and the results can serve as a management method for sewage sludge.

The effects of different sewage sludge amendment rates on the heavy metal bioaccumulation, growth and biomass of cucumbers ( Cucumis sativus L.)

AbstractWhen sewage sludge is incorrectly applied, it may adversely impact agro-system productivity. Thus, this study addresses the reaction of Cucumis sativus L. (cucumber) to different amendment rates (0, 10, 20, 30, 40 and 50xa0gxa0kg−1) of sewage sludge in a greenhouse pot experiment, in which the plant growth, heavy metal uptake and biomass were evaluated. A randomized complete block design with six treatments and six replications was used as the experimental design. The soil electrical conductivity, organic matter and Cr, Fe, Zn and Ni concentrations increased, but the soil pH decreased in response to the sewage sludge applications. As approved by the Council of European Communities, all of the heavy metal concentrations in the sewage sludge were less than the permitted limit for applying sewage sludge to land. Generally, applications of sewage sludge of up to 40xa0gxa0kg−1 resulted in a considerable increase in all of the morphometric parameters and biomass of cucumbers in contrast to plants grown on the control soil. Nevertheless, the cucumber shoot height; root length; number of leaves, internodes and fruits; leaf area; absolute growth rate and biomass decreased in response to 50xa0gxa0kg−1 of sewage sludge. All of the heavy metal concentrations (except the Cu, Zn and Ni in the roots, Mn in the fruits and Pb in the stems) in different cucumber tissues increased with increasing sewage sludge application rates. However, all of the heavy metal concentrations (except the Cr and Fe in the roots, Fe in the leaves and Cu in the fruits) were within the normal range and did not reach phytotoxic levels. A characteristic of these cucumbers was that all of the heavy metals had a bioaccumulation factor <1.0. All of the heavy metals (except Cd, Cu and Zn) had translocation factors that were <1.0. As a result, the sewage sludge used in this study could be considered for use as a fertilizer in cucumber production systems in Saudi Arabia and can also serve as a substitute method of sewage sludge disposal.n Graphical AbstractThe effects of different sewage sludge amendment rates on the heavy metal bioaccumulation, growth and biomass of cucumbers

Modeling the growth dynamics of Pistia stratiotes L. populations along the water courses of south Nile Delta, Egypt

We developed a dynamic numerical model to describe the growth production and the interaction between shoots and roots of Pistia stratiotes under natural conditions in south Nile Delta, Egypt. Two state variables, shoots and roots, were considered to simulate the growth of P. stratiotes. The biomass of each organ was formulated to incorporate the net growth of the plant as a function of photosynthesis, respiration, mortality, and translocation from shoots to roots. Shoots and roots biomasses of P. stratiotes was sampled monthly from May 2013 to February 2014 along three water courses of Giza Province using three randomly distributed quadrats (each of 0.5xa0×xa00.5xa0m) at each water course. General trends for shoots biomass, such as the slow initial growth rate followed by a high growth rate, the timing of peak biomass, and the decline of biomass due to senescence, were successfully reproduced by the model. Many characteristics typical for the roots biomass, such as the increase in the roots biomass during the early growing season because of the translocation of materials from shoots, and the reduction of roots biomass during the later period of the season, were also reproduced. In general, there was a good agreement between the calculated results and field data although simulated results were slightly different from observations for roots biomass. In conclusion, Pistia model could be used to predict the potential growth of P. stratiotes and this model might be useful for practical applications such as the management of water courses.

Effect of the different types of land-use on the distribution of soil organic carbon in north Nile Delta, Egypt

In Egypt, the need for accurate information on soil organic carbon (SOC) content has increased due to the importance of SOC stocks for sustainable use of natural resources and to meet the requirements of the Kyoto Protocol. Thus, the objectives of the present study are: (1) to quantify the vertical distribution of the soil bulk density (SBD) and SOC content in the soil of north Nile Delta, Egypt under different types of land-use; (2) to provide estimates of the carbon sequestration rate (CSR) of those soils under different types of land-use; and (3) to establish a baseline data on SOC stocks for future studies on SOC dynamics. Ten sampling stations were selected to represent the north Nile Delta during May 2014. In each of the sampling station, 4 sampling sites were selected to represent the virgin lands, 4 to represent fish farms and 12 to represent crop lands (four cultivation histories: 5, 15, 30 and 50xa0yearsxa0×xa0three crop types: clover, Trifolium alexandrinum L., sugar beet, Beta vulgaris L., and rice, Oryza sativa L.). Effect of crop type was significant in relation to SBD, SOC content, and SOC stock. In general, SOC stock increases as the number of years of cultivation increases. The SOC stock under crop land and fish farm were 1.6 and 1.5 times as that of virgin land. Rice was the crop with lowest SBD and highest SOC stock. The average CSR of crop land was 352, 134, 88 and 62xa0gxa0Cxa0m−2xa0year−1 for 5, 15, 30 and 50xa0years of cultivation, respectively. The highest CSR (545xa0gxa0Cxa0m−2xa0year−1) was observed in crop land cultivated for 5xa0years by rice, while the lowest (21xa0gxa0Cxa0m−2xa0year−1) was observed in crop land cultivated for 50xa0years by sugar beet. On the other hand, the average CSR of fish farm was 143xa0gxa0Cxa0m−2xa0year−1. In conclusion, the conversion of virgin land into crop land or fish farm contributed to SOC sequestration.

Growth dynamics of water hyacinth (Eichhornia crassipes): a modeling approach

The present study aims to develop a dynamic numerical model to describe the growth and interactions between the shoot and root systems of Eichhornia crassipes along the irrigation canals in the Nile Delta, Egypt. While carrying out this study, the shoot and root biomasses of E. crassipes were sampled monthly from April to November 2014 over three irrigation canals in the Nile Delta using five randomly distributed quadrats (each 0.5xa0×xa00.5xa0m) at each canal. Two state variables, shoot and root systems biomasses, were considered to follow the growth of E. crassipes. The biomass of each organ was simulated to incorporate the net growth of the plant as a function of photosynthesis, respiration, mortality and translocation from the shoot to the root system. After validating the model with data from the Nile Delta, it was verified using four independent sets of published field data: 19°50′S (Brazil), 19°57′N (Mexico), 29°38′N (USA) and 30°33′N (China). The level of agreement between the simulated values and actual field data indicated that the model was capable of simulating the total biomass of E. crassipes over a wide range of latitudes. Global sensitivity analysis showed that of all the parameters that were used, the model was most sensitive to the maximum photosynthetic growth rate. Based on our results, we recommend the following: first, if E. crassipes is used to remove water pollution or in animal feed, manure, mulch, or the production of biogas, pulp and paper, then E. crassipes stands should be harvested at peak net production. Second, if the main purpose of E. crassipes management is to suppress its growth or eradicate the plant from an irrigation canal, then the harvest should be at the point of the minimum net production.

Distribution of soil organic carbon in the mangrove forests along the southern Saudi Arabian Red Sea coast

Climate change is an issue that has huge concerns worldwide. Carbon dioxide (CO2) emission is one of the important factors in global climate change. Carbon sequestration potential (CSP) of various terrestrial ecosystems, especially wetlands, play a role in manipulating the excessive increase of CO2 in the atmosphere. In the current investigation, we report on the efficiency of mangrove forests located in the southern Saudi Arabian Red Sea coast in carbon sequestration and establishment of a baseline data on soil organic carbon (SOC) pools for future studies on SOC dynamics. Sampling was carried out in three locations along the southern Saudi Arabian Red Sea coast. The sampled locations were classified into landward and seaward stands. In each of the sampling location, ten sampling sites were selected to assure representative samples to each of the landward and seaward stands. Three soil cores were taken in each sampling site and were pooled together into one composite core per sampling site. A total of 480 soil samples were collected. The mean distribution of soil bulk density in the landward and seaward stands increased significantly with depth reaching the maximum at a depth of 20–25xa0cm. SOC concentration in the landward stands declined significantly with depth from 35.8xa0gxa0Cxa0kg−1 at depth 0–5xa0cm to 20.9xa0gxa0Cxa0kg−1 at depth 20–25xa0cm. SOC concentration in the seaward stands declined significantly with depth from 35.7xa0gxa0Cxa0kg−1 at depth 0–5xa0cm to 24.8xa0gxa0Cxa0kg−1 at depth 20–25xa0cm. The carbon sequestration rate (CSR) ranged between 11.7xa0gxa0Cxa0m−2xa0year−1 in the landward stands and 12.0xa0gxa0Cxa0m−2xa0year−1 in the seaward stands. Based on the area of mangrove stands (292xa0km2) and CSR, the total CSP of mangroves in Saudi Arabia was 3.47xa0±xa00.05xa0Ggxa0C year−1.

Bioaccumulation and rhizofiltration potential of Pistia stratiotes L. for mitigating water pollution in the Egyptian wetlands

ABSTRACT The bioaccumulation and rhizofiltration potential of P. stratiotes for heavy metals were investigated to mitigate water pollution in the Egyptian wetlands. Plant and water samples were collected monthly through nine quadrats equally distributed along three sites at Al-Sero drain in Giza Province. The annual mean of the shoot biomass was 10 times that of the root. The concentrations of shoot heavy metals fell in the order: Fe < Mn < Cr < Pb < Cu < Zn < Ni < Co < Cd, while that of the roots were: Fe < Mn < Cr < Pb < Zn < Ni < Co < Cu < Cd. The bio-concentration factor (BCF) of most investigated heavy metals, except Cr and Pb, was greater than 1000, while the translocation factor (TF) of most investigated metals, except Pb and Cu, did not exceed one. The rhizofiltration potential (RP) of heavy metals was higher than 1000 for Fe, and 100 for Cr, Pb and Cu. Significant positive correlations between Fe and Cu in water with those in plant roots and leaves, respectively were recorded, which, in addition to the high BCF and RP, indicate the potential use of P. stratiotes in mitigating these toxic metals.

Prediction models for evaluating the uptake of heavy metals by cucumbers (Cucumis sativus L.) grown in agricultural soils amended with sewage sludge

Heavy metal (HM) concentrations in edible plants can develop many serious health risks to humans. The precise prediction of plant uptake of HMs is highly important. Thus, the present investigation was carried out to develop regression models for predicting the concentrations of HMs in cucumbers (Cucumis sativus L.) from their concentration in the soil and using the organic matter (OM) content and soil pH as co-factors. The results showed that cucumber roots had the highest significant concentrations of all HMs at Pxa0<u20090.001, except Cd, Cu, and Zn were in fruits. The lowest concentrations of Cd, Co, Cr, Mn, Ni, and Pb were recorded in stems. HM concentrations in cucumbers were strongly correlated with soil HM, pH, and OM content. Soil pH and OM content had negative and positive correlations with all HMs in cucumber tissues, respectively. Regression analysis indicated that soil HM, pH, and OM contents were good predictors for HM concentrations in cucumbers. The regression models for root Co, Cr, Fe, and Zn were described by high model efficiency values that explain 48–58% variability. The best regression models for cucumber stem were for Cu, Mn, Ni, and Zn that are characterized by high R2 and model efficiency values. For cucumber fruits, R2 values were ranged from 54 to 82%, with best models for Cr, Pb, Cd, Cu, Ni, and Co in the fruit. We expect that these models will be beneficial for risk assessment studies on sewage sludge utilization in agriculture.

Phytomass and nutrient value of Potamogeton crispus L. in the water courses of Nile Delta, Egypt

The present study aims to assess the phenology, biomass, chemical composition and nutritional value of Potamogeton crispus L. in the water courses of Nile Delta, Egypt. The sampling process was carried out seasonally using 60 quadrats each of 1xa0×xa01xa0m distributed along 13 irrigation and two drainage canals in 5 locations of the area under study. Growth of P. crispus was markedly seasonal, starting in autumn and reaching the maximum phytomass yield in spring (400xa0g DM m−2). The mean biomass of the drainage canals (238xa0g DM m−2) was significantly lower than that of the irrigation canals (399xa0g DM m−2). The concentrations of P, Ca, Mg and Na in P. crispus were highest at the beginning of the growing season (autumn) and decreased throughout the population growth, while Mn and Cu showed the opposite trend. In addition, the concentrations of Mg, Pb and Zn in this plant in the drainage canals were significantly higher than those in the irrigation canals. The nutritive values of P. crispus are within the range of feed nutritive value for sheep, goat, dairy and beef cattle. P. crispus could be considered as a nutrients and heavy metals remover for wastewater treatment if it is harvested during its peak of biomass production. As feed supplement for animals and waterfowl, this plant could be considered excellent because of its high levels of total carbohydrate, total protein, digestible crude protein, total digestible nutrients and the lower crude fibre contents, provided that the concentration of heavy metals is not above the nutritional thresholds.