Biosorption of lead and cadmium using marine algae

The use of algae (Ulva fasciata, green and Sargassum sp., brown) to reduce lead and cadmium levels from mono-metal solutions was investigated. The brown algae showed higher efficiency for the accumulation of lead (～1.5 times) and cadmium (～2 times) than green algae. The optimum pH value is found to be between 4 and 5.5. Regarding biomass concentration, an increase in metals percentage removal and a decrease in metal uptake capacity coincided with the increase in biomass concentration. All light metals (Ca, Mg and Na) showed a suppressive effect on biosorption capacity. The enhancement of biosorption in the case of NaOH was obvious. The biosorption process (65–90%) occurred within 3?min. Experimental data were in high agreement with the pseudo-second-order kinetic model and Freundlich model for lead and cadmium biosorption using different biosorbents. In the desorption study, 0.2?mol?L^?1 HCl recorded the best concentration for the elution of metals from the biomass. The biosorption capacity decreased over the four operational cycles for both lead and cadmium. Infrared analysis showed that amino, hydroxyl and carboxyl functional groups provide the major biosorption sites for metal binding. Use of the above-mentioned algae for cheap metal absorbance is considered as one water treatment criterion.     

Ecotypes diversity in autumn olive (Elaeagnus umbellata Thunb): A single plant with multiple micronutrient genes

Elaeagnus umbellata, a member of the Elaeagnaceae family, is native to Pakistan, China, India, Korea, and Japan. It is found commonly at altitudes ranging from 1200 to 2100 m and thrives on eroded and degraded land due to its ability to fix nitrogen. The plant also grows under variable pH (4–8) and drought, and is used locally as fuel wood, fencing, fodder, basket making, and shelterbelts. The fruit of the plant is well known for its essential nutrients and medicinal compounds such as vitamins, minerals, essential fatty acids, carotenoids (lycopene), soluble solids, and sugars. Medicinally, it is widely believed to protect against myocardial infections, pulmonary infections, and various forms of cancers. Ten ecotypes from variable microclimatic conditions were investigated for their morphological, molecular and biochemical diversity improvement and commercialization purposes. Comparisons and disabilities indicated significant variability in terms of morphological (plant height, number of branches, thorn size and number, leaf area, fruit size, 100 fruit weight, and yield), molecular (SDS-PAGE), and micro- and macronutrient (vitamin C, Fe, mg, P, Na, K, essential oils, and sugar) bases among the ecotypes. This variability will be helpful in developing commercial varieties of the plant utilizing the conventional techniques of selection and hybridization for economic activities. The plant has ample quantities of multiple micronutrients, thus indicating their expression through a powerful promoter at one place (fruit mesocarp). Efforts to identify and isolate the micronutrient genes (vitamin A, C, E, and Fe), the deficiency of which causes malnutrition and disabilities within the population of developing countries. Micronutrient genes have also been initiated for their characterization and future transformation into staple food crops for stable bio-fortification.     

Application of enrichment factor,geoaccumulation index,and ecological risk index in assessing the elemental pollution status of surface sediments

Environmental Geochemistry and Health - Sediment can accumulate trace elements in the environment. This study profiled the magnitude of As, Ba, Cd, Co, Cu, Cr, Ni, Pb, Se, and Zn pollution in...     

Arachis hypogaea derived activated carbon steered remediation of Benzimidazole based fungicide adsorbed soils

Sorption characteristics of the Benzimidazole fungicide Carbendazim were assessed in seven different soils using batch equilibrium method and analysed by UV-Vis spectrophotometer. The values of adsorption co-efficient K_d ranged from 14.3 to 39.8?µg/mL depending upon unique physiochemical properties of soils. Negative values for Gibbs free energy (ΔG) proposed an exothermic and low interaction between Carbendazim and soil samples leading to physiosorption. Statistical analysis showed a negative correlation of soil pH and K_d (R²= ?0.80) and a positive correlation with organic matter (R^2?=?0.77). Activated carbon prepared from Arachis hypogaea (peanut shells) by acid activation for Carbendazim removal from soils was characterised by FTIR spectrometry, indicating the change in functional groups. The highest percentage removal observed was 70% in 5?ppm initial Carbendazim concentration while 65% in 7.5?ppm concentration. This method can be implied in agricultural soils as an efficient and cheap technique for removing the hazardous pesticides from the environment.     

Removal of heavy metals by leaves-derived biosorbents

Environmental Chemistry Letters - Among various remediation technologies, biosorption is promising for the removal of heavy metals from water and wastewater, since in many cases, it is fast,...     

Landfill leachate treatment using sub-surface flow constructed wetland by Cyperus haspan

Performance evaluation of pilot scale sub-surface constructed wetlands was carried out in treating leachate from Pulau Burung Sanitary Landfill (PBSL). The constructed wetland was planted with Cyperus haspan with sand and gravel used as substrate media. The experiment was operated for three weeks retention time and during the experimentation, the influent and effluent samples were tested for its pH, turbidity, color, total suspended solid (TSS), chemical oxygen demand (COD), biochemical oxygen demand (BOD(5)), ammonia nitrogen (NH(3)-N), Total phosphorus (TP), total nitrogen (TN) and also for heavy metals such as iron (Fe), magnesium (Mg), manganese (Mn) and zinc (Zn) concentrations. The results showed that the constructed wetlands with C. haspan were capable of removing 7.2-12.4% of pH, 39.3-86.6% of turbidity, 63.5-86.6% of color, 59.7-98.8% of TSS, 39.2-91.8% of COD, 60.8-78.7% of BOD(5), 29.8-53.8% of NH(3)-N, 59.8-99.7% of TP, 33.8-67.0% of TN, 34.9-59.0% of Fe, 29.0-75.0% of Mg, 51.2-70.5% of Mn, and 75.9-89.4% of Zn. The significance of removal was manifested in the quality of the effluent obtained at the end of the study. High removal efficiencies in the study proved that leachate could be treated effectively using subsurface constructed wetlands with C. haspan plant.     

Surfactant-enhanced release of carbaryl and ethion from two long-term contaminated soils

The potential of five nonionic surfactants, Triton X-100, Brij35, Ethylan GE08, Ethylan CD127, and Ethylan CPG660 for enhancing release of carbaryl and ethion from two long-term contaminated soils was evaluated using the batch method. Incorporation of the surfactants into soils enhanced the release of both pesticides to various extents, which could be related to the type of pesticides and type and the amount of surfactants added. Release of ethion was dramatically enhanced by aqueous concentrations of surfactants above their critical micelle concentration values. This was attributed to solubility enhancement through incorporation of the highly hydrophobic compound within surfactant micelles. A concentration of 10 g L(-1) of various surfactants released >70% of the total ethion from the soil irrespective of the surfactant. For carbaryl, the surfactants were effective at low concentrations and dependence on concentration was lower than in the case of ethion. The ethylan surfactants (GE08, CD127, and CPG660) had a higher potential than Triton X-100 and Brij35 for releasing the pesticides. However, there was still a significant portion of carbaryl (11% of the total) and ethion (17% of the total) left in the soil. Our study also showed that there must be an optimal concentration of each surfactant to maximize the mass transfer of pesticides. At some threshold concentration level, additional surfactant started to inhibit the mass transfer of solute from the soil into the water. The results suggested that surfactants could help remediation of soils polluted by pesticides. The choice of surfactant should be made based on the properties of pesticides.     

Caesium concentration in the Pakistani diet

Daily dietary intakes of radioactive and non-radioactive caesium for the Pakistani population were measured. Food samples were collected on market basket method and were analysed using Instrumental Neutron Activation Analysis technique. The radioactive caesium ((137)Cs) in these samples was below the detectable limit, i.e. 1 mBq g(-1). The geometric mean of the mass fraction of stable caesium was 9.56 x 1.53 ng g(-1). The estimated daily dietary intake of caesium was 5.65 x 1.53 microg d(-1) or 0.088 microg kg(-1) of body weight of the reference Pakistani man weighing 64 kg. These values are 38.2% smaller than the recommended ICRP values for a 70 kg standard man. However, caesium concentration in the Pakistani diet is comparable with other reported values in the literature.     

Off-site movement of endosulfan from irrigated cotton in New South Wales

The fate and transport of endosulfan (6,7,8,9,10,10-hexachloro-1,5, 5a,6,9,9a-hexahydro-6,9-methano-2,4,3-benzodioxathiepin 3-oxide) applied to cotton (Gossypium hirsutum L.) fields were studied throughout three consecutive years on two selected locations in New South Wales (Australia). Rates of dissipation from foliage and soil, volatilization from the field, and transport of residues in irrigation and/or storm runoff waters were measured in order to estimate a total field balance. Dissipation of endosulfan from both foliage and soil is best explained by a two-phase process rather than by a first-order decay. Half-lives of total endosulfan toxic residues (alpha- and beta-endosulfan and the sulfate product) in the first phase were 1.6 d in foliage and 7.1 d in soil, and could be explained by the rapid volatilization of the parent isomers in the first 5 d (up to 70% of endosulfan volatilizes). In the second phase, half-lives were 9.5 d in foliage and 82 d in soil, mostly due to the persistence of the sulfate product. Concentration of endosulfan residues in runoff water varied from 45 to 2.5 microg L(-1) depending on the residue levels present on field soil at the time of the irrigation or storm events. These in turn are related to the total amounts applied, the cotton canopy cover at application, and the time since last spraying. Most of the endosulfan in runoff was found in the water phase (80%), suggesting it was bound to colloidal matter. Total endosulfan residues in runoff for a whole season accounted for no more than 2% of the pesticide applied on-field.