Evidence of excessive releases of metals from primitive e-waste processing in Guiyu, China

Guiyu, China is infamous for its involvement in primitive e-waste processing and recycling activities. Freshwater samples were collected in and outside of Guiyu for dissolved metal analysis. It was found that dissolved metal concentrations were higher in Lianjiang and Nanyang River within Guiyu than the reservoir outside of Guiyu. Lianjiang was enriched with dissolved As, Cr, Li, Mo, Sb and Se, while Nanyang River had elevated dissolved Ag, Be, Cd, Co, Cu, Ni, Pb and Zn. Temporal distributions of the metals suggested recent discharges of metals attributable to a strong acid leaching operation of e-waste, where dissolved Ag, Cd, Cu and Ni (0.344+/-0.014, 0.547+/-0.074, 87.6+/-3.0 and 93.0+/-1.4 microg/L, respectively) were significantly elevated. Pb isotopic composition of dissolved Pb confirmed that more than one non-indigenous Pb were present in Lianjiang and Nanyang River. In summary, it was evident that the riverine environment of Guiyu was heavily impacted by e-waste related activities.     

Characterization, Fluxes and Toxicity of Leather Tanning Bath Chemicals in a Large Tanning District Area (IT)

The leather tanning industry is perceived as responsible of a significant consume of natural resources and output of wastes such as high concentration of organics, salts and heavy metals such as chromium, both in solid and liquid form as a result. Now as ever the future of tanneries strongly depends on the increase of their awareness that a sustainable industry for the future means embracing a forward-looking philosophy of the leather making process through optimal resource management within the tannery. This study reports the characterization of some chemicals used in a large tanning district area in terms of COD, BOD, aromaticity (UV₂₈₀) and double bond (UV₂₅₄) absorbance measurements, toxicity on fresh and saline water as well as terrestrial species, GC-MS scanning. The study provides a consistent set of information on tannin-associated concentration-related trends and suggests novel criteria in defining control quality for evaluating environmental impact of leather tanning industry.     

Perspectives for pilot scale study of RDF in Istanbul,Turkey

Municipal solid waste (MSW) is one of the most important environmental problems arising from rapid urbanization and industrialization. The use of alternative fuels in rotary kilns of cement plants is very important for reducing cost, saving fossil fuels and also eliminating waste materials, accumulated during production or after using these materials. Cement industries has an important potential for supplying preferable solutions to the waste management. Energy recovery from waste is also important for the reduction of CO₂ emissions.This paper presents an investigation of the development of refuse derived fuel (RDF) materials from non-recycling wastes and the determination of its potential use as an alternative fuel in cement production in Istanbul, Turkey. RDF produced from MSW was analyzed and its effects on cement production process were examined. For this purpose, the produced RDF was mixed with the main fuel (LPG) in ratios of 0%, 5%, 10%, 15% and 20%. Then chemical and mineralogical analyses of the produced clinker were carried out. It is believed that successful results of this study will be a good example for municipalities and cement industries in order to achieve both economic and environmental benefits.     

Trace metal contamination of sediments in an e-waste processing village in China

This study examined trace metal contamination of sediments in Guiyu, China where primitive e-waste processing activities have been carried out. It was found that some river sediments in Guiyu were contaminated with Cd (n.d.-10.3mg/kg), Cu (17.0-4540mg/kg), Ni (12.4-543mg/kg), Pb (28.6-590mg/kg), and Zn (51.3-324mg/kg). The (206)Pb/(207)Pb and (208)Pb/(207)Pb ratios of the Pb-contaminated sediments of Lianjiang (1.1787+/-0.0057 and 2.4531+/-0.0095, respectively) were lower than those of Nanyang River (1.1996+/-0.0059 and 2.4855+/-0.0082, respectively), indicating a significant input of non-indigenous Pb with low (206)Pb/(207)Pb and (208)Pb/(207)Pb ratios. Copper, Pb and Zn in the non-residual fractions noticeably increased in the contaminated sediments compared to those in the uncontaminated sediments. A genuine concern is associated with potential transport of the contaminated sediments downstream and enhanced solubility and mobility of trace metals in the non-residual fractions.     

Investigation of the response of bread wheat cultivars to salinity by using callus cultures

In this research, the response of four bread wheat cultivars (Bal-Atilla, Marmara-86, Seyhan-95, and Panda) to different NaCl concentrations (25.6, 51.3, 77.0, 99.4,119.7 mM) were investigated by using callus cultures. In the experiment, callus induction rates (%) and callus weights in solid and liquid MS media, callus weights in liquid MS media with different NaCl concentrations and in liquid MS media free NaCl concentrations, and callus weights and regeneration rates in MS solid media with NaCl concentrations were studied. Callus induction rates and weights were significantly different among genotypes. Callus weights in liquid MS media were higher than those obtained in the MS solid media. Panda cv. had the highest callus weight in the liquid MS media. Callus weights significantly decreased due to increased NaCl stress. Residual effect of NaCl concentrations on Calli weights was significant. Callus weights decreased due to increasing residue effects of NaCl concentrations. There was no cultivar resistance to salinity, high salinity and very high salinity concentrations. However, Panda cv. was more tolerant cultivar at the light salinity concentrations. Gametoclonal regeneration could not be obtained.     

A new view of dispersion in well-mixed estuaries

A two-dimensional simulation of Delaware estuary hydrodynamics has been constructed. This simulation has been achieved through a rational estimate of the character of natural turbulence. Non-homogeneous velocities, on the cross-section, are employed in two-dimensional, laterally homogeneous species mass balances. In turn, concentration profiles are interpreted in the form of classical, one-dimensional dispersion coefficients. Variation of dispersion as a function of both freshwater inflow and longitudinal distance was generated. Variation of dispersion in time within a tidal cycle was found to be insignificant while no significant variation from one tidal cycle to the next has been detected.The modeling process involves the solution of tractable equations by implicit numerical methods and is capable of being excited by a wide range of input conditions.A study of the sensitivity of dispersion due to vertical mass diffusion revealed that longitudinal mixing characteristics are inversely proportional to vertical eddy diffusivity and analysis of the numerical results showed the dispersion coefficient is essentially insensitive to variation of longitudinal mass diffusivity. This leads to the conclusion that turbulent diffusivity of mass in the longitudinal direction may be taken as constant for most purposes in the study of a two-dimensional species mass balance model.A field program was carried out near the Delaware Memorial Bridge to collect velocity profiles. Substantial portions of the scheme have been verified (i.e. one- and two-dimensional tidal dynamic models) through the use of these data.     

Diurnal photosynthesis, water use efficiency and light use efficiency of wheat under Mediterranean field conditions

Photosynthesis and transpiration rates of wheat leaves (Triticum aestivum L.) were measured at 30 min intervals under Mediterranean field conditions, using Photosynthesis Monitor system (PM-48M). The dynamics of net photosynthetic rate (P(N)), transpiration rate (E(T)), water use efficiency (WUE), light use efficiency (LUE), stomatal conductance (g(s)), photosynthetically active radiation (PAR), air temperature (T), relative humidity (RH), and atmospheric CO2 concentration (Catm) were quantified at five rainfed wheat sites with the same stages of development (midflowering) along south-to-north and east-to-west transects for eight days in April. Diurnal P(N) (3.6 to 6.6 micromol m(-2) s(-1)), PAR (392 to 564 micromol m2 sec(-1)), LUE (0.006 to 0.015) and WUE (0.0001 to 0.011) did not vary significantly across all five wheat sites (p > 0.05). P(N) and E(T) were strongly coupled and highly correlated with PAR (p < 0.001). Best multiple linear regression (MLR) models accounted for 92% of variations in P(N) as a function of PAR and E(T), and 90% in E(T) as a function of PAR and RH (p < 0.001). P(N) exhibited a peak at mid-morning, and a photosynthetic midday depression under the limiting effects of high evaporative demand. Diurnal variations in WUE and LUE showed a bimodal behavior with the maximum values in early morning and late afternoon. As the impacts of global climate change become increasingly felt, continuous measurements of climate-crop-soil-managementinteractions under natural conditions play a pivotal role not only in exploring changes in ecophysiological properties of strategic crops for food security such as wheat but also in devising preventive and mitigative management practices to ensure sustained agricultural productivity.     

Spatial autocorrelation analysis of small-scale genetic structure in a clonal soft coral with limited larval dispersal

The philopatric larval dispesal and small effective population sizes characteristic of many clonal species should promote the development of significant small-scale genetic structure within populations as a result of isolation-by-distance. We used spatial autocorrelation statistics to detect genetic structure, arising from both clonal reproduction and philopatric dispersal of sexual propagules, for five allozyme loci within populations of the soft coral Alcyonium sp. In a population on Tatoosh Island, Washington, USA, sampled in 1991/1992, we found significant positive spatial autocorrelation at all loci among individuals separated by <40 cm, reflecting the presence of significant smallscale genetic structure due to associations among clonemates. For 4 of 5 loci, however, we detected no significant spatial autocorrelation among the different clones within this population over distances of 1 to 40 m. Analysis of soft-coral populations from six additional, topographically diverse sites in the north-east Pacific also did not reveal significant spatial autocorrelation among clones at any loci. This general lack of spatial autocorrelation of genotypes among clones suggests that significant small-scale genetic structure has not arisen in populations of Alcyonium sp. as a consequence of isolation-by-distance.     

Removal of Pb(II) from wastewater using wheat bran

The adsorption of Pb(II) ions from aqueous solutions on wheat bran (WB) has been investigated as a function of initial concentration, adsorbent dose, adsorbent particle size, agitation speed, temperature, contact time and pH of solution. The equilibrium process was described well by the Langmuir isotherm model with maximum sorption capacities of 69.0, 80.7 and 87.0 mgg(-1) of Pb(II) on wheat bran at 20, 40 and 60 degrees C, respectively. Thermodynamic parameters, i.e. DeltaG(0), DeltaH(0) and DeltaS(0) have also been calculated for the system and the sorption process was found to be endothermic. Good correlation coefficients were obtained for the pseudo second-order kinetic model. The metal ion could be stripped by addition of 0.5M HCl, making the adsorbent regeneration and its reutilization possible.