Low levels of toxic elements in Dead Sea black mud and mud-derived cosmetic products

Natural muds used as or in cosmetics may expose consumers to toxic metals and elements via absorption through the skin, inhalation of the dried product, or ingestion (by children). Despite the extensive therapeutic and cosmetic use of the Dead Sea muds, there apparently has been no assessment of the levels of such toxic elements as Pb, As, or Cd in the mud and mud-based products. Inductively coupled plasma mass spectrometry analysis of eight toxic elements in samples collected from three black mud deposits (Lisan Marl, Pleistocene age) on the eastern shore of the Dead Sea in Jordan revealed no special enrichment of toxic elements in the mud. A similar analysis of 16 different commercial Dead Sea mud cosmetics, including packaged mud, likewise revealed no toxic elements at elevated levels of concern. From a toxic element standpoint, the Dead Sea black muds and derivative products appear to be safe for the consumer. Whatever the therapeutic benefits of the mud, our comparison of the elemental fingerprints of the consumer products with those of the field samples revealed one disturbing aspect: Dead Sea black mud should not be a significant component of such items as hand creams, body lotions, shampoo, and moisturizer.     

Role of plant growth promoting rhizobacteria in the remediation of metal contaminated soils

Pollution of the biosphere by the toxic metals is a global threat that has accelerated dramatically since the beginning of industrial revolution. The primary source of this pollution includes the industrial operations such as mining, smelting, metal forging, combustion of fossil fuels and sewage sludge application in agronomic practices. The metals released from these sources accumulate in soil and in turn, adversely affect the microbial population density and physico-chemical properties of soils, leading to the loss of soil fertility and yield of crops. The heavy metals in general cannot be biologically degraded to more or less toxic products and hence, persist in the environment. Conventional methods used for metal detoxification produce large quantities of toxic products and are cost-effective. The advent of bioremediation technology has provided an alternative to conventional methods for remediating the metal-poisoned soils. In metal-contaminated soils, the natural role of metal-tolerant plant growth promoting rhizobacteria in maintaining soil fertility is more important than in conventional agriculture, where greater use of agrochemicals minimize their significance. Besides their role in metal detoxification/removal, rhizobacteria also promote the growth of plants by other mechanisms such as production of growth promoting substances and siderophores. Phytoremediation is another emerging low-cost in situ technology employed to remove pollutants from the contaminated soils. The efficiency of phytoremediation can be enhanced by the judicious and careful application of appropriate heavy-metal tolerant, plant growth promoting rhizobacteria including symbiotic nitrogen-fixing organisms. This review presents the results of studies on the recent developments in the utilization of plant growth promoting rhizobacteria for direct application in soils contaminated with heavy metals under a wide range of agro-ecological conditions with a view to restore contaminated soils and consequently, promote crop productivity in metal-polluted soils across the globe and their significance in phytoremediation.     

Study of heat exposure in the work environment in Jeddah

The present work was conducted to define the magnitude of the problem of heat exposure in Jeddah and the role of both the climatic and the industrial factors on the total heat load. Indoor heat exposure was studied in an industrial complex of 5 plants for cables' manufacturing. Outdoor heat exposure was studied in shaded and unshaded operations in Jeddah Islamic Port (JIP). The heat exposure parameters, including air temperature (Ta), wet bulb temperature (Tw), and globe temperature (Tg), as well as the wet bulb globe temperature (WBGT) heat stress index, the relative humidity and the air velocity, were assessed at representative locations. Results of the study indicated that:

Measurement of soil radioactivity levels and radiation hazard assessment in southern Rechna interfluvial region, Pakistan

Rechna interfluvial region is one of the main regions of Punjab, Pakistan. It is the area which is lying between River Ravi and River Chenab, alluvial-filled. Radioactivity levels in soil samples, collected from southern Rechna interfluvial region, Pakistan, have been estimated by using gamma-ray spectrometric technique. ²²⁶Ra, ²³²Th, the primordial radionuclide ⁴⁰K, and the artificial radionuclide ¹³⁷Cs have been measured in the soil of the study area. The mean radioactivity levels of ²²⁶Ra, ²³²Th, ⁴⁰K, and ¹³⁷Cs were found to be 50.6 ± 1.7, 62.3 ± 3.2, 662.2 ± 32.1, and 3.1 ± 0.3 Bq kg^???1, respectively. The mean radium equivalent activity (Ra_eq), outdoor radiation hazard index (H _out), indoor radiation hazard index (H _in), and terrestrial absorbed dose rate for the area under study were determined as 190.8 ± 8.7 Bq kg^???1, 0.52, 0.65, and 69.8 nGy h^???1, respectively. The annual effective dose to the general public was found to be 0.43 mSv. This value lies well below the limit of 1 mSv for general public as recommended by the International Commission on Radiological Protection. The measured values are comparable with other global radioactivity measurements and are found to be safe for the public and the environment.     

Preconcentration of metal ions through chelation on a synthesized resin containing O, O donor atoms for quantitative analysis of environmental and biological samples

Nascent Amberlite XAD-4 has been used as the polymeric support for the synthesis of a stable extractor of metal ions, by incorporating phthalic acid through azo bridging. Elemental analyses and infra-red spectral and thermal studies were carried out for its characterization. The water regain value and hydrogen ion capacity were found to be 12.50 and 5.75 mmol g^?1, respectively. The optimum pH range for the maximum sorption of Ni(II), Mn(II), Cu(II), Zn(II), Cd(II), Cr(III), and Co(II) was observed at pH 5.5–8.0 with the corresponding half-loading time (t _1/2) of 9, 5, 9, 9, 3, 9, and 5 min, respectively. The preconcentration factor for Ni(II), Mn(II), Cu(II), Zn(II), Cd(II), Cr(III), and Co(II) are 190, 190, 190, 180, 180, 160, and 160, with the corresponding limit of preconcentration in the range of 5.25–6.25 μg L^?1. The detection limits, for flame atomic absorption spectrophotometry, were found to be 0.62, 0.60, 0.65, 0.75, 0.72, 0.84, and 0.85 μg L^?1, respectively. Method has been successfully applied to the analysis of water samples, multivitamin formulations, infant food substitutes, hydrogenated oil, and fishes.     

Pesticide burden on some insects of economic importance in Lucknow (India)

Some insects of economic importance from Lucknow (India) have been investigated for their pesticide burden. Chlorinated pesticide residues of DDT, BHC and aldrin along with their metabolites and isomers have been detected in crop pollinating insects, honeybees (Apis indica) and butterflies (Danais chrysippus and Eurema sp.) and predators, dragonfly (Platythemis sp.) and wasps (Polistes herebreus). DDT and their metabolites were present in concentrations which varied from 231–796 ng g^–1, followed by BHC (10–60 ng g^–1), and aldrin (0.26–6.68 ng g^–1). This finding is likely to stimulate newer interest in the area of pesticide research and start meaningful investigation to find if bioaccumulated pesticides would have adverse impact on otherwise beneficial potentials of such insects in our ecosystems.     

Particleboard manufacturing: an innovative way to recycle paper sludge

This paper presents the results on a study to use paper mill sludge for particleboard production. Single-layer board and three-layer board, with paper sludge on the surface, were fabricated. Four levels of mixing ratios of paper sludge to wood particles (0:100, 15:85, 30:70, and 45:55) were used. The boards were produced with 3% and 4% methylene diphenyl diisocyanate (MDI), and 10% and 12% urea-formaldehyde (UF) adhesives. The bending and shear strengths, water absorption, and thickness swelling of the boards were investigated. The results indicated that the mechanical properties of the boards were negatively affected by the paper sludge amount. Overall, UF-bonded particleboards gave superior mechanical performance, water resistance, and thickness swell than MDI-bonded particleboards. The strengths of the UF-bonded board decreased much more than those of MDI-bonded board as paper sludge content increased. The three-layer boards made from 15% paper sludge with 12% UF satisfied fully the minimum requirements set by EN, ASTM D 1037-99, and ANSI A208.1 standards for general uses.     

The effect of nutrients shortage on plant’s efficiency to capture solar radiations under semi-arid environments

Radiation use efficiency (RUE) is considered critical for calculation of crop yield. The crop productivity can be improved by increasing the interception of solar radiation and maintaining higher RUE for plants. Irrigation water and nitrogen (N) supply are the main limiting factors for RUE in maize (Zea mays L.) across the semi-arid environments. Field experiments were conducted during two consecutive growing seasons (2009–2010) to optimize RUE in relation to N application timings and rates with varying irrigation water management practices. In experiment 1, three N application timings were made, while in experiment 2, three possible water management practices were used. In both experiments, five N rates (100, 150, 200, 250, and 300 kg N ha⁻¹) were applied to evaluate the effects of irrigation water and N on cumulative photosynthetic active radiation (PARi), dry matter RUE (RUE_DM), and grain yield RUE (RUE_GY). The results demonstrated that cumulative PARi and RUEs were not constant during the plant growth under varying the nutrients. The water and N significantly influenced cumulative PARi and RUEs during the both growing seasons. In experiment 1, the maximum cumulative PARi was observed by application of 250 kg N ha⁻¹ in three splits (1/3 N at V2, 1/3 N at V16, and 1/3 N at R1 stage), and the highest RUE_DM was achieved by the application of 300 kg N ha⁻¹. However, the highest RUE_GY was observed by application of 250 kg N ha⁻¹. In experiment 2, the maximum cumulative PARi was attained at normal irrigation regime with 250 kg N ha⁻¹, while the highest RUE_DM and RUE_GY were recorded at normal irrigation regime with the application of 300 kg N ha⁻¹. The regression analysis showed significant and positive correlation of RUE_GY with grain yield. Therefore, optimum water and N doses are important for attaining higher RUE, which may enhance maize grain yield semi-arid environment; this may be considered in formulating good agricultural practices for the environmental conditions resembling to those of this study.