Parameters Influencing Sediments Resuspension and the Link to Sorption of Inorganic Compounds

In the aquatic environment, the accumulation of chemicalcontaminants by sediments poses a potential threat to endemiclife forms and drinking water resources. Trace metals such asCd, Cu, Cr, Ni, Pb, and toxic organic compounds, are among awide variety of contaminants having an affinity for sediments.In this study, experiments were performed simulating sedimentresuspension in the lower Housatonic River, Connecticut, using aParticle Entrainment Simulator. Analyses of grain sizedistributions, porosities and total organic contents of thesediments suggested that these parameters influence theredistribution and entrainment of settleable solids in the watercolumn. These findings were established by evaluating the impactof one parameter on sediment resuspension as a function ofstream flow with the other two characteristics being heldconstant. Total suspended solids and volatile suspended solidsresuspension concentration ranged from 3.2 to 20648.3 mg L^-1,and 1.5 to 1823.8 mg L^-1, respectively, with subsequentincreases in flow rates from 9 to 6 dynes cm^-2. The resuspension concentrations were augmentedby sediment porosity (22.0 to 57.5%), percent finer grain-size distributions at 0.1 mm, and total organic content (2.7 g kg^-1 to 29.0 g kg^-1). Using K _p values, and the dissolvedcontaminant levels of various trace metals, the particulatecontaminant levels of the metals were determined under variousoscillation rates. As sediment resuspension increased withincreased stream flow, there was an overall general increasefrom 0.02 to 33.6 g L^-1 in the particulatecontaminant levels of Cd, Cu, Cr, Ni and Pb.     

Insights into hazardous solid waste generation during COVID-19 pandemic and sustainable management approaches for developing countries

Journal of Material Cycles and Waste Management - The recent emergence of the COVID-19 pandemic has contributed to the drastic production and use of healthcare and personal protective equipment,...     

Heavy metal concentrations in roadside soil and street dust from Petra region,Jordan

Concentrations of Cd, Cu, Fe, Pb, and Zn were measured in the samples of street dust and surface roadside soil before Jordan switched to unleaded fuel usage. The samples were collected from Petra, the most tourist-attractive site in Jordan. The samples were analyzed for heavy metals by atomic absorption spectrophotometry. Our results show that the distribution of metals in the soil samples is affected by wind direction in the investigated area. The highest level of metals was found in the eastern parts of the roads due to the westerly-dominant wind in the studied area. The contamination levels of metals decrease as the distance from the edge of the road increases. In the roadside soil samples, the means for the concentrations of the metals at 1 m from the east side of the main road are 1.0, 19.1, 3791.4, 177.0, and 129.0 mg kg^?1 for Cd, Cu, Fe, Pb, and Zn, respectively. In the samples of street dust, the means of the concentrations of the metals in the investigated area are 9.7, 11.8, 4694.4, 31.6, and 24.8 mg kg^?1 for Cd, Cu, Fe, Pb, and Zn, respectively. In conclusion, the lithogenic origins (traffic emissions) are responsible for the diffusion of these metals in the studied region.     

Chrysin attenuates estradiol-induced endometrial hyperplasia in rats via enhancing PPARα activity

Environmental Science and Pollution Research - Endometrial hyperplasia (EH) is a complex condition that commonly affects women after menopause. Since the current available treatments for EH are...     

Impact of Climate Change on Possible Scenarios for Egyptian Agriculture in the Future

If no timely measures are taken to adapt Egyptian agriculture to possible climate warming, the effects may be negative and serious. Egypt appears to be particularly vulnerable to climate change because of its dependence on the Nile River as the primary water source, its large traditional agricultural base, and its long coastline, already undergoing both intensifying development and erosion. A simulation study characterized potential yield and water use efficiency decreases on two reference crops in the main agricultural regions with possible future climatic variation, even when the beneficial effects of increased CO₂ were taken into account. On-farm adaptation techniques which imply no additional cost to the agricultural system, did not compensate for the yield losses with the warmer climate or improve the crop water-use efficiency. Economic adjustments such as the improvement of the overall water-use efficiency of the agricultural system, soil drainage and conservation, land management, and crop alternatives are essential. If appropriate measures are taken, negative effects of climate change in agricultural production and other major resource sectors (water and land) may be lessened. This revised version was published online in August 2006 with corrections to the Cover Date.     

Effect of fasting on the pattern of urinary arsenic excretion

Millions of people in some of the poorest regions of the world are exposed to high levels of arsenic through drinking contaminated water. It has been reported that development of cancer caused by arsenic exposure in such populations is dependent on dietary and nutritional factors which can modulate arsenic metabolism. Many people in arsenic exposed regions of Bangladesh and India practice fasting for at least one month every year when they refrain from consumption of food and fluid during daylight hours. How such practices may modulate arsenic metabolism has not been previously investigated. This study investigated this issue by determining total arsenic and its species in urine samples from a group of 29 unexposed volunteers at the beginning of the fasting and at the end of approximately 12 h of fasting period. Inductively coupled plasma mass spectrometry (ICP-MS) and high performance liquid chromatography (HPLC) coupled with ICP-MS was used to measure the total arsenic and arsenic speciation in the urine samples, respectively. The mean total levels of arsenic at the beginning of fasting (18.3 microg g(-1) creatinine) and at the end of approximately 12 h of fasting (17.7 microg g(-1) creatinine) did not differ significantly (p > 0.05). However, the percentages of urinary arsenic as the methylated arsenic species methylarsonate (MA) were found to be significantly different (p < 0.05) and this species was observed more frequently at the end of fasting, although its overall concentration was similar. There were no significant differences (p > 0.05) in both the concentrations and percentages of other urinary arsenic species detected, namely arsenobetaine (AB) and dimethylarsinate (DMA). Arsenite (As(III)) and arsenate (As(V)) were also analyzed, but were not detected. We conclude that fasting for a period of 12 h results in a significant increase in the percentage of urinary arsenic as MA, and its frequency of detection in the volunteers at the end of the fasting period is almost nine fold higher. This suggests that metabolism of arsenic is altered by fasting.     

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

When 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 50 g kg^?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 40 g kg^?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 50 g kg^?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.

The effects of different sewage sludge amendment rates on the heavy metal bioaccumulation, growth and biomass of cucumbers

     

Icariin ameliorates metabolic syndrome-induced benign prostatic hyperplasia in rats

Environmental Science and Pollution Research - Metabolic syndrome (MetS) is an immense health issue that causes serious complications in aging males including BPH. Icariin (ICA) is a flavonol...     

Foliar use of TiO2-nanoparticles for okra (Abelmoschus esculentus L. Moench) cultivation on sewage sludge–amended soils: biochemical response and heavy metal accumulation

Considering its richness in organic and inorganic mineral nutrients, the recycling of sewage sludge (SS) is highly considered as a soil supplement in agriculture. However, the fate of hazardous heavy metal accumulation in the crops cultivated in SS amended soils is always a source of concern. Since nanoparticles are widely recognized to reduce heavy metal uptake by crop plants; thus, the present experiment deals with okra (Abelmoschus esculentus L. Moench) cultivation under the combined application of SS and TiO₂-nanoparticles (NPs). Triplicated pot experiments were conducted using different doses of SS and TiO₂-NPs such as 0 g/kg SS (control), 50 g/kg SS, 50 g/kg SS?+?TiO₂, 100 g/kg SS, and 100 g/kg SS?+?TiO₂, respectively. The findings of this study indicated that among the doses of treatment combinations investigated, 100 g/kg SS?+?TiO₂ showed a significant (p?<?0.05) increase in the okra plant yield (287.87?±?4.06 g/plant) and other biochemical parameters such as fruit length (13.97?±?0.54 cm), plant height (75.05?±?3.18 cm), superoxide dismutase (SOD: 110.68?±?3.11 μ/mg), catalase (CAT: 81.32?±?3.52 μ/mg), and chlorophyll content (3.12?±?0.05 mg/g fwt.). Also, the maximum contents of six heavy metals in the soil and cultivated okra plant tissues (fruit, stem, and root regions) followed the order of Fe?>?Mn?>?Cu?>?Zn?>?Cr?>?Cd using the same treatment. Bioaccumulation and health risk assessment indicated that foliar application of TiO₂-NPs significantly reduced the fate of heavy metal accumulation under higher doses of SS application. Therefore, the findings of this study suggested that the combined use of SS and TiO₂-NPs may be useful in ameliorating the negative consequences of heavy metal accumulation in cultivated okra crops.