Field accumulation risks of heavy metals in soil and vegetable crop irrigated with sewage water in western region of Saudi Arabia

Wastewater irrigated fields can cause potential contamination with heavy metals to soil and groundwater, thus pose a threat to human beings . The current study was designed to investigate the potential human health risks associated with the consumption of okra vegetable crop contaminated with toxic heavy metals. The crop was grown on a soil irrigated with treated wastewater in the western region of Saudi Arabia during 2010 and 2011. The monitored heavy metals included Cd, Cr, Cu, Pb and Zn for their bioaccumulation factors to provide baseline data regarding environmental safety and the suitability of sewage irrigation in the future. The pollution load index (PLI), enrichment factor (EF) and contamination factor (CF) of these metals were calculated. The pollution load index of the studied soils indicated their level of metal contamination. The concentrations of Ni, Pb, Cd and Cr in the edible portions were above the safe limit in 90%, 28%, 83% and 63% of the samples, respectively. The heavy metals in the edible portions were as follows: Cr > Zn > Ni > Cd > Mn > Pb > Cu > Fe. The Health Risk Index (HRI) was >1 indicating a potential health risk. The EF values designated an enhanced bio-contamination compared to other reports from Saudi Arabia and other countries around the world. The results indicated a potential pathway of human exposure to slow poisoning by heavy metals due to the indirect utilization of vegetables grown on heavy metal-contaminated soil that was irrigated by contaminated water sources. The okra tested was not safe for human use, especially for direct consumption by human beings. The irrigation source was identified as the source of the soil pollution in this study

The good, the bad, and the tiny: A simple, mechanistic-probabilistic model of virus-nutrient colimitation in microbes

For phytoplankton and other microbes, nutrient receptors are often the passages through which viruses invade. This presents a bottom-up vs. top-down, co-limitation scenario; how do these would-be-hosts balance minimizing viral susceptibility with maximizing uptake of limiting nutrient(s)? This question has been addressed in the biological literature on evolutionary timescales for populations, but a shorter timescale, mechanistic perspective is lacking, and marine viral literature suggests the strong influence of additional factors, e.g. host size; while the literature on both nutrient uptake and host-virus interactions is expansive, their intersection, of ubiquitous relevance to marine environments, is understudied. I present a simple, mechanistic model from first principles to analyze the effect of this co-limitation scenario on individual growth, which suggests that in environments with high risk of viral invasion or spatial/temporal heterogeneity, an individual host’s growth rate may be optimized with respect to receptor coverage, producing top-down selective pressure on short timescales. The model has general applicability, is suggestive of hypotheses for empirical exploration, and can be extended to theoretical studies of more complex behaviors and systems

Prevalence and pattern of dyslipidemia in hyperglycemic patients and its associated factors among Pakistani population

AbstractIn diabetes mellitus dyslipidemia is one of the major risk factors for cardiovascular disease. In type 2 diabetes mellitus early detection and treatment of dyslipidemia can avoid risk for cardiovascular disorder. The present study was carried to determine the prevalence and pattern of hyperlipidemia in patients with hyperglycemia. The cross sectional study was done in different laboratories of Pakistan, the laboratories served patients referred from different government and private hospitals between July 2014 and June 2015. All known cases of diabetes mellitus were evaluated for their lipid profile. Totally 200 diabetic patients were included in the study in which 120 (60%) were males and 80 (40%) were females. Prevalence of dyslipidemia among diabetic males was 97.18% while for females 87.15%. Among dyslipidemic male the proportion with mixed dyslipidemic patients was 17.5%, combined two parameters dyslipidemia was 47.5% and isolated single parameter dyslipidemia was 35%. In females these proportions in mixed, combined two parameters and isolated single parameter were 16.25%, 51.25% and 32.5%, respectively. Majority of hyperglycemic patients were dyslipidemic. The most prevalent pattern among male was combined dyslipidemia with high triglycerides (TG) and low High Density Lipoprotein (HDL) and in female it was high Low Density Lipoprotein (LDL) and low HDL. The most prevalent lipid abnormality in our study was low HDL followed by high TG

Water Pollution in Old Towns Affecting the Environment and Ecological Restoration

© 2019 Technoscience Publications. All rights reserved. In order to solve the problem that the traditional activated sludge method is not effective in recovering the ecological process of water pollution in urban areas, the membrane bioreactor-based sewage treatment process was studied experimentally. Two flat-plate ultrafiltration membranes were used to form the ultrafilter tank in the experimental device sampled, and the processes of nitrate cycle and sludge cycle were adopted. Ozonation and granular activated carbon filtration were adopted to treat the micropollutants. After repeated experiments in 17 experimental cycles, the obtained experimental data were analysed, and it was found that under different sewage treatment loads, the treatment quality of the device could reach p concentration \u3c 0.2mg/L and n concentration \u3c 6mg/L. Compared with the traditional sewage treatment process, the experimental device can better remove the common nutrient rich substances and micro-pollutants in urban sewage, better control the greenhouse gas emissions, and meet the demand for efficient ecological recovery of urban sewage

Application of Rb/Sr Ratio in Paleo-climate Inversion

In order to study the intensity of chemical weathering during the formation of sedimentary strata in the site profile, the evolution of climatic environment in the region where the site profile is located was revealed. The rubidium (Rb) and strontium (Sr) values in the rubidium (Rb) and strontium (Sr) were tested and analysed. The Rb/Sr ratio has become an ideal alternative indicator in the study of regional environmental evolution. The Rb value in the strata section of Zhongba site is low, and the average value (calculated based on 202 sample values) is only 80 g/g. The Sr value was higher, averaging 866 g/g. The average Rb/Sr ratio is 0.19

Morphology, Geology and Water Quality Assessment of Former Tin Mining Catchment

Bestari Jaya, former tin mining catchment covers an area of 2656.31 hectares comprised of four hundred and forty-two different-size lakes and ponds. The present study area comprise of 92 hectares of the catchment that include four large size lakes. Arc GIS version 9.2 used to develop bathymetric map, Global Positioning System (GPS) for hydrographical survey and flow meter was utilized for water discharge analysis (flow routing) of the catchment. The water quality parameters (pH, temperature, electric conductivity, dissolved oxygen DO, total dissolved solids TDS, chlorides, ammonium, nitrates) were analyzed by using Hydrolab. Quality assurance (QA) and quality control (QC) procedures were strictly followed throughout the field work and data analysis. Different procedures were employed to evaluate the analytical data and to check for possible transcription or dilution errors, changes during analysis, or unusual or unlikely values. The results obtained are compared with interim national water quality standards for Malaysia indicates that water quality of area is highly degraded. It is concluded that Bestri Jaya ex-mining catchment has a high pollution potential due to mining activities and River Ayer Hitam, recipient of catchment water, is a highly polluted river

Study on Dye-Sensitized Solar Cells Based on TiO2 Composite Nanomaterials

With the continuous development of nanomaterials, how to improve the conversion efficiency of DSSCs has been the focus of scholars. Nano-TiO2 material is a wide bandgap semiconductor with a bandgap of 3.2eV. It exhibits good performance in dye adsorption, charge separation, electron transport, etc., and has good chemical stability and strong acid and alkali resistance. Therefore, it was always the material of choice for the preparation of photoanodes. In this paper, different thicknesses of TiO2 NRs barrier layers were prepared on FTO substrates by solvothermal method and two-step spin coating method, and their electrochemical and photoelectric properties were tested by using relevant test instruments. The effects of barrier layers with different thicknesses of TiO2 NRs on the performance of DSSCs were analysed. The anatase TiO2 NRs with an average length of 28±10nm and a diameter of 2±1nm were obtained. The concentration of TiO2 NRs was 0.245mol·L-1 (TiO2 NRs-12). When the thickness is 88.58nm, DSSCs exhibit the best photoelectric performanc