Cytotoxicity,in vivo toxicity,and chemical composition of the hexane extract of Plectranthus amboinicus (Lour.) Spreng

Environmental Science and Pollution Research - Cancer is a universal health issue, and many anticancer therapeutic drugs have been isolated from natural products. This study analyzed the cytotoxic...     

Multi-objective optimization model for water resource management: a case study for Riyadh,Saudi Arabia

A multi-objective goal programming model was developed for water distribution from multiple sources to multiple users. The model was applied in Riyadh, Saudi Arabia, for the period of 2015–2050. In Riyadh, water sources are groundwater (GW), desalinated water (DW) and treated wastewater (TWW), while the users are domestic, agricultural and industrial sectors. The model was applied to: (1) satisfy water demands and quality; (2) maximize TWW reuse and GW conservation; and (3) minimize overproduction of DW and overall cost. In 2015, the required allocations of GW, DW and TWW are 3286, 662 and 609 MCM, respectively, which are projected to be 4345, 1554 and 1305 MCM in 2050, respectively. GW source is likely to satisfy the predicted withdrawal of GW till 2035, while probabilities of non-satisfaction of full demands of GW in 2040, 2045 and 2050 were 0.04, 0.23 and 0.51, respectively. Supply of DW and reuse of TWW are needed to be increased to satisfy the predicted quantities during 2015–2050.     

Water quality change in dam reservoir and shallow aquifer: analysis on trend,seasonal variability and data reduction

Change of water quality in dam reservoir and aquifer complicates safe drinking water supply. Few parameters are monitored to control water quality in these sources. Adequate knowledge on the correlation structure, interaction effect, trends and seasonal variability of these parameters is essential to control water quality. This study applied time series and multivariate analyses on 15 water quality parameters, collected from the King Fahd dam reservoir (L1) and aquifer (L2) in Saudi Arabia during April 2010 to February 2012. Moderate to strong correlations were observed between sulfate, hardness, fluoride, chloride, magnesium, conductivity, turbidity and total dissolved solids (TDS), while separate clusters were visible for TDS-chloride-magnesium-conductivity; fluoride-turbidity; chloride-hardness; ammonia-nitrate; and calcium-magnesium-hardness. Four major principal components explained 81.1 % and 83.2 % of the overall variances in L1 and L2, respectively. The factor analysis showed that 53 % and 67 % of the data were necessary to explain 81.3 % and 83.2 % of total variances for L1 and L2, respectively, indicating the possibility of data reduction. Possible degradation of water quality in these sources was highlighted, while such degradation may require enhanced treatment for producing drinking water in future.     

Fuzzy synthetic evaluation of treated wastewater reuse for agriculture

Reuse of treated wastewater (TWW) for agriculture is in practice in many countries. TWW reuse requires wastewater collection, treatment and recycling, which is associated with cost as well as risk to human and ecological systems. In contrast, it can increase agricultural production and reduce environmental risks by reducing wastewater discharge into the natural environment. In Saudi Arabia, where available water resources are extremely limited, TWW reuse can save significant amount of non-renewable groundwater used in agricultural development, which is a strategic goal for the country. In this paper, a multicriteria decision-making approach was developed where cost, risk, benefits and social acceptance of TWW reuse were considered to be the main criteria. A multistage hierarchy risk management model was constructed for this evaluation. Fuzzy synthetic evaluation technique was incorporated where fuzzy triangular membership functions were developed to capture uncertainties of the basic criteria. The analytic hierarchy process was used to determine the relative importance of various criteria at different hierarchy levels. This study indicated that TWW reuse could have positive impact on agriculture, risk reduction and groundwater conservation.