The present study was undertaken to examine the drinking water quality of Rawal Treatment Plant, Rawalpindi and its distribution
network by collecting samples from eight different locations. The aim was to determine potential relationship between the
presence of microorganisms and chlorine residual in the distribution network. Quantification of chlorine residual, turbidity,
standard plate count (SPC), fecal and total coliforms by Most Probable Number (MPN) was performed. Three different forms of chlorine were measured at each sampling station such
as free chlorine, residual chlorine, chloramines and total chlorine residual. A critical evaluation of data presented indicated
that pH generally ranged from 7.02–7.30; turbidity varied from 0.34–2.79 NTU; conductivity fluctuated from 359–374 μS/cm;
and TDS values were found to be ranging between 180–187 mg/l. Station # 7 was found to be most contaminated. The value of total chlorine was found to be 0.86 to1.7 mg/l at Station # 3 and 6, respectively. Highest standard plate count was 62 CFU/ml at Station # 7. Totalcoliforms were less than 1.1 MPN/100 ml at almost most of the stations except at Station # 3 where it was found to be greater than 23.0 MPN /100 ml. Overall aim of this study is to create awareness about contamination
of drinking water in the water distribution networks and to make recommendations to provincial agencies such as EPA, CDA and
WASA that regular monitoring should be carried out to ensure that the chlorine residual is available at consumer end. 相似文献
Environmental Science and Pollution Research - Recent environmental research has found that people with higher incomes and in more developed countries are more willing to pay (WTP) to protect their... 相似文献
Environmental Science and Pollution Research - In recent years, environmental change has arisen as a ubiquitous problem and gained environmentalist’s attention across the globe due to its... 相似文献
The environmental aging behaviour of montmorillonite (MMT) filled polylactic acid (PLA) nanocomposites (PLA/MMT) and linear
low density polyethylene (LLDPE)-toughened PLA (PLA/LLDPE ratio = 90/10) nanocomposites (PLA/LLDPE/MMT) were investigated
in this study. The nanocomposites were subjected to water absorption, hygrothermal degradation and soil burial analysis. Both
PLA/MMT and PLA/LLDPE/MMT nanocomposites were immersed in distilled water at three different temperatures (room temperature,
60, and 90 °C) and the weight difference before and after immersion was calculated. The kinetics of water absorption for both
nanocomposites followed the Fick’s second law of diffusion, where a linear relationship exists between the initial moisture
absorption at any time t and t1/2 (the square root of time), followed by a horizontal plateau (saturation). The equilibrium moisture content (Mm) and diffusion coefficient (D) of PLA nanocomposites increased with the addition of MMT (2 phr) and LLDPE. However, the D values of both nanocomposites decreased by increasing MMT (4 phr). The Mm for PLA/MMT and PLA/LLDPE/MMT nanocomposites increased by increasing immersion temperature (60 °C) and prolonged immersion
resulted in hygrothermal degradation of both nanocomposites. The hygrothermal degradation studies showed that PLA degrades
much faster at 90 °C as compared to 60 °C in both the nanocomposites. The addition of MMT and LLDPE improved the hygrothermal
stability of PLA in both nanocomposites. Soil burial test revealed deterioration of impact strength in all samples while the
rate of biodegradation was retarded in the presence of MMT and LLDPE. 相似文献
Groundwater is almost globally important for human consumption as well as for the support of habitat and for maintaining the quality of base flow to rivers, while its quality assessment is essential to ensure sustainable safe use of the resources for drinking, agricultural, and industrial purposes. In the current study, 50 groundwater samples were collected from parts of Palar river basin to assess water quality and investigate hydrochemical nature by analyzing the major cations (Ca, Mg, Na, K) and anions (HCO(3), Cl, F,SO(4), NO(3), PO(4),CO(3), HCO(3), and F) besides some physical and chemical parameters (pH, electrical conductivity, alkalinity, and total hardness). Also, geographic information system-based groundwater quality mapping in the form of visually communicating contour maps was developed using ArcGIS-9.2 to delineate spatial variation in physicochemical characteristics of groundwater samples. Wilcox classification and US Salinity Laboratory hazard diagram suggests that 52% of the groundwater fall in the field of C2-S1, indicating water of medium salinity and low sodium, which can be used for irrigation in almost all types of soil with little danger of exchangeable sodium. Remaining 48% is falling under C1-SI, indicating water of low salinity and low sodium. 相似文献
Date palm waste–derived biochar (DBC) was produced through pyrolysis (600 °C) and modified with zeolite (Z-DBC), silica (S-DBC), or nano-zerovalent iron (nZVI-DBC) to design efficient sorbents. The pristine and engineered biochars were characterized by SEM, XRD, BET, TGA, CHNS-O, and FTIR to investigate the surface, structural, and mineralogical composition. The nZVI-DBC exhibited lowest pH (6.15) and highest surface area (220.92 m2 g−1), carbon (80.55%), nitrogen (3.78%), and hydrogen (11.09%) contents compared with other biochars. Isotherm sorption data for chlortetracycline (CTC) removal from aqueous solutions was described well by Langmuir and Redlich–Peterson isotherms showing the highest fitness (R2 values in the range of 0.88–0.98 and 0.88–0.99, respectively). Langmuir predicted maximum CTC adsorption capacity was in order of nZVI-DBC (89.05 mg g−1) > S-DBC (45.57 mg g−1) > Z-DBC (30.42 mg g−1) > DBC (28.19 mg g−1). Kinetics adsorption data was best described by power function model (R2 = 0.93–0.99), followed by interaparticle diffusion (R2 = 0.85–0.96) model. The nZVI-DBC performed outclass by removing 98% of CTC, followed by S-DBC (68%), Z-DBC (35%), and DBC (36%). Chemisorption, H-bonding, and interaparticle diffusion were the operating mechanisms for CTC adsorption onto DBC, S-DBC, and Z-DBC, while π-π electron donor–accepter interactions and redox reactions augmented these mechanisms for highest CTC adsorption onto nZVI-DBC. Therefore, nZVI-DBC may serve as an efficient green technology for the removal of CTC from aqueous solutions and to reduce surface date palm waste pollution.
It has become apparent that the threat of an organic pollutant in soil is directly related to its bioavailable fraction and
that the use of total contaminant concentrations as a measure of potential contaminant exposure to plants or soil organisms
is inappropriate. In light of this, non-exhaustive extraction techniques are being investigated to assess their appropriateness
in determining bioavailability. To find a suitable and rapid extraction method to predict phenanthrene bioavailability, multiple
extraction techniques (i.e., mild hydroxypropyl-β-cyclodextrin (HPCD) and organic solvents extraction) were investigated in soil spiked to a range of phenanthrene levels (i.e.,
1.12, 8.52, 73, 136, and 335 μg g − 1 dry soil). The bioaccumulation of phenanthrene in earthworm (Eisenia fetida) was used as the reference system for bioavailability. Correlation results for phenanthrene suggested that mild HPCD extraction
was a better method to predict bioavailability of phenanthrene in soil compared with organic solvents extraction. Aged (i.e.,
150 days) and fresh (i.e., 0 day) soil samples were used to evaluate the extraction efficiency and the effect of soil contact
time on the availability of phenanthrene. The percentage of phenanthrene accumulated by earthworms and percent recoveries
by mild extractants changed significantly with aging time. Thus, aging significantly reduced the earthworm uptake and chemical
extractability of phenanthrene. In general, among organic extractants, methanol showed recoveries comparable to those of mild
HPCD for both aged and unaged soil matrices. Hence, this extractant can be suitable after HPCD to evaluate risk of contaminated
soils. 相似文献
Environmental Science and Pollution Research - Water pollution is one of the main threats to public health in Pakistan. The watchdogs for drinking water quality are toothless, hence... 相似文献
Environmental Science and Pollution Research - This study investigates the heterogeneous impact of air transport intensity, air passenger transport, and air freight transport on air... 相似文献