The potential of the flora from different regions of Pakistan in phytoremediation: a review

Soil and water quality is greatly affected by environmental pollution due to the increasing trend of urbanization and industrialization. In many developing countries, including Pakistan, the situation is more alarming as no preventive measures are still taken to tackle the problem. Although in developed countries, many techniques are used to remediate the environment including phytoremediation. It is the most eco-friendly technique in which plants are used to remove pollutants from the environment. Pakistan has also a great diversity of plants which could be used for the remediation of environmental pollutants. To our knowledge, few studies from Pakistan were reported about the use of flora for phytoremediation. According to recent literature, 50 plant species from Pakistan are studied for remediation purposes. In this review, the potential of different plant species for phytoremediation from Pakistan has been discussed along with their comparison to other countries to relate future perspectives.     

UV–visible light-activated Ag-decorated,monodisperse TiO2 aggregates for treatment of the pharmaceutical oxytetracycline

Noble metal Ag-decorated, monodisperse TiO₂ aggregates were successfully synthesized by an ionic strength-assisted, simple sol–gel method and were used for the photocatalytic degradation of the antibiotic oxytetracycline (OTC) under both UV and visible light (UV–visible light) irradiation. The synthesized samples were characterized by X-ray diffraction analysis (XRD); UV–vis diffuse reflectance spectroscopy; environmental scanning electron microscopy (ESEM); transmission electron microscopy (TEM); high-resolution TEM (HR-TEM); micro-Raman, energy-dispersive X-ray spectroscopy (EDS); and inductively coupled plasma optical emission spectrometry (ICP-OES). The results showed that the uniformity of TiO₂ aggregates was finely tuned by the sol–gel method, and Ag was well decorated on the monodisperse TiO₂ aggregates. The absorption of the samples in the visible light region increased with increasing Ag loading that was proportional to the amount of Ag precursor added in the solution over the tested concentration range. The Brunauer, Emmett, and Teller (The BET) surface area slightly decreased with increasing Ag loading on the TiO₂ aggregates. Ag-decorated TiO₂ samples demonstrated enhanced photocatalytic activity for the degradation of OTC under UV–visible light illumination compared to that of pure TiO₂. The sample containing 1.9 wt% Ag showed the highest photocatalytic activity for the degradation of OTC under both UV–visible light and visible light illumination. During the experiments, the detected Ag leaching for the best TiO₂-Ag photocatalyst was much lower than the National Secondary Drinking Water Regulation for Ag limit (0.1 mg L^?1) issued by the US Environmental Protection Agency.     

Impact of anthropogenic activities on physico-chemical parameters of water and mineral uptake in Catla catla from river Ravi, Pakistan

The river Ravi, while passing through Lahore, the second largest city of Pakistan, gets highly polluted owning heavy loads of untreated municipal sewage and industrial effluents of diverse kinds. The fish, Catla catla sampled in two different seasons from three downstream polluted sites were compared with the samples of the same fish from an upstream, a less polluted site, for their physico-chemical parameters. The data were statistically analysed to study the effect of sites, seasons and their interaction on the physico-chemical parameters of waters and mineral uptake in fish muscles. Significant differences (P?<?0.001) among the sampling sites and seasons were observed. The river appeared to be polluted as indicated by the high values of total suspended solids (909 mg/l) and sulphate (964 mg/l) in comparison to the respective values of 150 and 600 mg/l being suggested as the safer values of drinking water of the National Environmental Quality Standards. Most trace and macro elements in fish muscles were increased with the increasing pollution loads from the upstream to the downstream sites of this river. The remarkable increases in the levels of all the investigated minerals in fish muscles from the polluted sites raise concerns about the long-term health of the river Ravi ecosystem and consequently the fish and its consumer’s health. The results contradict the opinion of the local population that the riverine fish are natural, more health-promoting and precious than the pond fish. Therefore, we strongly argue for the utilization of an effect-based monitoring approach to alleviate the detrimental effects of anthropogenic activities on fish and the fish consumers’ health.     

Prenatal diagnosis of β-thalassemia in Southern Punjab,Pakistan

Pakistan has a large population of more than 150 million people with an overall carrier frequency of approximately 5.6% for β-thalassemia. Punjab is the largest province of the country having more than 50% of the population. The state of β-thalassemia is alarming as consanguinity is very high (>81%) and the literacy rate is low in South Punjab. A thalassemia prevention program is the need of the hour in this part of Pakistan. In this study, we initiated awareness, screening, and characterization of the mutations causing β-thalassemia as well as a genetic counseling program mainly in the districts of Faisalabad and D.G. Khan to establish prenatal diagnosis, a facility previously unavailable in this region for disease prevention. A total of 248 unrelated transfusion-dependent children and the available members of their families were screened to characterize the mutations and identify the carriers. Genetic counseling was provided to these families and prenatal diagnosis offered. In the samples analyzed, 11 β-thalassemia mutations and three hemoglobin variants were detected mainly by using the Monoplex and Multiplex ARMS-PCR. First-trimester prenatal diagnosis was carried out through chorionic villus sampling (CVS) in seven pregnancies at risk. As a result of our campaign, 145 carrier couples planning to have more children gave their consent to have retrospective prenatal diagnosis in every pregnancy in future. A cooperative trend and a positive attitude toward the prevention of β-thalassemia were noticed in the families with affected children and in the general population. Copyright © 2006 John Wiley & Sons, Ltd.     

Agroforestry environment,potentiality and risk in India: a remote sensing and GIS understanding

Environment, Development and Sustainability - The study utilized the tree covers per cent, agroforestry suitability, present and future (2050) climate, agriculture vulnerability (2050), percentage...     

Co-exposure of Bi2O3 nanoparticles and bezo[a]pyrene-enhanced in vitro cytotoxicity of mouse spermatogonia cells

Environmental Science and Pollution Research - Recent attention has been focused on reproductive toxicity of nanoscale materials in combination with pre-existing environmental pollutants. Due to...     

Multivariate statistics and entropy theory for irrigation water quality and entropy-weighted index development in a subtropical urban river,Bangladesh

Environmental Science and Pollution Research - Currently, a well-developed combination of irrigation water quality index (IWQIs) and entropy water quality index (EWQIs) for surface water appraisal...     

A comparative study of the toxicity of lead and its impact on the carbohydrate metabolism and some haematological parameters of cichlid fish,oreochromis niloticus and catfish,clarius gariepinus from saudi arabia

Fresh and healthy specimens of Oreochromis niloticus (mean weight 70.5± 1.23 g and mean length, 12.3± 1.5cm) and Clarias gariepinus (mean weight, 41.8±2.3 g and mean length 13.78 ± 1.2 cm) were exposed to heavy metal lead, ranging in concentration from 10 to 18 mg L^‐1 for O. niloticus and 20 to 28 mg L^‐1 for C. gariepinus respectively. The 96 h LC₅₀ for both the species was computed as 12.45 mg L^‐1 (O. niloticus) and 22.65 mg L^‐1 (C. gariepinus). The cichlid fish was exposed to sublethal concentration of lead (2, 4 and 6 mgL^‐1) and catfish (4, 8 and 12 mgL^‐1). The erythrocytes count, haemoglobin concentration, haematocrit and the value of serum glucose increased significantly (P < 0.01), whereas leucocytes count, serum protein and serum triglyceride after intoxication declined in both the species with the same pattern but in different quantity. After 96 h of time a significant depletion of muscle and liver glycogen was noted, being greater in muscle (16.7% in O. niloticus) and in liver (15.9% in C. gariepinus). The response of fish to lead was dose dependent.     

Cadmium-tolerant bacteria induce metal stress tolerance in cereals

Cadmium usually hampers plant growth, but bacterial inoculation may improve stress tolerance in plants to Cd by involving various mechanisms. The objective was to characterize and identify bacteria that improve plant growth under Cd stress and reduce Cd uptake. Cadmium-tolerant bacteria were isolated from rhizosphere soil, which was irrigated with tannery effluent, and six strains were selected as highly tolerant to Cd, showing minimum inhibitory concentration as 500 mg L^?1 or 4.45 mmol L^?1. These strains were identified by 16S rRNA gene analysis and functional analysis in regard to plant growth promotion characteristics. To determine their effect on cereal growth under Cd stress, seeds were inoculated with these strains individually and grown in soil contaminated with three Cd levels (0, 40 and 80 mg kg^?1). Biomass production, relative water content (RWC), electrolyte leakage (ELL) and tissue Cd concentration were measured. Biomass of both cereals was inhibited strongly when exposed to Cd; however, bacterial inoculation significantly reduced the suppressive effect of Cd on cereal growth and physiology. The bacterial isolates belonged to the genera Klebsiella, Stenotrophomonas, Bacillus and Serratia. Maize was more sensitive than wheat to Cd. Klebsiella sp. strain CIK-502 had the most pronounced effects in promoting maize and wheat growth and lowering Cd uptake under Cd stress.