Determination of heavy metal contents in water,sediments, and fish tissues of Shizothorax plagiostomus in river Panjkora at Lower Dir,Khyber Pakhtunkhwa,Pakistan

The present study was conducted to investigate the contamination of water, sediments, and fish tissues with heavy metals in river Panjkora at Lower Dir, Khyber Pakhtunkhwa, Pakistan. Water, sediments, and fish (Shizothorax plagiostomus) samples were collected from September 2012 to January 2013 at three different sites (upstream site at Sharigut, sewage site at Timergara, and downstream site at Sadoo) of river Panjkora. The concentrations of heavy metals in water were in the order Zn?>?Cu?≈?Pb?>?Ni?≈?Cd with mean values of 0.30, 0.01, 0.01, 0.0 and 0.0 mg/l, respectively, which were below the maximum permissible limits of WHO for drinking water. In sediments, heavy metals were found in the order Cu?>?Zn?>?Ni?>?Pb?>?Cd with mean concentrations of 50.6, 38.7, 9.3, 8, and 0.4 mg/kg, respectively. Ni and Cd were not found in any fish tissues, but Zn, Cu, and Pb were detected with the mean concentration ranges of 0.04–1.19, 0.03–0.12, and 0.01–0.09 μg/g, respectively. The present study demonstrates that disposal of waste effluents causes a slight increase in the concentration of heavy metals in river Panjkora as revealed by variation in metal concentrations from upstream to downstream site. Sewage disposal was also found to change physicochemical characteristics of Panjkora water. At present, water and fish of river Panjkora are safe for human consumption, but the continuous sewage disposal may create problems in the future.     

Elevated exposure to polycyclic aromatic hydrocarbons (PAHs) may trigger cancers in Pakistan: an environmental,occupational, and genetic perspective

Environmental Science and Pollution Research - Polycyclic aromatic hydrocarbons (PAHs) are carcinogenic compounds which are emitted through incomplete combustion of organic materials, fossil fuels,...     

Seasonal food insecurity in Bangladesh: evidences from northern areas

Seasonal food insecurity in Bangladesh is a multidimensional socioeconomic issue emanated from more than just access and availability of food. In general, it has been considered that the northern areas of Bangladesh, treated as monga-prone, is more vulnerable to seasonal food insecurity as compared to any other region of the country. The manifestation of monga is essentially food insecurity and consequent vulnerabilities. The paper investigates the seasonal food insecurity status, coping strategies along with its possible determinants linked to socioeconomic conditions of the affected households in Kurigram, one of the monga-prone districts of northern Bangladesh. A primary survey was conducted to explore the food insecurity status and diverse factors leading to food insecurity in terms of food consumption, livelihood and consequent family experiences in mitigating the severity of food insecurity during the monga (lean) period. The nature of household food insecurity seems to be an outcome of a variety of risk factors, as well as inability to manage those risks due to income and resource constraints. Moreover, a reduction in food intake during the monga period is one of the common scenarios in the study area. Marginal effects and elasticities after probit regression reveal that household’s income, share of per capita medical expenditure, safety net(s) involvement and the area of residence appear to be the leading factors affecting seasonal food insecurity during the monga period to a significant extent. Households with more medical expenditure (68 %), cultivable landholding (9 %) and households residing by the riverside (4 %) have a higher probability of food insecurity than their counterparts. On the contrary, relatively large size family (-16 %), higher income (-4 %) and safety net coverage (-19 %) have reduced the probability of food insecurity during the monga period. Finally, the paper concludes with some policy issues based on on-site observation and econometric analysis to overcome this transitory food insecurity in the monga-prone areas.     

The use of date palm as a potential adsorbent for wastewater treatment: a review

Background

In tropical countries, the palm tree is one of the most abundant and important trees. Date palm is a principal fruit grown in many regions of the world. It is abundant, locally available and effective material that could be used as an adsorbent for the removal of different pollutants from aqueous solution.

Review

This article presents a review on the role of date palm as adsorbents in the removal of unwanted materials such as acid and basic dyes, heavy metals, and phenolic compounds. Many studies on adsorption properties of various low cost adsorbent, such as agricultural waste and activated carbons based on agricultural waste have been reported in recent years.

Conclusion

Studies have shown that date palm-based adsorbents are the most promising adsorbents for removing unwanted materials. No previous review is available where researchers can get an overview of the adsorption capacities of date palm-based adsorbent used for the adsorption of different pollutants. This review provides the recent literature demonstrating the usefulness of date palm biomass-based adsorbents in the adsorption of various pollutants.     

Towards a sustainable energy future—exploring current barriers and potential solutions in Thailand

Renewable energy is considered an indispensable basis of sustainable energy systems as electricity generation from renewable sources results in low emissions of greenhouse gases compared to fossil fuel based electricity and contributes to sustainable development. However, effective strategies and conducive institutional settings are needed for advancement of such clean electricity systems. Although Thailand, as a nation, has a huge potential for renewable energy utilization, its total amount of electricity generation from renewables is relatively small and could be enlarged substantially. Lack of policy mechanisms, institutional development and financing exist as major barriers for Thailand in this regard. Investigation of the nation’s current energy strategy implementation shows that relevant energy and development policies are at different stages of implementation and institutional settings are continuously evolving. This paper argues that further significant efforts could be made towards advancement of renewable electricity and thus achievement of energy sustainability in Thailand. Resource planning, effective policy and institutions, focussed planning for energy sustainability and implementation of the Clean Development Mechanism (CDM) under the Kyoto Protocol could facilitate further advancement of renewables for the nation.     

Advancement of renewables in Bangladesh and Thailand: Policy intervention and institutional settings

This article reviews and analyses the advancement of renewable sources of energy in Bangladesh and Thailand in terms of policy intervention and institutional settings. Since renewable forms of energy emit far smaller amounts of greenhouse gas compared with fossil fuels, their use should mitigate climate change impacts while contributing to the provision of energy services. The article turns first to a review of energy–environment trends and the potential for renewables in these two nations. It then discusses strategies for the advancement of renewables. It is argued that further significant efforts can be made towards the advancement of renewables in Bangladesh and Thailand. These two nations could also learn from the experience in industrialized nations and other developing nations with regard to requisite policy instruments and processes. A number of barriers remain to the advancement of renewables, especially in terms of policy arrangements, institutional settings, financing mechanisms and technologies. Resources, cooperation and learning are required in order to overcome such barriers and to foster the development of necessary policy measures. Implementation of the clean development mechanism (CDM) under the Kyoto Protocol, and replication and adaptation of effective strategies from other settings are possible avenues for this.     

Assessment of municipal solid waste generation and recyclable materials potential in Kuala Lumpur,Malaysia

This paper presents a forecasting study of municipal solid waste generation (MSWG) rate and potential of its recyclable components in Kuala Lumpur (KL), the capital city of Malaysia. The generation rates and composition of solid wastes of various classes such as street cleansing, landscape and garden, industrial and constructional, institutional, residential and commercial are analyzed. The past and present trends are studied and extrapolated for the coming years using Microsoft office 2003 Excel spreadsheet assuming a linear behavior. The study shows that increased solid waste generation of KL is alarming. For instance, the amount of daily residential SWG is found to be about 1.62 kg/capita; with the national average at 0.8–0.9 kg/capita and is expected to be increasing linearly, reaching to 2.23 kg/capita by 2024. This figure seems reasonable for an urban developing area like KL city. It is also found that, food (organic) waste is the major recyclable component followed by mix paper and mix plastics. Along with estimated population growth and their business activities, it has been observed that the city is still lacking in terms of efficient waste treatment technology, sufficient fund, public awareness, maintaining the established norms of industrial waste treatment etc. Hence it is recommended that the concerned authority (DBKL) shall view this issue seriously.     

The effects of temperature on decomposition and allelopathic phytotoxicity of boneseed litter

Decomposition of plant litter is a fundamental process in ecosystem function, carbon and nutrient cycling and, by extension, climate change. This study aimed to investigate the role of temperature on the decomposition of water soluble phenolics(WSP), carbon and soil nutrients in conjunction with the phytotoxicity dynamics of Chrysanthemoides monilifera subsp. monilifera(boneseed) litter. Treatments consisted of three factors including decomposition materials(litter alone, litter with soil and soil alone), decomposition periods and temperatures(5–15, 15–25and 25–35°C(night/day)). Leachates were collected on 0, 5, 10, 20, 40 and 60 th days to analyse physico-chemical parameters and phytotoxicity. Water soluble phenolics and dissolved organic carbon(DOC) increased with increasing temperature while nutrients like SO-24 and NO-13 decreased. Speed of germination, hypocotyl and radical length and weight of Lactuca sativa exposed to leachates were decreased with increasing decomposition temperature. All treatment components had significant effects on these parameters. There had a strong correlation between DOC and WSP, and WSP content of the leachates with radical length of test species. This study identified complex interactivity among temperature, WSP, DOC and soil nutrient dynamics of litter occupied soil and that these factors work together to influence phytotoxicity.     

Denitrification potential of the Northern Arabian Gulf—an experimental study

The study aims to establish denitrification potential of the Northern Arabian Gulf (NAG), as nitrogen critically affects the ocean productivity, obliterates acidity, oxidative capacity and radiative transfer capability of atmosphere. The experimental study was conducted by taking cores from intertidal zones from two different sites in North and South, referred as sites N and S; representing two distinct environmental milieu. The experiment was conducted in controlled laboratory conditions simulating the tidal cycles. Multiple cores were taken and loaded with seawater with different N concentrations, the redox potential was established for each condition. Redox potential was significantly lower at 10?cm depth compared to the surface in all cores (P?<?0.001). The redox potential at surface and at 10?cm depth was significantly lower at site S compared to site N (P?<?0.001; F?=?714.2), suggesting anaerobic sediments at site S. Effects of nitrate spiked seawater on denitrification under nonflooded and flooded conditions at the two sites were also studied. Three-way ANOVA analysis indicated that site, nitrate concentration, and flooding had significant main and interactive effects on the rate of denitrification. The results suggest that under ambient nitrate concentrations (0.03?mg NO₃-N?l^?1), 6.3?±?2.1?g NO₃-N?ha?day can be denitrified by inter-tidal zone sediments. At a nitrate concentration of 1?mg NO₃-N?l^?1, 92?±?16?g NO₃-N?ha?day may be denitrified whilst at a very high nitrate load of 10?mg NO₃-N?l^?1, the sediments may attain a rate of denitrification close to 404?±?78?g NO₃-N?ha?day.