Acidification in Arabian Gulf--insights from pH and temperature measurements

The detrimental effects of increasing atmospheric levels of carbon dioxide (CO(2)) and other greenhouse gases since the industrial revolution has led to a concerted international effort to control their release and abate the environmental and human health impacts. CO(2) is removed from the atmosphere by photosynthesis of plants in the terrestrial environment and by aquatic sequestration. In the Middle East and other arid countries, terrestrial removal is minimal. The most likely removal pathway for CO(2) in arid regions around the world is by aquatic sequestration. In the Middle East the major sink is the Arabian Gulf which leads to acidification of the marine environment. Biweekly pH concentration measurements in surface waters of the northern Arabian Gulf over a four year period in this study suggest that the Arabian Gulf waters are becoming increasingly acidic with time. Supporting evidence for increased CO(2) sequestration comes from increased marine primary productivity over the past decade. Biological effects, such as coral bleaching, observed during this period suggest that urgent action is required to reverse the trend and protect marine life. The data highlight the fact that this semi-enclosed sea is undergoing a rapid degradation which may affect the oceanic chemistry and biogeochemical cycle much earlier than predicted for most oceanic waters.     

Qualitative assessment on premature human mortality due to the emission of fine particulate matter from the Matarbari coal power plant

This study reports the probability of increased mortality of people within the political border of Bangladesh due to the emission of fine particulate matter with diameters of 2.5 microns or less (PM_2.5) from the Matarbari coal power plant (MCPP). A Gaussian plume dispersion model has been used for this estimation. The PM_2.5 emission rate data are unavailable as the construction of MCPP is still in its initial stage; therefore, the anticipated PM_2.5 emission rate has been estimated based on data from a number of coal‐fired power plants in India and China. To make this study more meaningful, two different emission rates have been considered representing the best‐case and worst‐case scenarios. In both cases, the intake fraction has been found to be 0.12×10^?2, and the value of relative risk varies between 1.134 and 1.374, respectively. Finally, it is estimated that approximately 11.5 million people inside Bangladesh will be exposed to the PM_2.5 emission from MCPP, and between 7,667 and 17,675 people will experience premature death every year.     

Integrating livelihoods and conservation in protected areas: understanding the role and stakeholder views on prospects for non-timber forest products,a Bangladesh case study

Protected areas (PAs) represent a key global strategy in biodiversity conservation. In tropical developing countries, the management of PAs is a great challenge as many contain resources on which local communities rely. Collection and trading of non-timber forest products (NTFPs) is a well-established forest-based livelihood strategy, which has been promoted as a potential means for enhanced conservation and improved rural livelihoods in recent years, even though the sustainability or ecological implications have rarely been tested. We conducted an exploratory survey to understand the role and stakeholder views on conservation prospects and perceived ecological feasibility of NTFPs and harvesting schemes in a northeastern PA of Bangladesh, namely the Satchari National Park. Households (n?=?101) were interviewed from three different forest dependency categories, adopting a stratified random sampling approach and using a semi-structured questionnaire. The study identified 13 locally important NTFPs, with five being critically important to supporting local livelihoods. Our study suggests that collection, processing and trading in NTFPs constitutes the primary occupation for about 18% of local inhabitants and account for an estimated 19% of their cash annual income. The household consensus on issues relating to NTFPs and their prospective role in conservation was surprisingly high, with 48% of respondents believing that promotion of NTFPs in the PA could have positive conservation value. The majority (71%) of households also had some understanding of the ecological implications of NTFP harvesting, sustainability (53%) and possible management and monitoring regimes (100%). With little known about their real application in the field, our study suggests further investigations are required to understand the ecological compatibility of traditional NTFP harvesting patterns and management.     

Studies on heavy metals in the ground waters of the city of Aligarh U.P. (India)

A study was conducted to determine the levels of heavy metals Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn along with physico-chemical parameters in ground waters of Aligarh city, U.P. (India). Twenty seven samples of hand pump water and twenty three samples of municipal water supply were collected from different localities of the Aligarh city, five times during the period of two months at intervals of 12 days. The samples were analysed for physico-chemical characteristics (pH, electrical conductivity, chlorides, sulphates, total hardness, total alkalinity, nitrate-nitrogen, fluoride, calcium and magnesium) and heavy metal contents. The concentrations of heavy metals in the hand pump water samples were found in the ranges of Cd (ND-5.00); Cr (ND-30.00); Cu (ND-82.50); Fe (16.80–460.00); Mn (ND-425.00); Ni (ND-25.00); Pb (ND-25.00) and Zn (28.60–775.00) g l^–1. The heavy metal concentrations in the municipal water supply samples were found to be Cd (ND-5.00); Cr (ND-25.00); Cu (ND-37.50); Fe (8.00–37.50); Mn (ND-320.00); Ni (ND-25.00); Pb (ND-25.00) and Zn (2.00–271.87) g l^–1.It appears from the results of these studies the concentrations of Cd, Cr, Cu, Ni, Pb, and Zn in the ground waters of the Aligarh City were found to be lower than the prescribed limits of World Health Organisation (1984), whereas the values of Fe and Mn were found above the prescribed limits in some localities. The chloride total hardness and nitrate-nitrogen were comparatively higher in the hand pump water than the municipal supply water. The reason of higher values of these parameters may be ascribed to the surface disposal of sewage wastes, wastes from metal processing industries and other house hold refuses.     

Adsorption of methylene blue from aqueous solution by jackfruit (Artocarpus heteropyllus) leaf powder: A fixed-bed column study

Continuous fixed-bed studies were undertaken to evaluate the efficiency of jackfruit leaf powder (JLP) as an adsorbent for the removal of methylene blue (MB) from aqueous solution under the effect of various process parameters like bed depth (5–10 cm), flow rate (30–50 mL/min) and initial MB concentrations (100–300 mg/L). The pH at point of zero charge (pH_PZC) of the adsorbent was determined by the titration method and a value of 3.9 was obtained. A FTIR of the adsorbent was done before and after the adsorption to find the potential adsorption sites for interaction with methylene blue molecules. The results showed that the total adsorbed quantities and equilibrium uptake decreased with increasing flow rate and increased with increasing initial MB concentration. The longest breakthrough time and maximum MB adsorption were obtained at pH 10. The results showed that the column performed well at low flow rate. Also, breakthrough time and exhaustion time increased with increasing bed depth. The bed-depth service time (BDST) model and the Thomas model were applied to the adsorption of MB at different bed depths, flow rates, influent concentrations and pH to predict the breakthrough curves and to determine the characteristic parameters of the column that are useful for process design. The two model predictions were in very good agreement with the experimental results at all the process parameters studied indicating that they were very suitable for JLP column design.     

Quaternary stratigraphy, sediment characteristics and geochemistry of arsenic-contaminated alluvial aquifers in the Ganges-Brahmaputra floodplain in central Bangladesh

This study focuses on the Quaternary stratigraphy, sediment composition, mineralogy, and geochemistry of arsenic (As)-contaminated alluvial aquifers in the Ganges-Brahmaputra floodplain in the central Bangladesh. Arsenic concentrations in 85 tubewells in Manikganj area, 70 km northwest of Dhaka City, range from 0.25 microg/L to 191 microg/L with a mean concentration of 33 microg/L. Groundwater is mainly Ca-HCO(3) type with high concentrations of dissolved As, Fe, and Mn, but low level of SO(4). The uppermost aquifer occurs between 10 m and 80 m below the surface that has a mean arsenic concentration of 35 microg/L. Deeper aquifer (>100 m depth) has a mean arsenic concentration of 18 microg/L. Sediments in the upper aquifer are mostly gray to dark-gray, whereas sediments in the deep aquifer are mostly yellowing-gray to brown. Quartz, feldspar, mica, hornblende, garnet, kyanite, tourmaline, magnetite, ilmenite are the major minerals in sediments from both aquifers. Biotite and potassium feldspar are dominant in shallow aquifer, although plagioclase feldspar and garnet are abundant in deep aquifer sediments. Sediment composition suggests a mixed provenance with sediment supplies from both orogenic belts and cratons. High arsenic concentrations in sediments are found within the upper 50 m in drilled core samples. Statistical analysis shows that As, Fe, Mn, Ca, and P are strongly correlated in sediments. Concentrations of Cd, Cu, Ni, Zn, and Bi also show strong correlations with arsenic in the Manikganj sediment cores. Authigenic goethite concretions, possibly formed by bacteria, are found in the shallow sediments, which contain arsenic of a concentration as high as 8.8 mg/kg. High arsenic concentrations in aquifers are associated with fine-grained sediments that were derived mostly from the recycled orogens and relatively rapidly deposited mainly by meandering channels during the Early to Middle Holocene rising sea-level conditions.     

Heavy metals in water, sediments, plants and fish of Kali Nadi U.P. (India)

The distribution of heavy metals viz., Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn in the water, sediments, plants and fish samples collected from the Kali Nadi (India) have been determined. The studies have shown that there was considerable variation in the concentration of heavy metals from one sampling station to the other which may be due to the variation in the quality of industrial and sewage wastes being added to the river at different places. The orders of the concentration of heavy metals in water, sediments, plants (Eicchornia crassipes) and fish (Heteropnuestes fossilis) were Fe > Zn > Cu > Mn > Cr > Ni > Pb > Co > Cd; Fe > Zn > Mn > Ni > Cr > Co > Cu > Pb > Cd; Fe > Mn > Zn > Cu > Ni > Co > Pb > Cr > Cd and Fe > Zn > Mn > Ni > Pb > Co > Cr > Cu > Cd, respectively.