Environmetal Earth Science

Rate of Siltation in Wular Lake, (Jammu and Kashmir, India) with Special Emphasis on its Climate & Tectonics

by Ravindra Gavali

The siltation rate in the Lake Wular, one of the largest fresh water lakes in Asia, shows abnormality in space and... more The siltation rate in the Lake Wular, one of the largest fresh water lakes in Asia, shows abnormality in space and time, as evidenced from the preliminary geological survey of its catchment. The Panjal traps and limestones (with scanty intercalations of black shales) form the major provenance for the silt which drains into the lake. The lineament fabric suggests a strong structural control over the formation of the lake. The Tertiary uplift, as well as, the pulses of seismicity have been instrumental towards the modification of regional geomorphological relief and the resultant changes in the rate of siltation.
The climatic changes have also been influential in the varied rate of erosion and subsequent siltation rates. The valley of Kashmir, sheltered from the south-west monsoon by the Panjal range, has not the periodical rains of India. Its rainfall is irregular, greatest in the spring months. Occasional storms in the monsoon pass over the crests of the Panjal and give heavy rain on the elevated plateaus on the Kashmir side, being the main agent of erosion along the topography of the Wular lake. Also, the clouds passing over the valley are arrested by the higher hills on the north-east side, bringing torrential rains. These impacts have been further accelerated due to deforestation in the much fragile, mountainous topography of Wular. The topographic relief thus appears to have fluctuated in the recent geological past, as is evidenced from the silt deposits in and around the lake.
The environmental significance lies in the fact that such a rate of siltation would result in shallowing of the lake floor and may prove disastrous during higher degrees of run off, either due to excess precipitation or melting of ice. The present state of human interference, in the form of settlements around the lake and farming practices on the reclaimed and / or acquired land of the lake, are beyond permissible limits of the environmentally safety zones.
Keywords: Seismicity, Shales, Geomorphology

The International Journal of Climate Change: Impacts and Responses, Volume 1, Issue 3, pp.233-244. Article: Print (Spiral Bound). Article: Electronic (PDF File; 2.291MB).

Evidence for bias in C/N, δ13C and δ15N values of bulk organic matter, and on environmental interpretation, from a lake sedimentary sequence by pre-analysis acid treatment methods.

by Chris Brodie

In Press - Quaternary Science Reviews

Lead Author: Dr. Chris Brodie (Hong Kong University, Hong Kong)

Co-Authors: Dr. James Casford (Durham University); Dr. Jeremy Lloyd (Durham University, UK); Prof. Melanie Leng (NIGL, UK); Dr. Timothy Heaton (NIGL, UK); Christopher Kendrick (NIGL, UK); Dr. Zong Yongqiang (Hong Kong University, Hong Kong).

ABSTRACT:
There is a known bias in C/N, d13C and d15N values of organic matter (OM) due to pre-analysis acid... more ABSTRACT:
There is a known bias in C/N, d13C and d15N values of organic matter (OM) due to pre-analysis acid treatment methods. We report here, for the first time, the results of a pre-analysis acid treatment method comparison of measured C/N, d13C and d15N values in bulk OM from a sedimentary sequence of samples to illustrate this bias. Here we show that acid treatment significantly reduces the accuracy (between method biases) and precision (within method bias) of C/N, d13C and d15N values of OM, suggesting a differential response of sample OM between methods and sample horizons, and in some cases inefficient removal of inorganic carbon. We show that different methods can significantly influence environmental interpretation in some of our sample horizons (i.e. interpretation of aquatic vs. terrestrial OM source; C3 vs. C4 vegetation). Specifically, there are unpredictable and non-linear differences between methods for C/N values in the range of ~ 1 – 100; d13C values in the range of 0.2 – 6.8 ‰ and; d15Nvalues in the range of 0.3 – 0.7 ‰. Importantly, these ranges are mostly much greater than the instrument precision (defined as the standard deviation of replicate analysis of standard reference materials; for this study, ± 0.5 for C/N values, ± 0.1 ‰ for d13C values and; ± 0.1 ‰ for d15N). The accuracy and precision of measured C/N, d13C and d15N values of bulk OM is not just dependent upon environmental variability, but on acid pre-treatment, residual inorganic carbon and organic matter state and composition. Collectively, this makes the correlation between samples prepared in different ways, including those from down core reconstructions, highly questionable.

Keywords: C/N ratios, δ13C, δ15N, organic matter; pre-analysis acid treatment methods, environmental interpretation, palaeoclimate.

Arsenic Contamination of Groundwater in Nepal—An Overview

by Jay Krishna Thakur

http://www.mdpi.com/2073-4441/3/1/1/

Abstract: In Nepal, arsenic (As) contamination is a major issue of current drinking water supply systems using... more Abstract: In Nepal, arsenic (As) contamination is a major issue of current drinking water supply systems using groundwater and has recently been one of the major environmental health management issues especially in the plain region, i.e., in the Terai districts, where the population density is very high. The Terai inhabitants still use hand tube and dug wells (with hand held pumps that are bored at shallow to medium depth) for their daily water requirements, including drinking water. The National Sanitation Steering Committee (NSSC), with the help of many other organizations, has completed arsenic blanket test in 25 districts of Nepal by analysing 737,009 groundwater samples. Several organizations, including academic institutions, made an effort to determine the levels of arsenic concentrations in groundwater and their consequences in Nepal. The results of the analyses on 25,058 samples tested in 20 districts, published in the status report of arsenic in Nepal (2003), demonstrated that the 23% of the samples were containing 10–50 µg/L of As, and the 8% of the samples were containing more than 50 µg/L of As. Recent status of over 737,009 samples tested, the 7.9% and 2.3% were contaminated by 10–50 µg/L and >50 µg/L, respectively of As. The present paper examines the various techniques available for the reduction of arsenic concentrations in Nepal in combination with the main results achieved, the socio-economic status and the strategies. This paper aims to comprehensively compile all existing data sets and analyze them scientifically, by trying to suggest a common sustainable approach for identifying the As contamination in the nation, that can be easily adopted by local communities for developing a sustainable society. The paper aims also to find probable solutions to quantify and mitigate As problem without any external support. The outcome of this paper will ultimately help to identify various ways for: identify risk areas; develop awareness; adopt the World Health Organization (WHO) guideline; identify alternative safe water sources and assess their sustainability; give priorities to water supply and simple eco-friendly treatment techniques; investigate impacts of arsenic on health and agriculture; strengthen the capability of government, public, Non-governmental Organization (NGO) and research institutions.

Keywords: arsenic; arsenic contamination in groundwater of Nepal; drinking water; groundwater resources management

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http://www.mdpi.com/2073-4441/3/1/1/

A case for late-Archaean continental emergence from thermal evolution models and hypsometry

by Patrice Rey

N. Flament, N. Coltice, P. F. Rey, (2008). Earth Planet. Sci. Lett., 275, p. 326-336

The secular cooling of the Earth's mantle and the growth of the continental crust together imply changes in the... more The secular cooling of the Earth's mantle and the growth of the continental crust together imply changes in the isostatic balance between continents and oceans, in the oceanic bathymetry and in the area of emerged continental crust. The evolution of these variables is of fundamental importance to the geochemical coupling of mantle, continental crust, atmosphere and ocean. To explore this further, we developed a model that evaluates the area of emerged continental crust as a function of mantle temperature, continental area and hypsometry.
In this paper, we investigate the continental freeboard predicted using different models for the cooling of the Earth. We show that constancy of the continental freeboard (± 200 m) is possible throughout the history of the planet as long as the potential temperature of the upper mantle was never more than 110–210 °C hotter than present. Such numbers imply either a very limited cooling of the planet or, most likely, a change in continental freeboard since the Archaean. During the Archaean a greater radiogenic crustal heat production and a greater mantle heat flow would have reduced the strength of the continental lithosphere, thus limiting crustal thickening due to mountain building processes and the maximum elevation in the Earth's topography [Rey, P. F., Coltice, N., Neoarchean strengthening of the lithosphere and the coupling of the Earth's geochemical reservoirs, Geology 36, 635–638 (2008)]. Taking this into account, we show that the continents were mostly flooded until the end of the Archaean and that only 2–3% of the Earth's area consisted of emerged continental crust by around 2.5 Ga. These results are consistent with widespread Archaean submarine continental flood basalts, and with the appearance and strengthening of the geochemical fingerprint of felsic sources in the sedimentary record from 2.5 Ga. The progressive emergence of the continents as shown by our models from the late-Archaean onward had major implications for the Earth's environment, particularly by contributing to the rise of atmospheric oxygen and to the geochemical coupling between the Earth's deep and surface reservoirs.

Groundwater and Soil Geochemistry of the Eastern Kopaida Region (Beotia, Central Greece)

by Evangelos Tziritis

The upper Miocene of Karlovassi Basin, Samos Island, Greece, contain continental evaporites such as colemanite,... more The upper Miocene of Karlovassi Basin, Samos Island, Greece, contain continental evaporites such as colemanite, ulexite, celestite, gypsum and thenardite. These evaporites are related with volcanic tuffs, diagenetically altered in a saline-alkaline lake environment. The aim of the present paper is to: a) define the impact of the already known and possible buried borates and other evaporites to the geochemistry of the hydrogeological system of Karlovassi Basin, and; b) to assess the correlation between surface and underground evaporite deposits considering the spatial changes in the concentrations of the examined physicochemical parameters. Fieldwork, laboratory measurements and literature data revealed elevated boron values (2136-33012 μg/L) in the central part of Karlovassi Basin. In the same area, high amounts of strontium, sodium, lithium and sulfates also occur. It is proposed that these ions originate from the leaching of evaporites and authigenic minerals such as the Sr-rich clinoptilolite and the boron-bearing potassium feldspar. Boron values are abnormally high for freshwater aquifers, and are indicative of the presence of buried evaporites in the basin with unknown significance.

Numerical modelling – An emerging tool for sustainable management of aquifers

by Elango L

Geological setting and groundwater chemistry in Chithar river basin Tamil Nadu India

by Elango L

Distribution of Iron, Manganese, Zinc and Atrazine in groundwater in parts of Palar and Cheyyar river basins, South India

by Elango L

Groundwater quality assessment in Tondiar basin, Tamil Nadu, India

by Elango L

Hydrogeochemistry and its relation to groundwater level fluctuation in the Palar and Cheyyar river basins, southern India

by Elango L

Hydrogeochemical reactions in aquifers and its identification by geochemical modelling

by Elango L

Modelling the effect of subsurface barrier on groundwater flow regime

by Elango L

Numerical modelling of groundwater flow in south Chennai coastal aquifer

by Elango L

Mobility of major ions and nutrients in the unsaturated zone during paddy cultivation: a field study and solute transport modelling approach

by Elango L

Seasonal and spatial variation in magnesium and chloride concentration in groundwater of deltaic regions of Kumbakonam, Nannilam and Karaikal, Tamil Nadu

by Elango L

Spatial variation of groundwater quality and inter elemental correlation studies in lower Bhavani river basin, Tamil Nadu, India

by Elango L

Rainfall variation analysis of Vattamalaikarai sub-basin, Tamil Nadu, India

by Elango L

Spatial variation and seasonal behaviour of rainfall pattern in lower Bhavani river basin, Tamil Nadu, India

by Elango L

GIS based groundwater quality of Vattamalaikarai basin, Tamil Nadu, India

by Elango L

Assessment of water quality in Kalpakkam region, Tamil Nadu

by Elango L

2008