Water quality prediction capabilities of WASP model for a tropical lake system

Water quality modelling facilitates our better understanding of the processes taking place in a lake system, and conservation plans to address them. The water quality analysis simulation programme (WASP) was used in this study to predict daily variations in water quality parameters, namely dissolved oxygen, nitrate, phosphate and chlorophyll‐a and biochemical oxygen demand concentrations in a tropical lake system. The lake was divided into eight segments with the respective morphological, environmental and flow details being model inputs. The monthly concentration of each water quality parameter also comprised model input. The model output was daily spatiotemporal variation in these parameters over a period of 476 days. This study also indicated that the occurrence of precipitation plays a major role in defining the water quality of a tropical lake. The heavy precipitation after a long gap, especially during the summer season, results in a large quantity of organic matter entering the lake through drains, thereby increasing the organic matter and phosphate in the water body, and subsequently resulting in high chlorophyll‐a concentrations in the lake. A reduced chlorophyll‐a concentration was observed during the heavy rains. The water quality fluctuations are more pronounced with precipitation, especially where polluted drains enter the lake. An improved water quality can be observed downstream, including increased dissolved oxygen and nitrate concentrations. Improved water quality was observed during the postmonsoon period, with increased salinity and dissolved oxygen concentrations, a finding that confirms generalized and specific conclusions can be achieved with the use of the WASP model.     

Thermal comfort study of Kerala traditional residential buildings based on questionnaire survey among occupants of traditional and modern buildings

Thermal comfort studies on traditional residential buildings of Kerala that is known for its use of natural and passive methods for a comfortable indoor environment, are under progress. Scientific analyses of the environmental parameters determining thermal comfort have already been reported. Similar studies on modern residential buildings are underway. In order to compare the results of the scientific analysis with the user responses from the residents of traditional as well as modern residential buildings, a questionnaire survey was conducted during various seasons such as winter, summer and monsoon. A questionnaire was prepared in detail to understand the effect of factors which affect thermal comfort such as temperature, humidity and air flow in the evaluation of thermal comfort. This paper is based on the compilation of responses from the conducted survey. A comparison of the study results with that of scientific analysis already reported is also incorporated at the end of this paper. This study further confirms that Kerala traditional residential buildings are very effective in providing comfortable indoor environment irrespective of various seasons.     

Heavy metal concentrations in fish,shellfish and fish products from internal markets of India vis-a-vis international standards

Heavy metals are an important group of chemical contaminants and food is the major vehicle for entry into the system. Fish constitute a major source of heavy metals in food. Concentration of heavy metals in commercially important species of fish, shellfish and fish products from fish markets in and around the Cochin area was evaluated using an atomic absorption spectrometer. The concentration ranges of Cd, Pb, Hg, Cr, As, Zn, Cu, Co, Mn, Ni, and Se in the samples were <0.07–1, <0.07–1.32, <0.05–2.31, <0.05 to 3.65, <0.1–4.14, 0.6 to 165, 0.15 to 24, <0.02 to 0.85, <0.08 to 9.2, <0.032–1.38 and; <0.03–1.35 mg/kg, respectively. The present study showed that different metals were present in the samples at different levels but within the maximum residual levels prescribed by the EU and USFDA and the fish and shellfish from these areas, in general, are safe for human consumption.     

Mathew & Ghosh Architects

The work of Mathew & Ghosh Architects (Nisha Mathew-Ghosh and Soumitro Ghosh) boldly extends an abstract Modernist language and at the same time draws from the vitality of places. While the firm's early works were small in scale, mostly residential in nature and based on a reappraisal of the early Corbusian idiom, recent projects include large-scale urban and landscape interventions with diverse conceptual and metaphorical imperatives. They have moved from a more reticent stance to the urban exuberance of their more recent projects (for example, their own office building), something akin to a ‘savage architecture’ as posited by Kazuo Shinohara in the context of the unsynchronised nature of the modern city. The architects' object of contemplation is the urban ‘box’, whether a private residence, office or part of a church. The box is first fractured and reconstructed as a bricolage of tectonic fragments, memories and events, all tenuously related as if unity in a contemporary culture is for ever denied. Like the Japanese notion of ‘ma’, the moment between fragments - a slit or an emptiness between two hovering planes - is telling. Mathew & Ghosh participate in the continuity of a historical narrative yet mark out the fissures and disjunctions; sometimes negotiations with the continuity emerge from unintended interstices. While these configurations of the contemporary urban ‘box’ are both contextual and abstract, they are also phenomenologically rich. There is a sustained dialect to the architecture of Mathew & Ghosh that includes consummate materiality and fine crafting, light as a medium, and always, as Nisha Mathew-Ghosh states, ‘good spatial possibilities’. Copyright © 2007 John Wiley & Sons, Ltd.     

Cancer ecology in Kerala,India

Studies carried out on the spatial distribution of cancer in India reveal a high intensity zone of cancer in Kerala, especially in respect of tumours of the oral cavity, pharynx and respiratory system. It is suggested that an ecological approach involving the study of environmental deficiencies or overloads of minerals and radio‐active elements in the soil and dietary habits, could provide useful guidelines for the control of cancer in Kerala.     

The occurrence of vulnerable seagrass species Halophila beccarii Ascherson, 1871 from restored mangrove of Koduvally Estuary,south‐west coast of India

The ocean turf grass, Halophila beccarii Ascherson, 1871 was recorded for the first time in the intertidal region of the restored mangrove ecosystem of the Koduvally Estuary on the south‐west coast of India. It was found co‐existing in the shallow muddy area of the mangroves, dominated by mangrove trees of Rhizophora mucronata and Sonneratia alba, and macroalgae, Ulva sp., Enteromorpha sp. and Chaetomorpha sp. The meadow is sparsely scattered with shoots near the mangroves, with a mean density of 720 shoots/m². Details regarding the morphology and hydrographic conditions are described. The occurrence of H. beccarii in the Koduvally estuary is an encouraging sign of improved ecosystem health through mangrove restoration. The development of seagrass meadow in the estuary will improve the sediment stability and water quality. A further comprehensive study on the spatiotemporal variation of this species in the estuary is also recommended for conservation and management of this vulnerable seagrass species.     

Multivariate analysis of the sediment quality of a tropical coastal lake system

Accurate knowledge of sediment quality is essential because it affects the magnitude and trends of water quality constituents. There are only a few analyses of sediment quality characteristics using multivariate analysis tools. This study utilizes hierarchical cluster analysis (HCA), factor analysis (FA) and multiple regression analysis (MRA) to demonstrate the usefulness of these techniques to analyse sediment quality for Akkulam–Veli Lake, a tropical coastal lake system in Kerala, India. The variation of sediment quality patterns during the premonsoon (PRM), monsoon (MON) and postmonsoon (POM) periods were assessed with cluster analysis. Factor analysis was used to identify prominent factors influencing sediment quality, while the factors influencing heavy metal partitioning in the sediment and overlying water were identified using multiple regression analysis. The study results indicated the sediment in the upstream portion of the lake was polluted during PRM, with the prominent factors being the ‘heavy metal factor’ and the ‘organic pollution factor’, followed by the ‘phosphorus pollution factor’ and the ‘cadmium pollution factor’. The ‘heavy metal factor’ and the ‘organic pollution factor’ are the prominent factors during MON, whereas the ‘heavy metal factor’, ‘organic pollution factor’ and ‘salinity factor’ were prominent POM factors. The salinity of the overlying water above the sediments plays an important role during PRM and POM, whereas the dissolved oxygen content was important during MON.     

Prioritization of pollution potential zones for conservation activities of a lake system

Many coastal lakes are under serious threats due to increased pressures associated with population growth, accelerated eutrophication, invasive species and toxic contamination. The extent of the pollution depends almost entirely on the characteristics and processes taking place in the lake basin. The objective of this study was to identify the pollution potential zones (very high, high, medium and low) in the Akkulam–Veli (A–V) Lake Basin (Thiruvananthapuram, Kerala) using GIS‐enabled, multithematic overlay analysis. The primary characteristics considered were geomorphology, lithology, land use, soil, slope and population density. The results of this study indicated the major portion of the lake basin exhibits very high or high pollution potential zones, with the drains passing through the very high pollution potential zone being mainly responsible for the contamination of the lake water. High population density, predominant commercial use and settlement with mixed tree crop, level and gentle slope (low slope) are the factors responsible for the very high pollution potential. The organic pollutants in the lake system increase with the increased extent of the very high pollution potential area. This analysis approach will help authorities to identify the underlying causes of lake water quality degradation and plan and implement effective measures for protecting the lake. This process can also be utilized by scientists elsewhere to facilitate lake protection.     

Passive control methods of Kerala traditional architecture for a comfortable indoor environment: A comparative investigation during winter and summer

Kerala is a strip of land on the southwest coast of India lying between Arabian Sea on the west and Western Ghats on the east. The traditional architecture of Kerala is known for its use of natural and passive methods for a comfortable indoor environment. However, it has not been proved by a detailed and quantitative evaluation method so far. A field study was thus conducted in the winter and summer periods to investigate the indoor environmental condition of a typical Kerala traditional residential building. The objective of the investigation was to understand the passive environment control system of Kerala traditional architecture by quantitative analysis of various thermal comfort parameters. It was done by continuously monitoring the indoor and outdoor conditions using a custom made instrument called “Architectural Evaluation System”. The results show that the natural and passive control system of Kerala traditional architecture provides comfortable indoor environment irrespective of the outdoor climatic conditions.     

Landfill sites,solid waste management and people’s resistance: a study of two municipal corporations in Kerala

This paper examines some issues associated with the centralised waste management system and the ways in which urban local bodies tackled the resistance against centralised waste management. The study is based on a sample survey of 175 households located in the landfill sites connected with two Municipal Corporations, viz. Thrissur and Kochi. The study observed that the local government resists change in solid waste management. When the resistance is strong alternative methods like decentralised waste management are chosen; and where the resistance is weak there is a tendency to maintain the centralised waste management system.