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Über dieses Buch

This book critically analyzes the water quality in the lower Gangetic delta, and examines the environmental conditions and physical processes operating in this rich ecosystem. Readers with an interest in environmental science, geography, oceanography, marine biology, environmental biology, aquatic pollution and ecology will find the research presented here most appealing.
Readers will discover critical aspects of the chemistry of the estuarine water (particularly that of Hooghly and Matla estuaries) in the lower stretch of the delta region along with the causes and effects of pollution in and around this region. Particular attention is given to the bioaccumulation of conservative pollutants in edible fishes and floral communities thriving in this region. Several case studies are also incorporated to highlight the vulnerability of pollution in this region. Chapters also address the impacts of climate change (specifically acidification) on the concentration and behavior of conservative pollutants. Finally, the book highlights some mitigation measures at the technology and policy level to minimize the negative impacts posed by different groups of pollutants on the estuarine biodiversity.

Inhaltsverzeichnis

Frontmatter

Chapter 1. Lower Gangetic Delta: An Overview

Abstract
Two mighty river systems, the Ganga and the Brahmaputra, enter the plains of Bengal through a 150-km-wide stretch as Rajmahal–Meghalaya gap. These two rivers drain a large catchment area covering more than 1.50 million sq. km. and carry annually 1254 billion cubic meters of water with suspended sediment load of about 1000 million tonnes. The fragile Himalayan terrain and southwest monsoon are two major factors contributing to huge volume of water and sediment load. After entering Bengal, the Ganga flows in southeast direction, and the Brahmaputra flows in the southern direction before they unite at a place called Gaolando in Bangladesh. These two rivers discharged into the sea independently till 1830. Further downstream, another river called Meghna joins, and the combined flow goes into the Bay of Bengal (Fig. 1.1).
Abhijit Mitra

Chapter 2. Aquatic Status of Gangetic Estuaries

Abstract
Estuaries have been defined by ecologists from various points of view, but the basic key words are semi-enclosed coastal body of water, salinity, tidal action and dilution factor.
Abhijit Mitra

Chapter 3. Heavy Metal Status in the Lower Gangetic Delta

Abstract
A heavy metal may be defined as an element with higher atomic weight, which has the properties of a metallic substance at room temperature. There are several different definitions of heavy metals, but none of them are cent percent accurate to explain the term.
Abhijit Mitra

Chapter 4. Nutrient Level in the Lower Gangetic Estuaries

Abstract
Very little research work is available on the comparative account of natural and man-made (anthropogenic) sources of nutrients in the aquatic ecosystem. The estimate made by Ferguson is presented in Table 4.1.
Abhijit Mitra

Chapter 5. Pesticide Level in the Lower Gangetic Delta

Abstract
Persistent organic pollutants (POPs) are organic compounds that are resistant to environmental degradation through chemical, biological and photolytic processes. Due to this nature, they persist in the environment, bioaccumulate in human and animal tissue, biomagnify in food chains and have potential significant impacts on human health and the environment. Thus these groups of chemicals are not materially broken down over a reasonable period of time and are usually measured in decades or more. The POPs of most concern are those that build up in the environment or get bioaccumulated and/or biomagnified in the food chain.
Abhijit Mitra

Chapter 6. Climate Change and Pollution

Abstract
The climate of the planet Earth is regulated by the balance between the amount of energy the Earth receives from the Sun, in the form of light and ultraviolet radiation, and the amount of energy the Earth releases back to space, in the form of infrared heat energy. The basic causes of climate change involve any process that can alter this global energy balance. Scientists call this “climate forcing”. Climate forcing “forces” or induces the climate to change.
Abhijit Mitra

Chapter 7. Pollution from Aquaculture

Abstract
Aquaculture, particularly shrimp culture, has developed rapidly over the last three decades to become an important economic activity worldwide. It has confronted many of the developmental problems in this relatively short period including sector competition, overproduction, trade restrictions, overcapitalization and concerns over environmental impacts. The significance of aquaculture in the context of global food production sector, the management of aquatic resources and the socioeconomic development of coastal rural areas is now fully appreciated worldwide. Significant advances have also been made globally to make shrimp aquaculture development responsible and sustainable.
Abhijit Mitra

Chapter 8. Monitoring and Management of Pollution Level

Abstract
The health of any aquatic ecosystem or the survival of biota in the system is a function of its physico-chemical variables. The domain of physico-chemical variables includes parameters like water temperature, dissolved oxygen (DO), pH, salinity and nutrients (like nitrate, phosphate and silicate). Also the measurements of toxicants like insecticides, herbicides and metals are included within the list of physico-chemical variables. Physico-chemical indicators provide information on what is impacting on the system. For example, is it an organic waste that affects DO or is it some specific type of toxicants? Sometimes excessive nutrient load in the aquatic ecosystem (that originates from the domestic and municipal sewage) triggers the growth of phytoplankton and causes eutrophication. Thus biological organisms are also being affected by physico-chemical variables.
Abhijit Mitra

Backmatter

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