Udayakumar, P; Dr.Ouseph, P P(Cochin University Of Science And Technology, July 19, 2012)
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Abstract:
The nearshore marine ecosystem is a dynamic environment impacted by
many activities, especially the coastal waters and sediments contiguous to major
urban areas. Although heavy metals are natural constituents of the marine
environment, inputs are considered to be conservative pollutants and are
potentially toxic, accumulate in the sediment, are bioconcentrated by organisms
and may cause health problems to humans via the food chain. A variety of
metals in trace amounts are essential for biological processes in all organisms,
but excessive levels can be detrimental by acting as enzyme inhibitors.
Discharge of industrial wastewater, agriculture runoff and untreated sewage
pose a particularly serious threat to the coastal environment of Kerala, but there
is a dearth of studies in documenting the contaminant metals. This study aimed
principally to assess such contamination by examining the results of heavy
metal (Cu, Pb, Cr, Ni, Zn, Cd and Hg) analysis in seawater, sediment and
benthic biota from a survey of five transects along the central and northern
coast of Kerala in 2008 covering a 10.0 km stretch of near shore environment in
each transect. Trophic transfer of metal contaminants from aquatic invertebrates
to its predators was also assessed, by employing a suitable benthic food chain
model in order to understand which all metals are undergoing biotransference
(transfer of metals from a food source to consumer).The study of present contamination levels will be useful for potential
environmental remediation and ecosystem restoration at contaminated sites and
provides a scientific basis for standards and protective measures for the coastal
waters and sediments. The usefulness of biomonitor proposed in this study
would allow identification of different bioavailable metals as well as provide an
assessment of the magnitude of metal contamination in the coastal marine
milieu. The increments in concentration of certain metals between the predator
and prey discerned through benthic food chain can be interpreted as evidence of
biotransference.
Description:
School of Environmental Studies
Cochin University of Science and Technology
Latha, C; Dr.Ammini, Joseph(Cochin University of Science and Technology, April , 1998)
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Abstract:
In the last decades considerable headway has been made in research and development
of phyto-chemical pesticides. The most notable recent success is the commercial
development of neem products for insect control. The present investigation on
Environmentally Compatible Phyto-Chemical Larvicides for Mosquito Control was
undertaken to identify plants of the locality with potential larvicidal activity on mosquito
larvae. This has been achieved by screening 17 plant species against four mosquito species.
The observation and data are compiled in six chapters .
Description:
School of Environmental Studies, Cochin University of Science and Technology
Philip,Mathew; Dr.Ravindranatha Menon,N(Cochin University of Science and Technology, August , 1990)
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Abstract:
The present scientific investigation of the effects of copper, mercury and cadmium has focussed on their effects on two commercially important marine bivalve species, Perna indica (brown mussel) and Donax incarnatus (wedge clam), conspicuous representatives of the tropical intertidal areas. The investigation centred around delineating the cause and effects of heavy metal stress, individually and in combination on these species under laboratory conditions. A clear understanding of the cause and effect can be had only if laboratory experiments are conducted employing sub-lethal concentrations of the above toxicants. Therefore, during the course of the investigation, sub-lethal concentrations of copper, mercury and cadmium were employed to assess the concentration dependent effects on survival, ventilation rate, O:N ratio and tissues. The results obtained are compared with the already available information and partitioned in sections to make a meaningful presentation.The thesis is presented in five chapters comprising INTRODUCTION, ACUTE TOXICITY, VENTILATION RATE, OXYGEN : NITROGEN RATIO and HISTOPATHOLOGY. Each chapter has been divided into various sections such as INTRODUCTION, REVIEW OF LITERATURE, MATERIAL AND METHODS, RESULTS and DISCUSSION
Description:
Head, Division of Marine Biology, Microbiology and
Biochemistry, School of Marine Sciences, Cochin University
of Science and Technology
Prabhudeva,K N; Dr.Ravindranatha Menon,N(Cochin University of Science and Technology, August , 1987)
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Abstract:
In this thesis certain important aspects of heavy metal toxicity have been worked out. Recent studies have clearly shown that when experimental media contained more than one heavy metals, such metals could conspicuously influence the toxic reaction of the animals both in terms of quantity and nature. The experimental results available on individual metal toxicity show that, in majority of such results, unrealistically high concentrations of dissolved metals are involved. A remarkable number of factors have been shown to influence metal toxicity such as various environmental factors particularly temperature and salinity, the condition of the organism and the ability of some of the marine organisms to adapt to metallic contamination. Further, some of the more sensitive functions like embryonic and larval development, growth and fecundity, oxygen utilization and the function of various enzymes are found to be demonstrably sensitive in the presence of heavy metals. However, some of the above functions could be compensated for by adaptive process. If it is assumed that the presence of a single metal in higher concentrations could affect the life function of marine animals, more than one metal in the experimental media should manifest such effects in a greater scale. Commonly known as synergism or more than additivity, majority of heavy metals bring about synergistic reaction .The work presented in this thesis comprises lethal and sublethal toxicities of different salt forms of copper and silver on the brown mussel Perna indica. during the present investigation sublethal concentrations of copper and silver in their dent effects on survival, oxygen consumption, filtration, accumulation and depuration on Perna indica. The results are presented under different sections to make the presentation meaningful .
Description:
Division of Marine
Biology, Microbiology and Biochemistry, School of Marine Sciences, Cochin University of Science and Technology