PhD Theses (SACON)
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Item Polycyclic aromatic hydrocarbon contamination in Pallikaranai wetland, Chennai, Tamil Nadu, India; Fish as an Indicator.(SACON, 2020) Mythreyi, D.; Muralidharan, S.Enormous quantities of man-made chemicals are being used every day to meet the ever increasing food, energy, transport and industrial demands. During the past few decades, there has only been a steady increase in the use of these chemicals leading to their excessive presence throughout the global environment. Wetlands, being the most fragile ecosystems have suffered the maximum. Extensive stretches of wetland habitats have been altered and destroyed. Among the gazillion types of chemicals, Persistent Organic Pollutants (POPs) are significant because they are resistant to degradation in the environment and biota. Due to their fat soluble nature and resistance to degradation, ingestion of certain POPs by fauna leads to bioaccumulation throughout their lives, generally in fat tissues, and biomagnification through food chain. Among the POPs, Polycyclic Aromatic Hydrocarbons (PAHs) are highly prevalent in vertebrates, particularly fishes. Polycyclic Aromatic Hydrocarbons (PAHs) are a unique class of POPs constituted by hundreds of individual organic compounds. These ubiquitous environmental contaminants are wide-spread in the air, bonded to particulate matter and readily bioavailable. Studies have demonstrated the carcinogenic, mutagenic and teratogenic behaviour of many of the PAHs. Based on their properties, 16 PAHs are listed as “priority pollutants” by the U.S. Environmental Protection Agency (EPA). These 16 PAHs are being measured and monitored in different environmental components in ecosystem throughout the globe.Item Levels of metal contamination in various species of birds in select states in India.(SACON, 2019) Kirubhanandhini, V.; Murlidharan, S.In India, studies on metal contamination on birds are a few. There is a growing concern to examine metal contamination in birds and interpret their levels; thereby appropriate measures may be taken to conserve the species. Metal levels in tissues can serve as an indication of the potential effects for alerting managers and the public to mitigating ecological problems. The presence of metal contaminants in tissues of birds is a problem that has not been fully resolved, given the ethical and legal impediments associated with the hunting and killing of bird species. The use of body feathers for studying metal contamination is another possible solution to this problem, as removal of these feathers does not injure the birds. In reference of seabirds, breast feathers are especially useful for establishing spatio and temporal patterns in bird populations and for evaluating metal contamination in species that are threatened or in danger of extinction. The present study was conducted with objective to document the levels of accumulalion of metals such as Cd, Pb, Cr, Ni , Cu and Zn in different species of birds in select states of India.Item Pesticide Residues in select components of an Agroecosystem adopting organic and conventional farming in Padayetti Village, Palakkad District, Kerala(SACON, 2014) Ganesan, K.; Muralidharan, S.The ever increasing human population and the corresponding demand for food have forced the producers to intensify their efforts to increase the productivity. Among the grain crops, paddy is the highest pesticide consuming crop in India. Increasing awareness on health and many environmental issues associated with the indiscriminate use of chemical fertilizers and pesticides has led to interest in alternate methods of agricultural farming which are environment-friendly and economically feasib le. The Kerala State Biodiversity Board (KSBB) through Department of environment and Climate Change (DoEee) launched a demonstration project known as "Granary of Kerola" in Palakkad district in 2009 to conserve biodiversity associated with agroecosystems by totally avoiding chemical inputs in agriculture. To protect the paddy crop from weeds, insects and diseases, pesticides such as insecticides, herbicides and fungicides are used. Moreover, determination of pesticide residues in paddy has become increasingly essential for consumers, producers and authorities responsible for quality control. Hence, this study was conducted to investigate pesti cide residues in different environmental components adopting two different types of cultivation methods, namely organic and conventional.Item Organochlorine pesticides, population and reproductive success of fish-eating birds in select heronries in Tamil Nadu(SACON, 2013) Jayakumar, S.; Murlidharan, S.Colonial water birds are one of the major vital components of a wetland ecosystem. They serve as an excellent indicator of wetland health. In India. destruction of fresh water wetlands and entry of contaminants pose significant threats to the long-term stability of the population of colonial water birds and their habitats. Enormous quantities of man-made chemicals are used in modern agriculture. Despite obvious benefits, their indiscriminately has resulted in accumulation of residues in food and animal tissues causing environmental and ecological impact. Presence of pesticide residues, particularly persistent organochlorines in different biological and non-biological components has raised concern about their long-term accumulation and effects. Birds occupy different trophic levels in different food chains and hence are exposed to different concentrations of contaminants through their food. III effects of pesticides on wildlife. especially raptors, waterfowl and fish-eating birds have been extensively studied around the world. But, in India such information on birds particularly fish-eating birds (colonial birds) is limited. Although. some information is available on the residue levels of pesticides present in eggs of fish-eating and insectivorous birds in lndia, they fail to bring out the exact scenario of pesticide usage in agricultural areas and residue levels in eggs, and the consequent impact on breeding outcome. Further. there are 110 studies which have repol1ed the residue levels in eggs and simultaneously monitored the population of birds over a period of time in India. The present work was conducted in select heronries in Tamil Nadu with the following objectives; identify the heronries in Tamil Nadu, monitor the population and study breeding ecology of colonial nesting birds in select locations. document the residue levels of organochlorine pesticides in fishes, eggs and tissues of colonial nesting birds and asses the impacts.Item Polychlorinated Biphenyl (PCB) residues in marine fishes available in Coimbatore market and their suitability for human consumption(SACON, 2011) Alaguraj, A.; Muralidharan, S.Seven species of marine fishes totalling 732 individuals caught at Cochin and Rameshwaram coasts, and sold in Ukkadam fish market. Coimbatore between October 2004 and October 2006 were analysed for residues of 32 individual congeners, including six indicator PCBs (PCB 28, 52, 101, 138, 153 and 180) with Gas Chromatograph coupled with Mass Selective Detector. Fishes included in the present study are Indian Mackerel (Rastrelliger kanagurta), Japanese Threadfin Bream (Nemipterus japonicus), Oil Sardine (Sardinela Iongiceps), Great Barracuda (Sphyraena barracuda), Malabar Travelly (Carangoides malabaricus), Tongue Sole (Cyanoglossus macrolepidotus) and King Seer (Scomberomollus commersonil)' Selection was based on human consumption (preference), commercial value and availability throughout the year in both the locations.Item Organochlorine Pesticide Residues in the Marine Fishes of Coimbatore Market – Suitability for Human Consumption(SACON, 2012) Jayanthi, P.; Muralidharan, S.The current study has attempted to document the organochlorine pesticide residues in select species of commercially important marine fishes, received from Cochin and Rameshwararn, and sold at Coimbatore market. A total of 716 fish samples belonging to seven species, namely Carangoides malabaric, Cynoglossus macrolepidotus, Nemipterus japonicus, Rastrelliger kanagurta, Sardinella longiceps, Scomberomorus commersonn and Sphyraena barracuda caught at Cochin and Rameshwaram were collected from the Coimhatore market. The samples were collected with regular intervals during the study period (October 2004 . September 2006) which fell into eight quarters, with three months being one quarter.