Browsing by Author "Murlidharan, S."

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Heavy metal contamination in the fishes of Inland wetlands of India.
(SACON, 2007) Jayakumar, R.; Murlidharan, S.
Heavy metals are one of the most toxic, persistent and widespread group of contaminants in aquatic systems. Their effects may often occur and remain unrecognized at the individual level but slowly, over a period of time, show up at population level. It is well known that heavy metals measured in tissues of aquatic organisms can reflect past exposures. They can also be a reasonable measurement for public health standards and in the point of view of animals' health. Over a few decades globally there has been growing interest to determine levels of heavy metals in the aquatic environment and public food supplies, particularly fish due to their known hazards. In India heavy metals although have not created any major problems, varying magnitudes of heavy metal contamination do exist in various biotic and abiotic components. Information on heavy metal contamination in fishes lay scattered and many of them do illustrate the toxic effects at laboratory conditions. Further information on the suitability of fishes for human consumption, in the perspective of metal contamination, is limited. The current study has attempted to document the heavy metal contamination status of select wetlands spread across the country using fish as an indicator. Altogether 8S9 fishes comprising 19 species were collected from 90 wetlands spread across 10 states in the country and examined for heavy metal contamination, Further, biomarkers of metal contamination, namely Metallothionein and Glutathione were also quantified in a few species of fishes collected from select wetlands in Tamil Nadu. Biomarkers are expected to indicate the stress in fishes and serve as an early warning signal. Suitability of fishes for human consumption was evaluated as it will help assess the impact on human beings in tong run.
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.
Levels of organic contaminates and select biomarkers in the birds of Gujarat and Tamil Nadu, India
(SACON, 2009) Dhananjayan, V.; Murlidharan, S.
There has been an ongoing concern about the presence of different types of contaminants in the environment and their ill effects on wildlife, particularly birds. While substantial information is available on such in effects on birds elsewhere in the world , very limited data exist in India, A study was initiated to document the environmental residue levels of certain persistent organic contaminants, chemicals responsible for incidences of mortality of birds and, generate information on the levels of cholinesterase in brain and blood plasma of birds. The major objectives were to understand tissue specific accumulation of contaminants, namely organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs) and polycyclic a romatic hydrocarbons (PAHs) in birds, examine the variation in accumulation pattern between sexes and feeding habits, identify normal or reference levels of biomarkers, namely acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) to explain mortality of birds. Two representative cities, namely Ahmedabad, Gujarat in the west and Coimbatore, Tamil Nadu in the south were selected as study locations
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.