Nilanjana Chatterjee

Harmful Impact of ZnS Nanoparticles on Daphnia sp. in the Western Part (Districts of Bankura and Purulia) of West Bengal, India

ZnS nanoparticles of different sizes are synthesized employing a simple wet chemical method. These nanoparticles are used to study their impact on the Daphnia sp. through traditional toxicity tests. The percentage of mortality is found to increase initially with increasing nanoparticle concentration or exposure time and is finally found to saturate for higher concentrations or exposure times. Mortality is found to be higher for smaller particles. Hopping frequency and heart rate are also found to increase with increasing nanoparticle exposure time for a fixed nanoparticle concentration. These observations can be attributed to the enhanced surface photooxidation property of the ZnS nanoparticles. Thus the present study will help people to understand the hitherto unknown harmful impact of ZnS nanoparticles on aquatic organisms in the western part of West Bengal (Bankura and Purulia districts), India.

Hazardous effect of ZnS nanoparticles on the feeding behaviour, growth and maturation process of the Asian striped catfish, Mystus vittatus (Bloch, 1794)

The Asian striped catfish Mystus vittatus (Bloch) are exposed to ZnS nanoparticles of different concentrations and its impact on feeding behaviour, growth and maturity of the fish is studied. The study reveals the fact that under nanoparticle exposure, the feeding behaviour, growth and maturation stages depart from that of the controlled conditions. The growth is found to be restricted with increasing nanoparticle concentration. Gonadal maturity has also found to be constrained with increasing nanoparticle concentrations up to a certain level. These effects are found to be more pronounced for nanoparticles of smaller sizes. The observations are explained on the basis of the enhanced photo-oxidation property of the ZnS nanoparticles.

Revelation of ZnS Nanoparticles Induces Follicular Atresia and Apoptosis in the Ovarian Preovulatory Follicles in the Catfish Mystus tengara (Hamilton, 1822)

Important physicochemical characteristics of water like dissolved oxygen content, pH, and so forth were found to change in a dose dependent manner, showing a negative correlation with the nanoparticle concentration, when ZnS nanoparticle (NP) was exposed to water. This observation could be attributed to the enhanced photooxidation property associated with ZnS in its NP form. Under this situation, the catfish Mystus tengara was forced to live in hypoxia in its habitat. This condition was found to hamper the natural oogenesis process of the fish. Due to exposure at relatively lower concentration of ZnS NPs (250 μg/L), most of the maturing follicles of M. tengara failed to complete the process of vitellogenesis properly and underwent preovulatory atresia followed by oocytic apoptosis. For relatively higher concentration of ZnS nanoparticles (500 μg/L), the previtellogenic process continued with increasing number of apoptotic cells; however the vitellogenic process was found to be totally blocked. This unusual reproductive behaviour in female M. tengara can be attributed to the decreased metabolism of the fishes under ZnS nanoparticle induced hypoxia.

An Analytic Contemplation of the Conspicuous Vicissitudes in the Histomorphology of Corpuscles of Stannius of a Freshwater Catfish Mystus tengara (Hamilton, 1822) due to the Exposure of ZnS Nanoparticles

Enhanced surface photooxidation property associated with the ZnS nanoparticles caused the reduction of dissolved oxygen content in water in a dose dependent manner, when ZnS nanoparticles of different sizes are exposed to the water in various concentrations. This property was more prominent for ZnS nanoparticles with smaller sizes. Mystus tengara, exposed to ZnS nanoparticles, responded to hypoxia with varied behavioural, physiological, and cellular responses in order to maintain homeostasis and organ function in an oxygen-depleted environment. The histomorphology of corpuscles of Stannius of the fish showed conspicuous vicissitudes under exposure of ZnS nanoparticles. The population of the cell type with granular cytoplasm showed significant increase at the expense of the other that consisted of agranular cytoplasm with increasing nanoparticle concentration. This can be explained as the defence mechanism of the fish against ZnS nanoparticle induced hypoxia and environmental acidification. The altering histomorphology has been studied employing an analytical approach.

DISQUIETING EFFECT OF ZNS NANOPARTICLES ON AN INDIAN MINOR CARP, LABEO BATA (HAMILTON, 1822) AND THE ASIAN DWARF STRIPED CATFISH MYSTUS VITTATUS (BLOCH, 1794) WITH RESPECT TO SOME OF THEIR VITAL ORGANS: A COMPARATIVE STUDY.

Nilanjana Chatterjee 1 and * Baibaswata Bhattacharjee 2 . 1. Department of Zoology, Ramananda College, Bishnupur-722122, Bankura, India. 2. Department of Physics, Ramananda College, Bishnupur-722122, Bankura, India. ...................................................................................................................... Manuscript Info Abstract ......................... ........................................................................ Manuscript History