Assessment of Arsenic (As), Lead (Pb) and Chromium (Cr) Accumulation in Different Organs of Commercially Important Fish Species Collected from Chattogram Coastal Region of Bangladesh.

Aims: The purpose of this study was to evaluate whether there are any significant toxic effects of the widely exposed metals on different organs (gill, liver, kidney, and muscle) of some commercially important marine fish species (Herpodon nehereus, Pampus chinensis and Hilsa ilisha). Study Design: The collection of the samples was done from January to March 2018 from Bay of Bengal near Chattogram city of Bangladesh. The study is based on randomly collected samples from the intended sampling sites (Randomized Block Design) to ensure the evenness and unbiases of the collected samples. Methodology: Analyses were performed for metals such as arsenic (As), lead (Pb) and chromium (Cr) using Atomic Absorption Spectrophotometer (AAS). During each month, five individuals each with three replications from the three targeted species were collected, with a total of 135 (45*3) fishes in the study period. Results: The concentrations of the metals found in the fishes varied in the following ranges: As: 0.029-0.071 ppm, Pb: 0.008-0.083 ppm and Cr: 0.0001-0.03 ppm. The obtained result revealed the highest concentrations of all three metals were recorded in H.nehereus fish. The organ wise lead concentration was recorded highest in kidneys and gills of examined fishes with significant variation in muscles and liver. The scenario depicted quite differently in case of chromium where concentration in gills was found to be the highest with insignificant variation in accumulation in other three organs. In case of Arsenic, kidneys and livers were the most exposed two organs in comparison to significant exposure to muscles and gills. The obtained values of arsenic accumulation were considered critical for human consumption as it was higher than the recommended values stated by WHO and FAO; but the concentration of lead and chromium were found to be safe for human consumption. The values recorded for lead were increasingly approached to the safety values. Conclusion: So, crucial steps should be taken regarding safety and environmentally friendly discharge of arsenic and lead; high levels of pollution will not only affect aquatic life but will also invite socio-economic disasters.

Seasonal variability of coastal water quality in bay of Bengal and Palk Strait, Tamilnadu, Southeast Coast of India

The aim of this work was to study the physicochemical parameters of water quality collected from 12 sampling stations from Topputhurai to Muthupet in Vedaranyam located on the southeast coast of India from January to December 2008. Results showed that the DO and nutrients were the maximum in the Bay of Bengal during the monsoon period. High concentration of the nutrients in summer season was obtained near the Muthupet mangroves compared to the Palk Strait, which showed that this acted as a source of nutrients to the adjacent coastal waters. Low concentrations of the nutrients observed in the monsoon could be attributed to the terrestrial runoff from Muthupet lagoon. The physicochemical characteristics of coastal waters between the Point Calimere and Muthupet could be used as a baseline data for the monitoring, conservation and management of Point Calimere Wildlife and Bird sanctuary, Great Vedaranyam swamp and Muthupet mangrove ecosystem.

Copepod population in Vellar estuary, Parangipettai coast in relation to environmental conditions.

Distribution and abundance of copepods were studied in relation to environmental conditions at two different ecosystems viz: Neritic (Bay of Bengal) and estuarine (Vellar estuary) of Parangipettai coast from September, 1998 to August, 2000. Over the study period, total 85 species of copepods were reported. Among these, the calanoid copepods constituted the major component with 63.52% followed by cyclopoids (29.41%) and harpacticoids (7.05%). The copepods population density was found to be high (2, 53, 000 org l-1) in estuarine water, while the species diversity was higher (5.47) in neritic water. The observed spatio-temporal variations in the population density and species diversity of copepods were more related to the environmental state of respective study area.

Biogeochemical processes in the continental slope of Bay of Bengal: I. Bacterial solubilization of inorganic phosphate

Microorganisms play a vital role in the biogeochemical cycles of various marine environments, but studies on occurrence and distribution of such bacteria in the marine environment from India are meager. We studied the phosphate solubilizing property of bacteria from the deep sea sediment of Bay of Bengal, India, to understand their role in phosphorous cycle (and thereby the benthic productivity of the deep sea environment). Sediment samples were obtained from 33 stations between 10 degrees 36'N-20 degrees 01' N and 79 degrees 59' E-87 degrees 30' E along 11 transects at 3 different depths i.e. ca. 200 m, 500 m, 1000 m in each transect. Total heterotrophic bacterial (THB) counts ranged from 0.42 to 37.38 x 10(4) CFU g(-1) dry sediment weight. Of the isolates tested, 7.57% showed the phosphate solubilizing property. The phosphate solubilizing bacterial genera were Pseudomonas, Bacillus, Vibrio, Alcaligenes, Micrococcus, Corynebacterium and Flavobacterium. These strains are good solubilizers of phosphates which ultimately may play a major role in the biogeochemical cycle and the benthic productivity of the Exclusive Economic Zone (EEZ) of Bay of Bengal, because this enzyme is important for the slow, but steady regeneration of phosphate and organic carbon in the deep sea.