Search

The focuses a study related to possible threats to fishes of Simsang river in Meghalaya, India caused by acid mine drainage (AMD). It states the process of AMD formation, citing that AMD contains high levels of heavy metals like cobalt aluminum and copper. It mentions that the Simsang River receives significant amounts of AMD while passing through various regions having coal mines and notes that the fishes in the river have been reportedly declining over the past years, as of 2015.

Mercury, a global pollutant, has become a real threat to the developing countries like India and China, where high usage of mercury is reported. Mercury and other heavy metals deposited in to the aquatic system can cause health risk to the biota. The common edible fishes such as Mugil cephalus, Arius arius, Lutjanus ehrenbergii, Etroplus suratensis were collected from Cochin backwaters, Southwest India and analysed for mercury and other heavy metals (zinc, cadmium, lead and copper) in various body parts. Kidney and liver showed highest concentration of metals in most fishes. The omnivore and bottom feeder ( E. suratensis) showed high concentration of mercury (14.71 mg/kg dry weight) and other metals (1.74 mg/g-total metal concentration). The average mercury concentration obtained in muscle was 1.6 mg/kg dry weight (0.352 mg/kg wet weight), which is higher than the prescribed limits (0.3 mg/kg wet weight). The concentration of other heavy metals in the muscles of fishes were found in a decreasing order Zn>Cu>Cd>Pb and are well below WHO permissible limits that were safe for human consumption. Metal selectivity index (MSI) obtained for all the metals except mercury showed that both carnivores and omnivores have almost same kind of affinity towards the metals especially Zn and Cd, irrespective of their feeding habit. The MSI values also indicate that the fishes have the potential to accumulate metals. High tissue selectivity index (TSI) values were reported for kidney, muscle and brain for all metals suggests that the metal concentration in these tissues can serve as an indication of metal polluted environment. Even if the daily intakes of Zn, Cd, Pb and Cu from these fishes are within the provisional maximum daily intake recommended by WHO/FAO, the quality is questionable due to the high hazard index obtained for mercury (>1). Fishes like E. suratensis being a favourite food of people in this region, the high consumption of it can lead to chronic disorders as this fish has high concentration of metals. [ABSTRACT FROM AUTHOR]

The toxicity of Metal-cyanide complex (copper cyanide) to the freshwater fish, Catla catla was studied using static bioassay method. The LC50 in 96 h was found to be 32 μg/L. Behavioural changes when exposed to lethal concentration of copper cyanide showed increased opercular movement, increased surface behaviour, loss of equilibrium, change in body colour, increased secretion of mucus, irregular swimming activity, rapid jerk movement, 'S' jerk, partial jerk and aggressiveness. Oxygen consumption was decreased in lethal concentration, but in sub lethal concentration decreased trend was improved and reached normal level at 21st day. [ABSTRACT FROM AUTHOR]

The distributions of trace metals (Pb, Cd, Cr Mn, Zn and Cu) in water, sediment, plankton and four fish species (Labeo rohita, Catla catla, Pangasius pangasius and Cirrhinus mrigala) from fishponds of Kolleru Lake, India were determined using atomic absorption spectroscopy. The concentrations of lead (0.01–0.03mg/l) and copper (0.01–0.08mg/l) in water and cadmium (3.0–9.0mg/kg), chromium (47–211mg/kg) and copper (10–64mg/kg) in sediment were above the EPA threshold effects level (TEL) and are of biological concern. The abundance orders of metals were Mn>Cd>Cu>Pb in water, Mn>Cr>Zn>Cu >Pb>Cd in sediment and Cu>Mn>Cr>Zn>Pb>Cd in plankton. The concentrations of the metals in the muscles of these four fish species apparently decrease in the order Zn>Cu>Cr>Mn=Pb>Cd and were well below WHO permissible limits that were safe for human consumption. [Copyright &y& Elsevier]

The paper describes a quantitative analysis of mercury done on samples of freshwater fish, Channa punctatus, collected from Bhaba Atomic Research Centre campus and from certain beaches of Mumbai, India. Concentration of mercury found in the fish samples is much higher than the permissible level of 0.1-0.15 ppm. The study indicates that normal scale structure has circuli all over. These are the signs of calcium deposition or the growth of rings. The study demonstrates that mercury has a direct effect on the fish scales. The mercury contaminated fish can prove dangerous for people's health. So it is suggested that scales can be used to assess the heavy metal pollution in an aquatic ecosystem.