P. K. Ray

Bio: P. K. Ray is an academic researcher from Indian Institute of Toxicology Research. The author has contributed to research in topics: Freshwater snail & Zinc toxicity. The author has an hindex of 4, co-authored 4 publications receiving 176 citations.

Correlation between heavy metal acute toxicity values in Daphnia magna and fish.

Abstract: In the toxicant bioassays, invertebrates with special reference to aquatic arthropod species have been of recent interest as test models due to the need for developing nonmammalian tests system. The cladoceran Daphnia magna bioassays have several practical advantages. D. magna has been used as a useful test species and its sensitivity to environmental pollutants have been recognized as a general representative of other freshwater zooplankton species. The objectives of this study were to determine the acute toxicity of various heavy metals to Daphnia magna for 48 h of exposure and to compare these values with the existing LC50 values for rainbow trout (Salmo gairdneri); which is commonly used as a test animal in aquatic bioassay studies.

Sensitivity of toad tadpoles, Bufo melanostictus (Schneider), to heavy metals.

Abstract: Amphibian larval stages have several qualities which make them as a useful indicator of harmful levels of pollutants in bioassay tests. Amphibian tadpoles show a variety of sublethal responses such as changes in growth, development rates, pigmentation and expression of morphological deformities in a lesser time of exposure to the environmental pollutants. The objective of the work reported in this paper was to determine the acute toxicity of cadmium, copper, chromium, mercury, nickel, silver and zinc to the tadpoles of toad Bufo melanostictus (Schneider), which is commonly available and breed in aquatic habitats exhibiting a wide range of temperature and varying water quality.

Immune responses to Aeromonas hydrophila in cat fish (Heteropneustis fossilis) exposed to cadmium and hexachlorocyclohexane.

Abstract: Fishes are poikilothermic vertebrates hence all the body functions including immunological defense may be susceptible to adverse changes in the aquatic environment. Environmental pollutants, especially heavy metals and pesticides are known to contribute to outbreaks of infectious bacterial diseases in fishes. Pesticides enter the aquatic environment through intentional application, aerial drift or runoff from applications or accidental release and then become rapidly distributed. Major routes of pesticide movement into water are agricultural runoff from fields and grazing lands. Several investigators have evaluated the toxicity of hexachlorocyclohexane (HCH) in fishes, however, only sporadic observations on the humoral immune responses have been made. Cadmium has been demonstrated to affect the immune system of teleost. The effects of sublethal concentrations of methylmercury and copper on the immune response of blue gourami (Trichogaster trichopterus) have also been studied. Attempts have been made to investigate the effect of the HCH and cadmium on the humoral immune responses to bacterial antigen using H. fossilis as test species. Attempt is also made to evaluate the vascular function at sublethal doses.

Zinc sensitivity of a freshwater snail, Lymnaea luteola L., in relation to seasonal variations in temperature.

Abstract: The aquatic environment has numerous physical and chemical parameters that may influence the physiology and chemical toxicity to freshwater organisms. Temperature is one of the these factors having a marked influence on heavy metal toxicity to fishes and macroinvertebrates. There is a limited and scattered information available on temperature induced changes in acute toxicity of zinc compounds to freshwater pond snails. This information is essential because there are large temperature differences with season and latitudes and the aquatic organisms are subjected to seasonal temperature changes of 20-25/sup 0/C or even more. It is proposed to study the effect of seasonal changes in temperature on zinc toxicity to a freshwater pond snail, Lymnaea luteola (Lamarck), which form an important link in aquatic food chain(s) and are widely distributed in lakes, ponds and rivers of India.

Tin Hazards to Fish, Wildlife, and Invertebrates: A Synoptic Review.

Abstract: : Interest in the toxicity of tin compounds dates to the early 1800's when investigators demonstrated that inorganic tin compounds produced muscular weakness, loss of pain sensation, and immobility in dogs (Reiter and Ruppert 1984; Idemudia and McMillan 198Gb). In man, organotins can be assimilated by inhalation, absorption through the skin, and from food and drinking water (Zuckerman et al. 1978). The first documented case of organotin poisoning of humans was in 1880 when workers complained of headaches, general weakness, nausea, and diarrhea after exposure to triethyltin acetate vapors (Reiter and Ruppert 1984). Renewed interest in the toxicity of organotin compounds resulted from a medical tragedy in France in 1954. Stalinon, a proprietary compound of diethyltin diiodide plus linoic acid used to treat furuncles and other skin infections, caused 217 poisonings and 111 deaths (Piver 1973; Duncan 1980; Idemudia and McMillan 198Gb). The identified toxic components in Stalinon were triethyltin contaminants; victims received a total dose of 3 grams over a 6- to 8-week period. Symptoms included constant severe headache, rapid weight loss, vomiting, urine retention, vertigo, hypothermia, abdominal pain, and visual and psychic disturbances. Some of the more severely affected patients had convulsions. Death usually occurred in coma or from respiratory or cardiac failure. In survivors, headaches and diminished visual acuity remained for at least 4 years.

Bioaccumulation of Chromium, Manganese, Nickel and Lead in the Tissues of the Moggel, Labeo umbratus (Cyprinidae), From Witbank Dam, Mpumalanga

Abstract: This paper focuses on the extent of Cr, Mn, Ni and Pb bioaccumulation in the different tissues of a cyprinid fish, namely the moggel (Labeo umbratus) from Witbank Dam in the Upper Olifants River catchment, The dependence of bioaccumulation on size, gender and seasons was specifically addressed. Bioaccumulation of Cr, Mn, Ni and Pb varied between the gills, liver, muscle and skin. The gills generally had the highest metal concentrations, due to their intimate contact with the environment and their importance as an effector of ionic and osmotic regulation. The liver, in its role as a storage and detoxification organ, can also accumulate high levels of metals. Muscles and skin accumulated much less metal concentrations. These two organs must be included in biomonitoring programmes because they are consumed hy the general public. Accumulation of the metals decreased with an increase in fish length Therefore the smaller the fish the higher the body load of metals due to various bioaccumulation processes. The accumulation of Cr, Mn and Ni in the different tissues of male and female fish did not differ markedly It is suggested that the male testes and female ovaries should also be compared, in order to obtain further data on the differences of accumulation of metals between males and females The highest tissue concentrat ions of Cr, Mn, Ni and Pb with the exception of the muscle and skin tissues, were recorded in the summer of 1995. The higher metal concentrations in the summer, compared to autumn and winter, can possibly he attributed to a varied water temperature.