Zoology
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Item Use of liver histological alterations and erythrocytic nuclear abnormalities of two native fish in Kelani River, Sri Lanka as biomarkers for pollution impact assessments(Journal of the National Science Foundation of Sri Lanka, 2020) Ruvinda, K.; Pathiratne, A.Multi-biomarker approach is recognised as a complementary tool for environmental monitoring studies to better appraise how pollutants affect ecosystems. This study examined histological alterations in the liver tissues and nuclear abnormalities in the peripheral erythrocytes of two native fish species inhabiting the Kelani River (Etroplus suratensis and Dawkinsia singhala) as ‘effect biomarkers’ for assessing pollution impacts. Surface water and native fish were sampled from two polluted sites in the lower reach (Kaduwela and Mattakkuliya) and a less polluted site in the upper reach (Ruwanwella) of the river covering rainy and dry periods. Physico-chemical analyses of surface water confirmed an increasing trend of pollution towards the lower reach of the river. Significantly greater liver histopathologic condition indices and erythrocytic nuclear abnormality frequencies (p < 0.05) were found in the fish inhabiting lower reaches of the river compared to those in the upper catchment at Ruwanwella. Biomarker responses revealed that the fish populations inhabiting the polluted sites in the river are under stress especially due to hepatic damage and genotoxicity. The results suggest that endemic and nationally threatened fish species in the riverine ecosystem may be at risk due to the contaminant stress under long term exposure. This study supports utility of erythrocyte nuclear abnormality and liver histopathological biomarker responses of native fish as cost effective tools for the identification of potential biological hazards of river pollution.Item Toxic hazards of industrial waste receiving canal system in the lower catchment of Kelani River basin, Sri Lanka(2020) Kuruppuarachchi, H.; Pathiratne, A.Assessing toxic hazards associated with polluted riverine ecosystems is essential for the development of effective strategies for their management. The present study explored the combined utility of bioassay responses of the plant, Allium cepa and surface water physico-chemical characteristics to assess the toxic hazards of an industrial waste receiving canal system located in the lower catchment of the Kelani River basin, Sri Lanka. Surface water samples from seven sites, viz. Maha Ela upstream (Site A), Manikagara Ela (Site B), Manikagara Ela - Maha Ela confluence (Site C), Maha Ela downstream (Site D), Maha Ela - Kelani River confluence (Site E), River downreach (Site F) and upper-reach (Site R) were analysed on three occasions in 2015 covering dry and wet periods. Irrespective of the sampling periods, exposure of A. cepa bulbs to water from the Sites B, C, D and E resulted in root growth retardation and mitosis depression (p < 0.05) in the root meristem signifying toxic/cytotoxic hazards. Occasional micronuclei evolution and nuclear bud induction were also found in the root cells exposed to Site B and C samples indicating genotoxicity. Toxic hazards were somewhat reduced towards down-reach of the river, which may be associated with self-depuration effects. The principal component analysis based on surface water characteristics and bioassay responses revealed clear separations of Sites B and C from the other sites. The results revealed that water quality of Manikagara Ela and Maha Ela needs improvements considering toxic hazards to the riverine ecosystem and human healthItem Comparison of Sensitivity of Tropical Freshwater Microalgae to Environmentally Relevant Concentrations of Cadmium and Hexavalent Chromium in Three Types of Growth Media(Bull Environ Contam Toxicol, 2020) Munagamage, T.; Rathnayake, I.V.N.; Pathiratne, A.Sensitivity of tropical freshwater microalgae (Mesotaenium sp., Chlorococcum sp. and Scenedesmus sp.) to environmentally relevant concentrations of hexavalent chromium (Cr6+) and cadmium (Cd2+) was compared individually in three growth media viz. Bold’s Basal Medium (BBM), Test Medium 1 (TM1) and Test Medium 2 (TM2) based on fluorescence reduction. Free metal content of growth media was determined by Visual MINTEQ (version 3.1). After 24 h, relative fluorescence of microalgae in the three media decreased with increased metal concentration showing a concentration dependent graded toxicity response. All microalgae were more sensitive to the metals when grown in TM1, when compared, more sensitive to Cr6+ than Cd2+. Metal speciation indicated that TM1 and TM2 media have higher percentage of bioavailable Cd2+ than BBM, and chromium was present mainly as CrO42− and HCrO4−. The results suggest that the TM1 medium is more suitable under short term exposure of microalgae to metals in environmental monitoring.Item Cadmium and arsenic levels in edible fi shes, Oreochromis niloticus (Nile tilapia) and Ompok bimaculatus (butter catfi sh) from Padaviya Reservoir, Sri Lanka and human health risk assessment associated with their dietary exposure(2020) Weerasekara, K. A. W. S.; Pathiratne, A.; Kithsiri, H. M. P.Consumption of fi sh contaminated with toxic heavy metals is a threat to human health. Cadmium and arsenic are suspected as potential risk factors for chronic kidney disease of unknown aetiology (CKDu), which is highly prevalent in agricultural settlements in dry zone districts of Sri Lanka causing a severe public health crisis. Objectives of this study were (i) to determine cadmium and arsenic levels in muscle, liver and kidney of two edible fi shes (Nile tilapia and butter catfi sh) from the Padaviya reservoir located in the North Central Province, Sri Lanka where CKDu is highly prevalent and (ii) to assess the potential human health risks associated with the dietary exposure through edible muscle of these fi shes. Cadmium and arsenic levels of the tissues in the two fi sh species were determined using inductively coupled plasma mass spectrometry. In both fi sh species, highest cadmium levels were found in kidney (p < 0.05) whereas no signifi cant tissue specifi c diff erences (p > 0.05) were evident for arsenic. In the edible muscle, the maximum detected cadmium level in Nile tilapia was 0.1 mg/kg in wet weight. However, cadmium levels in the muscle of all Butter catfi sh were < 0.05 mg/kg. Arsenic levels in the muscle of all Nile tilapia and Butter catfi sh were < 0.05 mg/kg. Cadmium contents in muscle of most fi shes and arsenic contents in all fi shes (n = 60) were within the maximum permissible limits set by the international food standards regulatory authorities. Based on the estimated daily intake and target hazard quotients (< 1) for lifetime exposure, it is highly unlikely that cadmium and arsenic contents of the muscle meat of these fi shes would pose human health risks to moderate level consumers.Item Application of cytogenetic model Allium cepa for screening potential cytogenotoxicity of herbal-based hair dyes(Journal of Environmental Science and Health, 2020) Nawalage, K. S.; Pathiratne, A.Plant models may be useful as test organisms for initial screening of potential toxicity of personal care products. The objective of the present study was to assess the efficacy of the Allium cepa (common onion) test system as a bioanalytical tool for screening potential cytotoxicity and genotoxicity of herbal-based hair dye formulations. Exposure of black hair dye formulations for 48 hours resulted in root growth retardation and mitosis suppression in the root meristems of A. cepa bulbs indicating concentration dependent cytotoxicity. At the 72 hour post exposure, cytotoxic effects on the roots were reduced but not recovered completely signifying prolong toxic action of the hair dyes. The condensed nuclei was the most frequent nuclear abnormality found in the dye exposed root meristematic cells indicating the cell death process. Induction of micronuclei and chromosomal aberrations in the root meristematic cells even at the post exposure stage indicates persistent genotoxicity of the hair dyes which may be attributed to the interactive effects of chemical mixtures present in the commercial hair dye formulations. The results revealed that A. cepa test system is an effective bioanalytical tool for screening cytogenotoxicity of commercial hair dye formulations.Item Heavy metal levels in two food fish species from Negombo estuary, Sri Lanka: relationship with the body size(Sri Lanka Association for Fisheries and Aquatic Resources, 2008) Indrajith, H.A.P.; Pathiratne, K.A.S.; Pathiratne, A.Item Effect of Titanium Dioxide Nanoparticles on Haematological and Immunological Parameters and Histological Structure of Nile Tilapia Oreochromis niloticus(Sri Lanka Association for Fisheries and Aquatic Resources, 2012) Perera, S.A.D.S.; Pathiratne, A.The increased industrial application of nanotechnology has potential to contaminate aquatic ecosystems with nanoparticles. However effects of nanoparticles on fish health are little known. Present study was carried out to evaluate the effect of Titanium dioxide (TiO,) nanoparticle exposure on haematological/immunological parameters and histological structure of the food fish, Nile tilapia. Fish were exposed to TiO, nanoparticles (0, 1, 10, SO mgL") through water borne exposure under laboratory controlled conditions and haematological and immunological parameters in the blood, histological structures of gills, stomach and liver were assessed using standard methods at pre-determined time periods (7, 14 days). Exposure to 50 mgL-' TiO, was found to be lethal for Nile tilapia as 33% mortalities occurred after exposure of seven days. Increased opercular movement rates, erratic swimming patterns were observed within two hours of exposure in the fish exposed to 10, 50 mgL-' TiO, concentrations. Hyperplasial conditions of the gills of the fish exposed to TiO, confirmed that the fish were under respiratory stress. Erythrocyte and haemoglobin levels in the blood of fish exposed to TiO, were increased significantly which may indicate the homeostatic responses in order to compromise the reduced oxygen extraction capacity. Neutrophil and lysozyme levels in the blood were increased in the fish exposed to TiO, whereas myeloperoxidase activity of the TiO, exposed fish was decreased indicating the stress induced by TiO, exposure. Histological structure of liver at high exposure levels displayed cellular vacuolations, sinusoidal congestions and focal necrosis where as stomach mucosa showed autolysis. The present study revealed that short term exposure to high concentrations of TiO, nanoparticles can lead to ill health conditions of Nile tilapia. Detail studies on effect of environmentally relevant levels of nanoparticles on fish health are recommended as increased usage of nanoparticles will result in contaminations of inland water bodies.Item Assessment of Bio Available Polycyclic Aromatic Hydrocarbons and Induction of Erythrocytic Nuclear Abnormalities Associated with Petroleum Refinery Wastewater Exposure Using Fish Models(Sri Lanka Association for Fisheries and Aquatic Resources, 2012) Rukmalee, W.N.; Pathiratne, A.Petroleum refinery wastewater may contain different chemicals including polycyclic aromatic hydrocarbons (PAHs) some of which are genotoxie. Release of the refinery wastewater to the aquatic environments may pose a threat to the aquatic fauna especially fish populations. Biological effects associated with wastewater can be assessed using biomarkers as early warning signals. The objective of the present study was to assess biological effects associated with wastewaters of Petroleum Refinery, Sri Lanka using a selected PAH indicative biomarker (bile fluorescent PAH metabolite patterns) and a genotoxic biomarker (erythrocytic micronuclei in the blood) using fish models. The fish species used in the study were Oreochromis niloticus for controlled laboratory exposure and Trichogaster pectoralis and Puntius filamentosus, inhabiting water canals located near the Petroleum refinery (Pattiwila canal and Heiyanthuduwa canal) for exposure assessments under natural conditions. A less polluted water body was selected as the control site for field studies (Bathalagoda reservoir). Bile fluorescence patterns of the fish were assessed using fixed fluorescence and synchronous fluorescence spectrometry. Erythrocytic nuclear abnormalities in the blood (micronuclei, binuclei and other nuclear abnormalities) were examined using cytogenetic tests. The results showed that several PAHs metabolites (Napthalene-, Phenanthrene-, Fluoranthene-, Chrysene- and Benzo(a)pyrenetype) accumulate in bile of 0. niloticus as a result of being exposed to the Petroleum refinery wastewater under laboratory conditions. Bile of T. pectoralis and P. fjlamentosus collected from the nearby canals also displayed PAH exposure in comparison to the fish collected from the control site. Erythrocytic micronuclei in the blood were highly induced in the fish species examined under laboratory (upto 20 fold) and field conditions (upto 26 folds) in comparison to the comparable controls. The present study revealed that tested petroleum refinery wastewater contains micronuclei inducible contaminants including PAHs.Item Heavy metal levels in water and sediments of Bathalagoda Reservoir, Sri Lanka(Sri Lanka Association for Fisheries and Aquatic Resources, 2010) Hemachandra, C.K.; Pathiratne, A.; Pathiratne, K.A.S.Bathalagoda reservoir, a fresh water body located in the Kurunegala District of Sri Lanka is used by the residents in the area for irrigating paddy fields, drinking and bathing purposes and for culture-based fisheries. The present study was carried out to determine the selected heavy metal levels viz. lead, cadmium and copper in water and sediments of the reservoir to assess the extent of heavy metal pollution. Water and sediment samples were obtained from three locations of the reservoir namely Ibbagamuwa, Moragolla and Madihe- Mudunduwa during the period September 2007 - July 2009 and the heavy metal levels were determined by Atomic Absorption Spectrometry following standard procedures. The results showed that lead, cadmium and copper levels in water ranged from not detectable level to 2 g L", not detectable level to 3 g L" and not detectable level to 3 g L" respectively. Corresponding metal levels in the sediments (dry weight basis) ranged from not detectable level to 523 g g", not detectable level to 0.1 g g" and not detectable level to 26 g g" respectively. Significant site specific variations or seasonal variations were not observed in relation to the heavy metal levels in water and sediments of the reservoir. The results revealed that the levels of lead, cadmium and copper in the reservoir water are far below the maximum permissible levels specified by the international regulatory authorities (World Health Organization and United States Environmental Protection Agency) for drinking water and water used for irrigation purposes.Item Gill cholinesterases in bivalves, Crassostrea madrasensis and Anadara antiquata: Evaluation of their potential use as biomarkers of neurotoxic contamination in brackish water bodies in Sri Lanka(Sri Lanka Association for Fisheries and Aquatic Resources, 2010) Liyanage, T.D.; Pathiratne, A.Estuaries and lagoons in Sri Lanka are increasingly threatened by anthropogenic pollution. Cholinesterases (ChEs) of bivalves inhabiting these brackish water bodies may be used as ecotoxicological waming signals of the occurrence and effects of aquatic pollution. The present study was undertaken to characterize the biochemical properties of ChEs in the gill tissues of two bivalves, Crassestrea madrasensis and Anadara antiquata using different substrates and selective inhibitors. In addition, sensitivities of gill ChEs of these bivalves to selected aquatic pollutants viz, Cadmium and Copper (heavy metals) and Chlorpyrifos (an organophosphate insecticide) were assessed. Responses to specific substrates and inhibitors suggested the presence of two types of ChEs viz. Acetylcholinesterase and Butyrylcholinesterase in the gill tissues of both species. Dose dependent inhibition in the enzyme activ ies was observed in response to in vitro exposure to Copper and Cadmium and in vivo exposure to Chlorpyrifos. Both species showed similar sensitivity to the tested heavy metals. However gill ChEs of Anadara antiquata were more sens ive to Chlopyrifos exposure than that of the other species. In conclusion, gill cholinesterases in the two bivalve species have a potential as biomarkers for mon oring neurotoxic polluants in brackish water bodies in Sri Lanka .