Acute toxicity of cadmium to Channa punctatus (BLOCH)

Effects of acute cadmium poisoning on survival, its residual values and histopathology in certain organs of a freshwater airbreathing fish, Channa punctatus (BLOCH ) were investigated. The threshold concentration, MATC and LC₅₀ values obtained from 96 h static bioassay, revealed that Channa is more susceptible to cadmium ions at higher temperature. The atomic absorption spectrophotometric determination of cadmium residues differed significantly in organs of specimens having survived and died after 96 h of exposure. The gill accumulate the highest amount of cadmium, the liver accumulated a slightly smaller amount than the gill, while the kidney accumulated the least. The histopathological lesions subjected to sublethal (5.2 mg/l Cd) and lethal (8.4 mg/l Cd) concentrations of cadmium were: detachment and rupture of lamellar epithelium, collapse of pillar cells and hypertrophy in mucus producing gland cells in the gill; vacuolization and coagulative necrosis in hepatic cells of the liver; and expansion, necrosis and accumulation of cellular debris in renal tubules of the kidney. The probable causes for death of fish due to cadmium ions have been discussed.     

Histological Changes in a Few Tissues of Notopterus notopterus Induced by Sublethal and Lethal Concentrations of Pulp,Paper and Mixed Pulp and Paper Wastes

In the present work, histological changes in the gill, liver, kidney and intestine of Notopterus notopterus, induced by pulp waste, paper waste and mixed pulp and paper waste, have been studied both at sublethal and lethal concentrations. The pulp waste produces much more histological changes both at sublethal and lethal concentrations in the gill, liver, kidney and intestine as compared to paper waste and mixed pulp and paper waste. The changes are much more remarkable in the case of sublethal concentration, as compared to a lethal concentration. In a sublethal concentration, the localized necrosis, atrophy and partial and total liquefaction of epithelial cells, pilaster cells, mucous cells of the gill, hepatic cells of the liver, mesenchymatous cells, renal tubule cells and Bowman's capsule of the kidney, mucosal and submucosal cells and blood vessels of intestine have been observed. In lethal concentration, the changes are much more marked in the gill, as compared to the liver, kidney and intestine. The histological changes, produced in the different types of cells and in the tissue as a whole, can be correlated with the different chemical components present in the pulp waste, paper waste and mixed pulp and paper waste.     

Alterations in the architecture of the gill surface produced by water-borne copper in Heteropneustes fossilis (BLOCH)

In the present investigation the effect of water-borne copper on the gill architecture of a freshwater teleost, Heteropneustes fossilis (BLOCH ) was studied through scanning electron microscopy. The changes produced on the gill surface in a sublethal measured copper concentration (8.17 mg/1) in static bioassay after 96 h of exposure were fusion of secondary lamellae, rupture of various cellular components and deposition of excessive mucus and blood on the gill surface. The epithelial surface of treated gill thus lost the organized structures like microvilli, arborizing ridges and channels. The cause of fish mortality due to action of copper has been discussed in reference to reduced relative diffusing capacity along with other wide ranging effects on the metabolism of fish.     

A time series of mercury accumulation and improvement of dietary feed in net caged Atlantic salmon (Salmo salar)

The study was undertaken to investigate the uptake of mercury in salmon throughout the entire farming period at the net cage. Mercury concentrations in muscle, liver, kidney, and gill and responses to the various dietary mercury concentrations were determined. The accumulation of mercury is in the order of kidney>gill=liver>muscle. The highest mercury peak concentrations were observed for both kidney and gill at the parr-smolt period, while liver and muscle mercury peaked one month later after caging at the grow-out site. High dietary sodium and calcium fed to the salmon contributed to the elevation of mercury in kidney and gill during the smolting process. The mercury burden over the grow-out period increased sharply with a linear relationship of mercury uptake. The tissue mercury burden per gram of growth was calculated using the slope of mercury burden and the slope of growth over the period of each stage. The results showed dietary mercury loadings on marketable salmon were within tolerance limits of FDA and US EPA. Rapid growth of salmon and low dietary mercury progressively reduces the uptake of mercury in salmon. The time series of mercury monitoring showed that mercury concentrations in salmon were greater at the parr stage in freshwater than at the grow-out stage in salt water.     

Plastic debris ingestion by sea turtle in Paraíba, Brazil

Coastal gill net entanglement and debris intake are important threats to the survival of sea turtles. Two sea turtles (Lepidochelys olivacea and Chelonia mydas) were found stranded along the coast of Paraíba. After necropsy, plastic debris were found in the stomach. The debris is described. This is the first record of this sort of problem for the Paraíba littoral.     

Dating of post-glacial landforms in the central howgills

Little is known of Holocene landform development in Upland Britain. This paper describes a site at Middle Langdale in the Howgill Fells of Cumbria where large, but now stabilized and inactive gullies cut through periglacial material. At the base of the gullies large debris cones have buried earlier alluvial sediments on the valley floor. On these sediments and buried by the debris cones is a well-developed organic soil from which two ¹⁴C dates have been obtained in an attempt to estimate the age range of the soil. These dates range from 2580±55 years BP for the fine particulate fraction from the base of the organic horizon to 940±95 years BP for fossil rootlets from the uppermost organic layer, immediately below the overlying debris cones. The pollen evidence suggests that the valley floor site was initially dominated by alder carr and later by a Juncus marsh with birch, alder and hazel nearby. The pollen, from the surrounding upland area suggests woodland on the valley sides, dominated by oak and elm that was later replaced by a more open environment rich in heath species and in which disturbed ground species were present. The magnetic evidence indicates a stable local environment during soil formation but shows a sudden inwash of unweathered debris at the top of the buried soil. The evidence suggests that the valley floor was geomorphologically stable throughout the period of soil formation, although there was a local change in valley floor vegetation and a reduction of woodland cover on the valley sides at sometime during the period. The evidence then points to major geomorphological changes; a wave of soil erosion, gully development and debris cone deposition, perhaps following the Scandinavian introduction of sheep farming in the tenth century A.D.     

Tolerance measurement and histopathological observations on the gills of Mystus M. vittatus under the toxic stress of the fertilizer NPK

The tolerance level of the fertilizer NPK for the freshwater siluroid Mystus M. vittatus (BL .) and histopathological changes in the gill of this fish against two concentrations of NPK were investigated. It was found that at 400 ppm (24 h) mortality in the fish started, and at 700 ppm (96 h) all the fish died. Hence the concentration of NPK at 400 ppm was taken as an experimental concentration for this fish. Curling towards the upperside in the secondary lamellae resulting in the joining with each other and profuse mucus secretion and subsequent death of 40% of the fish (96 h) were observed. At 700 ppm (96 h) NPK, which is far higher than the highest tolerance limit of the fish, all the fish died. Profuse mucus secretion, formation of subepithelial spaces, sloughing of epithelial layer, leaving only the rows of pilaster cells, resulting in the death of the fish, were observed. The mortality of the fish was due to asphyxiation and damage in the gill tissues resulting in the alteration in the respiratory and osmoregulatory metabolism.     

A model for debris accumulation and mobilization in steep mountain streams

Abstract

Previous work on the initiation of debris flows has emphasized the roles played by material strength, stream gradient, and fluid pressure, but in most published models the friction angle (φ′) of the channel material is assigned some characteristic or constant value. The model presented here retains gradient and pressure as variables, and considers the probable changes in φ′ and hydraulic conductivity, K, of channel debris over time. Preliminary results from the Howe Sound area in southwest British Columbia suggest that stream reworking may lead to small increases in φ′ and large increases in K, rendering channel debris more stable with time. This is partially offset by a local increase in channel gradient as debris accumulates. These factors favour the growth of large, marginally stable debris deposits, and may lead to high-magnitude, low-frequency debris torrents in channels not steep enough to produce torrents directly from hillslope failure events.     

Hämatologische,enzymatische und histologische Untersuchungen an Fischen der Weser im Mai 1983

The momentary condition concerning the haematological, physiological, macro-and microscopical constitution of the fishes of the Weser at Grohnde was investigated. The fishes were caught electrically at 22 positions in front of and behind the power-station at Grohnde. In the experiments the blood parameters, the biochemical, enzymatical, parasitological and microscopical changes of several species of fishes were analysed. You can see the details of these changes in the figures and pictures of the publication. It is supposed that organic toxic substances are given into the river in front of the power station, because in this region an industrial undertaking is posted. But also the general water quality of the Weser shows a significant toxicological degree, though the content of salt had been reduced in the former time. One can see that at all positions the blood parameters have changed, we also found haemorrhages in the gills, liver, kidney and spleen, little blood swellings, lymphocysts, necrosis, external and internal parasites, enzymatical changes and inflammations of the liver, kidney and myocard in the fishes. The investigations are being continued.     

Tree‐age control on reconstructed debris‐flow frequencies: examples from a regional dendrogeomorphic reconstruction in the Crimean Mountains

The Crimean Mountains (Ukraine) are renowned for the highest occurrence of debris flows along the northern coast of the Black Sea, but information on their origin, frequency and triggers is widely lacking. This study reconstructs a regional time series of debris flows in eight catchments located on the slopes above Yalta. Dendrogeomorphic analyses were performed on 1122 increment cores selected from 566 black pines (Pinus nigra ssp. pallasiana) with clear signs of external damage induced by past debris‐flow activity. The trees sampled were divided into old and young trees. The sample contains 361 young trees with post‐1930 innermost rings and 205 old trees with pre‐1930 germination dates. The two groups of trees were analyzed separately to identify possible age effects in the reconstructed debris‐flow series and to assess the ability of P. nigra to record geomorphic disturbances over time. We date a total of 215 debris flows back to ad 1701 and observe a mean decadal frequency of 6.9 events, with a peak in activity during the 1940s (20 events). The young trees record an increase in debris‐flow activity over the last 70 years, whereas the frequency of events remained fairly constant in the old trees for the same period. By contrast, the formation of reaction wood became increasingly scarce with increasing tree age whereas the occurrence of abrupt growth suppression increased. Copyright © 2014 John Wiley & Sons, Ltd.     

The formation of supraglacial debris covers by primary dispersal from transverse englacial debris bands

Glaciological controls on debris cover formation are investigated from the perspective of primary dispersal of supraglacial debris across a melting ice surface. This involves the migration of angled debris septa outcrops across a melting, thinning glacier ablation zone. Three measures of a glacier's ability to evacuate supraglacial debris are outlined: (1) a concentration factor describing the focusing of englacial debris into specific supraglacial mass loads; (2) the rate of migration of a septum outcrop relative to the local ice surface; and (3) a downstream velocity differential between a slower septum outcrop and the faster ice surface velocity. Measures (1) and (2) are inversely related, while measure (3) increases down‐glacier to explain why slow‐moving, thinning ice rapidly becomes debris covered. Data from Glacier d'Estelette (Italian Alps) are used to illustrate these processes, and to explore the potential for debris cover formation and growth in different glaciological environments. The transition from a ‘clean’, transport‐dominated to a debris‐covered ablation‐dominated glacier is explained by the melting out of more closely‐spaced debris septa, in combination with the geometric interactions of angled septa and ice surface in a field of reducing flow and increasing ablation. The growth and shrinkage of debris covers are most sensitive to glaciological changes at glaciers with gently‐dipping debris‐bearing foliation, but less sensitive at high‐compression glaciers whose termini are constrained by moraine dams and other forms of obstruction. These findings show that a variety of debris‐covered glacier types will show a spectrum of response characteristics to negative mass balance. Copyright © 2013 John Wiley & Sons, Ltd.     

Seasonal Liza aurata tissue-specific DNA integrity in a multi-contaminated coastal lagoon (Ria de Aveiro, Portugal)

In this study, the DNA integrity of golden grey mullet (Liza aurata) collected in differently contaminated sites of a coastal lagoon, Ria de Aveiro (Portugal), was assessed, over the period of 1 year, using the DNA alkaline unwinding assay, in four different tissues (gill, kidney, liver and blood) and compared to a reference site. The four tissues displayed different DNA integrity basal levels, clearly affected by seasonal factors. Gill and kidney were, respectively, the most and least sensitive tissues. All sites demonstrated the capacity to interfere with DNA integrity. The sites displaying the highest and lowest DNA damage capability were, respectively, Barra (subject to naval traffic) and Vagos (contaminated with polycyclic aromatic hydrocarbons). In terms of seasonal variability, autumn seems to be the more critical season (more DNA damage) unlike summer when no DNA damage was found in any tissue. Data recommend the continued monitoring of this aquatic system.     

Acute and chronic toxic effects of the carbamate pesticide Sevin on some haematological,biochemical and enzymatic parameters in the fresh water teleost fish Channa punctatus

The effects of exposure to LC₅₀ (10.5 mg/l) for 96 h and to a sublethal concentration (1.05 mg/l) of Sevin for 120 days have been observed on some haematological, biochemical and enzymatic parameters of Channa punctatus. The fish were hyperglycemic and hyperlactemic and the glycogen content of the liver and muscles decreased, but the lactic acid content of two tissues increased. The activity of hexokinase increased in the kidney, intestine, liver and muscles but decreased in the gills and brain. The activity of lactate dehydrogenase decreased in the kidney and intestine, and increased in the liver, muscles, brain and gills. The pyruvate dehydrogenase activity decreased in all the six tissues. Both the exposures produced a decrease in the succinate dehydrogenase activity of the liver. The enzyme activity decreased in the brain, gills and muscles after chronic exposure, whereas the kidney and intestine showed an elevation in enzyme activity.     

Plastic debris collars on juvenile carcharhinid sharks (Rhizoprionodon lalandii) in southwest Atlantic

Three juvenile Brazilian sharpnose sharks (Rhizoprionodon lalandii) caught in gillnets in southeast Brazil, southwest Atlantic, were found with plastic debris rings around their gill or mouth region. The rings caused severe abrasion on the sharks' tissues as the animal grew, the collars probably hampering normal feeding and/or ventilation since two of the collared individuals were emaciated. The rings were identified as detachable lid parts from plastic bottles, likely thrown overboard by fishery and/or recreation boats. As several carcharhinid shark species dwells and reproduce in shallow waters, the impact of discarded plastic debris likely is greater on this shark type.     

The significance of channel recharge rates for estimating debris‐flow magnitude and frequency

The quantification of debris‐flow hazard requires estimates of debris‐flow frequency and magnitude. Several methods have been proposed to determine the probable volume of future debris flows from a given basin, but most have neglected to account for debris recharge rates over time, which may lead to underestimation of debris‐flow volumes in basins with rare debris flows. This paper deals with the determination of debris recharge rates in debris‐flow channels based on knowledge of debris storage and the elapsed time since the last debris flow. Data are obtained from coastal British Columbia and a relation is obtained across a sample of basins with similar terrain and climatic conditions. For Rennell Sound on the west coast of the Queen Charlotte Islands, the power‐law relation for area‐normalized recharge rate, R_t, versus elapsed time, t_e was R_t = 0·23t_e^?0·58 with an explained variance of 75 per cent. A difference in recharge rates may exist between creeks in logged and unlogged forested terrain. The power function for undisturbed terrain was R_t = 0·20t_e^?0·49, while the function for logged areas was R_t = 0·30t_e^?0·77. This result suggests that for the same elapsed time since the last debris flow, clearcut gullies tend to recharge at a slower rate than creeks in old growth forest. This finding requires verification, particularly for longer elapsed times since debris flow, but would have important implications for forest resource management in steep coastal terrain. This study demonstrates that commonly used encounter probability equations are inappropriate for recharge‐limited debris flow channels. Copyright © 2005 John Wiley & Sons, Ltd.     

Estuarine fish health assessment: evidence of wastewater impacts based on nitrogen isotopes and histopathology

Sewage effluent is a powerful agent of ecological change in estuaries. While the effects of sewage pollution on water quality are usually well documented, biological responses of exposed organisms are not. We quantified health impacts in the form of pathological tissue changes across multiple organs in estuarine fish exposed to elevated levels of treated wastewater. Structural pathologies were compared in wild populations of four fish species from two subtropical estuaries on the east coast of Australia that differ substantially in the amount of direct wastewater loadings. Uptake of sewage-derived nitrogen by fish was traced with stable nitrogen isotopes. Pathologies were common in the liver, spleen, gill, kidney and muscle tissues, and included granulomas, melanomacrophage aggregates, and multiple deformities of the gill epithelia. Tissue deformities were more frequent in fish exposed directly to wastewater discharges. Mullet (Valamugil georgii) were most affected, with only a single specimen free of pathologies in the sewage-impacted estuary. Similarly, in those fish that had structural abnormalities, more deformities were generally found in individuals from sites receiving sewage. These spatial contrasts in impaired fish health correspond to significantly enriched delta15N values in fish muscle as a consequence of fish assimilating sewage-N. Overall, the pattern of lower health and enriched delta15N values in fish from sewage-impacted areas suggests that organism health is lowered by sewage inputs to estuaries. Measurements of organism health are required to understand the effects of sewage on estuarine ecosystems, and histopathology of fishes is a powerful tool to achieve this.     

Water Quality Estimation Based on Histological Investigations of Fish: Case Study of Kenozero Lake

Specific hydrological and hydrochemical conditions in Kenozero Lake have led to changes in the morphology of fishes at a cellular level. The abnormalities in the function of the respiratory, digestive, and excretory systems were recorded. The degree of pathology depended on the ecological features of the fish. The pathological changes were most pronounced in the gills of the fish species (orfe, perch, and roach) characterized by active mode of life and sensible to oxygen deficiency. The changes in the epithelium of gill filaments had a compensatory significance and were aimed at increasing the area of the functional surface of the gills under the conditions of hypoxia.     

Marine debris and human impacts on sea turtles in southern Brazil

Dead stranded sea turtles were recovered and examined to determine the impact of anthropogenic debris and fishery activities on sea turtles on the coast of Rio Grande do Sul State, Brazil. Esophagus/stomach contents of 38 juvenile green Chelonia mydas, 10 adults and sub-adults loggerhead Caretta caretta, and two leatherback Dermochelys coriacea turtles (adult or sub-adult) included plastic bags as the main debris ingested, predominated by white and colorless pieces. The ingestion of anthropogenic debris accounted for the death of 13.2% of the green turtles examined. Signs of damage over the body and carapace indicated that fishing activities caused the death of 13.6% (3/22) of loggerheads and 1.5% (1/56) of green turtles. Therefore, it appears that direct and indirect effects of fishing activities may pose a threat to these species in Brazilian waters. Other sources of plastic debris should be investigated as well as the direct impact of fisheries, especially bottom trawl and gill nets, in order to establish effective conservation action.     

Dendrogeomorphic reconstruction of past debris‐flow activity using injured broad‐leaved trees

Tree‐ring records from conifers have been regularly used over the last few decades to date debris‐flow events. The reconstruction of past debris‐flow activity was, in contrast, only very rarely based on growth anomalies in broad‐leaved trees. Consequently, this study aimed at dating the occurrence of former debris flows from growth series of broad‐leaved trees and at determining their suitability for dendrogeomorphic research. Results were obtained from gray alder (Alnus incana (L.) Moench), silver birch and pubescent birch (Betula pendula Roth and Betula pubescens Ehrh.), aspen (Populus tremula L.), white poplar, black poplar and gray poplar (Populus alba L., Populus nigra L. and Populus x canescens (Ait.) Sm.), goat willow (Salix caprea L.) and black elder (Sambucus nigra L.) injured by debris‐flow activity at Illgraben (Valais, Swiss Alps). Tree‐ring analysis of 104 increment cores, 118 wedges and 93 cross‐sections from 154 injured broad‐leaved trees allowed the reconstruction of 14 debris‐flow events between AD 1965 and 2007. These events were compared with archival records on debris‐flow activity at Illgraben. It appears that debris flows are very common at Illgraben, but only very rarely left the channel over the period AD 1965–2007. Furthermore, analysis of the spatial distribution of disturbed trees contributed to the identification of six patterns of debris‐flow routing and led to the determination of preferential breakout locations of events. The results of this study demonstrate the high potential of broad‐leaved trees for dendrogeomorphic research and for the assessment of the travel distance and lateral spread of debris‐flow surges. Copyright © 2010 John Wiley & Sons, Ltd.     

Alteration in the Acid and Alkaline Phosphatase Activity of a Freshwater Prawn after in vitro Aldrin Exposure

In vitro effects of aldrin on acid and alkaline phosphatase activities in various tissues, viz. hepatopancreas, stomach, muscle, gill and brain, of a freshwater prawn Macrobrachium lamarrei have been studied. Aldrin exposure inhibited the activities of both the phosphatases in all the tissues and this inhibition in enzyme activity showed a dose-dependent response. The results were discussed in relation to in vivo findings and it is concluded that aldrin causes some enzymological changes and thereby creates widespread disturbance in the metabolism.