Zoology

Fish are susceptible to harmful effects of heavy metals and other effluents which influence the hematological profile. Hematological parameters are considered as pathophysiological indicators and are important in diagnosing the structural and functional status of fish exposed to toxicants. Ultrastructural analyses can be used to study the alterations in erythrocytes due to environmental stress. The aim of the present study was to evaluate the toxicity of mercuric chloride on erythrocytes of fish, Channa punctatus. The experiments were conducted in accordance with the standard methods given in APHA (2005) and EPA (1996). Erythrocytes of the fish are nucleated and elliptical in shape. Scanning electron micrographs revealed the presence of spherocytes, crenation of membrane, membrane internalization and development of lobopodial projections in the erythrocytes of exposed fish. The study substantiates the hypothesis that assessment of morphological damage to erythrocytes through scannin...

The COVID-19 pandemic has significant affect on every aspect of human lives. The spread of virus hasbeen controlled by taking certain measures that have slowed down the economic activities alongwith significant effect on the environment. This review intends to explore the various negative andpositive impacts of COVID-19 pandemic on our environment. Various lockdown measures thatwere used to contain the spread of virus has improved the air quality, reduced noise and waterpollution, restoration of ecological systems through reduction of tourist’s activities. But there aresome negative impacts such as an increase in medical waste and municipal waste.

Fingerlings of Labeo rohita were exposed to geometric concentrations (6.25 to 100%) of municipal wastewater of Tung Dhab Drain, Amritsar, India. 96h static non-renewal acute toxicity tests were conducted and simultaneously behavioural and morphological observations were noted. The 96h LC50 value along with 95% confidence limits were found to be 44.25% (38.47-50.92). The recorded values for chemical parameters such as TSS, BOD, NO3-N, O&G and heavy metals like Cr (VI), Mn, Pb and As were far more than
standard discharge limits of effluents into inland surface waters. Fish in toxic media exhibited increased air gulping, surfacing, abnormal schooling, irregular, erratic and hyperactive swimming movements, hyper excitability, loss of equilibrium and showed vertical position prior to death. Morphological deformities included dark body colouration, excessive mucus secretion, loosening and loss of scales, haemorrhages on skin and fins, lateral flexure in caudal region and altered posturing of pectoral fins.

The aim of the study was to evaluate the toxic
impact of wastewater from sites 1 and 2 of Tung Dhab drain
in the state of Punjab, India, on fish behaviour, morphology
and gill histopathological biomarkers in comparison to control group. Static non-renewal tests were conducted for 96 h to determine LC50 of the wastewater for both sites using five concentrations (6.25–100 %). Fish were regularly noticed for any deviation in behaviour and external morphology. Physicochemical analysis of wastewater was done using standard methods recommended by APHA/AWWA/WEF (2005). Chronic toxicity tests were conducted for 15 and 30 days with sublethal concentrations of wastewater (50–90 % of LC50) and gill histopathology was assessed.Wastewater near a paper mill was more toxic as observed from LC50 values of 72.45 %. There was evident deterioration of water quality as the recorded values of some parameters were higher than the standard discharge limits. The test fish exhibited increased air gulping and surfacing, erratic movements initially and decreased opercular movements as the exposure period increased. Morphological observations include increased body
colouration, mucus secretion, scale loss and haemorrhages on
the skin and lower lip. Alterations in the gill histology such as
complete lamellar fusion, epithelial lifting and intraepithelial
oedema, haemorrhages, lamellar necrosis and aneurysm were
noted in the test fish. Results demonstrate that the fish exposed to wastewater from both sites showed significantly greater change in gill organ index (IG) as compared to control fish for 15 and 30 days.

The fingerlings of fish Labeo rohita were subjected to chronic (15, 30, and 60 days)
and recovery (60 days) experiments for histopathological studies using sublethal
concentrations (35.4%, 26.6%, and 17.7% v/v) of municipal wastewater of Tung Dhab
drain, Amritsar, India. Control fish were maintained for same exposure periods using
tap water. Scanning electron microscopic studies exhibited dose- and durationdependent
alterations on gill surface ultra-structure. Control fish exhibited
functionally normal gills with normal mean degree of tissue change. Fifteen different
types of lesions were identified out of which 9, 5, and 1 were of the stage I, II, and III,
respectively. The mean degree of change values in the treated groups ranged from
14.8 § 0.5 (17.7%, 15 days) to 116. § 17 (35.4%, 60 days) demonstrated gill damages
of slight to irreparable lesions. The recorded alterations were epithelial lifting and
intraepithelial edema, reduction of water spaces, lamellar fusion, lamellar
telangiectasia, swelling and fusion of filaments, sloughing of lamellar epithelium,
hypertrophy and hyperplasia of mucous and chloride cells, and necrotic lamellae. The
recovery experiments showed positive improvement as the intensity of damage was
less than recorded for 60 days of treatment. This study clearly indicated toxicity of
drain water to fish at cellular and organ level. The study recommends environmental
agencies to make and enforce decisions regarding improvement of water quality of
Tung Dhab drain, and further incorporating histopathological studies as an analytical
tool.

Labeo rohita were subjected to chronic (15, 30, and 60 days) and recovery (60 days) experiments for kidney histopathology
studies using sublethal concentrations (35.4%, 26.6%, and 17.7%) of municipal wastewater collected from Tung Dhab Drain, Amritsar,
India. Control fish were maintained simultaneously using laboratory tap water, and exhibited normal structures. The results exhibited
both dose- and duration-dependent alterations in exposed tissues. The mean degree of tissue change (DTC) values in treated groups
ranged from 37.5 ± 6.60 (17.7%, 15 days) to 149.33 ± 7.75 (35.4%, 60 days), demonstrating reparable to irreparable structural changes. The
recorded observations showed changes in tubules that included nuclear and cellular hypertrophy, cytoplasmic vacuolation, narrowing
of the tubular lumen (stage I), hyaline droplet degeneration, occlusion of the tubular lumen (stage II), and tubular necrosis (stage III).
Clear damage was also witnessed in corpuscles that included enlargement of glomerulus, dilatation of glomerular capillaries (stage I),
and reduction of Bowman’s space (stage II). The recovery experiments showed statistically significant improvement, as the intensity of
damage was less than that recorded after 60 days of treatment. The present study indicates toxicity of drain water at the cellular and
organ levels, and recommends the use of kidney histopathology as an analytical tool in toxicology and water surveillance studies.

Different multivariate statistical techniques were applied to interpret the temporal variations in water quality of Tung Dhab drain, Amritsar, India and further to identify water pollution sources. Data was collected seasonally for a period of two years (2012-2013) using 34 water quality parameters. The recorded values for variables like turbidity, total suspended solids, biochemical oxygen demand, chemical oxygen demand, oil & grease, nitrate as N, lead, chromium, nickel and zinc were much higher than the recommended permissible discharge limits into inland waters. Significant correlations were found in between different physicochemical parameters (p ≤ 0.05; p ≤ 0.01). Cluster Analysis (CA) grouped four sampling seasons into two clusters. CA confirmed that the water quality of rainy season was different from other three seasons in terms of similarity and distance indices. Principal Component Analysis/Factor Analysis (PCA/FA) explained minerals, organic, agricultural and industrial pollutants responsible for deterioration of drain water quality. The present study will help environmental agencies to make and enforce decisions regarding improvement of water quality of Tung Dhab drain.

This study examined the impact of municipal wastewater on scale morphology of freshwater fish Labeo rohita. Fish were exposed to sublethal concentrations (17.7, 26.6, or 35.4%) of municipal wastewater for durations of 15, 30, and 60 d. Recovery experiments were also performed for a duration of 60 d. Scales were extracted after respective exposure periods, cleaned, and processed for scanning electron microscopy. Results showed concentration- and exposure duration-dependent alterations in the morphology of scales. Severe damage was observed at the anterior and posterior portions of scales in the form of lepidontal breakage and uprooting, destructions at the base of circuli and radii along with complete structural loss in the focal region and adjacent circuli and radii, and alterations in structure of tubercles. Data indicate that scales of fish L. rohita may be employed as bioindicators of water pollution and could be incorporated into water monitoring surveillance.

The present study was aimed to evaluate the effect of municipal wastewater of Tung Dhab drain on morphology of scale melanophores in freshwater fish Labeo rohita (Ham.). Chronic, non-renewal toxicity tests were performed with sub lethal concentrations (17.7, 26.6 and 35.4%) of wastewater for exposure durations of 15, 30 and 60 days. Recovery experiments were also performed for duration of 60 days. The scales were removed, processed and diameters of melanophores were measured using an ocular micrometer. The results showed concentration and duration dependent changes in melanophore morphology (size and dendricity) in experimental fish as compared to control fish. The values of mean melanophore size index (MMSI) varied from 5.37±0.49 (17.7%) to 12.12±0.81 (35.5%) in comparison to control values of 4.32±0.32 and 4.55±0.29 for 15 and 60 days respectively. The recovery experiments suggested that observed dark colouration due to pigment translocation is reversible, even after chronic expos...

The aim of the study was to evaluate the toxic impact of wastewater from sites 1 and 2 of Tung Dhab drain in the state of Punjab, India, on fish behaviour, morphology and gill histopathological biomarkers in comparison to control group. Static non-renewal tests were conducted for 96 h to determine LC50 of the wastewater for both sites using five concentrations (6.25-100 %). Fish were regularly noticed for any deviation in behaviour and external morphology. Physico-chemical analysis of wastewater was done using standard methods recommended by APHA/AWWA/WEF (2005). Chronic toxicity tests were conducted for 15 and 30 days with sublethal concentrations of wastewater (50-90 % of LC50) and gill histopathology was assessed. Wastewater near a paper mill was more toxic as observed from LC50 values of 72.45 %. There was evident deterioration of water quality as the recorded values of some parameters were higher than the standard discharge limits. The test fish exhibited increased air gulping ...

The present study was aimed to evaluate the effect of municipal wastewater of Tung Dhab drain to freshwater fish Labeo rohita through genotoxicity assays. The idea is to explore and standardize procedures for assessment of toxic impact of pollutant at the cellular level in aquatic species. Hence, chronic, non-renewal toxicity tests were performed with sublethal concentrations (17.7, 26.6 and 35.4 %) of wastewater for exposure durations of 15, 30 and 60 days. Recovery experiments were also performed for duration of 60 days. Higher micronuclei (MN) and binuclei (BN) frequencies were recorded in fluorescently stained liver cells as compared to frequencies obtained for gill cells and erythrocytes. The induced frequencies of MN, BN and nuclear abnormalities (NA) were found in the following order: MN (liver cells) > BN (liver cells) > BN (gill cells) > MN (gill cells) > NA (erythrocytes) > MN (erythrocytes). The results pointed towards the mutagenic nature of water quality ...