Comet Assay and Micronucleus Test in Circulating Erythrocytes of Ctenopharyngodon idella Exposed to Nickel Oxide Nanoparticles.

The number of pollutants released into freshwater and marine environments has increased due to the widespread use of nanoparticles. Nickel oxide nanoparticles (NiO-NPs) were tested for genotoxicity in fish fingerlings of the species Ctenopharyngodon idella. For 7, 14, and 21 days, fingerlings were exposed to NiO-NPs with each increasing concentrations of 2.25 mg/L, 4.50 mg/L, and 6.75 mg/L, respectively. The micronuclei assay and comet assay were used to evaluate the DNA damage. The experiment revealed that with the increase in nanoparticle concentration and exposure duration, the level of DNA damage also increased. The experiment resulted to be time and dose dependent, and the damage was found as follows: 6.75 mg/L > 4.50 mg/L > 2.25 mg/L against each exposure period. In terms of comet assay, the results showed that after 7 days, the level of DNA damage in all the concentrations was highly significant (P < 0.001). Increased DNA damage was calculated at the higher administered dose of 6.75 mg/L for 21 days of exposition, followed by 14 and 7 days, respectively. The second high toxic effect was observed in the fish blood at the exposure concentration of 4.50 mg/L for 21 days, followed by 14 and 7 days, respectively. The micronuclei induction in the nanoparticle's administered blood could be detected only for a 7-day exposition period. Whereas for the exposed duration of 14 and 21 days, the entire red blood cells of the grass carp were completely destroyed demonstrating the ability of the nanoparticles to cause anomalies in aquatic life.

Exome sequencing identifies homozygous variants in MBOAT7 associated with neurodevelopmental disorder.

Intellectual disability (ID) is a large group of neurodevelopmental disorders characterized by a congenital limitation in intellectual functioning (reasoning, learning, and problem solving), adaptive behavior (conceptual, social, and practical skills), originated at birth and manifested before the age of 18. By whole exome sequencing of five consanguineous Pakistani families presenting hallmark features of ID, global developmental delay, aggressive and self-injurious behaviors, microcephaly, febrile seizures and facial dysmorphic features, we identified three novel homozygous missense variants (NM_024298.5: c.588G > T; p.Trp196Cys, c.736 T > C; p.Tyr246His and c.524A > C; p. Asp175Ala) and one rare homozygous in-frame deletion variant (c.758_778del;p.Glu253_Ala259del) in membrane-bound O-acyltransferase family member 7 (MBOAT7) gene previously associated with autosomal recessive neurodevelopmental disorder. The segregation of the variants was validated by Sanger sequencing in all family members. In silico homology modeling of wild-type and mutated proteins revealed substantial changes in the structure of both proteins, indicating a possible effect on function. The identification and validation of new pathogenic MBOAT7 variants in five cases of autosomal recessive ID further highlight the importance of this genes in proper brain function and development.

Unveiling genetics of non-syndromic albinism using whole exome sequencing: A comprehensive study of TYR, TYRP1, OCA2 and MC1R genes in 17 families.

BACKGROUND: Oculocutaneous albinism (OCA) is a group of skin depigmentation disorders. Clinical presentation of OCA includes defects in melanocyte differentiation, melanin biosynthesis, and melanosome maturation and transport. OBJECTIVES: A molecular diagnostics study of families presenting oculocutaneous albinism. METHODS: In this study, 17 consanguineous OCA families consisting of 93 patients were investigated. Whole Exome Sequencing (WES) of the index patient in each family were performed. Short listed variants of WES were Sanger validated for Mendelian segregation in obligate carriers and other available family members. Variant prioritization and pathogenicity were classified as per the criteria of American College Medical Genetics and Genomics (ACMG). Comparative computational modelling was performed to predict the potential damaging effect of the altered proteins. RESULTS: 15 pathogenic variations: c.132 T > A, c.346C > T, c.488C > G, c.1037G > A in TYR, c.1211C > T, c.1441G > A, c.1706_1707insT, c.2020C > G, c.2402G > C, c.2430del, in OCA2, c.1067G > A in TYRP1 and c.451C > T, c.515G > T, c.766C > T, c.917G > A in MC1R genes were identified. Three variants in OCA2 gene were characterized: c.1706_1707insT, c.2430del, and c.2402G > C, all of which were not reported before in OCA families. CONCLUSION: A few studies focusing on mutation screening of OCA patients have been reported before; however, this study has uniquely presents the Pakhtun ethnic population residing on the North-Western boarder. It explains that TYR, OCA2, TYRP1, and MC1R variations lead to non-syndromic OCA phenotype The overlapping phenotypes of OCA can precisely be diagnosed for its molecular pathogenicity using WES. This study recommends WES as a first-line molecular diagnostic tool, and provides a basis for developing customized genetic tests i.e. pre-marital screening to reduce the disease burden in the future generations.

Genotoxicity of Copper, Silver and Green Synthetic Gold Nanoparticles in Fish (Ctenopharyngodon idella).

Grass carp (Ctenopharyngodon idella) was exposed to nanoparticles of different concentrations, i.e., copper oxide nanoparticles (CuO-NPs), silver nanoparticles (Ag-NPs), and green synthetic gold nanoparticles (Au-NPs).The administered doses of the three concentration groups were 20mg L-1, 30 mg L-1, and 40mg L-1 each for a period of 14 and 28 days, respectively. The DNA damage in the erythrocytes of grass carp was detected through a comet assay technique. The values of total comet score (TCS) were noted for the exposed concentrations with a significant increasing trend (p < 0.05) and ordered as CuO-NPs > Ag-NPs > Au-NPs. The highest TCS value of the exposed erythrocytes was recorded for CuO-NPs at 40 mg L-1 after 14 days of exposition period. Comparatively, TCS values of erythrocytes exposed to green synthetic Au-NPs at all the concentrations and exposed time were less as compared to the Ag-NPs and CuO-NPs. The study confirmed the adverse effects of nanoparticles on the genetic material of fish cells.

Appearances often deceive in racerunners: integrative approach reveals two new species of Eremias (Squamata: Lacertidae) from Pakistan.

Based on newly provided morphological and previously published genetic data, we describe two new distinctive sympatric lacertid lizards of the genus Eremias (subgenus Aspidorhinus) from the arid mountains of northwestern Balochistan Province, Pakistan. The new species, Eremias killasaifullahi sp. nov. and Eremias rafiqi sp. nov. are distinguished from all other species of the subgenus Aspidorhinus (E. afghanistanica, E. fahimii, E. isfahanica, E. kopetdaghica, E. lalezharica, E. montana, E. nikolskii, E. papenfussi, E. persica, E. regeli, E. roborowskii, E. strauchi, E. suphani, and E. velox) by unique morphological characters and genetic differentiation. In the molecular phylogeny of Aspidorhinus, both new taxa are well-supported lineages differentiated from other species of this subgenus by uncorrected p distances from 8.5% to 21.6%, respectively. Both new species belong to E. persica complex where E. rafiqi sp. nov. is partly similar in dorsal color pattern to E. persica but can be distinguished from this species by unique meristic and morphometric characters. Eremias rafiqi sp. nov. is found in Pakistan, Afghanistan, and eastern Iran. Eremias killasaifullahi sp. nov. can be differentiated from E. persica by its distant distribution, dorsal color and pattern, smaller size, and less number of gulars and ventral scales. Eremias killasaifullahi sp. nov. is only known from the type locality and represents the local microendemism, along with other endemic species of reptiles reported from this part of Pakistan. We, however, expect that E. killasaifullahi sp. nov. could have a broader range in northwestern Pakistan and southeastern Afghanistan, which should be an object of following investigations. Our data show that remote areas between Hindu Kush Mountains and Indus River need attention as they most probably represent possible sources of genetic and species diversity in the region.

Out of the blue: The first record of the genus Heremites Gray, 1845 (Squamata, Scincidae) from Pakistan.

The genus Heremites Gray, 1845 is endemic to the Western Palearctic region, containing morphologically similar species with a not well resolved taxonomy. The genus has a broad distribution from North Africa to Central Asia, with the only known record from northeastern Afghanistan. Three species are currently recognized in the genus with one, H. septemtaeniatus (Reuss, 1834), representing populations at the eastern edge of the genus range. During extensive fieldwork, we discovered H. septemtaeniatus from northwestern Pakistan and provisionally suggest that this population could be morphologically defined as H. septemtaeniatus transcaucasicus (Chernov, 1926). This important contribution to the knowledge regarding the family Scincidae in Pakistan, however, needs further investigation using an integrative approach.

Assessment of DNA damage induced by endosulfan in grass carp (Ctenopharyngodon idella Valenciennes, 1844).

Endosulfan is an organochlorine pesticide, which is commonly used throughout the world. It accumulates in the environment and may cause significant damage to the ecosystems, particularly to the aquatic environments. The present study was conducted to evaluate the genotoxic effect of endosulfan on the grass carp (Ctenopharyngodon idella) blood. The fish were exposed to three different concentrations, 0.75 ppb/day, 1.0 ppb/day, and 1.5ppb/day of endosulfan for 7, 14, 21, and 28 days. The study was a randomized control trial and the control group was not exposed to endosulfan. The results showed that after 7 days, the level of DNA damage in all the concentrations was significant (P < 0.05), while after 14, 21, and 28 days' trials, highly significant (P < 0.000) level of DNA damage was observed. Hence, time- and dose-dependent DNA damage was observed in fish DNA by comet assay. It is concluded from our results that with the increase in endosulfan concentration and exposure duration, the level of DNA damage also increased. As the current study showed the severe genotoxic effect of endosulfan in Ctenopharyngodon idella, therefore, the imprudent and indiscriminate use of endosulfan should be controlled and monitored by the concerned government authorities.

Genotoxic Consequences in Common Grass Carp (Ctenopharyngodon idella Valenciennes, 1844) Exposed to Selected Toxic Metals.

The primary aim of the current study was to recognize the biomarker approach as the finest tool to identify the geno-toxicological effects of copper, chromium, and lead inside the blood of grass carp using micronucleus test and comet assay. The induced micronuclei frequency in response to the administered concentrations of LC50 metals was discovered in the erythrocytes of metal-exposed fish at four-time intervals. The genotoxic effect of these metals with respect to the formation of micronuclei was ranked as chromium > lead > copper. Percentages of other cellular and nuclear abnormalities were also determined in the exposed blood films. Equally, the genotoxic studies in terms of comet assay in fish blood revealed significant deviations p < 0.05 against each of the studied metal at their respective time interval as compared with the healthy fish group. However, induced frequency of micronuclei and the calculated DNA damage were not found to be duration dependent. Consequently, copper, chromium, and lead have been explored as cytotoxic elements that can be responsible for inducing genotoxic effects in fish existing aquatic habitats.

Metals Distribution, Histopathological Alterations, and Health Risk Assessment in Different Tissues of Fish (Ctenopharyngodon idella).

Grass carps were exposed to the established lethal concentration (LC) values of copper (Cu), chromium (Cr), and lead (Pb) each for the exposed period of 24, 48, 72, and 96 h respectively. Concentrations of these metals were determined in the brain, liver, muscles, gills, kidneys, and intestinal tissues of exposed and control fish through the atomic absorption spectrophotometer after the wet digestion process. The metals accumulation inside these tissues confirmed the absorption of metals from media into the tissues of the model organism. The accumulated concentration in fish tissues was confirmed to be concentration-dependent with significant (p < 0.05) elevated mean values seen for the lead followed by chromium and copper as compared with the mean concentration values of their respective control group. Levels of metals were found above the permissible standards suggested by the regulatory authorities in the fish's body. Histological sections of the same targeted organs exposed to the three exposure concentration groups were studied and compared with the sections of the healthy group. The histopathological lesions were scored to rank the deleterious effects of metals. The histopathological changes were recorded in concentration and progressive time-related series where gills had the greatest number of scored lesions followed by the kidneys and intestines, muscles, brain, and finally the liver as the least affected organ. Moreover, the organs were not affected uniformly by the metals; in fact, every studied organ has given mild to severe responses towards the toxic metals where lead had proven to cause more severe lesions as compared with copper and chromium. The histological lesions recorded mostly were thus concentration-dependent as revealed in the bioaccumulation of these metals with the effects ranked as lead > chromium > copper with a few exceptions. The findings can be used as a benchmark for the evaluation of the fate and effects of the toxic metals in the expanded aquaculture production of grass carp nationwide. Further investigations with respect to other potentially toxic metals like arsenic, mercury, and cadmium could address the problem towards additional studies.

Scalp Hair Metal Analysis Concerning DNA Damage in Welders of Peshawar Khyber Pakhtunkhwa Pakistan.

Welding is used throughout the world in refineries, thermal power plants, chemical facilities, and pressurized containers, and the welders are exposed to toxic heavy metals, electromagnetic fields, polycyclic aromatic hydrocarbon, and ultraviolet radiations. In the present study, 59 welders and an equal number of control subjects were assessed for DNA damage in the lymphocytes using the comet assay. Heavy metals such as lead (Pb), iron (Fe), nickel (Ni), chromium (Cr), manganese (Mn), and cadmium (Cd) levels in the scalp hair of the subjects were evaluated by using atomic absorption spectroscopy (AAS). The results of the current study showed that DNA damage in the lymphocytes of welders (121.8 ± 10.7) was significantly higher as compared with controls (56.5 ± 17.6) (P < 0.001). Besides, the levels of Pb, Fe, Ni, Cr, Mn, and Cd were remarkably higher in the scalp hair of workers as compared with the control group (P < 0.001). Regression analysis showed a prominent association between the heavy metals and total comet score (TCS) in the exposed subjects. Age and duration of occupational exposure had significant effects (P < 0.05) on TCS values. Our results concluded that occupational exposure to welding fumes may cause DNA damage and can lead to important health hazards in the workers.

A new species of Microgecko Nikolsky, 1907 (Squamata: Gekkonidae) from Pakistan.

Members of the dwarf geckos of the genus Microgecko Nikolsky, 1907 are distributed from western Iran to northwestern India, with seven currently recognized species. Three taxa have been reported from Pakistan, M. depressus, M. persicus persicus and M. p. euphorbiacola. The former is the only endemic species restricted to Pakistan. Herein, we describe a new species, Microgecko tanishpaensis sp. nov., on the basis of four specimens collected from the remote area of the Toba Kakar Range in northwestern Balochistan. The type locality lies in an isolated valley in mountainous terrain known for the occurrence of other endemic reptile species, including geckos. Microgecko tanishpaensis sp. nov. is differentiated from the morphologically similar species M. depressus by possessing larger size, five scales bordering the nostril, internasals (supranasals) scales in contact with nostril, two large pairs of postmentals, higher numbers of interorbitals (27-30), scales around midbody (76-84), ventral scales from the postmental to vent (144-156) and scales along dorsal midline from axilla to groin (75-86). A morphological comparison of M. tanishpaensis sp. nov. with other species of the genus and an updated identification key for the genus Microgecko are presented.

A new species of Eremias (Squamata: Lacertidae) from the arid mountains of Pakistan.

A new, morphologically distinctive lacertid lizard of the genus Eremias (Rhabderemias) is described from the arid mountains of northwestern Balochistan Province in Pakistan. Eremias kakari sp. nov. has an isolated distribution and can be easily distinguished from all other species of mainly desert subgenus Rhabderemias (E. andersoni, E. cholistanica, E. fasciata, E. lineolata, E. pleskei, E. scripta, E. vermiculata). Apart from other differences, E. kakari sp. nov. can be distinguished from geographically close members of the subgenus Rhabderemias (E. cholistanica, E. fasciata, and E. scripta) by having a single row of subdigital lamellae and a complete row of lateral scales and hence three scales around the penultimate phalanx of 4th toe. The new species is morphologically (dorsal pattern) very similar to E. fasciata but can be distinguished from this species for having 22-26 subdigital lamellae under 4th toe, 48-55 dorsal scales across midbody, ventrals in 11-14 oblique longitudinal series across the belly, 17-21 femoral pores and 17-21 scales in the 9th-10th annulus posterior to the postcloacal granules. The new species is currently known only from the type locality situated in the Toba Kakar Range, near to Tanishpa village. However, we expect that Eremias kakari sp. nov. would have a broader range in northwestern Pakistan and southeastern Afghanistan. An identification key for the Pakistani Eremias, together with other remarks to the new species, is presented.

Biomonitoring of DNA Damage in Photocopiers' Workers From Peshawar, Khyber Pakhtunkhwa, Pakistan.

OBJECTIVES: The study was performed to know about the extent of occupational DNA damage in photocopiers' workers. METHODS: Blood samples were collected from 136 exposed group and 74 control group. Comet assay was performed to assess the DNA damage caused by emissions from photocopiers. RESULTS: The results indicated that there was a significant increase (P < 0.05) in DNA damage in persons working in photocopiers (122.1 ±â€Š60.7) than the controls (56.6 ±â€Š17.2). Duration of occupational exposure had positive correlation (r = 0.793, P < 0.001) with DNA damage. Age had significant effects on the total comet score (TCS) of the exposed group as compared to the control group (P < 0.05). CONCLUSIONS: In conclusion, these findings indicate significant genotoxicity in photocopiers' workers.

Polymorphism in GSTM1 and GSTT1 genes influence DNA damage in personnel occupationally exposed to volatile anaesthetics (VA), from Peshawar, Pakistan.

OBJECTIVES: The objective of this study was to assess the influence of antioxidant gene GSTM1 and GSTT1 on DNA damage in personnel occupationally exposed to volatile anaesthetics (VA). METHODS: The study groups were composed of 50 exposed subjects (anaesthesia workers) and 49 controls. Blood samples were collected from both subjects. DNA damage was analysed through the comet assay technique. Biomarker genes GSTM1 and GSTT1 were inspected through PCR technique for polymorphism. RESULTS: The comet assay technique showed that the Total Comet Score (TCS) in exposed subjects was significantly higher (p=0.0001) than the control. Age and smoking had significant effects on TCS in the study groups (p<0.05). Duration of occupational exposure had significant positive correlation (r=0.755, p<0.001) with DNA damage. The null polymorphism in GSTM1 and GSTT1 gene showed a significant effect (p<0.001 and p<0.000) on the DNA damage. CONCLUSIONS: The polymorphism in GSTM1 and GSTT1 gene significantly damage DNA in personnel occupationally exposed to VA.

DNA damage analysis concerning GSTM1 and GSTT1 gene polymorphism in gold jewellery workers from Peshawar Pakistan.

PURPOSE: To evaluate the genotoxic effects of gold jewellery fumes and its association with GSTM1 and GSTT1 genetic polymorphisms. MATERIALS AND METHODS: We examined 94 subjects including 54 gold jewellery workers and 40 controls. The DNA damage was evaluated by alkaline comet assay and genotyping by PCR. RESULTS: The mean total comet score (TCS) in gold jewellery workers was significantly higher as compared to the control subjects (128.0 ± 60.6 versus 47.7 ± 21.4; p = 0.0001). Duration of occupational exposure had positive correlation (r = 0.453, p < 0.01) with DNA damage. Age and tobacco use had significant effects on the TCS of the exposed group as compared to the control group (p < 0.05). The frequency of the GSTM1-null genotype in the exposed group was significant (p = 0.004) as compared to the control group. No significant association (p > 0.05) between the GSTM1 and GSTT1 genotypes and DNA damage was found. CONCLUSIONS: Our results suggest that there is increased DNA damage in gold jewellery workers due to their occupational surroundings. Hence there is a strong need to educate the workers about the adverse health effects of potentially hazardous chemicals and highlight the importance of using protective measures.

Assessment of copper, chromium, and lead toxicity in fish (Ctenopharyngodon idella Valenciennes, 1844) through hematological biomarkers.

Hematological variances were seen in Ctenopharyngodon idella when exposed to (LC50 and LC85) copper, chromium, and lead concentration groups. The metal-exposed blood samples after collection were analyzed for comparative analysis of hematological alterations in the reference and treated groups at the different exposure hours. A significant reduction (p < 0.05) in hemoglobin, RBC, hematocrit, total leucocyte, and lymphocyte counts was observed with the increase in metal concentrations, whereas a significant incline (p < 0.05) in granulocyte and monocyte counts was observed with the administered doses of selected toxic metals as compared with the values obtained from the reference group. More pronounced changes in hematological indices both for the red and white blood cells were noticed at the highest dose of LC85-administered metal groups. The induced hematological changes were independent of the exposed duration pattern. The present investigation has significantly contributed in knowledge assessment of metal toxicity based on inclusive evaluation of dose-response relationships.

Monitoring Bioaccumulation (in Gills and Muscle Tissues), Hematology, and Genotoxic Alteration in Ctenopharyngodon idella Exposed to Selected Heavy Metals.

Health and environmental problems arising from metals present in the aquatic ecosystem are very well known. The present study investigated toxicological effects of LC15 of metals such as copper, chromium, and lead for 24, 48, 72, and 96 h on hematological indices, RBC nucleus and cell morphology, and gill and muscle tissues of grass carp (Ctenopharyngodon idella). Experimental dose concentrations of copper were 1.5, 1.4, 1.2, and 1 mgL-1. Similarly, dose concentrations of chromium were 25.5, 22.5, 20, and 18 mgL-1 while those of lead were 250, 235, 225, and 216 mgL-1, respectively. Maximum decrease in the concentration of Hb, RBCs, and monocytes was observed against chromium, while maximum increase in the concentration of lymphocytes was reported against lead. Abnormalities such as single and double micronuclei, deformed nucleus, nuclear shift, irregular nucleus, deformed cells, microcyte cells, and vacuolated and swollen cells were observed. Gill tissues absorbed maximum concentration of lead followed by chromium and copper. Muscle tissues also absorbed maximum concentration of lead followed by chromium and copper, respectively. Histological alterations such as epithelial lifting, interlamellar spaces, club gill filaments, gill bridging, curling filaments, swelling and fusion of cells, irregular cells, destruction of epithelial cells, cellular necrosis, and inflammatory cells were observed in gill tissues while inflammation and necrosis of muscle fibers, degeneration of muscle fibers, edema of muscle bundles, zig-zag of muscle fibers, and lesions were observed in muscle tissues of fish exposed with different doses of these heavy metals, indicating the toxicity of metals to aquatic fauna as well as to human being via food chain.

Toxicity evaluation of pesticide chlorpyrifos in male Japanese quails (Coturnix japonica).

In the current study, chlorpyrifos was used as a test chemical to evaluate its possible toxicological effect on birds. A total of 45 adult male Japanese quails were divided into five groups (A to E). Each group, containing 9 birds was further divided into 3 sub-groups (containing 3 birds each). Group A served as control, while all other groups and sub-groups were exposed to selected pesticide for different trial periods. Chlorpyrifos sub-lethal doses were orally administered daily at the rate of 3, 6, 9, and 12 mg/kg body weight per day to group B, C, D, and E, respectively. Birds were kept under observation for behavioral changes throughout the trial periods. Clinical signs, histological alterations, genotoxicity, and blood biochemical alterations were recorded after each 15-day trial. Mild to moderate clinical signs like staggering gait, tremors, diarrhea, dullness, less frequency of crowing, and decrease foam production were observed in group D and E throughout the study. The changes in the body weight gain and blood biochemical parameters among different groups at a given trial period were insignificant. The appearance of micronuclei in group E birds was more significant, indicating that nucleus damage was dose-dependent while to lesser extent duration-dependent. The comet assay showed significant dose- and duration-dependent DNA damage among various groups. In comparison with control group, extensive histological degenerative alterations in the liver, testes, and kidneys were observed in birds of group D and E, where mild to severe alteration like congestion, vacuolation, necrosis, apoptosis, karyopyknosis, extensive degeneration, and alteration in many cellular structures were noticeable.

Association of Non-Hodgkin lymphoma risk with CYP1A1, GSTM1 and GSTT1 gene variants, in tobacco addicted patients of Pashtun ethnicity of Khyber Pakhtunkhwa, Pakistan.

The current study determines the possible antitumor and immunomodulatory effects of thymosin against the in vivo and in vitro growth of tumor-derived cell line in mice. Peritoneal phagocytes count, Ehrlich ascites tumor (EAT) cells, T- lymphocytes, and B- lymphocytes activities were determined. In addition, serum level of interleukin 2 (IL-2) and liver functions were measured. In animal testing, thymosin at doses of 0.50 and 1mg activated the phagocytic function of macrophages, as well as T- and B- cell function. Thymosin caused a marked shortage in the proliferation of EAT cells in the peritoneal fluid with dose 0.50g as compared with that of the corresponding control group. Furthermore, treatment with thymosin caused effectively elevate in serum level of IL-2, on the contrary reduce in serum levels of ALT, AST and total proteins. The size of solid Ehrlich tumor was significantly decreased, as measured morphologically with the doses 0.50 and 1 mg (P<0.01). These results confirmed that many biological activities attributed to thymosin and is as an adjuvant for immune enhancement.

Bioaccumulation of Heavy Metals and their Genotoxic Effect on Freshwater Mussel.

Contamination of fresh water bodies like riverine system is utmost concerned environmental issue. This study was aimed to assess the concentration of heavy metals in River Kabul and their bioaccumulation by freshwater mussel. Comet assay was used to evaluate the genotoxic effect of heavy metals on hemocytes of freshwater mussel. The concentration of heavy metals in water was in the order of Zn > Pb > Ni > Cu > Mn > Fe > Cr > Cd, in sediments were Fe > Zn > Cr > Ni > Mn > Pb > Cu > Cd and in the soft tissues of freshwater mussel were in order of Fe > Zn > Mn > Pb > Cu > Cr > Ni > Cd. The hemocytes of mussels from polluted sites showed significantly higher (p < 0.05) DNA damage as compared to reference site. The study showed that pollutants from industries, municipal, domestic and agricultural sources cause heavy metals contamination in River Kabul.