Biochemical and histopathological effects in muscular tissue of carp fish (Labeo rohita, Hamilton 1822) following exposure to untreated and treated sewage water.

Present work describes a laboratory study aiming at assessing the impact of sewage treatment plant (STP) effluents on fish health by means of biochemical and histopathological biomarkers in muscular tissue of fish. Labeo rohita (7.62 ±0.25 cm, 8.25±0.32 g) was exposed to sub-lethal concentrations of untreated (UT) and treated (T) sewage water obtained from STP, Ludhiana, India. Following the determination of the 96h lethal concentration (LC50), the fish were exposed to control (de-chlorinated tap water), treated sewage water, 1/10th of LC50 UT and 1/20th of LC50 UT sewage water. The experiment was conducted for the period of 60 days. Experimental results depicted significant reduction (p<0.05) in muscle-somatic index of 1/10th LC50 UT and 1/20th LC50 UT groups compared to control and treated groups. Fish toxicity induced by untreated sewage water was evident from the significant decrease (p<0.05) in the levels of proteins and significant increase (p<0.05) in content of total lipids in muscular tissue of exposed group fingerlings. Drastic changes in the fatty acids profile and severe histological abnormalities viz. shortening of muscle bundles, edema, hyper-vacuolization, elongation of muscle bundles, gap formation in myofibrils, degenerated myotomes, hemorrhage, inter-myofibrillar space, necrosis, were also recorded in muscular tissue of exposed fingerlings. The intensity of muscular damage in L.rohita was found to increase with increase in duration of exposure. Results demonstrated that untreated sewage water could potentially induce physiological stress and somatic cell toxicity in fish L.rohita. Genotoxicity studies on germ cells of L.rohita fingerlings are further suggested to examine the genotoxic potential of untreated sewage water at high concentrations; this is especially of interest given that many effluents are genotoxic to fish.

Assessment of cytotoxicity in gills of fish Labeo rohita reared in untreated and treated sewage water.

The unregulated discharge of untreated municipal sewage water to the natural water bodies is a major threat to the aquatic ecosystems. In the present study, the fingerlings of Labeo rohita were exposed to treated sewage water and 1/10th of LC50 and 1/20th of LC50 of untreated sewage water (UT) obtained from sewage water treatment plant, Ludhiana, India. After determining 96-h LC50 value of UT, fingerlings were divided into four groups: control, treated, 1/10th of LC50 UT and 1/20th of LC50 UT and exposed for a period of 2 months. Our study revealed that 1/10th LC50 UT and 1/20th LC50 UT groups had significant reduction in body weight, total body length, standard body length and gills somatic index in comparison with the control and treated groups. Histopathological alterations in cellular structure of gills such as ruptured primary lamellae, broken secondary lamellae, distorted chloride cells and goblet cells, missing lamellae and disintegrated lamellar epithelium were also observed in 1/10th LC50 UT and 1/20th LC50 UT groups. A significantly high frequency of micronucleated (MN) cells was observed in 1/10th LC50 UT and 1/20th LC50 UT groups along with the presence of binucleated cells (BN), elongated nuclei (EN) and nuclear buds in gill cells. Genotoxic nature of UT was further confirmed from significantly high values of genetic damage index (GDI) and percentage (%) DNA damage in gill cells of fingerlings exposed to sub-lethal concentrations of UT. The study concluded that untreated sewage water has potential to induce anatomical and physiological defects in gills cells and the severity of toxicity increases with the increase in duration of exposure.

Assessment of genotoxic potential of arsenic in female albino rats at permissible dose levels.

BACKGROUND: Arsenic is a wide spread environmental contaminant and has been recognized as a genotoxic element which is of major public health concern. AIM: The present study evaluates the genotoxic potential of arsenic at low permissible dose levels. MATERIALS AND METHODS: Forty-eight mature female rats were divided into four groups of 12 animals each. Group I animals received distilled water and served as control. Group II-IV animals received sodium arsenite dissolved in distilled water continuously for a period of 60 days at the dose of 10, 30 and 50 µg/L (ppb) respectively. Six rats from each group were sacrificed after 30 days of arsenic exposure and the remaining animals were sacrificed after 60 days. Liver was excised from the sacrificed animals to study the probable advent signs of carcinogenicity measured through microsomal degranulation test. Assessment of mutagenic potential of arsenic was evaluated through chromosomal aberrations observed in the bone marrow cells. RESULTS: The levels of RNA and proteins decreased significantly (P ≤ 0.01) in all the three doses administered along with an increase in % microsomal degranulation in hepatic fraction when compared to control at both 30 and 60 days time period. A dose-dependent increase in chromosome aberrations like fragmentation, breakage has been observed in all the treated animals. CONCLUSION: The results of present study revealed that chronic exposure of arsenic even at its low permissible dose limits results in carcinogenic and mutagenic effects which emphasize its genotoxic possibility.

Chlorpyrifos induced toxicity in reproductive organs of female Wistar rats.

Chlorpyrifos (CPF) is an organophosphate (OP) insecticide extensively used in agricultural and domestic settings. Healthy adult female albino rats were divided into three groups of six rats in each. Two groups were dosed orally with CPF in vegetable oil (0.1 and 2.5 mg/kg/day) and third group was given vegetable oil for 8 weeks. Non-significant changes were observed for body weight and feed intake. A disruption in estrous cyclicity was observed with a prolonged metestrous. Erythrocyte osmotic fragility and lipid peroxidation levels increased significantly. Mammary gland whole mounts revealed a significant (P<0.05-0.0001) increase in the ductal thickness, number of branches, alveolar and terminal end bud number and terminal end bud diameter. A significant increase in ovarian surface epithelium height, follicular diameter and follicular atresia was observed in treated rats (P<0.05-0.0001). A similar significant increase in the uterine surface epithelium height, endometrial gland epithelium height and myometrium thickness in higher dose group was recorded (P<0.05-0.0001). Luminal epithelium height and endometrial gland diameter was increased significantly in both the treated groups (P<0.05-0.0001). The results indicate that sub-chronic exposure of CPF causes oxidative stress and negative effects on the reproductive organs of female rats, which may be a pointer towards beginning of cancer incidence.