Haematotoxic effect of linear alkyl benzene sulphonate (LAS) in fish,Heteropneustes fossilis

It was observed that clotting time decreased with the increased concentrations of LAS. However, the decrease was more pronounced at LC50 for 24 h and at the end of 96 h LC50, it was very close to control values.     

Environmental effects of nanosilver: impact on castor seed germination, seedling growth, and plant physiology

Increasing use of nanoparticles in daily products is of great concern today, especially when their positive and negative impact on environment is not known. Hence, in current research, we have studied the impact of silver nanoparticle (AgNPs) and silver nitrate (AgNO₃) application on seed germination, root, and shoot length of castor bean, Ricinus communis L. plant. Silver nanoparticles had no significant effects on seedling growth even at higher concentration of 4,000 mg L^?1, while the silver in bulk form as AgNO₃ applied on the castor bean seeds inhibited the seed germination. Silver uptake in seedlings of the castor seeds on treatment with both the forms of silver was confirmed through atomic absorption spectroscopy studies. The silver nanoparticle and silver nitrate application to castor seeds also caused an enhanced enzymatic activity of ROS enzymes and phenolic content in castor seedlings. High-performance liquid chromatography analysis of individual phenols indicated enhanced content of parahydroxy benzoic acid. These kinds of studies are of great interest in order to unveil the movement and accumulation of nanoparticles in plant tissues for assessing future applications in the field or laboratory.     

Detection of DNA damage in fish Oreochromis mossambicus induced by co-exposure to phenanthrene and nitrite by ESI-MS/MS

Background, aim, and scope

Mutagenic nitrated polycyclic aromatic hydrocarbons (nitro-PAHs) have been known to arise in the environment through direct emissions from combustion sources and nitration of PAHs, primarily in the atmosphere. In the marine environment, PAHs are one of the classic anthropogenic organic pollutants, while nitrite (NO ₂ ^– ) is produced naturally via various biological processes like imbalance in nitrification/denitrification or eutrophication and subsequent oxygen depletion from an oversupply of nutrients. In this paper, we report the formation of PAH-DNA adducts in fish contaminated with PAHs and exposed to NO ₂ ^– in the ambient water. Electrospray ionization tandem mass spectrometric (ESI-MS/MS) analysis of the bile of the euryhaline fish Oreochromis mossambicus exposed simultaneously to field relevant sublethal concentrations of phenanthrene and NO ₂ ^– and collision-induced dissociation of selected ions revealed the presence of DNA-PAH adducts. The present study indicates that, although several high sensitivity techniques have been developed for the analysis of PAH derived DNA adducts, MS/MS has emerged as a powerful tool in the detection and structure elucidation of DNA adducts.

Materials and methods

Juvenile O. mossambicus from a local estuarine fish farm were used with increasing frequency for carcinogenicity testing and comparative cancer research. The fish were exposed to the alkylating agent phenanthrene in the presence of NO ₂ ^– . Composite untreated bile samples after dilution with methanol: water (1:1; v/v) were analyzed by ESI-MS.

Results

Several adducts could be evidenced in the bile by MS/MS. Deoxyadenosine/deoxyguanosine having a mass in the range of 450–650 amu is detected. In addition, a segment of modified dinucleotide with a mass that corresponds to a dimer consisting of a modified guanosine and a normal guanosine has also been identified in the bile.

Discussion

The formation of certain types of DNA adducts is a crucial step in the induction of cancer and a primary stage in mutagenesis. Phenanthrene injected by i.p. route led to the transformation of phenanthrene to N-formyl amino phenanthrene-N ⁶-deoxyadenosine adduct, whereas the fish co-exposed to phenanthrene and ambient nitrite metabolizes PAH to mono-, di- as well as trinitro derivatives, which then react with DNA leading to the formation of mainly modified guanosine and adenosine adducts. In the present investigation, dinitrophenanthrene diol epoxide (DNPDE) adduct with guanosine (m/z 587) seems to be the dominant adduct in the mixture, and its presence is shown first as a comparatively less stable adduct, which decomposes to give a more stable N² adduct (m/z 567).

Conclusions

MS/MS has proved to be useful in the rapid determination and discrimination of structurally different phenanthrene/derivatives DNA adducts in a complex mixture of fish bile co-exposed to phenanthrene and nitrite. However, the nature of metabolites formed is likely determined by the route of PAH administration, and there is a need to further define the early biochemical events of carcinogenesis in these species.

Recommendations and perspectives

DNA adduct analysis in fish bile offers a promising approach to study the risk of potentiation of anthropogenic chemicals into genotoxic compounds in the presence of nitrite in the marine environment. We believe this is the first report on the formation of DNA-phenanthrene adducts on co-exposure of the fish to PAH and nitrite.     

The incorporation and validation of empirical crawling data into the buildingEXODUS model

The deterioration of environmental conditions can influence evacuee decisions and their subsequent behaviors. Simulating evacuee behaviors enhances the robustness of engineering procedural designs, improves the accuracy of egress models, and better evaluates the safety of evacuees. The purpose of this paper is to more accurately incorporate and validate evacuee crawling behavior into the buildingEXODUS egress model. Crawling data were incorporated into the model and tested for accurate representation. Once confirmed, the data were compared to another crawling data set for validation. The buildingEXODUS model demonstrated the ability to incorporate and compare the effects of crawling behavior. The paper further suggests some enhancements to be made to models that attempt to simulate crawling.     

Studies on antioxidant status in Mugil cephalus in response to heavy metal pollution at Ennore estuary

Estuaries, the important component of natural environment are under pressure nowadays due to pollution from different sources like industries, agricultural fields etc. Ennore estuary one of the highly polluted estuary situated in Chennai, Tamilnadu, India, due to heavy industrialization surrounding this site poses serious threat to its inhabitants. The present paper focuses on studying the response of the fish Mugil cephalus with reference to its antioxidants during their exposure to metals like iron and chromium present in the industrial effluents that are discharged into the Ennore estuary. The results on comparison with unpolluted Kovalam estuary showed that fish from Ennore experiences severe oxidative stress with significant alteration being observed with antioxidant enzyme activities. Since these results were also found to vary with seasons, the determination of oxidative stress biomarkers in M. cephalus along with seasonal variations may serve as a convenient approach during pollution biomonitoring programme.     

Leaching behaviour of chlorpyriphos and cypermethrin in sandy loam soil

The mobility of chlorpyriphos and cypermethrin in sandy loam soil was studied in soil columns under laboratory conditions at two application rates, 25 and 50 μg, with simulated rainfall of 300 mm. Residues of chlorpyriphos and cypermethrin in soil and leachate were estimated by gas–liquid chromatography and confirmed by gas chromatography–mass spectrometry. Though maximum concentration of both the insecticides was found in the top 10-cm layer, chlorpyriphos was found distributed in the soil up to a depth of 35 cm and cypermethrin remained up to 15 cm. Results indicated the low mobility of both the insecticides under saturated moisture condition and hence may not contaminate ground water. No residues of any insecticide were detected in the leachate fractions.     

Dynamics of toxic heavy metals in different compartments of a highly urbanized closed aquatic system

This paper deals with the dynamics of chromium, nickel, copper and lead among the different components namely water, surface sediments, submerged and free floating macrophytes and fish of the twin manmade lakes, Upper and Lower lakes, of Bhopal (M.P., India). Some basic parameters of water and sediment have also been studied. The basin of the lake system is densely populated and the water is used for various purposes including drinking. Ni and Pb along with nitrate in both lakes are significantly higher than the drinking water quality criteria of USEPA. The concentration of the metals in the sediments is noticeably higher than that present in the adjoining rock, particularly Ni and Pb. There is a significant uptake of metals by the macrophytes (Eichhornia crassipes and Hydrilla verticillata) and fish (Labeo rohita and Oreochromis niloticus) mainly in summer. The fish of Lower lake (O. niloticus) is unfit for human consumption. The data have been statistically treated. Principle component analysis and cluster analysis were performed to define the origin of metals and to assess the relationship among the sites. Overall the Lower lake is more polluted than the Upper lake. In aggregate, the lake system is under an environmental stress due to certain practices.     

Antibiotic uptake by plants from manure-amended soils

Antibiotics are extensively given to livestock to promote growth and reduce diseases. Therefore, animal manure often contains antibiotics. Once manure is applied to agricultural land to improve soil productivity, crops would be exposed to antibiotics which may persist in soils from a few to several hundred days. The objective of this study was to evaluate the uptake of gentamicin and streptomycin by carrot (Daucus carota), lettuce (Lactuca sativa) and radish (Rhaphanus sativus) from manure-amended soil. The treatments were 0, 0.5 and 1 mg of antibiotic kg^?1 of soil. Two pot experiments were carried out in the greenhouse. The first was conducted on the three crops and the second exclusively on radish. In radish, the increase in the concentrations of gentamicin was significant between the 0 and both of 0.5 and 1.0 mg kg^?1 treatments, but not significant between the 0.5 and 1.0 mg kg^?1. The average values were 35.5, 60.0 and 57.4 μg kg^?1 for the 0, 0.5 and 1 mg kg^?1 rates, respectively. However, the increase in streptomycin concentration in radish was not significant between the three treatments, and the average values were, 12.1, 15.2 and 17.4 μg kg^?1 for the 0, 0.5 and 1 mg kg^?1 rates, respectively. In carrot roots and lettuce leaves no significant increase in the concentrations of gentamicin or streptomycin was observed between the treatments. The three crops absorbed relatively higher amounts of gentamicin (small molecule) than streptomycin (large molecule). Generally the levels of antibiotics in plant tissue increased with increasing the antibiotic concentration in the manure (1 mg kg^?1 > 0.5 mg kg^?1).     

Removal of propylene and butylene as individual compounds with compost and wood chip biofilters

Propylene and butylene are highly reactive volatile organic compounds (HRVOCs) in terms of ground-level ozone formation. This study examined the effectiveness of biofiltration in removing propylene and butylene as separate compounds. Specific objectives were (1) to measure maximum removal efficiencies for propylene and butylene and the corresponding microbial acclimation times, which will be useful in the design of future biofilters for removal of these compounds; (2) to compare removal efficiencies of propylene and butylene for different ratios of compost/hard wood-chip media; and (3) to identify the microorganisms responsible for propylene and butylene degradation. Two laboratory-scale polyvinyl chloride biofilter columns were filled with 28 in. of biofilter media (compost/wood-chip mixtures of 80:20 and 50:50 ratios). Close to 100% removal efficiency was obtained for propylene for inlet concentrations ranging from 2.9 x 10(4) to 6.3 x 10(4) parts per million (ppm) (232-602 g/m3-hr) and for butylene for inlet concentrations ranging from 91 to 643 ppm (1.7-13.6 g/m3-hr). The microbial acclimation period to attain 100% removal efficiency was 12-13 weeks for both compounds. The lack of similar microbial species in the fresh and used media likely accounts for the long acclimation time required. Both ratios of compost/wood chips (80:20 and 50:50) gave similar results. During the testing, media pH increased slightly from 7.1 to 7.5-7.7. None of the species in the used media that treated butylene were the same as those in the used media that treated propylene, indicating that different microbes are adept at degrading the two compounds.     

Spectrophotometric determination of nitrite with diphenylamine in potable and polluted water

This paper describes a new method for the determination of nitrite in potable and polluted water, based on the reaction of nitrite with p-nitroaniline to form diazonium salt and its subsequent coupling with diphenylamine in acidic medium. The pink coloured dye formed obeys Beer's law in the range 0.16 to 0.56 μg/ml at λ_max = 540 nm. The molar absorptivity and Sandell's sensitivity being 57.5 × 10³ lmole^?3cm^?1 and 0.0008 μg/cm², respectively. The optimum reaction conditions and other analytical parameters have been studied. Extraction of the dye with chloroform enhances the sensitivity considerably and makes 0.04 μg/ml of nitrite determinable.