Population exposure to airborne thorium at the high natural radiation areas in India

High natural radiation areas in the coastal and peninsular India were studied for airborne thorium and resultant population exposure due to inhalation. Four locations covering three states viz., Ayiramthengu and Neendakara in Kerala, Kudiraimozhi in Tamil Nadu and Bhimilipatnam in Andhra Pradesh were investigated. External gamma radiation fields 1 m above the monazite ore bodies ranged from 200 to 3000 nGy h^-1. Soil samples showed ²³²Th specific activity varying from 0·1 to 1·5 Bq g^-1 with surface alpha activity in the range of 1·0–12·5 Bq cm^-2. Suspended particulates in the samples ranged from 60–140 μg m^-3 with ²³²Th showing a wider variation of <0·03–0·3 mBq m^-3. There was poor correlation between suspended particulates and long-lived alpha airborne activity . The resuspension factors for ²³²Th were in the range of 1·5×10^-8–7·9×10^-7 cm^-1. Higher resuspension was correlated with dry sand dunes. The upper limits for Committed Effective Dose (CED) due to inhalation of airborne ²³²Th at the respective high natural radiation areas were estimated to range from 50±30 to 300±130 μSv (5–30 mrem) per year per adult member of public assuming an activity median aerodynamic diameter of 1 μm for the airborne particulates.     

Response of embryos of the sea urchin Strongylocentrotus purpuratus to aqueous petroleum waste includes the expression of a high molecular weight glycoprotein

The present study investigated the sublethal effects of the largest aqueous waste associated with offshore oil development, produced water (PW), on sea urchin embryo development. PW inhibited normal gastrulation in purple sea urchin (Strongylocentrotus purpuratus) embryos exposed at the hatching stage. The exposed embryos did not form complete archenterons, and secondary mesenchyme cells exhibited an unusual behavior with respect to the wall of the blastocoelic cavity. In addition, an abundance of extracellular matrix was observed in the blastocoelic cavities in the embryos exposed to higher concentrations of PW. An inhibition of the development of embryos through the pluteus stage was observed as a result of PW exposure. This was manifested by inhibition of normal spicule formation with concomitant abnormal pluteus morphology. To determine if a biochemical stress response occurs as a result of PW exposure, embryos at the early gastrula stage were exposed to PW for 2 h, followed by an additional 1 h in 3H-leucine and PW. These embryos expressed a 253 kDa protein as observed by one-dimensional SDS (sodium dodecyl sulfate) polyacrylamide gel electrophoresis and autoradiography. This protein could occasionally be observed in gels stained for protein, and was glycosylated as demonstrated by staining with periodic acid Schiff (PAS). The 70 to 73 kDa heat-shock proteins previously described in sea urchin embryos (and other organisms) as a result of stress were not synthesized as a result of PW exposure. Heat shock did not induce synthesis of the 253 kDa glycoprotein. Combined PW and heat-shock exposure elicited both the heat-shock response (73 kDa protein) as well as expression of the 253 kDa glycoprotein. These data demonstrate the use of expression of endogenous macromolecular markers to distinguish exposures of embryos to different perturbations. Arsenic (as sodium arsenite), a metal constituent of PW, also induced the 253 kDa glycoprotein in early gastrula-stage embryos. We suggest that this glycoprotein may be a marker for PW (and a metal constituent) exposure in sea urchin embryos, and may be related to morphological abnormalities.     

Chemical composition of fresh snow from Gulmarg, North India

The chemical composition and pH of 30 fresh snow samples collected during December 1986 to May 1987 at Gulmarg (34 degrees 03' N, 74 degrees 24' E, 2655 m above mean sea level), a remote place in north India, were studied. The snow samples were, by and large, alkaline in nature and were largely influenced by non-marine aerosols. The concentrations of cations (Ca(2+), K(+) and Mg(2+)) were more than the anions (SO(2-)(4) and NO(-)(3)). Factor analysis indicated that most of the ionic components were transported into the region during the period of measurements. The transport of ionic components could be attributed to the passage of western disturbances over this region. The comparison of concentrations of anions and cations in the snow samples at Gulmarg with those reported from a few countries in the west revealed that the composition of Gulmarg snow largely differs in the concentrations of cations rather than anions. Among the cations, the concentration of Ca(2+) was high at Gulmarg and this could be responsible for buffering the pH of snow in the alkaline range.     

Recovery of a marker strain of Salmonella typhimurium in litter and aerosols from isolation rooms containing infected chickens

Screening of poultry flocks for foodborne pathogen Salmonella contamination is critical for Salmonella control in preharvest stages of poultry production. In this study, two sampling methods (litter and air filter) were compared for detection of S. typhimurium from experimentally infected chicks some of which had received either a probiotic competitive exclusion culture or transfer of cecal contents from salmonellae-free adult birds. At 4, 9, and 11 days after inoculation, S. typhimurium samples were enumerated by selective plating. For both types of sampling, the control birds yielded the greatest levels of environmental contamination followed by the samples from the probiotic inoculated birds with the birds receiving the cecal transfer culture having the lowest levels of contamination. Although the two sampling methods responded in a similar fashion, detection sensitivity needs to be increased for air filter sampling.     

Do we need to examine the quantitative data obtained from toxicity studies for both normality and homogeneity of variance?

Most of the statistical techniques used to evaluate the data obtained from toxicity studies are based on the assumption that the data show a normal distribution and homogeneity of variance. Literature review on toxicity studies on laboratory animals reveals that in most of the cases homogeneity of variance alone is examined for the data obtained from these studies. But the data that show homogeneity of variance need not always show a normal distribution. In fact, most of the data derived from toxicity studies, including hematological and biochemical parameters show a non-normal distribution. On examining normality of data obtained from various toxicity studies using different normality tests, we observed that Shapiro-Wilk test is more appropriate than Kolmogorov-Smimov test, Lilliefors test, the normal probability paper analysis and Chi square test. But there are situations, especially in the long-term toxicity studies, where normality is not shown by one or more than one of the dosage groups. In this situation, we propose that the data maybe analyzed using Dunnett multiple comparison test after excluding the data of the groups that do not show normality However, the biological relevance of the excluded data has to be carefully scrutinized. We also observed that the tendency of the data to show a normal distribution seems to be related to the age of the animals. Present paper describes various tests commonly used to test normality and their power, and also emphasizes the need of subjecting the data obtained from toxicity studies to both normality and homogeneity tests. A flow chart suggesting the statistical techniques that maybe used for both the types of data showing a normal or non-normal distribution is also proposed.     

Soil-catalyzed oxidation of aniline

Aniline partially degraded in sterile soil to azobenzene, azoxybenzene, phenazine, form=anilide, and acetanilide. Nitrobenzene, $\text{p}$-benzoquinone, and unidentified species were possible products; substantial bound residues may also have formed. Soil-catalyzed conversion of aniline or [$\text{d}$₅]aniline seems evidenced by 6-24X more product recovery in sterile soil than in sterile water alone, a process inhibited by Na₂S₂O₄. Freundlich adsorption constants showed: azobenzene > azoxybenzene > phenazine > aniline.