Toxicologie environnementale et analytique

Arsenic (As), a well-known environmental toxicant naturally found in rocks in the earth’s crust contaminates groundwater. Patna, a highly populated district of Bihar, India, is situated on the banks of the river Ganges in the area commonly referred to as the Gangetic-Zone. The entire district of Patna is divided into 23 blocks. The purpose of this study was to assess the concentration of As in drinking water and blood samples of people residing in different blocks of Patna.

Drinking water and blood samples were collected from all 23 blocks of Patna. Estimation of As in water samples was done using Arsenic Kit. The observed value was further validated using Atomic Absorption Spectrophotometry with Vapor Generation Assembly (AAS-VGA). More than 50 ppb of As was observed in drinking water samples of 15 blocks (Athmalgola, Bakhtiyarpur, Barh, Belchhi, Bikram, Bihta, Daniyawan, Dulhin Bazaar, Fatuha, Ghoswari, Khusrupur, Maner, Mokama, Paliganj and Pandarakh). A concentration of more than100 ppb of As was detected in the samples from Danapur and Naubatpur, which is more than10 times the WHO permissible limit of 10 ppb. Sample population exhibited high incidence of cancers of various organs such as skin, breast, liver, and gall bladder. Nodular keratosis on palm and sole of the affected population was also observed. As contamination was not observed in the blood samples of healthy people included in the study.

The study showed that surveyed population of blocks of Patna district with high As accumulation in groundwater had a high accumulation of As in their blood samples. High incidence of cancers of skin, liver, breast and gall bladder was also observed in these blocks. The study therefore demonstrates a high degree of correlation between elevated groundwater As concentration and high As concentration in blood stream of persons affected by cancer. The study further concludes that As accumulation is one of the factors causing high rate of cancer in affected areas.

We examined the effects of selenium (Se) on coleus (Coleus blumei Benth.) under lead (Pb) stress, to determine possible mitigating mechanisms of Se. Coleus plants were exposed to 1.0 mM Pb(NO3)2 and varying concentrations of Na2SeO3 for 21 d. Application of 1.0 mM Se enhanced biomass allocation and Pb distribution in different organs, decreased superoxide dismutase (SOD) and peroxidase (POD) activity in the roots, and acted as an antioxidant by inhibiting lipid peroxidation via increasing glutathione levels. Root catalase (CAT) and glutathione peroxidase (GSH-Px) activities increased with Se concentration, and changes to root and leaf particles were observed by scanning electron microscopy and X-ray diffraction. Our results indicate Pb is tolerated by coleus plants through allocation plasticity, activation of antioxidant systems, and improvements in particle size and mineralogical effects. C. blumei can be useful in phytoremediation of aquatic systems contaminated with Pb, especially with addition of low concentrations of Se.

Península Valdes, Argentina, is a nursing ground for a population of southern right whales (Eubalaena australis). In the last two decades this area has been subjected to an increase in population, tourism and industrial growth. This has raised the concern for exposure to chemical contaminants such as metals. In this study we measured nonessential metals (Ag, Al, As, Au, Ba, Be, Co, Cd, Cr, Hg, Li, Ni, Pb, Sb, Sn, Sr, U and Ti), essential metals (Cu, Fe, Mg, Mn, Mo and Zn) and an essential element (Se) in skin biopsies from female southern right whales (n=10). This is the first report on tissue concentrations of metals in adult southern right whales. Overall, tissue values were on the low end of the spectrum and similar to the values reported in studies of mysticetes from other regions. Measured values do not reflect substantial amounts of accumulation and thus serve as a baseline.

Pollution of terrestrial ecosystem is a serious environmental problem worldwide. Earthworm is considered as a domain soil organism. It has been recommended test species to evaluate soil contaminations in acute toxicity. Earthworm density and biomass are strongly influence by pollution. In this study, mortality, biomass, cocoon number of Eisenia fetida were examined during 14 days of exposure to series percentage (100, 75, 50, 25%) for each soil of (Bouatni, Hawari, Lowifia, and Jarotha) locations around Benghazi city, under control conditions. The locations soil was mixed with artificial soil to get the desired percentages. Mortality was recorded in Bouatni soil 100%. However, no mortality observed elsewhere. No cocoon numbers were account in all locations at 100, 75% as well as in Lowifia soil 50%. However, Cocoon numbers were significantly reduced in Bouatni, Hawari and Jarothaat50, 25% compared to control. Interestingly, earthworms body weight were increased significantly, in all locations soil (25, 50, 75%) compared to control earthworm. Our results had shown decreased in cocoon number which can lead to decline in earthworm populations and consequence to reduce soil fertility. This study was first investigation of contamination soils around Benghazi city by using biota as well as put more emphasis on using earthworm as bioindicator.

Background: Infectious diarrhea is the most significant cause of morbidity and mortality in neonatal dairy sheep throughout the world. This is the first study conducted on isolation and biotyping of E. coli from lamb diarrhea in and around Debre Birhan. The present study was undertaken with the objective of isolation, omnilog characterization and biotyping of E. coli isolates from faecal samples around Debrebrhan.

Methods: A cross-sectional study was conducted from October, 2012 to April, 2013. The study focused on lambs less than three months of age showing clinical symptoms of diarrhea. Standard cultural and Omnilog tests were done to identify E. coli species and biotypes; descriptive statistics and Chi-square were used to analyze the collected data.

Results: From a total of 100 diarrheic lambs examined, 84% were found to be positive for E. coli. On the basis of fermentation reactions of sugars viz. dulcitol, raffinose, rhamnose, salicin, starch and sucrose, 70 isolates utilized one or more sugar while 14 isolates failed to utilize any of the sugars. 70 E. coli isolates were biotyped into 15 different combinations. Association between different age groups and occurrence of lamb diarrhea caused by E. coli strains showed a significant association (p < 0.05). From the questionnaire findings, 60% of all the health problems in lambs were due to diarrhea where young sheep were more affected.

Conclusion: pathogenic E. coli has the potential to cause sheep diarrhea. The distribution of the E. coli isolates into different biotypes indicates the diverse nature of the organism. Therefore, further detailed study should be carried out to understand the role of E. coli in lamb diarrhea and identify the virulent strains involved.