Movement and Transformation of Selected Organic Pollutants in Subsurface Environmet in Arkansas

Several subsurface soil and groundwater samples from eastern, southern and central Arkansas were analyzed for chlorinated organic compounds commonly used as pesticides and industrial chemicals. No significant amount of these compounds were found in these samples. The adsorption/partition characteristics of some of these compounds, such as dichlorophenols, aldrin and endrin, were determined in siltloam, sandyloam and clay soils collected from the above geographical locations. Results indicate that there is considerable difference in retention capability of different types of soils with respect to different pollutants. The partition coefficient of a particular compound in a certain type of soil can be related to both the pH and the organic matter content of the soil

A Systematic Study to Reduce Trihalomethane Precursors in Little Rock Drinking Water by Combined Alum Coagulation-Powdered Activated Carbon Treatment

Studies have been conducted to evaluate powdered activated carbon (PAC) as an agent for controlling trihalomethanes in drinking water. Laboratory studies indicate that PAC is highly efficient in removing free trihalomethanes in water within a few hours. The removal efficiency of humic acid, a known THM precursor, by PAC is considerably less. However, longer treatment time can remove the precursors quite significantly. Humic substances in surface water samples can also be removed by PAC

Electrochemistry of Dihalogenated Nicotonic Acids in Aqueous and Aprotic Media

The electrochemical reduction of several 2,5- and 5,6- dihalonicotinic acids have been studied in dimethyl sulfoxide as well as in aqueous buffers of different pH. The polarographic half-wave potentials for the reduction of these compounds in both media are reported here. The compounds appear to reduce at the carboxyl group. The presence of halogen atoms on the pyridine ring facilitates reduction

Studies on some free living protozoan from Salim Ali lake. Aurangabad

Protozoa are one-celled animals found worldwide in most habitats. Most species are free living, but all higher animals are infected with one or more species of protozoa. Infections range from asymptomatic to life threatening, depending on the species and strain of the parasite and the resistance of the host. Present study deals with the free living protozoa inhabiting fresh water bodies. The factor which influence their distribution and population in a given water bodies temperature, light, pH, chemical composition, acidity, and amount of food present in water and degree of adaptability of the individual protozoa to various environmental changes.&nbsp

Histopathological changes in the hepatopancreas of Lamellidens marginalis exposed to cadmium in winter

In the present study, the destruction of the basement membrane of the hepatic tubules and cell surface of the digestive cells after cadmium exposure probably caused disfunction of the surface receptors resulting in the disturbance of the lysosomal system functioning

Analysis of a Mixture of Several Dihalonicotinic Acids by Gas Chromotography and Gas Chromotography-Mass Spectrometry

Six 2,5- and 5,6- dihalonicotinic acids in a mixture were converted to their corresponding methyl esters and then analyzed by gas chromatography and gas chromatography-mass spectrometry. Four methods of conversion were compared for their GC sensitivity, efficiency and analysis time. In Method #1, using HC1 and methanol as the reagents, the displacement of the halogens by chlorine (from HC1) at 2- and 6-positions was a common occurrence, rendering the method inefficient. In Method #2 (BF3/methanol), the displacement of halogens by methoxide was evident. Method #3 (dicyclohexylcarbodiimide/methanol) produced a mixture of derivatives with a poor yield. Method #4 (diazomethane) gave a quantitative yield of the corresponding methyl esters without any side reactions and was suitable for analytical method development. The latest method provided short analysis time with all six methyl dihalonicotinates eluting within nineteen minutes. The resolution of the ester peaks was excellent and the detection limit was about 1ng/|Mu L for the dihalonicotinic acids

Association of AM fungi in important Pteridophytic plants of Maharashtra, India.

Four pteridophytic plants were studied for their Arbuscular mycorrhizal (AM) fungal association. All tested plants were distributed in Maharashtra state. The result revealed that all the tested pteridophytic plants (viz. Equisetum spp, Marsilea spp, Nephrelepis spp, and Adiantum spp) had AM association in the roots and spore population in the soil. However, maximum root colonization was observed in Equisetum spp (96%) where as minimum was observed in Nephrelepis spp (28%). Equisetum spp (208) showed more spore density where as less in Adiantum spp (27). Total 15 AM fungal species were identified and quantified in which Glomus spp were dominant followed by Acaulospora spp Sclerocystis spp and Gigaspora spp were found less frequently distributed