Downcore sulphur isotope ratios and diatom inferred pH in an artificially acidified Canadian shield lake

Three gravity cores were removed from near the deepest point in Lake 223 on 9 June 1984, eight years after the Experimental Lakes Area (ELA) staff began the artificial acidification of the lake with sulphuric acid. The first of these cores was analysed for diatoms and pollen stratigraphy while the second and third were analysed for downcore sulphur isotope ratios (H. Thode) and downcore changes in sulphur reducing bacterial densities (S. Rao). Sediment core chronologies were based on lead-210 and cesium-137 data (R. Anderson) and the Ambrosia pollen rise (M. Dickman). Analysis of the first core to the depth of the Ambrosia pollen rise (9 cm) indicated that diatom inferred pH in Lake 223 at the time of the Ambrosia rise (circa 1890) was 6.8-7.0. At a sediment depth of 3 cm the diatom inferred pH was 6.7. Thereafter diatom inferred pH began a decline culminating in the present day (observed) pH range for 1984 (5.3-5.5). At a sediment depth of 1 cm, an increase in the abundance of two benthic alkalophilic diatoms occurred. The increase in the abundance of these diatoms was ascribed to an increase in hypolimnetic alkalinity following the artificial acidification of Lake 223. This is the first time that lake acidification has been linked to an increase in benthic alkalophilic diatoms associated with hypolimnetic alkalinity production following sulphate reduction. Sulphur in the anaerobic (black) sediment layers (0-1.5 cm) was isotopically light relative to the sulphur in the deeper layers. This was due to sulphur isotope fractionation resulting from the bacterial reduction of sulphate to hydrogen sulphide in the anaerobic portion of the water column. A jet black FeS-rich layer in the uppermost 1.5 cm of the lake's sediments was associated with an increase in the abundance of sulphate reducing bacteria (e.g. Desulfovibrio spp.).     

Combinations of Azadirachta indica and Cedrus deodara oil with piperonyl butoxide, MGK-264 and Embelia ribes against Lymnaea acuminata

The binary and tertiary combinations of plant-derived molluscicides Azadirachta indica and Cedrus deodara oil with synergists MGK-264, piperonyl butoxide (PB) and fruit powder of Embelia ribes were used against the Lymnaea acuminata. It was observed that the toxic effects of these mixtures were time- and dose-dependent. The binary and tertiary mixtures of plant-derived molluscicides with synergists were more toxic with respect to the single treatment of the plant-derived molluscicides. Maximum synergistic action in binary and tertiary combinations was found in A. indica + C. deodara oil and A. indica + PB + C. deodara in 1:7 and 1:5:7 ratio, respectively.     

Spatial and temporal variations in the trace elemental data over the northeastern United States

Time series of trace elemental concentrations (14 species) of atmospheric fine particles measured in the northeastern United States between 1988 and 1998 are analyzed for spatial and temporal variations. The influence of synoptic-scale systems to the transport and accumulation of pollutants can be investigated successfully if the short-term fluctuations (i.e. weather-induced variations) embedded in the time series of pollutant concentrations are separated from the original time series. The spatial short-term correlation coefficients for Al, Br, Fe, Se, and Zn permit good predictions of pollutant concentrations up to distances of about 350 km from a given monitor. The species correlation matrices for individual sites reveal that As, Br, Se, and Zn are highly correlated in New York State, while Fe, Mn, and V show also strong correlations, suggesting the commonality of source regions for these industrial and urban pollutants impacting New York.     

Evaluation of different granulated active carbons for removal of Microcystin-LR from contaminated water

Most frequently encountered freshwater cyanobacterial toxin is Microcystin-LR (MC-LR). Microcystins released from cells into water have been responsible for the death of humans, domestic and wild animals. Removal of microcystin by active carbon has been one of the best methods available so far. This study evaluates three grades of active carbon namely 40, 60 and 80 CTC for their removal efficiency of MC-LR from contaminated water. Kinetics of toxin removal was studied in time course experiments. Protection in mouse model was studied for the samples after the adsorption. Toxin quantitation was done by HPLC method. The MC-LR concentration after 24 hr treatment with 40, 60 and 80 CTC carbons were 4.8, 3.3 and 1.3 microg/ml respectively from an initial concentration of 5.2 microg/ml. Protection in mouse bioassay was seen after 48, 24 and 2 hr of adsorption time respectively for 40, 60 and 80 CTC carbons. 80 CTC carbon was found to be most efficient in removing MC-LR from contaminated water.     

Statistics: an essential technology in environmental research and management

Statistical methods as developed and used in decision making and scientific research are of recent origin. The logical foundations of statistics are still under discussion and some care is needed in applying the existing methodology and interpreting results. Some pitfalls in statistical data analysis are discussed and the importance of cross examination of data (or exploratory data analysis) before using specific statistical techniques are emphasized. Comments are made on the treatment of outliers, choice of stochastic models, use of multivariate techniques and the choice of software (expert systems) in statistical analysis. The need for developing new methodology with particular relevance to environmental research and policy is stressed.Dr Rao is Eberly Professor of Statistics and Director of the Penn State Center for Multivariate Analysis. He has received PhD and ScD degrees from Cambridge University, and has been awarded numerous honorary doctorates from universities around the world. He is a Fellow of Royal Society, UK; Fellow of Indian National Science Academy; Foreign Honorary Member of American Academy of Arts and Science; Life Fellow of King's College, Cambridge; and Founder Fellow of the Third World Academy of Sciences. He is Honorary Fellow and President of International Statistical Institute, Biometric Society and elected Fellow of the Institute of Mathematical Statistics. He has made outstanding contributions to virtually all important topics of theoretical and applied statistics, and many results bear his name. He has been Editor of Sankhya and theJournal of Multivariate Analysis, and serves on international advisory boards of several professional journals, includingEnvironmetrics and theJournal of Environmental Statistics. This paper is based on the keynote address to the Seventh Annual Conference on Statistics of the United States Environmental Protection Agency.     

De-fluoridation of groundwater using magnesium oxide

Fluorosis, which severely affects teeth and bones, is one of the common water-related diseases listed by the World Health Organization. Fluorosis is caused by ingestion of groundwater containing fluoride in excess of 1.5 mg/l and is widespread in about 25 countries. As majority of fluorosis affected regions occur in arid or semi-arid regions of the world, de-fluoridation of the limited available water resource forms the viable solution. Though several methods of de-fluoridation have been proposed, only few are implemented in field. Further, the existing field methods have various limitations such as cost, efficiency, quality of treated water and disposal of byproducts of treatment. In search of a sustainable solution towards mitigating the fluorosis problem, a new method of de-fluoridation using magnesium oxide has been developed in laboratory. Present study addresses issues that will assist in successful implementation of the new de-fluoridation method in field, using a domestic de-fluoridation unit.     

Amelioration of toxicopathological effects of cadmium with silymarin and milk thistle in male Japanese quail (Coturnix japonica)

Environmental Science and Pollution Research - Cadmium is an important widely distributed heavy metal in the environment due to its several industrial uses, while milk thistle is an important herb...