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Abstracts
Impact of manganese oxides on plant growth Sarah Atkinson, Brian McGaw and Keith Nicholson Environmental Division, School of Applied Sciences, Gordon University, Aberdeen AB 1 1HG, Scotland, UK
Manganese oxides have a strong sorption capacity for metals, effectively binding and reducing bioavailability of essential trace elements to plants. This study was initiated to evaluate the impact varying proportions of manganese oxides in different "soil" media had on plant growth. Manganese oxide-coated sand, described e l s e w h e r e ( E l e y and N i c h o l s o n , 1993), was employed as this was known to have a uniform composition w h i c h had earlier been well-characterised. Varying proportions of the oxides (0%, 0.5%, 2%, 4%, 6%, 8%, 10% and 50% oxide by volume) were mixed with two growth media: multipurpose compost and vermiculite. Mung beans were grown from seed in each media and their growth rate monitored over 16 weeks. Mung beans were selected for study because of their rapid germination and growth rate. The metal content of the plants and manganese oxides was d e t e r m i n e d by f l a m e a t o m i c a b s o r p t i o n spectroscopy. The d e v e l o p m e n t of the plants visually deteriorated with increasing concentrations of manganese oxides in the growth media. Analysis of the p l a n t s g r o w n in the c o m p o s t s h o w e d concentrations of Fe, Zn, Mg and Ca were less than
in the control samples. Potassium showed a variable b e h a v i o u r but was g e n e r a l l y at h i g h e r concentrations than in the control, while Mn levels did not display any consistent trend. Plants grown in the vermiculite showed Mn and Fe concentrations greater than the control, but lower concentrations of Zn and Mg. The low levels of magnesium, an order of magnitude less than the control samples, was particularly striking. Potassium and Ca showed a variable behaviour but were generally at levels greater than in the control samples. The variations in element behaviour, with respect to the control, between growth media is in part due to the properties of the medium itself Analysis of the manganese oxides retrieved from the "soils" shows, for example, than the striking loss of Mg from the plants is probably due to take-up of Mg on the vermiculite rather than on the oxides. Reference
Eley, M. and Nicholson, K. 1993. Chemistry and adsorption-desorption properties of manganese oxides deposited in Forehill water Treatment Plant, Grampian, Scotland. Environmental Geochemistry and Health (in press).
Identification of element associations and controls on freshwater chemistry in Grampian Region, Scotland Margaret Tse Tig Cheong and Keith Nicholson Environment Division, School of Applied Sciences, The Robert Gordon University, Aberdeen AB1 1HG, Scotland, UK Data from weekly chemical analyses of feed waters to water treatment plants in Grampian Region, Scotland, were examined to identify any element associations and common controls on the chemistry of these waters. The sample data spanned three years and covered water abstracted from Blackhill Springs, River Ugie, River Deveron and the i m p o u n d i n g r e s e r v o i r s Huntly, R o c h o m i e , Bogensourie and Glenlatterach. Of the parameters determined colour, turbidity, pH, total Fe and total Mn occurred in all analyses with conductivity,
chlorophyll, total A1 and algal count present in some data sets. A total of 750 observations were employed in the statistical analyses. The statistical analyses were performed using the Minitab computer package. To avoid the introduction of bias in the multivariate analyses, an initial data evaluation was performed to remove data with missing values and to delete outliers, identified by histograms and scatter plots. Simple descriptive statistics, correlation matrices, principal component analyses and linear discriminant analyses were
Abstracts
Impact of manganese oxides on plant growth Sarah Atkinson, Brian McGaw and Keith Nicholson Environmental Division, School of Applied Sciences, Gordon University, Aberdeen AB 1 1HG, Scotland, UK
Manganese oxides have a strong sorption capacity for metals, effectively binding and reducing bioavailability of essential trace elements to plants. This study was initiated to evaluate the impact varying proportions of manganese oxides in different "soil" media had on plant growth. Manganese oxide-coated sand, described e l s e w h e r e ( E l e y and N i c h o l s o n , 1993), was employed as this was known to have a uniform composition w h i c h had earlier been well-characterised. Varying proportions of the oxides (0%, 0.5%, 2%, 4%, 6%, 8%, 10% and 50% oxide by volume) were mixed with two growth media: multipurpose compost and vermiculite. Mung beans were grown from seed in each media and their growth rate monitored over 16 weeks. Mung beans were selected for study because of their rapid germination and growth rate. The metal content of the plants and manganese oxides was d e t e r m i n e d by f l a m e a t o m i c a b s o r p t i o n spectroscopy. The d e v e l o p m e n t of the plants visually deteriorated with increasing concentrations of manganese oxides in the growth media. Analysis of the p l a n t s g r o w n in the c o m p o s t s h o w e d concentrations of Fe, Zn, Mg and Ca were less than
in the control samples. Potassium showed a variable b e h a v i o u r but was g e n e r a l l y at h i g h e r concentrations than in the control, while Mn levels did not display any consistent trend. Plants grown in the vermiculite showed Mn and Fe concentrations greater than the control, but lower concentrations of Zn and Mg. The low levels of magnesium, an order of magnitude less than the control samples, was particularly striking. Potassium and Ca showed a variable behaviour but were generally at levels greater than in the control samples. The variations in element behaviour, with respect to the control, between growth media is in part due to the properties of the medium itself Analysis of the manganese oxides retrieved from the "soils" shows, for example, than the striking loss of Mg from the plants is probably due to take-up of Mg on the vermiculite rather than on the oxides. Reference
Eley, M. and Nicholson, K. 1993. Chemistry and adsorption-desorption properties of manganese oxides deposited in Forehill water Treatment Plant, Grampian, Scotland. Environmental Geochemistry and Health (in press).
Identification of element associations and controls on freshwater chemistry in Grampian Region, Scotland Margaret Tse Tig Cheong and Keith Nicholson Environment Division, School of Applied Sciences, The Robert Gordon University, Aberdeen AB1 1HG, Scotland, UK Data from weekly chemical analyses of feed waters to water treatment plants in Grampian Region, Scotland, were examined to identify any element associations and common controls on the chemistry of these waters. The sample data spanned three years and covered water abstracted from Blackhill Springs, River Ugie, River Deveron and the i m p o u n d i n g r e s e r v o i r s Huntly, R o c h o m i e , Bogensourie and Glenlatterach. Of the parameters determined colour, turbidity, pH, total Fe and total Mn occurred in all analyses with conductivity,
chlorophyll, total A1 and algal count present in some data sets. A total of 750 observations were employed in the statistical analyses. The statistical analyses were performed using the Minitab computer package. To avoid the introduction of bias in the multivariate analyses, an initial data evaluation was performed to remove data with missing values and to delete outliers, identified by histograms and scatter plots. Simple descriptive statistics, correlation matrices, principal component analyses and linear discriminant analyses were
