Suresh Nesaratnam

Copper and lead concentrations in salt marsh plants on the Suir Estuary, Ireland

Concentrations of Cu and Pb were determined in the roots and shoots of six salt marsh plant species, and in sediment taken from between the roots of the plants, sampled from the lower salt marsh zone at four sites along the Suir Estuary in autumn 1997. Cu was mainly accumulated in the roots of monocotyledonous and dicotyledonous species. Pb was mainly accumulated in the roots of monocotyledons, while dicotyledons tended to accumulate Pb in the shoots. In the case of Aster tripolium there was a clear differentiation in the partitioning of Pb within the plant, between low and high salinity sites. At the low salinity sites, Pb accumulated only in the roots while at the high salinity sites there was a marked translocation to the shoots. The increase in Pb concentrations in roots and shoots of A. tripolium was accompanied by a concomitant decrease in sediment concentrations of Pb. This inverse correlation between sediment and plant concentrations of Pb was also recorded for Spartina spp. and Schoenoplectus tabernaemontani but in the case of these species the roots contained higher concentrations of Pb regardless of salinity levels. These differences in accumulation of Cu and Pb in various salt marsh species, and the influence of salinity on the translocation of Pb in A. tripolium in particular, should be taken into account when using these plants for biomonitoring purposes.

Optimisation of activated carbon production from date pits

This study investigates the optimal process conditions for activated carbon production from local date palm pits using response surface methodology (RSM). Box Behnken statistical technique was used to design the production process in order to determine the influence of activation temperature (300oC to 700oC), % H3PO4 (30% to 70%) and activation time (1 to 3 hours) on the BET surface area. Second-order model developed via regression analysis to describe the BET surface area response was found to be appropriate in predicting the responses within the experimental region to a considerable extent. Analysis of variance (ANOVA) revealed that the influence of the independent variables on the BET surface area is in the order: activation temperature > % H3PO4 > activation time with only temperature and % H3PO4 possessing moderate interaction. The maximum BET surface area from RSM optimisation was estimated to be 1,337.54.2 m2/g achievable at optimum conditions of 54% H3PO4 and 547oC carbonisation temperature at an activation time of 2.067 hours.

DISTANCE TEACHING OF ENVIRONMENTAL ENGINEERING COURSES AT THE OPEN UNIVERSITY

SUMMARY In environmental engineering curricula, pollution abatement technologies are best taught taking a holistic approach to the environment, since the transfer of pollutants from one medium to another will not eliminate the problem. This paper describes two integrated distance-learning environmental engineering degree courses offered by the environmental engineering group of the Open University in the UK. Distance learning is reputed to be the most cost-effective way of acquiring knowledge and is an especially attractive continuing education tool for working professionals. This is exemplified by the number of distance-learning courses now offered by a variety of establishments covering a whole multitude of subjects.