No description available.

No description available.

No description available.

A study was made of a range of aquatic plants from various parts of the River Wear system, for 15 metal elements. The heavy metal content of the plants was related to the chemistry of the water using the enrichment ratio. Different chemical environments were studied in an attempt to establish factors affecting the accumulation of heavy metals. Marked Increases were found in Zn, Pb and Cd tn Cladophora glomerata and Fontinalis antipyretioa sampled downstream of the entry of an industrial effluent as compared to a site upstream of this effluent. A clear linear relationship was established for Zn and Pb between the concentration in the plant and that in the water for Cladopkora glomerata, in strictly comparable situations at sites above and. below the effluent. Divided samples of 'Fontinalis antipyretica showed marked increases in many heavy metals in the older material as compared to the younger tips. It is suggested that bryophyte tips could reliably indicate the heavy metal concentration of river water. It is also suggested that leaves of Ramunculus penicillatus var. calcareus might be useful in indicating heavy metals. Plants from a Zn and Pb polluted tributary (Rookhope Burn) showed marked accumulation of Zn and Pb compared to similar plants from waters with low concentrations of these heavy metals. In Brandon Pithouse acid streams enrichment ratios were encountered, at pH <3, several orders of magnitude lower than sites of pH 6-8. It is suggested that pH might have a direct or indirect influence in reducing this ratio. It is also suggested that both physiological and environmental parameters, notably chemical speciation, are important factors affecting enrichment ratios. Importance was attached to defining limits to enrichment ratios so that aquatic plants could be used to' indicate heavy metal concentrations in a wide range of flowing waters.

No description available.

No description available.

Utilization of sophisticated hydroinformatic systems depends on the optimum use of appropriate input data. The main focus of the present project has been the development of a number of auxiliary data handling modules for a previously constructed IPT system. This system is an elaborate software capable of modelling a wide range of hydro-environmental phenomena. Data required for the implementation of the IPT system consist of hydro graphic and physical data regarding the geometry of hydro-environmental system and boundary and initial conditions. Due to inevitable high cost of these surveys in most cases the available data are scarce which reduces the efficiency of computer models. In this respect development of more sophisticated computer modelling schemes is in effective and techniques for enhancing the quality of the input data must be employed. The aim of this project has been to eliminate such difficulties by the use of modern IT techniques such as the optimization of physical data by genetic algorithms, fuzzy logic procedures, intelligent data bases and case based reasoning. To demonstrate the efficiency of the developed data handling modules a number of hydro-environmental problems in tidal river networks have been solved. It is shown that the modules developed in this project have general applicability and can be used to assist computer aided design and systems management in a wide variety of cases.

Peatlands contain a significant proportion of the worlds’ total soil carbon, and are commonly assumed to serve as carbon sinks. There is however increasing evidence of carbon loss from peat soils, and DOC concentrations in UK rivers have increased markedly over the past three decades. Numerous drivers for increasing DOC release have been proposed but to date the potential role of land management has not been fully explored. This study examines the potential effects of land management on DOC production and release from upland peat for a series of catchments in the South Pennines and North Yorkshire Moors. Spatial variability in drainage DOC concentration was examined in 50 small headwater catchments (<3 km 2 ) and nine reservoir catchments (1.5-21 km 2 ). A subset of the reservoir catchments was further examined through time to establish any relationship between land management and DOC. Of the factors assessed, representing all combinations of soil type and land use, the proportion of new vegetation burn on blanket peat was consistently identified as the most significant predictor of spatial variation in DOC concentration. Significant relationships were identified between both temperature and sulphate deposition and longer-term DOC concentrations, but no interaction or cumulative effect of these two factors was shown. In contrast, the area of new burn on blanket peat explains more than twice the degree of variance in DOC over the same period. For catchments where no change in the area of new burn was determined, drainage DOC increases were minimal. This study demonstrates that land management activities are important landscape-scale drivers of DOC concentration. Exposed peat surface following burning may be altering peat hydrology and improving conditions for microbial activity and enhanced DOC production. Land management therefore has significant consequence for water utilities facing increased costs of treatment and also for the conservation of blanket bog and blanket peat ecosystems currently managed by fire.

Widespread use of depleted uranium (DU) in munitions around the world has raised questions about contamination of soils, water and vegetation with uranium (U). However, understanding of processes controlling the fate and behaviour of U in soils is poor. The aim of this research was to investigate the contributions of abiotic and biotic processes to U transport in soils, by measuring transport in well-controlled experimental systems, and comparing the results with predictions of models of solute transport and reaction. Investigating the role of abiotic processes is challenging due to the complex speciation chemistry of U in soil solutions, sorption reactions with soil surfaces, and the kinetics of local equilibration with soil particles. To simplify the system, the self- diffusion of 235 U against 238 U isotopes was considered, such that speciation and sorption environments were constant. Rates of self-diffusion of these isotopes were measured in four contrasting soils, together with the components of the soil U diffusion coefficient. The results showed that U diffusion was controlled by sorption processes in all the soils, and that slow local-equilibration processes had a major effect. The concentration-distance profiles of U in the soils could not be explained with a simple model assuming instantaneous solid:solution equilibration, and some U spread far further than predicted for equilibrium sorption. Differences in U sorption between the soils were not simply related to differences in soil pH, clay content, CEC or mineralogy. To investigate biotic effects, rates of bulk diffusion of U were measured in sterilised soil, and soil in which prokaryotes or eukaryotes were inhibited by biocides. Slow local-equilibration processes were again found to affect diffusion, but transport was also somewhat increased by biotic processes, hypothesised to be due to differences in CO2 pressure arising from microbial activity and thereby U speciation. This has implications for the effects of perturbation on rates of U transport through soil.

Several plant species are able to accumulate and withstand large quantities of heavy metals in their tissues without dramatic alterations in their growth usually observed in plants. Such metal accumulating plants are tested and used for remediation of contaminated soils and waters. Although the literature provides extensive information on the effect of heavy metals in growth and development of several metal-accumulating and non accumulating plants, nitrogen metabolism and the regulation of related enzymes have not been widely studied. In an effort to better understand the responses of plants species under heavy metal stress, a comparative study was held between two solanaceous species, Nicotiana tabacum and Nicotiana glauca, plants with promising properties for phytoremediation. Plants of the two species were grown in the presence of different concentrations of the heavy metals zinc (Zn), nickel (Ni) and cadmium (Cd) in the following experimental systems in the greenhouse: in pots containing artificial substrate for 6 weeks and hydroponically for 8 days. In order to get a global picture for the heavy metal –induced variations concerned the examined species, the accumulation and distribution of metals in various plants tissues (lower and upper leaves, lower and upper shoots, roots) was determined. Also, several morphological parameters related with plants growth, physiological related with light and dark reactions of photosynthesis and water balance, biochemical related with nitrogenous compounds metabolism and the enzymes involved in ammonia assimilation, were followed. The presence of the referenced metals in the culture medium induced alterations, in all the parameters examined. In particular, strong positive correlations exhibited between the accumulation of Zn, Ni and Cd in the examined tissues and the supplied metals concnentrations. Our data revealed different accumulation patterns for each examined metal at tissue and species level. Furthermore, both growth and physiological parameters were negatively affected at least by the higher concentration of the three metals tested. However, differential responses were observed between N. tabacum and N. glauca, where the latter seemed to be more sensitive at the higher concentration of the metals, especially for Ni and Cd, showing heavier symptoms. In addition, proline accumulation was positively affected over the range of the three metals concentrations. Alterationsinduced in quantitive and qualitive profile of soluble proteins corresponding to Zn, Ni and Cd treatments. Furthermore, the concentration of Zn, Ni and Cd differentially affected the specific activities and the protein levels of ammonia assimilating enzymes glutamine synthetase (GS), glutamate synthase (Fd-GOGAT) and glutamate dehydrogenase (GDH).