Objectif 1) TO DETERMINE THE PRINCIPAL FACTORS CONTROLLING THE KINETICS OF H+ UPTAKE BY SELECTED BRITISH SOILS AND ROCKS, 2) TO DEVELOP CHEMICAL MODEL DESCRIBING THIS UPTAKE, 3) TO DEFINE A SET OF STANDARD EXPERIMENTAL CONDITIONS FOR COMPARING THE ACID SUSCEPTIBILITY OF DIFFERENT GEOLOGICAL MATERIALS. UNLIKE OTHER POLLUTANTS, SUCH AS NITRATE, THE STRONG ACID COMPONENT OF ACID DEPOSITION (H+) IS HIGHLY REACTIVE WITH MOST SOILS AND ROCKS. SOME OF THE H+ REMAINS IN SOLUTION WHILST THE REST IS USED UP IN CATION EXCHANGE AND WEATHERING REACTIONS. THIS PARTITIONING OF H+ BETWEEN SOLID AND SOLUTION PHASES IS CRITICAL IN DETERMINING THE FATE AND CONSEQUENCES OF ACID DEPOSITION: IF THE H+ REMAINS IN SOLUTION THEN IT IS AVAILABLE FOR ACIDIFICATION OF RIVERS AND LAKES ETC., WHEREAS IF IT STAYS IN THE SOIL, THEN SOIL ACIDIFICATION (LOSS OF ACID NEUTRALISING CAPACITY) WILL RESULT. THE CONCEPT OF THE VARYING ACID SUSCEPTIBILITY OF DIFFERENT SOILS AND ROCKS IS WELL ESTABLISHED AND NUMEROUS DEFINITIONS (MOSTLY QUALITATIVE) OF THIS ALREADY EXIST. THE PRINCIPAL PROBLEM IN ARRIVING AT QUANTITATIVE DEFINITIONS AKIN TO THOSE USED FOR AQUEOUS SOLUTIONS IS THAT THE INTERACTION OF H+ WITH MINERAL INVOLVES SLOW SOLID-SOLUTION REACTIONS. EQUILIBRIUM OFTEN TAKES WEEKS OR LONGER TO ACHIEVE. THE PROPOSED PROJECT WILL USE LABORATORY METHODS TO IDENTIFY THE PRINCIPAL FACTORS CONTROLLING THE EXTENT AND KINETICS OF H+ UPTAKE. PH-STAT, RAPID AND SLOW (BATCH) TITRATIONS AND CHEMICAL ANALYSIS WILL BE USED. CHEMICAL MODELS WILL BE DEVELOPED TO DESCRIBE BOTH THE KINETIC AND EQUILIBRIUM ASPECTS OF H+ UPTAKE USING ROCKS AND SOILS SELECTED FROM AREAS IN BRITAIN CONSIDERED SUSPECTIBLE TO ACIDIFICATION. THE AIM IS TO UNDERSTAND THE FATE OF H+ IN TERMS OF THE CHEMICAL REACTIONS INVOLVED (ION EXCHANGE), MINERAL DISSOLUTION, ETC.) AND TO DEFINE A SET OF STANDARD CONDITIONS UNDER WHICH TO MEASURE BUFFER CAPACITIES IN THE LABORATORY. ONCE THIS HAS BEEN ACHIEVED IT SHOULD BE POSSIBLE TO COMPARE THE ACID SUSCEPTIBILITY OF DIFFERENT SOILS AND ROCKS QUANTITATIVELY AND TO DEVELOP CORRELATIONS BETWEEN SHORT-TERM EXPERIMENTAL BUFFER CAPACITIES AND THE LONGER-TERM BUFFER CAPACITIES APPLICABLE TO FIELD CONDITIONS. THE RESULTS OF THIS RESEARCH THEREFORE SHOULD HAVE APPLICABILITY TO OTHER EEC COUNTRIES AND BEYOND. Programme(s) PRE-ENVPROT 3C - Sectoral research and development programme (EEC) in the field of environment (environmental protection and climatology) - indirect and concerted actions - Environmental protection -, 1981-1985 Thème(s) Data not available Appel à propositions Data not available Régime de financement CSC - Cost-sharing contracts Coordinateur NERC British Geological Survey Contribution de l’UE Aucune donnée Adresse Maclean Building Crowmarsh Gifford OX10 8BB Wallingford Royaume-Uni Voir sur la carte Coût total Aucune donnée
