Regional geochemical mapping.

One of the prime requirements for effective study of environmental geochemistry in relation to health is the production of multi-element atlases showing the distribution of the elements on the regional scale. The choice of method for compiling such atlases can vary according to a number of geological, environmental and other factors. The overriding consideration, however, is to assist (in conjunction with other relevant sources of information) in defining, quickly and cheaply, potential problem areas wherein to concentrate more detailed studies to ensure maximum return from the funds and scientific manpower available. Numerous sampling and analytical techniques have been employed. Each technique and approach has its own scope, limitation and problems of interpretation. Whatever method is chosen, the use of computer-based statistical data reduction, analysis and map compilation is mandatory. Although it was apparent more than 20 years ago that geochemical atlases would eventually become a national cartographic requirement, regional geochemical mapping is still in the experimental stage. This trend is now evident in activity in a number of countries. The methods being employed, however, are so diverse that there is an urgent need for international collaboration aimed at securing data that are as mutually compatible as possible, having regard to the conditions, needs and resources of the individual countries involved.