trends in analytical chemistry, vol. 3, no. 4, I9tH XXI

pared various organisms for their use pollution. G. Wagner (Saarbriicken) as indicators. He discussed how analysed metal concentrations in normal deviation may be distinguished from environmental influences. L.

leaves of poplars for monitoring

Zadory (Saarbriicken) compared environmental pollution.

freshwater molluscs as accumulation E. Steinnes (Gradvoll) is monitoring

indicators for monitoring heavy metal trace element deposition using mosses and had obtained interesting surveys

ofdistribution ofPb, Sb, As, V, Cr, Cu, I, Br and Se.

ERNEST MERIAN

Dr Ernest Merian is at the Intemationul Association of Environmental Analytical Ctumis- try, Im Kirsgarten 22, CH-4106 Then&l, Switzerland.

Acid rain again! reduction in the number of animal and

Report on the VDI-International Con- ference held at Lindau, Lake Con- stance 7-9 June 1983, on Acid Precipitation-Origin and Effects

This conference, organized by the Society of German Engineers, was opened by Dr-Ing. 0. Schwarz, and Prof. Dr A. Dick. 530 participants from 12 countries discussed 50 lectures on this important subject. The Confer- ence was divided into nine sections. 1. Emissions of precursors 2. Transformations in the atmosphere 3. Atmospheric dispersion and trans-

port 4. Dry deposition 5. Measuring techniques (ambient

air) 6. Effects on vegetation 7. Effects on soil 8. Effects on aquatic ecosystems 9. Effects on materials A bibliography (1980-1983) contain- ing 450 abstracts and an index of important authors working in this field is available from VDI.

On the first day interesting meas- urement results and models were presented, but in most cases they were unfortunately not interpreted. Sampl- ing techniques - for instance for sampling cloud and mist water - have made progress, and the latest analyti- cal results must thus have been improved. Unfortunately, the discus- sion at the conference was also too limited in the discussion of to what extent SO2 emissions should be reduced (which is, of course, only one factor to be considered). There was a certain helplessness among the too technologically oriented participants about what should be done, and many of the engineers had already made their own decisions, either in a positive or negative way. The results reached

during the lectures can be briefly summarized as below.

It has just been established that firs (and other trees) are suddenly showing new types of damage. As well as SO2 emissions, which should be reduced anyway, other emissions, diseases and interactions may be causing this damage. There seems to be some correlation between fir damage and magnesium deficiency in the trees, even when there is sufficient mag- nesium in the soil. Information about pH-values of different waters, sampled at different times cannot normally be compared and one should be cautious when interpreting results. Information about the amount of acid present and about acid deposition is more mean- ingful than simple pH-values. Acidili- cation of water in different locations took place to very dissimilar amounts during the last 50-100 years, and the reasons for these differences are not yet understood. It is now clear that some soils are no longer in the ecologically safe bicarbonate buffer region. They have now changed to the aluminium buffer region with the following consequences: aluminium ions in- crease acidity, and are toxic for some organisms (especially for fish), there-

plant species in a region. It has now been recognized that at

some altitudes polluted mist is at least as much of a problem as acid precipitation. The much smaller drop- lets have higher concentrations of total electrolytes. Not enough is known about the effects of snow, which precipitates air pollutants in a particu- larly complete way. About 20-50% of the precipitated acids are concentrated in the bark run off, and then damage soil vegetation below the trees. Evalua- tions of average concentrations or total annual emissions are not conclusive and should not be over emphasized.

While the information available in 1983 was well presented at this conference the sections, lectures and respective discussions did not have enough interdisciplinary organization. The subject was restricted to acid precipitation, as a result not enough was said about other causes of damage to forests. Effects on land organisms, fish, historic buildings and metal constructions were not discussed.

ERNEST MERIAN

Dr Ernest Median is at the international Association of Environmental Analytical Chis- try, Im Kirsgarten 22, CH-4106 Thnuill,

fore such a change may lead to a Switzerland.

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