In this issue

	ECOS Issue 50

Oysters and zinc - the Derwent revisited Pollution in the estuary of Tasmania's Derwent river was reported in the first edition of Ecos in 1974. The problem concerned the presence of heavy metals, particularly zinc. Most would now agree that, although the Derwent is not exactly clean, the pollution by heavy metals has decreased considerably since 1974. Download Article

Melbourne smog and the new breed of cars
Australian Design Rule 37 is intended to reduce the smog levels in our major cities to healthier levels. From the beginning of 1986, all new cars have had to comply with new emission limits. As a result, new cars have catalytic converters in their exhaust systems, incorporate measures to reduce evaporative losses of petrol, and use unleaded petrol.
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The European wasp - here to stay? 'God made the bee but the Devil made the wasp' according to an old German proverb. This denouncement of the wasp is perhaps prompted by its failure to provide honey and its ability to sting painfully and repeatedly. Download Article

Water bombing of fires: no magic solution Contrary to popular belief, a water-bombing aircraft does not dump its tank load on top of a fire, extinguishing it in one fell swoop. Only the smallest of fires could be treated in this way. Download Article

Problems for the west's cockatoos Western Australia's landscape has experienced radical change over the last century. Clearing of forests and woodlands - with replacement by cereal crops - has been on a scale, and at a rate, with few parallels anywhere else on this earth. Download Article

Giant chromosomes and the Z-DNA story Chromosomes made of DNA and protein, and are at the very core of genetics. Download Article

It rains formic acid in the Top End Atmospheric scientists have found that rain falling in tropical Australia can contain appreciable amounts of organic acids, principally formic acid (as in ants) and acetic acid (vinegar). Download Article

Managing our water use They provide a delivery service to every home-owner in our cities, with their product on tap at any time of day or night, whenever and wherever it is needed, and charge less than 40 cents for every tonne delivered. A superb service, but who are they? The answer is Australia's water supply authorities. Download Article

Floating islands How do you explain islands, complete with trees 8 metre tall, floating freely within a lake? How did the floating islands of Lake Pirron Yallock in western Victoria come to be? Download Article