By Alex Kirby
BBC News Online environment correspondent in Budapest, Hungary
The amount of raw sewage entering the river Ganges every minute is 1.1 million litres, the World Health Organisation (WHO) says.
Children often bear the brunt of environmental hazards says the WHO
Its Atlas Of Children's Health And The Environment says large quantities of sewage are also flushed into rivers, lakes and oceans worldwide.
One gram of faeces can contain 10 million viruses, one million bacteria, 1,000 parasite cysts and 100 worm eggs.
It also says up to a million lives could be saved annually by hand-washing
Launched at a conference of European health and environment ministers in Budapest, Hungary, the atlas says injuries, polluted water and air, together with other hazards linked to the environment, kill more than three million children under the age of five every year.
While 10% of the world population falls within that age group, it says, 40% of the environment related disease burden affects these small children.
This is partly because they absorb more harmful substances in relation to their body weight, and also because they lack the strength and knowledge to protect themselves properly.
Dr Lee Jong-wook, WHO's director-general, said: "Children are the main sufferers from environmental hazards. It is unacceptable from every point of view that the most vulnerable members of a society should be the ones who pay the price for failures to protect health from environmental dangers.
"All too frequently adults do not listen to the voices of children or act upon their most urgent needs."
The United Nations Millennium Goals commit governments to cut the under-five mortality rate by two-thirds by 2015, an aim which WHO says "may be one of the most ambitious goals".
The atlas says poverty is the single biggest threat to children's health, and a rising income gap between the rich and the poor within countries means millions of children may not enjoy the health benefits of emerging prosperity.
While traditional risks gradually vanish as improvements are made, new ones emerge, including an increase in road traffic, air pollution, and chemical use.
One traditional health threat highlighted in the atlas is malaria. It says this is estimated to cost Africa more than $12bn a year in lost GDP, though it could be controlled for a fraction of the cost.
It says about 700 million children, almost half of all in the world, are exposed to smoke from burning tobacco and exhaled smoke at home. Last week the WHO said four conditions accounted for one death in three among young Europeans - injuries, unsafe water, and indoor and outdoor air pollution. Lead poisoning also continued to be a major health concern.
WHO has also launched what it says is its first "global e-library on children`s health and environment", a collection of more than 100 documents on a CD-Rom, entitled the Budapest Collection. It is available from email@example.com or firstname.lastname@example.org.