Berlin  - A survey of tap water across Germany that found higher than recommended levels of uranium provoked calls from state Environment Ministries for a fixed legal limit Tuesday.

The German environmental organization Foodwatch uncovered levels of the toxic heavy metal exceeding 10 micrograms per litre in 150 of the 8,200 measurements it took across the 16 states.

Levels above 2 micrograms a litre were found in 950 measurements. Foodwatch noted that German law set this as the upper limit for uranium in water used to prepare baby food.

The federal German Environment Ministry lays down a guideline of a maximum of 10 micrograms.

The Social Minister for Saxony-Anhalt, where around 30 measurements were recorded above 10 micrograms, called for stricter controls.

"Both consumers and business would be safer if Germany had the courage to set a firm limit rather than a soft guideline," she told the Wednesday edition of the daily Mitteldeutsche Zeitung.

Rhineland-Palatinate Environment Minister Margit Conrad said she had called for a countrywide fixed limit in March and welcomed plans by the federal government to discuss the issue with the states.

Foodwatch head Thilo Bode said filtering uranium from tap water was relatively simple and inexpensive, accusing the local water authorities of "passivity."

Sources with levels above 10 micrograms should either be filtered or closed, he said.

According to the Foodwatch survey, south and south-western German states were worst affected. Mecklenburg-Western Pomerania north of Berlin and Saxony-Anhalt to the east of the capital also had a relatively high number of contaminated sources.

Ingesting uranium can harm the kidneys and the reproductive system. (dpa)