After 30 - 40 years of intensive use of
fertilizer in lowland areas of West Java,
including rock phosphate, the concentration in
the soil of heavy metals such as lead and
cadmium still remains below toxic levels.
However, these elements are sometimes present
naturally in rock phosphate, so that continuous
monitoring is needed.
Sewage sludge from the textile industry
contains high concentrations of elements such
as boron, lead, cadmium, copper and chromium.
Disposal of these wastes into rivers decreased
rice production and was a potential cause of