Rizal Harahap, The Jakarta Post 18 Feb 08;
The cadmium pollution was caused by illegal gold mining
The four main rivers in Riau province are contaminated by hazardous levels of cadmium and zinc, posing a serious threat to the health of residents, say local authorities.
According to a recent study by the Riau Environmental Impact Management Agency, the cadmium and zinc levels in the Indragiri, Siak, Rokan and Kampar rivers have exceeded the maximum limits set by the government in a 2001 regulation.
Head of the agency's contamination control division, Makruf Siregar, said here Friday the cadmium level in the Kampar River reached 0.012 mg/liter, and 0.11 mg/liter in the Indragiri River.
That is far above the government-set limit of 0.01 mg/liter.
The zinc content has reached 0.18 mg/liter in the Siak River and 0.2 mg/liter in the Rokan River, above the limit of 0.05 mg/liter.
Provincial health office chief Burhanuddin Agung said high levels of cadmium and zinc posed a danger to humans.
"A high concentration of cadmium in the human body can cause anemia, teeth discoloration, loss of smell and kidney failure. The most serious effect of chronic cadmium poisoning is lung and prostate cancer," he said.
High concentrations of zinc can cause stomach ailments, nausea, anemia and a decrease in the levels of good cholesterol. It is also reported that inhaling large amounts of zinc, in the form of dust or fumes, can cause a short-term disease called metal fume fever.
Makruf said the cadmium pollution was caused by illegal gold mining near several tributaries in Logas district, Kuantan Singingi regency. He said miners here used hazardous metals in the gold purification process.
"Contamination in the Indragiri River was detected at least three years ago. Cadmium usually is used to purify gold and is often mixed with mercury. Even though we have not tested the mercury levels in the rivers due to a lack of lab equipment, we are sure the mercury level is also high," Makruf said.
He called on residents not to use water from the rivers for cooking or cleaning.
Makruf said the high zinc levels were caused by sand mining at several rivers in the province.
He said the environmental agency had asked the Kampar and Rokan Hulu regency administrations to put a stop to the mining activities.
"However, they have failed because sand mining is the main source of livelihood for poor families in the regency," he said.
Makruf said the agency had yet to bring the case to the courts, while waiting for prompt action from local authorities to manage the river pollution.
The Kuantan Singingi regency administration is reportedly planning to legalize hundreds of illegal gold mines to increase revenue from the mining sector.
