GYOR, Hungary: A toxic red sludge spill from an alumina plant in western Hungary reached the Danube river Thursday and crews were trying to dilute it to protect the major European waterway. Tibor Dobson, a spokesman for Hungarian disaster crews, told Reuters at 1600 GMT that there were reports of sporadic fish death in the Raba and the Mosoni-Danube rivers, affected by the spill earlier. He said all fish had died in the smaller Marcal River, which was hit first. Crews were working to reduce the alkalinity of the spill, which poured from the containment reservoir of an alumina plant Monday and tore through local villages, killing four people and injuring over 150. Three people were still reported missing. The spill's alkaline content when it reached the Raba, the Mosoni-Danube and the Danube itself, was still around pH 9 – above the normal, harmless level of between 6 and 8, Dobson said. In Gyor, a city in the northwest of Hungary where the Raba flows into the Mosoni-Danube, a Reuters reporter saw white froth on the river and lots of small dead fish washed ashore. Ambulance crews were distributing leaflets calling on residents not to fish or eat fish from the river, and avoid contact with the water. Gabor Figeczky, Hungarian branch director of the WWF environmental group who visited the scene of the disaster along with experts, said the impact on the river Marcal was worse than expected. It was hoped the alkalinity would drop once it reached the Raba, a bigger river, but it was still between pH 9 and 10. “Based on our current estimates, it (pollution) will remain contained in Hungary, and we also trust that it will reach Budapest with acceptable pH values,” he added. Downstream from the disaster site, the Danube flows through or touches on Croatian, Serbian, Bulgarian, Romanian, Moldovan and Ukrainian territory en route to the Black Sea. Nebojsa Pokimica, Serbia's deputy environment minister, told Reuters Serbia had increased monitoring and water quality control of the Danube river since Monday. “We are constantly in touch with Hungarian authorities. I can say that the quality of water in the Danube river has not changed since Oct. 4,” Pokimica said. Hungary declared a state of emergency in three counties on Tuesday after the sludge -waste from bauxite refining that has a strong caustic effect – hit Kolontar, Devecser and other villages 160 km west of Budapest. Prime Minister Viktor Orban visited Kolontar on Thursday and said there was no point in even removing the rubble from part of the village as it was impossible to live there again.