Greens have again locked horns with the State Pollution Control Board here over the alleged pollution of Periyar waters. Environmentalists on Wednesday alleged that the board officials at the environment surveillance centre in Eloor failed to collect samples from near Edayar where discolouration of the river was reported on Tuesday. Purushan Eloor, spokesperson of the Periyar Malineekarana Virudha Samithi, said the board officials refused to collect the samples stating that there was only a patch of white discharge near the region close to Merchem company. We had alerted the board officials immediately after detecting the discolouration but they were late to reach the site, he said. Recalling that industrial units were dumping effluents in to the river during the last few weeks, Mr. Purushan said the board had failed miserably to check the pollution of Periyar. The ecological condition of Kuzhikandam creek has worsened, thanks to the rampant discharge of chemical effluents, he said. Denying the allegations, senior officials of the board at the surveillance centre said that they had collected samples from near the Merchem company. We are verifying whether there was any presence of pollutants in it, they said. The board representatives also pointed out that there was only a white patch visible in the river and rejected claims made by the greens that the local residents had experienced foul smell immediately after the discolouration was reported. Dredging work was progressing in the area as part of the setting up of the regulator-cum-bridge at Pathalam. This might be a reason for the white patches found in the area, they said.