The unions representing Dunkirk's police and fire departments say contract negotiations with the city have stalled, placing the blame on Mayor Kate Wdowiasz. However, Wdowiasz says the unions are the reason for the impasse.Patrick Ossman, president of the Dunkirk Professional Firefighters Association, and John Arns, president of the Dunkirk Police Benevolent Association, sat down with WKBW.According to Ossman, the fire department has been workin…