ORCHARD BEACH - Mayor Michael Bloomberg has issued a health advisory for swimmers planning on taking a dip at Orchard Beach this weekend. The warning was issued after a quality assessment test revealed high bacteria levels. Officials say the contamination may be linked to floating debris, oil products or sewage. Some people say, if the waters are potentially toxic, the warning signs should be larger and the beach should be completely closed. City officials have yet to indicate how long the advisory will be in place.