Aerial photo of Lake Merritt. "Handwritten on back of photo, "Lake Merritt". Newspaper caption reads, " Today is the 44th day since Dr. Malcolm Nelson, Alameda County health officer, declared Lake Merritt to be contaminated and posted signs along the shoreline warning against wading, fishing or water contact sports. Initially, health officials posted 75 signs along the shore of the 160-acre lake, but the notices vanished at the rate of five to 10 per day. The disappearance rate dropped after health inspectors put signs onto eight-foot-long poles and buried them in the mud at some distance from the shoreline.