SAN DIEGO (CNS) - Another razor blade was found Monday morning in the grass near a playground at a Mission Bay park, bringing the total found to seven, according to the San Diego police.

Razor blades have been found in Bonita Cove Park at least four times over the past 18 months.

Six others were found Sunday at the park, next to West Mission Bay Drive at Mission Boulevard, with the sharp edge facing up, according to San Diego police.

No injuries have been reported.

At least three razor blades were found stuck into grass Sept. 13, but no one was injured in that incident.

In late April, 19 blades were found in the park's grass. A 7-year-old boy and a 15-year-old boy cut their feet on razor blades, which police said

were planted. In August 2013, a 41-year-old woman was cut by one of a half-dozen blades left there.

The park is across from Belmont Park and next to a popular Mission Bay swimming area.