Soil and river bottom samples taken along Alexandria's waterfront on the former site of the R.H. Bogle chemical plant detected only two cases of dioxin contamination, the Environmental Protection Agency said yesterday, and in both cases the levels were well below what the agency regards as hazardous.

City officials said they were pleased with the results of the test on the site now occupied by the Dalton Wharf office complex and Tobacco Quay town houses. Renovation of the Oronoco Bay Park will proceed on schedule as a result of the findings, they said.

The agency tested the property as part of a national dioxin detection program to identify sites that may have been contaminated by former chemical operations. The Bogle plant manufactured herbicides from the 1920s until it closed in 1976.

The only negative effect of the test could be a possible delay in issuing dredging permits for some new construction projects that are planned along the waterfront, the EPA said.

The agency said it will review those permits and determine whether to do more sampling before approving them.

The affected projects are the renovation of the Torpedo Factory piers and the restoration of the old Alexandria Canal lock at the Trans- Potomac Canal Center.

The EPA said dioxin found in two samples of river bottom sediments ranged from less than 1 part per trillion to 23 parts per trillion, far below the level of concern, which is 1,000 parts per trillion.

Dioxin concentrations found in fish taken from the Potomac was 6.3 parts per trillion. The danger level is 25 parts per trillion.