Environmental monitoring results continue to demonstrate that, except for penetrating radiation, environmental radiological impact due to SLAC operation is not distinguishable from natural environmental sources. During 1978, the maximum neutron dose near the site boundary was 6.6 mrem. This represents about 6.6% of the annual dose from natural sources at this elevation, and 1.3% of the technical standard of 500 mrem per person annually. There have been no measurable increases in radioactivity in ground water attributable to SLAC operations since 1966. Because of major new construction, well water samples were not collected and analyzed during 1978. Construction activities have also temporarily placed our sampling stations for the sanitary and storm sewers out of service. They will be re-established as soon as construction activities permit. Airborne radioactivity released from SLAC continues to make only a negligible environmental impact, and results in a site boundary annual dose of less than 0.01 mrem; this represents less than 0.01% of the annual dose from the natural radiation environment, and about 0.002% of the technical standard.

This progress report discusses environmental monitoring activities at the Stanford Linear Accelerator Center for 1989. Topics include climate, site geology, site water usage, land use, demography, unusual events or releases, radioactive and nonradioactive releases, compliance summary, environmental nonradiological program information, environmental radiological program information, groundwater protection monitoring ad quality assurance. 5 figs., 7 tabs. (KJD).

Environmental monitoring results continue to demonstrate that, except for penetrating radiation, environmental radiological impact due to SLAC operation is not distinguishable from natural environmantal sources. During 1977, the maximum neutron dose near the site boundary was 8.2 mrem. This represents about 8.2% of the annual dose from natural sources at this elevation, and 1.6% of the technical standard of 500 mrem per person annually.

Environmental monitoring and remedial actions at the Stanford Linear Accelerator Center are reported. The local climate, site geology, site water usage, land use, and demography are briefly reviewed. Among the activities reported are waste solvent tank remedial action and testing of underground storage tanks. The SLAC Linear Collider Project is discussed insofar as it impacts the environment. Neutron radiation dose to the surrounding environment and radioactive effluents are reported. (LEW).

Environmental monitoring results continue to demonstrate that, except for penetrating radiation, environmental radiological impact due to SLAC operation is not distinguishable from natural environmental sources. During 1979, the maximum measured neutron dose near the site boundary was not distinguishable from the cosmic ray neutron background. There have been no measurable increases in radioactivity in ground water attributable to SLAC operations since 1966. Because of major new construction, well water samples were not collected and analyzed during 1979. Construction activities have also temporarily placed our sampling stations for the sanitary and storm sewers out of service. They will be reestablished as soon as construction activities permit (mid 1980). Airborne radioactivity released from SLAC continues to make only a negligible environmental impact, and results in a site boundary annual dose of less than 0.3 mrem; this represents less than 0.3% of the annual dose from the natural radiation environment, and about 0.06% of the technical standard.