Low dose exposure in the environment is an important area of research nowadays.This book is based on our investigation on assessment of alpha-activity for fishes and vegetables along with annual dose committed using samples from 4 important sites in this regard. A comprehensive background for this work is presented before the data. The book is organized as follow: Chapter 1 presents a brief introduction about ionizing radiation as pollutants .objectives of our work related with fish and vegetables are described in Chapter 2. In Chapter 3 discussion has been taken up on radioactive particles. Discussion with dose and units of radioactivity has been made in Chapter 4. Chapter 5 contains discussion on radio-toxicity and annual limits of intake. Topic of discussion of Chapter 6 is the effects of ionization radiation on cells and tissues. The Chapter 7 deals with a brief overview of detectors for analysis of environmental radio-nuclides. In Chapter 8 details of measurement has been incorporated. In Chapter 9, the subject matter of discussion is alpha radioactivity and dose assessment at different sites. The book ends with a conclusion .