Radionuclide contents and physico-chemical characterization of solid waste and effluent samples of some selected industries in the city of Lagos, Nigeria

The radionuclide contents in waste products and physico-chemical characterization of effluent samples from some selected industries in the city of La os were carried out. The radioactivity concentration levels due to 40K, Ra-226 and Th-228 in the solid wastes were determined using gamma-ray spectrometry while physico-chemical determination of parameters were based on standard methods of measurements. The average radioactivity levels obtained was between 104 +/- 14 Bq kg(-1) and 1276 +/- 31 Bq kg(-1) for K-40, 86 +/- 18 Bq kg(-1) and 122 +/- 23 Bq kg(-1) for Ra-226 and while for Th-228 it ranged between 14 +/- 2 Bq kg-1 and 73 +/- 10 Bq kg(-1). No artificial radioactive elements were detected in any of the samples. The average outdoor effective dose rate due to gamma exposure from these waste materials in the city was calculated as 0.12 mSv y(-1). This is far less than 1 mSv y(-1) recommended limit for the member of the public by United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR). The pH of the effluent samples was slightly alkaline, while (be electrical conductivity ranged between 275 and 455 mu S cm(-1) and total suspended solids ranged from 104 to 5616 mg l(-1). All these ranges and those of biochemical and chemical oxygen demand values were all higher than the prescribed limits. Presence of heavy metals in the effluent samples was however lower than prescribed with the exception of iron.