Chioma, Okereke, Agomuo Emmanuel, and Amadi Peter. 2017. “Accumulation and Toxicological Risk Assessment of Cd, As, Pb, Hg, and Cu from Topsoils of School Playgrounds at Obio-Akpor LGA Rivers State Nigeria”. International Journal of Scientific World 5 (1): 38-46. https://doi.org/10.14419/ijsw.v5i1.6710.