Third evaluation of Hg, Cd, Cr and Co elements distribution in water, sediment and water Hyacinth from Surabaya river

Evaluation of heavy metal elements content of environmental samples of Kenjeran and Morokrembangan river Surabaya using Neutron Activation Analysis (NAA) Technique have been done. The environment samples i.e. water, sediment and water hyacinth have been taken from 6 sampling stations at Morokrembangan and Kenjeran river. The samples have been ground, homogenized and 12 hours irradiated by 1.05 x 10¹¹ n.cm^-2.sec^-1 neutron flux. The elements ¹⁹⁷Hg (77.6 keV), ³¹Cr (320 keV), ¹¹⁵Cd (527.7 keV) dan ⁶⁰Co (1173.1 keV) in all samples have been detected. The result showed that the concentration of Hg. Cd, Cr and Co of water samples were higher than that of maximum permissible concentration for D-class water according to the threshold value decided by Environmental Minister, Act. Kep.02/MENKLH/I/1988. The concentration of those metals in sediment and water hyacinth samples cannot be evaluated, because the regulation related to the maximum permissible concentration of the heavy metals decided by Indonesian Health Minister or Environmental Minister Act are not available. The data showed that the distribution factor (Fd) is greater than that the bioaccumulation factor (FB) for Hg, Cd, Cr and Co elements. (author)