A Little Fish with a High Heavy Metals Burden: The Case of Straightfin Barb, Enteromius paludinosus (Peters 1852) from River Malewa, Naivasha, Kenya

Abstract

This paper addresses the accumulation of heavy metals namely; Arsenic (As), Chromium (Cr), Lead (Pb) and Mercury (Hg) in the tissues of Straightfin barb, Enteromius paludinosus (Peters 1852) from the mouth of River Malewa in Lake Naivasha, Kenya. A total of 1307 fish were collected from the lake during the month of November, 2017. Water samples, sediment samples, 25 fish muscle tissues and its endoparasite, the cestode Ligula intestinalis were collected and heavy metal concentrations determined using the Thermal-electron atomic absorption spectrophotometer. The concentrations of these heavy metals in the sediment showed no signs of pollution. In the muscle tissues of the fish, As, Cr, Pb and Hg showed high levels with mean concentrations of 5.0696, 22.0854, 45.2108 and 1.5458 mg/kg ww respectively. The Target hazard quotients of As, Cr, Pb and Hg obtained were 98.5066, 42.9138, 65.8863 and 90.1086 respectively, indicating a possible health risk associated with the consumption of the straightfin barb. The bioaccumulation factors for L. intestinalis were 2.4093, 2.1873, 5.8601 and 5.1395 for As, Cr, Pb and Hg, respectively, indicating the potential of the cestode in accumulation of heavy metals from the host inferring that these parasites can be used as an accumulation bioindicator instead of its host fish because of its better heavy metal accumulation potential.