Comparative partition coefficients of BTEX and OCPs between host Synodontis clarias and parasite Wenyonia acuminata

Abstract Background The study was aimed at comparing the bioaccumulation of BTEX and organochlorine pesticides (OCP) in the intestine of host fish—Synodontis clarias relative to water and in its parasite—Wenyonia acuminata relative to host intestine. The study was carried out in Lekki lagoon, Nigeria, between April and August, 2017. BTEX was analyzed in water, fish, and parasite tissues using the EPA method 8260B Agilent 7890B gas chromatograph coupled to a mass spectrophotometer (GC-MS). Organochlorophosphate (OCP) was analyzed in tested media using Agilent 7890B gas chromatograph coupled to flame ionization detector (FID). Results High concentrations of most BTEX components such as benzene, toluene, chlorobenzene, ethylbenzene, meta- and para-xylene (m + p-xylene), and ortho-xylene (o-xylene) bioaccumulated into the intestinal tissues of S. clarias from the water medium. This is partly attributable to the fact that the S. clarias is a detritus and bottom feeder and to the hydrophilic properties of the components of BTEX. Despite the significant concentrations of benzene, toluene, and chlorobenzene accumulated in the intestine of S. clarias, no intestine-parasite partition coefficient was observed in the W. acuminata, i.e., the chemicals were not accumulated by the intestinal parasite. This is attributable to very low bioaccumulation factors of the chemicals in W. acuminata. W. acuminata exhibited significant bioaccumulation of 4,4-DDT, endosulfan 1, aldrin, and heptachlor, irrespective of their concentrations in the water and intestine of S. clarias. This indicates high affinity for the OCPs in the parasites. Conclusion Synodontis clarias of Lekki lagoon showed higher vulnerability to the BTEX than the OCPs in the aquatic habitat. This implies that Lekki lagoon was impacted by oil-related anthropogenic activities. Weyonia acuminata exhibited some tendency to alleviate concentrations of the OCPs in S. clarias. It is more imperative to mitigate the activities that release BTEX into the aquatic environment.