Bioaccumulation of BTEX and PAHs in Heterotis niloticus (Actinopterygii) from the Epe Lagoon, Lagos, Nigeria

Toxicity studies in the aquatic ecosystem have shown that petrol and its product have adverse effects on aquatic biota. They are able to easily absorb these toxic substances into their bodies from sediment, water or even food items that are contaminated, thus impacting the food chain. In this study, water, sediment and fish (Heterotis niloticus) from the Epe Lagoon were investigated for the presence of BTEX (benzene, toluene, ethylbenzene and the three xylene isomers m, o and p-xylenes), and PAHs using GC-MS. Total concentration of BTEX in sediment and water was respectively 32.37 � 1.07 μg/g, 49.86 � 7.30 μg/L; while total concentration of BTEX in fish liver and intestine was 33.75 � 10.09 and 40.16 � 9.64 μg/g respectively. Benzene, 1,2-Dichlorobenzene and 1,3- Dichlorobenzene components of BTEX were not detected in both sediment and water. Total concentration of PAH in sediment and water was 7.46 � 1.73 μg/g and 19.33 � 1.31 μg/L respectively. Total PAHs concentration in liver and fish intestine was 141.23 � 5.89 and 173.34 � 4.677 μg/g respectively. Majority of the PAHs congeners were found to be higher than the acceptable limits. Findings from this study shows the need for continuous monitoring of our natural waters as the present situation portends a potential concern for ecological risk

Accumulation of PCBs and Infections of Parasitic helminthes in Synodontis filamentosus (Boulenger, 1901) and Tilapia zillii (Gervais, 1848) of Epe Lagoon, Lagos, Nigeria

The study was carried out on 120 Synodontis filamentosus (11 – 26.5cm, 22 - 88g) and 120 Tilapia zillii (15 - 21cm, 67 – 187g) captured from Epe Lagoon, Lagos State, Nigeria. The aim was to comparatively analyze the bioaccumulation of polybiphenyl chlorides (PCBs) and prevalence of parasitic helminthes in S. filamentosus and T. zillii relative to their respective habits. The comparison was done using indices such as bioaccumulation factors, biota-soil accumulation factors, and parasite prevalence. Profiles of PCB accumulation showed that T. zillii followed by their endoparasites accumulated outstanding concentrations, suggesting that T. zillii might be a greater bioaccumulator of PCBs than S. filamentosus. Significant biota-soil accumulation factors observed in the T. zilliii and their endoparasites were accompanied by significant sorption capacities of PCBs into the soil at impacted locations of the lagoon. This implies that T. zillii accumulated significant PCB from the soil and shared with its endoparasites, justifying host-parasite xenobiotic transfer. S. filamentosus had higher levels of parasitic infections than T. zillii, males of both species were more infected than the females. The intestine and liver tissues of S. filamentosus showed greater alterations than the tissues of T. zillii. Findings showed that S. filamentosus is a better bioindicator in histopathological studies while T. zillii is a better bioaccumulator

Heavy metals, parasitologic and oxidative stress biomarker investigations in Heterotis niloticus from Lekki Lagoon, Lagos, Nigeria

Heavy metal toxicity in aquatic life as a result of human activities poses a grave health threat to water quality, aquatic and human life. Parasites may serve as indicators of heavy metal pollution. This research investigated the health status of the fish Heterotis niloticus viz-a-viz quality of the water and sediments in Lekki lagoon, parasitic infection, presence of heavy metals and oxidative stress response in the liver and intestine of the fish. Parasites recovered were also analyzed for the extent of bioaccumulation of heavy metals. The metals in water, sediments, parasites, and fish were analyzed using Atomic Absorption Spectrometry. Heavy metal concentrations in the surface water were generally below regulatory limits of World Health Organization. Sediment had high levels of aluminium (124.78 mg/kg) and iron (327.41 mg/kg); other heavy metals were below regulatory limits. Tenuisentis niloticus, an acanthocephalan, was the only parasite recovered. Seventy (70) out of 100 fish sampled were infected with the parasite. T. niloticus bioaccumulated Cd, Ni, and Pb between 65 to 100 times more than the liver and 12 to 200 times more than the intestine. Other metals bioaccumulated from the host tissues by the parasite had the magnitude between 1 to 12 times as the liver and 1 to 30 times as the intestine. There were significant differences in the activities of antioxidant enzymes between the parasitized and non-parasitized fishes. Fish tissues also showed histological alterations, ranging from mild infiltration of inflammatory cells to moderate inflammation and haemorrhagic lesions. Human activities that introduce stressors into the lagoon should be controlled

Parasite prevalence and bioaccumulation of polycyclic aromatic hydrocarbons as stressors in the silver catfish, chrysichthys nigrodigitatus (Siluriformes: Claroteidae)

The experiment explored the impacts of polycyclic aromatic hydrocarbons (PAHs) and the prevalence of Aspidogastrea africanus (endoparasite) in Chrysichthys nigrodigitatus (host) in Lekki lagoon, Lagos State, Nigeria. Host-parasite allotment of PAHs, histopathological analy- sis, and the oxidative status of parasite and host were investigated. Oxidative status of fish and endoparasites were determined by assessing the levels of reduced glutathion (GST), superoxide dismutase (SOD), catalase (CAT) and malondialdehyde (MDA). PAH concentra- tions were determined in the tissues of the host and parasite using gas chromatograph coupled to flame ionization detector (GC-FID). Physico-chemical parameters of water and sediment were assessed using a handheld multi-parameter probe (Horiba Water Checker Model U-10). The parasitic prevalence in the examined fish was proportional to length and weight of fish individuals. The parasites were more predominant among the length and weight cohorts of the female fishes than the males. Higher induction of oxidative stress en- zymes in the intestine of the male C. nigrodigitatus than in the female, and the parasite can be attributed to the higher levels PAH and partly absence of parasites to depurate the tox- icant in the fish. A. africanus shared the toxic burdens of chrysene, benzo(b)fluoranthene, dibenz(a,h)anthracene, benzo(g,h,i)perylene, dibenzo(a,l)pyrene, dibenzo(a,i)pyrene and particularly indo(1.2,3-cd)pyrene from the intestine of both sexes. In return, the endopara- site contributed to the oxidative stress in the intestine of the fish. Synergistic and antago- nistic interactions between PAH congeners and A. africanus on silver catfish, C.nigrodigitatus is evident in the current study. We suggest mitigation of PAH-releasing anthropogenic ac- tivities around Lekki lagoon for the protection of C. nigrodigitatus

Parasite Prevalence and Bioaccumulation of Polycyclic Aromatic Hydrocarbons as Stressors in the Silver Catfish, Chrysichthys nigrodigitatus (Siluriformes: Claroteidae)

The experiment explored the impacts of polycyclic aromatic hydrocarbons (PAHs) and the prevalence of Aspidogastrea africanus (endoparasite) in Chrysichthys nigrodigitatus (host). Host-parasite allotment of PAHs, histopathological analysis, and the oxidative status of parasite and host were investigated. Oxidative status of fish and endoparasites were determined by assessing the levels of Glutathion-S-Transferase (GST), Sodium Oxide Dismutase (SOD), and Catalase (CAT). PAH concentrations were determined in the tissues of the host and parasite using gas chromatograph coupled to flame ionization detector (GC-FID). Physico-chemical parameters of water and sediment were assessed using a handheld multi-parameter probe (Horiba Water Checker Model U-10). The parasitic prevalence in the examined fish was proportional to length and weight of fish individuals. The parasites were more predominant among the length and weight cohorts of the female fishes than the males. Higher induction of oxidative stress enzymes in the intestine of the male C. nigrodigitatus than in the female, and the parasite can be attributed to the higher levels PAH and partly absence of parasites to depurate the fish. A. africanus shared the toxic burdens of chrysene, benzo(b)fluoranthene, dibenz(a,h)anthracene, benzo(g,h,i)perylene, dibenzo(a,l)pyrene, dibenzo(a,i)pyrene and particularly indo(1.2,3- cd)pyrene from the intestine of both sexes. In return, the endoparasite contributed the oxidative stress in the intestine of the fish. Synergistic and antagonistic interactions between PAH congeners and A. africanus on silver catfish, C.nigrodigitatus is evident in the current study. We suggest mitigation of PAH-releasing anthropogenic activities around Lekki lagoon for the protection of C. nigrodigitatus

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

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, metaand 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 environmen

Aspidogastrea africanus Infections, comparative assessment of BTEX and heavy metals Bioaccumulation, and histopathological alterations as biomarker response in Chrysichthys nigrodigitatus (Lacépède, 1803) of Lekki Lagoon, Nigeria

The study was carried out on 120 randomly selected fresh specimens of Chrysichthys ni- grodigitatus (males and females of different trophic levels) from Lekki lagoon, Lagos, Nige- ria. The aim was to investigate the heavy metals and endoparasitic infection in the fish. We compared the impacts of both stressors on the liver and intestine of C. nigrodigitatus. Water samples were tested for pH, dissolved oxygen (DO), salinity, electrical conductiv- ity, total dissolved solids using a multiprobe meter. Nitrate, nitrite, phosphorus, ammonia, total suspended solids and colour were measured using VR 50 0 0 spectrophotometer. Alka- linity, acidity, biological oxygen demand (BOD) and chloride were measured via Titrimetry method. Chemical oxygen demand (COD) was measured via a closed reflux titration., and turbidity was measured via a VR 2010. Aspidogastrea africanus was the only parasitic in- fection detected in C. nigrodigitatus; though of low intensity. We also observed low heavy metal levels in the environmental media tested. However, the study showed that the liver and intestinal tissues of C. nigrodigitatus were slightly impacted by the stressors even at low levels. We therefore suspect synergy between Aspidogasrea infection and heavy met- als toxicity. We recommend a further biomonitoring of the aquatic environment in order to ascertain the actual causative factors contributing to tissue injuries in the fish. Findings will help mitigate future aggravation of the tissue toxicity. Low levels of Aspidogastrea in- fection is an early prognostic information against outbreak of the disease in the aquatic environment

Raphidascaroides brasiliensis (Nematoda: Anisakidae) infection and Bioaccumulation of Polycyclic Aromatic Hydrocarbons in Gymnarchus niloticus (Cuvier, 1829) in Lekki Lagoon, Nigeria

The study aimed at determining the ability of Raphidascaroides brasiliensis to depurate polycyclic aromatic hydrocarbons (PAHs) in its host, Gymnarchus niloticus. PAHs levels were determined in the water, sediments, intestine of Gymnarchus niloticus and its enteric parasites sampled at Lekki Lagoon, Nigeria. PAHs were determined using High Performance Liquid Chromatograph (HPLC) (Prominence Dual brand from HGE) equipped with a detector Shimadzu UV-Visible (UV-Vis Prominence SPD 20 A). The levels of superoxide dismutase (SOD), catalase (CAT), reduced glutathione (GSH), lipid peroxidation (MDA) and bioaccumulation in the fish intestine, liver and parasites were assessed as biomarkers. Analyses were conducted equally for the infected and uninfected fishes. The sequence of accumulation in the environmental matrices was parasite > intestine > sediment > water. The ratios of phenanthrene/anthracene, fluorene/pyerene and acenaphthene/fluorene in the sediment were 1.820, 29.667, and 4.33 respectively. The source indices (> 1.0) indicate a petrogenic source. The carcinogenic health risks posed by both the low and high molecular weight PAHs (0.027 and 0.476 respectively) were insignificant; hence the fish may not pose toxicological threats to the consumers. Higher levels of PAHs and biochemical biomarkers in the uninfected fish compared to the infected suggest the differences could be linked to depurative tendencies of Raphidascaroides brasiliensis which might have contributed to alleviation of the PAH burden in the host Gymnarchus niloticus. A study on significant depuration at minimal parasite intensity is warranted

Bioaccumulation of Pyrethroid in Parasite Wenyonia acuminata (Cestoda: Caryophyllaeidae) and Host fish Synodontis clarias (Linnaeus, 1758) from Lekki Lagoon, Lagos Nigeria

This study was aimed at determining the concentration of pyrethroid in the surface water, sediment, Weyonia acuminata and Synodontis clarias fish in Lekki lagoon, Lagos, Nigeria. In-situ physicochemical analysis of the surface water was conducted using a calibrated handheld multi-parameter probe (Horiba Checker Model U-10). Intestinal samples from infected and uninfected fish were analyzed for pyrethroid concentrations, microbial colonization, proteins (PRO), superoxide dismutase (SOD), catalase (CAT), reduced glutathione (GSH), malonaldehyde (MDA) and glutathione peroxidase (GPx). The histopathology of infected and uninfected intestinal tissues were analyzed using Haematoxylin and Eosin (H&E) stains and examined under a binocular light microscope (Model 230485). A total of 39 out of 98 S. clarias fish were infected with cestode parasite, Wenyonia acuminate, amounting to 39% parasite prevalence. Among the tested pyrethroids, Cyfluthrin and Alpha –cypermethrin had significant sorption of 1.62 and 3.27 respectively from the aqueous phase to the bottom sediment of the lagoon. Pyrethroid concentration was in the order of sediment > parasite> water > intestine> liver. The cholesterol, triglycerides, and LDL (low density lipids) in the parasite were higher than in the host fish (p<0.05). On the other hand, the fish hepatic protein, high density lipids (HDL) and glucose were higher than the levels in the parasites (p<0.05). There was a high prevalence of gut microbes (30 - 40%), which include Salmonella sp, Escherichia coli, Pseudomonas sp and Bacillus sp among individuals infected with gut Cestodes, Wenyonia sp compared with uninfected individual which had higher gut Staphylococcus sp., Klebsiella sp., and Proteus sp. (10- 40%). among the congeners of pyrethroids analyzed, Cyfluthrin > Alpha-Cyermethrin had significant sorption on the sediment, however unlike a benthopelagic fish, no pyrethroid was accumulated in the S. clarias from the sediment. The fish however accumulated Alpha-Cypermethrin from the aqueous phase. The parasite on the other hand accumulated Bathroid significantly from the surface water and bottom sediment which may be linked to the higher stress levels observed in the parasite than the host fish. The parasite in turn inflicted histological alterations on the host intestine, marked by moderate inflammation of mucosa, alteration of the villi microstructure, moderate stunting of the villous structure and moderate fibrosis of villous structure. The study demonstrated the efficiency of histopathological and microbial analysis in biomonitoring studies enteric parasites and early detection of pyrethroid toxicity respectively compared to bioaccumulation analysis

Biochemical Effects of the Toxic Interaction of Copper, Lead and Cadmium on Clarias gariepinus

Background. The presence of heavy metals in the aquatic environment is a concern because of potential toxicity and threats to plant and animal life. Objective. The present study evaluated the joint action toxicity and biochemical effects of sublethal concentrations of copper (Cu), lead (Pb) and cadmium (Cd) against Clarias gariepinus over a period of 28 days. Methods. We procured fingerlings (weight: 5–8 g; length: 4.5–6.0 cm) and juveniles (weight: 20–25 g; length: 14.5–17.5 cm) from a commercial fish farm in Bariga, Lagos state, Nigeria. Test toxicants were selected from the analyzed heavy metals in the field based on their deviation from World Health Organization, Federal Environmental Protection Agency and United States Environmental Protection Agency standards. Fish were randomly loaded into a 4-L glass aquaria for the bioassay per toxicant concentration of two replicates and untreated control (dechlorinated tap water). Results. The derived 96 hour lethal concentration 50 (LC50) value of Cu (2.11 mg/L) was the most toxic followed by Cd (24.18 mg/L) and Pb (34.48 mg/L), which was the least toxic of the singly tested pollutants. The analysis of dose-response data of the joint action toxicity of Cu and Cd, and Cu and Pb determined 96 hour LC50 values of 1.804 mg/L and 2.15 mg/L, respectively. The interactions between the mixture of Cu:Cd conformed with the model of synergism (synergistic ratio (SR)>1 and relative toxic units (RTU)>1), while the interaction between Cu:Pb was found to be antagonistic (SR<1), with an SR value of 0.98. The biochemical effects study revealed that malondialdehyde (MDA) levels decreased significantly (P<0.05) in the exposed fish, reduced glutathione was not significant at (P<0.05), and levels of superoxide dismutase (SOD), catalase, glucose and cholesterol were significantly different (P<0.05). Discussion. The observed increased in the glutathione level in the Cu:Cd mixture and a corresponding decrease in MDA concentration in the liver of test animals revealed the ability of fish to overcome the effects of lipid peroxidation in this group because the Cu ion is displaced by Cd, and the fish were able to catalyze the breakdown of hydrogen peroxide via the Fenton reaction. Conclusions. Further studies on the joint action toxicity of heavy metals are needed in order to further determine their concentration in the local environment. Ethics Approval. Study protocols were approved by the Health Research Ethics Committee of the University of Lagos. Competing Interests. The authors declare no financial competing interest