Isibor Patrick Omoregie, Akinsanya Bamidele, Sogbamu Temitope, Olaleru Fatsuma, Excellence Akeredolu, Komolafe Benjamin, Kayode Saliu Joseph
Department of Biological Sciences, Covenant University, PMB 1023, Ota, Ogun State, Nigeria.
Department of Zoology, University of Lagos, P.O. Box 156, Akoka, Nigeria.
Heliyon. 2020 Sep 28;6(9):e04959. doi: 10.1016/j.heliyon.2020.e04959. eCollection 2020 Sep.
The presence of trace metals in the sediment, water, and biota of the Epe lagoon has been recently linked to oil exploration and municipal perturbations around the lagoon. The study was aimed at assessing the concentrations and associated health risks of Fe, Zn, Cu, Ni, Pb, Cd, Cr, Mn, Co and V in the water, sediment, and of Epe lagoon and to evaluate the role of the enteric parasite in bioaccumulation of the metals in the fish. The temperature, pH, redox potential, conductivity, turbidity, dissolved oxygen (DO), total dissolved solids (TDS), and salinity were determined in-situ using a handheld multi-parameter probe (Horiba Water Checker Model U-10). The concentrations of Fe, Zn, Cu, Ni, Pb, Cd, Cr, Mn, Co, and V were determined in the surface water, bottom sediment, and its enteric parasites, in Epe lagoon using the Flame Atomic Absorption Spectrometer (Philips model PU 9100). The bioaccumulation factors and target hazard quotients of the trace metals in the infected and uninfected fish were estimated and compared. The intestinal tissue sections of the infected and uninfected fish were examined using a binocular dissecting microscope (American Optical Corporation, Model 570) using hematoxylin and eosin (H&E) stain. Biochemical markers such as reduced glutathione (GSH), superoxide dismutase (SOD), catalase (CAT), and lipid peroxidation (MDA) were determined in the liver of the infected and uninfected fish. The SOD level was higher in the uninfected fish than the infected ones supports the indications deduced from the bioaccumulation analysis. Strong positive correlations between SOD and most of the metals- Fe (0.916), Zn (0.919), Cu (0.896), and Ni (0.917) suggests that the metals may have inflicted more toxicity in the uninfected. The histopathological comparisons made between the uninfected and infected fish showed consistency with the outcomes of other comparisons made in this study. These evidence were marked by tissue alterations in the infected fish ranging from no observed changes to mild alterations, while the uninfected exhibited more severe tissue injuries such as hemorrhagic lesions, severe vascular congestion, edema, the increased connective tissue of the submucosa, and vascular congestion. The condition factors of the infected (0.252) and uninfected (0.268) fish indicated slenderness and unfitness possibly due to environmental stressors such as trace metals. The parasitized fish showing better-coping potentials than the uninfected, coupled with the significant bioaccumulation interferences exhibited by the parasite is an indication that the parasites may be a good metal sequestration agent for the fish and can be used to forestall the significant health hazard quotient posed by the current level of iron and the synergy of all metals analyzed in the lagoon.
埃佩泻湖沉积物、水体及生物群中痕量金属的存在，近来被认为与该泻湖周边的石油勘探及城市干扰有关。本研究旨在评估埃佩泻湖水体、沉积物及鱼类中，铁（Fe）、锌（Zn）、铜（Cu）、镍（Ni）、铅（Pb）、镉（Cd）、铬（Cr）、锰（Mn）、钴（Co）和钒（V）的浓度及相关健康风险，并评估肠道寄生虫在鱼类体内金属生物累积过程中的作用。使用手持式多参数探头（堀场水质检测仪U - 10型）现场测定温度、pH值、氧化还原电位、电导率、浊度、溶解氧（DO）、总溶解固体（TDS）和盐度。采用火焰原子吸收光谱仪（飞利浦PU 9100型）测定埃佩泻湖表层水、底部沉积物、鱼类及其肠道寄生虫中铁、锌、铜、镍、铅、镉、铬、锰、钴和钒的浓度。估算并比较感染和未感染鱼类中痕量金属的生物累积因子和目标危害商数。使用双目解剖显微镜（美国光学公司570型），对感染和未感染鱼类的肠道组织切片进行苏木精和伊红（H&E）染色检查。测定感染和未感染鱼类肝脏中的生化标志物，如还原型谷胱甘肽（GSH）、超氧化物歧化酶（SOD）、过氧化氢酶（CAT）和脂质过氧化产物（MDA）。未感染鱼类的SOD水平高于感染鱼类，这与生物累积分析得出的结果相符。SOD与大多数金属——铁（0.916）、锌（0.919）、铜（0.896）和镍（0.917）之间呈强正相关，表明这些金属可能对未感染鱼类造成了更大的毒性。对未感染和感染鱼类进行的组织病理学比较，与本研究中其他比较结果一致。这些证据表现为感染鱼类的组织变化，从未观察到变化到轻度改变，而未感染鱼类则表现出更严重的组织损伤，如出血性病变、严重血管充血、水肿、黏膜下层结缔组织增加和血管充血。感染（0.252）和未感染（0.268）鱼类的状况因子表明，它们可能因痕量金属等环境应激因素而体型细长且不健康。寄生鱼类比未感染鱼类表现出更好的应对潜力，再加上寄生虫表现出的显著生物累积干扰，这表明寄生虫可能是鱼类良好的金属螯合剂，可用于预防当前铁含量水平以及泻湖分析的所有金属协同作用所带来的显著健康危害商数。
