Polycyclic Aromatic Hydrocarbons (PAHs) levels in four commonly consumed smoked fish species from markets in Southern Nigeria were assessed to evaluate possible human health risks associated with consumption. Varying levels of PAH congeners were observed in the fish tissues with the highest total concentration of PAHs in Scomber scombrus. High concentrations of benzo(a)pyrene was observed in Clarias gariepinus and Ethmalosa fimbriata with values above the guideline value of 0.05 mg/kg. The Dietary Daily Intake (DDI) value for total PAHs (∑PAHs) was highest for S. scombrus while the DDI value for the total carcinogenic PAHs (∑CPAHs) was highest for E. fimbriata. Carcinogenic human health risk assessment using carcinogenic toxic equivalents (TEQ), indicated that consumption of E. fimbriata has a higher potential to cause carcinogenic risks. TEQ values for all the fish species were however, below the estimated screening value (SV) of 3.556 mg/kg, while the estimated cumulative excess cancer risk (ECR) for E. fimbriata and C. gariepinus and PAH4 index for all the assessed fish species exceeded threshold values indicating potential carcinogenic risk from consumption.

The use of free range animals for monitoring environmental health offers opportunities to detect exposure and assess the toxicological effects of pollutants in terrestrial ecosystems. Potential human health risk of dietary intake of metals and metalloid via consumption of offal and muscle of free range chicken, cattle and goats by the urban population in Benin City was evaluated. Muscle, gizzard, liver and kidney samples were analyzed for Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Cd, and Pb concentrations using inductively coupled plasma mass spectrometer (ICP-MS) while Hg was determined using Hg analyzer. Mean concentrations of metals (mg/kg ww) varied significantly depending upon the tissues and animal species. Human health risk estimations for children and adults showed estimated daily intake (EDI) values of tissues below oral reference dose (RfD) threshold for non essential metals Cd, As, Pb and Hg thus strongly indicating no possible health risk via consumption of animal based food. Calculated Hazard quotient (THQ) was less than 1 (< 1) for all the metals analyzed for both adult and children. However, Cd and As had the highest value of THQ suggestive of possible health risk associated with continuous consumption of Cd and As contaminated animal based foods. Hazard Index (HI) for additive effect of metals was higher in chicken liver and gizzard for children and chicken liver for adults. Thus, HI indicated that chicken liver and gizzard may contribute significantly to adult and children dietary exposure to heavy metals. Principal component analysis (PCA) showed a clear species difference in metal accumulation between chickens and the ruminants. This study provides baseline data for future studies and also valuable evidence of anthropogenic impacts necessary to initiate national and international policies for control of heavy metal and metalloid content in food items.

The potential ecological and human health risk of heavy metal pollution in sediment and Benthic Fauna (Chrysichthys auratus and Tympanotonus fuscatus) of Benin River, Southern Nigeria, was evaluated. Three sampling sites associated with heavy anthropogenic activities along the course of the river were sampled. Heavy metals concentrations were determined in the samples using atomic absorption spectrophotometer (Model 210 VGP, Buck Scientific). In all sediment samples, only Pb exceeded the threshold/probable effect level (TEL). Very high contamination degrees (CD > 24) 181.74, 50.11, and 101.96) for stations 1, 2, and 3, respectively, were observed indicating serious anthropogenic pollution. Geoaccumulation index (i geo) showed slight pollution with Pb and Cd and severely to extremely polluted with Fe across the stations. Cd exhibited moderate individual potential risk (E i r), and the other heavy metals showed low E i r. Potential ecological risk index (RI) showed low risk of contamination for heavy metals in sediment. Human health risk assessment for Co, Cd, Cu, Zn, Mn, Fe, and Ni in C. auratus and Co, Zn, Mn, Fe, and Ni in T. fuscatus indicated no obvious health risk from these heavy metals over a lifetime of exposure. However, hazard quotient (HQ) values for Pb in C. auratus and Cd, Cu, and Pb in T. fuscatus indicated significant health risk. The hazard index (HI) values for both C. auratus and T. fuscatus were > 1 indicating significant adverse health risk of non-carcinogenic effect. Therefore, the consumption of these contaminated fish and shellfish by the people of Koko portends risks of the health of the public. The industries operating in this community should adopt more sustainable and eco-innovative management options in order to attenuate potential ecological and human health risk of metal pollution.

The distribution of pesticides in water, sediments, Clarias gariepinus, and Tilapia zilli from the Owan River was investigated to evaluate the pollution status and potential hazard in the river system. A total of 16 pesticides were analyzed using gas chromatography (GC) equipped with electron capture detector (ECD). The concentration of pesticide residues ranged from ND to 0.43 μg/l for water samples, 0.82 to 2.14 μg/kg/dw for sediment, 0.04 to 2.34 μg/kg/ww for C. gariepinus, and 0.02 to 1.73 μg/kg/ww for T. zilli. High concentrations of organochlorine pesticides, specifically benzenehexachloride (α-BHC, γ-BHC, and β-BHC) observed in all environmental media, are an indication of the current illegal use of banned pesticides for agricultural activities in the region. Analysis of data showed a strong correlation (r (2) = 0.7) between total organic carbon (TOC) and total pesticide residues in sediment samples. Meanwhile, risk quotient estimates for heptachlor epoxide, dieldrin, endrin, dichlorodiphenyltrichloroethane (4,4'-DDT), endosulfan I, endosulfan II, endosulfan aldehyde, and phosphomethylglycine showed potential risk to aquatic organism under observed mean concentrations (risk quotient (RQ) ≥ 1). Estimated average daily intake (EADI) for organochlorine pesticides (γ-BHC, heptachlor epoxide, aldrin, dieldrin, and endrin) was above their respective acceptable average daily intake (ADI), while hazard quotient for each of these pesticides was above the unity value (1). This indicates that there is a potential cancer risk for the local residents with life time consumption of pesticide-contaminated fish.

No abstract

No abstract

The concentrations of 16 pesticides residues (alpha BHC, gamma BHC (lindane), beta BHC, Heptachlor, Aldrin, Heptachlor Epoxide, Endosulfan I, Dieldrin, Endrin, Endosulfan II, 4, 4 DDT, Endosulfan Aldehyde, Endosulfan sulfate, Atrazine, Phosphomethylglycine and Carbofuran) in two fish species (Tilapia zilli and Clarias gariepinus) from selected rivers (Illushi, Owan and Ogbesse) in Edo State, Nigeria was investigated and the associated human health risks from the consumption of contaminated fishes was also determined. Fish species were collected for a period of 18 months, and pesticides analyses was carried out using Gas Chromatography (GC) equipped with Electron Capture Detector (GC-ECD). The distribution of pesticide residues was more in the tissues of Clarias gariepinus (5.53-9.98 μg/g wet weight) than Tilapia zilli (3.49-4.98 μg/g wet weight), while the most dominant pesticide in all the stations and all fish species was the persistent organochlorine; ∑BHC. Furthermore, the estimated dose for alpha BHC, beta BHC, Endosulfan Aldehyde, DDT, Endosulfan I, Endosulfan II, gamma BHC, Heptachlor, Endosulfan sulfate, Atrazine, Phosphomethylglycine and Carbofuran, do not pose direct hazard to human health since values were lower than the reference dose and Hazard quotient (HQ) were lower than toxic threshold of 1. However, estimated dose for, Heptachlor epoxide, Dieldrin, Endrin and Aldrin exceeded the reference dose and were higher than toxic threshold indicating a potential toxicity in humans.

No abstract