Background. With a population of over 165,000,000, growing at an average rate of 2.7% per annum and an economic growth rate of about 5.7% in the past five years, the market for refined petroleum products in Nigeria is growing. As a result, the number of filling stations is increasing. Objectives. The present study evaluated the reproductive and genetic toxicity of simulated leachate of soil from petrol, diesel and kerosene dispensing sites in a filling station using the murine sperm abnormality test, sperm count and bone marrow micronucleus assay. Methods. Simulated leachate of soil collected from petrol, diesel and kerosene dispensing sites in a filling station was intraperitoneally administered to mice at different concentrations. Bone marrow micronucleus assay was carried out after 5-days exposure, while sperm morphology assay was carried out 35 days from the first day of exposure. Alterations to hematological parameters were evaluated and physico-chemical analysis of the leachate samples was also carried out. Results. The results showed a significant (p<0.05) concentration-dependent increase in abnormal sperm cells and decrease in mean sperm count in all the samples tested. Increased induction of micronucleated polychromatic erythrocytes was observed in the exposed mice. Hematological analysis showed a significant (p<0.05) increase in the values of white blood cell count (WBC), lymphocytes, neutrophils, monocytes, eosinophils and mean corpuscular volume (MCV), while a significant (p<0.05) reduction in basophils, hemoglobin, mean corpuscular hemoglobin (MCH), packed cell volume and mean corpuscular hemoglobin concentration (MCHC) values were observed. Discussion. In the present study, simulated leachates from soil obtained from petrol, diesel and kerosene dispensing sites were shown to cause genomic disruptions in germ and somatic cells, and hematotoxicity in an animal model. These observed reproductive, genetic and hemato-toxicities are believed to be caused by the presence of lead, copper, mercury, polycyclic aromatic hydrocarbons, and benzene in the samples. Conclusions. This study showed the negative impact of petroleum products in the contamination of soil, with a capability of inducing genetic damage in somatic and germ cells of exposed plants and animals. Competing Interests. The authors declare no financial competing interests. Ethics Approval. The study was approved by the ethical committee of the Federal University of Technology, Akure, Ondo State, Nigeria.

Background. Cleanup of soils contaminated with toxic metals is a difficult task due to the method inefficiency and the destructive nature of clean-up techniques on soil ecosystems. Objectives. This study was performed to improve the removal efficiency of an acetic acid washing solution for the removal of lead (Pb) from soil. Acetic acid was used in combination with different concentrations of potassium chloride. In order to maximize the removal of Pb from the leachate, different electrode combinations were applied to the washing solutions. Methods. Acetic acid/potassium chloride washing solutions and electrochemical reduction were applied to lead-contaminated soil obtained from an impact berm of a major military shooting range in Ibadan, southwestern Nigeria. The soil was subjected to 5% acetic acid/5% potassium chloride (KCL) and 5% acetic acid/10% KCL solutions in an ex-situ batch experiment. The leachate was electrochemically reduced using 12 volt direct current with a current of 7 amps and 2.5 amps, with aluminum (Al)-Al, iron (Fe)-Fe, Al-Fe and Fe-Al electrodes. Results. The 5% acetic acid/5% KCL proved more efficient for Pb removal in soil with values ranging from 74.9% to 86.9% for 3% soil pulp densities with one washing time of 6 hours. Removal efficiency of Pb from the contaminated soil significantly decreased as the soil pulp density increased. The Al-Al and Al-Fe bipolar electrode combinations showed better removal efficiency of Pb from the leachates with values of 93.7% and 95.6% for 7 amps and 94.5% and 97.3% for 2.5 amps, respectively. Conclusions. The combined 5% acetic acid and 5% potassium chloride washing solution enhances the removal efficiency of Pb in soil and poses less risk to the soil ecosystem and the environment in general. Competing Interests. The authors declare no competing financial interests.

Background. Due to an increase in population density and industrialization, the capital city of Mongolia, Ulaanbaatar, has been experiencing an increase in environmental pollution; especially soil contamination. Environmental pollutants include solid waste, silt and wastewater coming out of tanneries in three micro districts of the Khan-Uul district of Ulaanbaatar. Among the many types of chemicals these tanneries use, chromium (III) sulfate (Cr2(SO4)3) poses the most serious environmental health risk. In addition, the surrounding areas around the tanneries include schools, hospitals and residential buildings, presenting additional risks to the people living and working in this area. Objectives. The present study aims to identify heavy metal contamination in the tannery area using a portable x-ray fluorescence reader (XRF). Methods. The study area (112 ha) was divided into 6 zones depending on usage and XRF readings were taken in each zone. Results. Results showed a mean or median lead (Pb) concentration of 2–405 mg/kg (33±2), chromium (Cr) concentration of 18–10,752 mg/kg (685±80), zinc (Zn) concentration of 5–1,316 mg/kg (113±6.5), and arsenic (As) concentration of 0–84 mg/kg (10.2±0.46) Five soil samples were collected from sites where Cr concentrations were extremely elevated and analyzed in two different laboratories to confirm XRF readings. Using the results from XRF readings and two different lab results, heavy metal distribution mapping was produced using geographic information system (GIS) tools, statistical processing tools and pollution indices for each heavy metal were determined using base heavy metals content in the soil. The distribution percentage of each of the heavy metals in the topsoil was 37.7% for Pb, 78.5% for Cr, 43.8% for Zn, and 51.3% for As. Discussion. There are 140 tannery facilities in Mongolia of which 60 processing facilities reside in the Khan-Uul district of Ulaanbaatar. Tanneries use chromium (III) sulfate and other environmentally hazardous chemicals often in tandem with less costly technologies. This increases the amount of wastewater and contaminated silt going onto and into soil. The baseline level of heavy metals content was indicated by 7 XRF readings taken along the side of the Tuul river (relatively untouched soil). The present study shows that the Cr contamination in soil surrounding the tannery area was very high and the main source of the pollutants are wastewater and silt highly contaminated with chromium sulfate originating from the tanneries. Conclusions. The present study found that the tannery area is heavily contaminated and may pose serious threats to human health, the surrounding environment and underground water resources. In order to reduce the health risk of the people working and living in the study area and remove contamination and rehabilitate the area, further studies are needed to determine heavy metal leakage into soil and underground water and to determine the volume of work needed for neutralization and rehabilitation. Competing Interests. The authors declare no competing financial interests

Background. Extracts from medicinal plants have been widely used in the treatment of public health ailments, however, medicinal plants may be grown in polluted soil/water environments. Many of these plants are harvested and processed by local and illiterate natural healers and other vendors in an unhygienic manner. This results in the possibility of contamination with potentially toxic metals from the environment. Objectives. This study evaluated the concentrations of lead (Pb), cadmium (Cd), chromium (Cr), nickel (Ni), copper (Cu) and zinc (Zn) in 25 samples of different medicinal plants procured from stores in open markets in Ibadan, Nigeria. Methods. After procurement, the samples were air dried, pulverized and dry ashed. All ashes were dissolved with dilute acid solutions, filtered and the filtrates were stored for metal analysis. Samples with elevated metal concentrations were extracted with water and alcohol solutions to mimic the medicinal extracts obtained from these plants. Metal concentrations were analysed in all extracts and filtrates using atomic absorption spectrophotometry. Results. Metal concentrations (mg/kg dry weight) in all samples ranged as follows: Cu, 0.04 - 9.44; Zn, 0.36 – 35.4 and Pb, below detection limits (BDL) – 6.15. The concentrations of Cd, Cr and Ni in all samples were BDL. The concentrations of all metals in the samples were within accepted limits set for medicinal plants according to international regulatory bodies. All ethanol extracts and 1 out of 4 water extracts contained Pb. Conclusions. Medicinal plants could pose chronic metal toxicity effects from continual bioaccumulation along the food chain. Furthermore, extraction of active ingredients with water was deemed to be safer than the use of alcohol extracts. Continuous monitoring of these medicinal plant materials is needed. Competing Interests. The authors declare no competing financial interests.

Background. Nigeria has a growing spray painting industry, however, the burden of occupational health problems related to organic solvent exposure among spray painters in Nigeria is under-studied. Objectives. This study aimed to assess workshop characteristics and ambient concentration of total volatile organic compounds (VOCs) in spray painting workshops and to compare lung function status and total serum bile acid levels of spray painters and controls. Methods. A cross-sectional study design was employed to survey 120 spray painters and 120 controls (electronic technicians). A semi-structured questionnaire was used to obtain data on socio-demographics characteristics of the respondents. Weight, height and lung function of respondents were measured. In addition, a checklist was used to survey the spray painting workshops. Total VOC levels were determined in 37 spray painting and 31 electronic workshops. Data were analyzed using Statistical Program for the Social Sciences (SPSS) version 20 and a p-value of <0.05 was considered to be statistically significant. Results. Windows were present in only 5 (13.5%) spray painting workshops and 23 (62%) workshops had a retractable tarpaulin at the entrance. Only 9 (24%) workshops had changing rooms, while fire extinguishers and first aid kits were not present in any of the surveyed workshops. A respirator with filter was sighted in only 1 (3%) workshop. The 8-hour time weighted average concentration of total VOCs in spray painting workshops was 13.4 ppm, which is above the national permissible exposure limits of 1.9 ppm. Forced vital capacity (FVC) percent predicted was significantly lower in spray painters (93.9 ±10.8%) than controls (96.7± 8.2%) (t = −2.326, df=238 p< 0.001). In addition, forced expiratory volume in the first second (FEV1) percent predicted was lower in spray painters (94.6±12.2%) than controls (100.3±9.1%) (t=−4.058, df=238, p=0.002). FEV1/FVC% was significantly lower among spray painters (85.48±8.70%) compared with controls (87.88±6.22%) (t=−2.861 df=238, p= 0.005). Total serum bile acids was significantly elevated in painters (8.71±3.39 mmol/l) compared to controls (4.67 ±2.15 mmol/l) (t=10.358, df=213, p<0.05). Conclusions. Spray painters in the present study conduct their activities in hazardous work settings. More needs to be done concerning workplace regulation and enforcements to ensure that spray painters comply with minimum standards of occupational safety, workplace hygiene and sanitation. Patient Consent. Obtained Ethics Approval. Ethical approval was granted by the Health Research and Ethics Committee of the Institute of Public Health, Obafemi Awolowo University. Competing Interests. The authors declare no competing financial interests.

Background. Lakes are a vital water resource, but are adversely affected by pollutants such as heavy metals and polychlorinated biphenyls (PCBs) from urban, agricultural and industrial activities. This can give rise to potential pollution-related health problems such as cancer and infectious diseases. Risk assessments are necessary to determine the degree of pollution and its effects on human health and ecological systems. Objectives. This study assessed the pollution status and a risk assessment was calculated to determine the degree of the pollution and its effects on the human health and the ecological system of Eleyele Lake in Ibadan, Nigeria. Methods. Physical and chemical parameters, heavy metals and PCBs were determined in the lake water using standard methods from December 2013 to February 2014 at ten different sites of anthropogenic activity. Results. Water pH ranged from 6.00–7.50, while electrical conductivity ranged from 205.00–221.00 μs/cm3. Dissolved oxygen ranged from 0.30–6.00 mg/L and total dissolved solids ranged from 105.00–113.00 mg/L. Phosphate levels ranged from 13–0.99 mg/L. Nitrate and sulphate in the dry season ranged from (3.10–3.80 and 35.81–40.97 mg/L) and (0.12– 0.37 and 6.10–10.30 mg/L) in the wet season. Heavy metal concentrations were in the order cadmium (Cd) > zinc (Zn) > copper (Cu) > chromium (Cr) > lead (Pb) for the dry season and Cd > Zn > Cr > Pb > Cu for the wet season. Total PCBs ranged from 493.90–732.55 μg/L and 52.00–390.03 μg/L for the dry and wet seasons, respectively. All determined physical and chemical parameters were within permissible levels, while heavy metals and PCB concentrations were higher than permissible levels. Discussion. The hazard quotients and carcinogenic risk values were greater than acceptable limits, indicating that PCBs in Eleyele lake water pose adverse health effects to the local population. It was observed in this study that lower chlorinated PCBs were more prevalent than higher chlorinated PCBs. This may be attributed to the fact that the lower chlorinated PCBs are influenced by atmospheric deposition as a result of their volatility, and they are more susceptible to atmospheric transport than highly chlorinated PCBs. Conclusions. PCBs possess serious health risks to the population that depends on the lake as a source of domestic water and its aquatic organisms. Efforts are needed to reduce anthropogenic influence on the lake through strict environmental controls. Competing Interests. The authors declare no financial competing interests.

Background. Many companies in Nigeria generate industrial effluents, including heavy metals. These metals can be accumulated by biota such as mushrooms, which are then eaten by the populace. Objectives. The present study investigates the metal content of wild mushrooms in order to educate the local population on the safety of their consumption. Methods. Seven different species of wild mushrooms (Cortinarius melliolens, Chlorophyllum brunneum, Pleurotus florida, Volvariella speciosa, Cantharellus cibarius, Entoloma spp and Coprinus africana) growing in Ibadan, southwest Nigeria were analyzed for their heavy metal (copper (Cu), cadmium (Cd) and lead (Pb)) contents using atomic absorption spectrophotometry. Results. The concentrations of the heavy metals in the mushrooms and substrate varied by site of collection. The highest concentrations of Cu (92.31±8.42 mg/kg), Pb (76.00±9.78 mg/kg) and Cd (92.45±12.34 mg/kg) were obtained in C. africana, P. florida and V. speciosa, respectively. The lowest contents of Cu (56.00±5.02 mg/kg), and Cd (67.92±5.89 mg/kg) were obtained from C. melliolens, while C. cibarius had the lowest concentration of Pb (40.00±3.56 mg/kg). The highest concentrations of Pb (20.40±3.43 mg/kg) and Cd (26.40±4.34 mg/kg) were obtained in the substrate of C. molybdites, while the lowest Pb (12.40±2.12 mg/kg) and Cd (18.00±3.90 mg/kg) occurred in V. speciosa and C. cibarius, respectively. The bioaccumulation factors of the mushroom species studied ranged from 2.84 – 14.60. Conclusions. The present study found that heavy metal accumulation varied by species of mushroom, metal content of the substrate and the bioavailability of the metal in the mushroom. The level of metals in mushrooms in the present study was relatively high. Therefore, cultivation of mushrooms in heavy metal-free soil should be encouraged. Competing Interests. The authors declare no competing financial interests.