The contamination of soil with toxic metals poses serious threats to the survival of living organisms including humans. We determined the contamination levels of cadmium (Cd), chromium (Cr), copper (Cu), lead (Pb) and nickel (Ni) in soil samples from a typical agrarian soil in Nigeria, using various single and complex geochemical indices along with principal component analysis (PCA) for source determination. Ten soil samples (S1-S10) were collected from depths of 20 cm, with a clean shovel and brush from farmlands in Ihiala, South-East Nigeria. Three single pollution indices: geoaccumulation index (I_geo), pollution index (PI) and ecological risk index (E_r), as well as four complex indices: pollution load index (PLI), Nemerow pollution index (PI_Nemerow), average single pollution index (PI_ave) and Potential ecological risk (RI) were used for the geochemical analysis. The mean soil levels of Cd (1.94ppm) and Pb (60.83ppm) exceeded their corresponding world averages. The results of the single pollution indices of the soil samples revealed heavy Cd, moderate Pb and low Ni, Cr and Cu contaminations, while the PI_avg, PI_Nemerow and RI graded the soil samples as moderately to seriously polluted. The correlation analysis revealed that the general contamination was mostly contributed by Cd and partly by Cr. The findings showed that Cd and Pb were the main heavy metal soil contaminants in the area. The levels of toxic metals found in the soils could pose health and ecological risks. The probable sources of these metals include pesticides use and poor waste disposal systems.

Waste disposal on dumpsites has resulted in significant vanadium pollution of the soil and ecosystem. This study assessed the pollution status and potential ecological risk of vanadium in some selected waste dumpsites in southeastern Nigeria. In this study, the soil samples were taken from the active waste dumpsites using a stainless-steel soil auger at a depth of 0 - 20 cm. Five sub-samples were taken from each sample location. A control sample was taken from an area devoid of industrial activities and waste dumps. Soil samples were air-dried at room temperature, pulverized with an agate mortar and pestle, and stored using appropriately labeled polythene bags prior to analysis. Vanadium analysis was conducted using an FS240AA atomic absorption spectrophotometer, and the data generated was analysed using IBM SPSS version 20.0 and Ms-Excel 2007. The mean vanadium concentrations in the studied waste dumpsites were found to be in the following order: Okpuno-Egbu dumpsite > Nekede dumpsite > Enyimba dumpsite > Rice-mill dumpsite. Acceptable potential ecological risk indices were observed in the Rice-mill, Enyimba, and Okpuno-Egbu dumpsites, while Nekede dumpsite recorded a high potential ecological risk. Furthermore, the pollution load index revealed that all the studied dumpsites were heavily polluted. Statistical analysis revealed no significant variations in vanadium concentrations in the studied dumpsites (p>0.05). Additionally, there was a strong and positive correlation between the dumpsites of Enyimba/Nnewi (r = 0.634), Nekede/Nnewi (r = 0.615), and Nekede/Rice-mill (r = 0.842). This indicated that the metal found in the dumpsites is of the same origin.

The level of heavy metals (Pb, Cd, As, Cr, Ni, Co, Zn) and physicochemical parameters in borehole water sources within selected mining sites in Ebonyi State, Nigeria were determined using FS240AA Atomic Absorption Spectrophotometer (AAS) according to the method of American Public Health Association (APHA). Water samples were collected from Enyigba mining site, Ikwo mining site, Ameri Amekamining site, Izza mining site, Mkpume Akwatakwa mining site and Mpume Akwaokuku mining sites. Composite water samples were collected within the mining locales and 500 metres away from the mining locations using two liters plastic jars. Similarly, the control samples were taken from Abakaliki (about 15 km away from mining area) where there was no evidence of mining activity. A total of 14 sub-samples were collected for this study. Generally, the levels of heavy metals in the borehole water samples were higher than the values recommended by the World Health Organization (WHO). This however suggests a possible mobility of the metals from mining sites into the groundwater sources through leaching. The findings from this study have revealed the need to purify borehole water within mining areas prior to industrial and domestic use.

Heavy metals pollution has been a great concern generally due to their toxicity and persistence in environment. This study evaluated the level of pollution and health risks of heavy metals in surface irrigation water used for vegetable cultivation and sediment from Nimo vegetable farm. Three samples each from three different sampling points for water and sediment were collected in dry and rainy seasons and analyzed for Pb, Cd, Mn, Fe, Zn, Cu and Ni concentrations using Atomic Absorption Spectrophotometer. The result showed that heavy metal concentrations in the irrigation water ranged from 0.004 to 0.147 mg/l, 0.119 to 0.773 mg/l, 0.014 to 1.644 mg/l, 0.006 to 0.056 mg/l, 0.009 to 0.576 mg/l, 0.040 to 0.181 mg/l, 0.082 to 0.147 mg/l, for Cd, Pb, Fe, Cu, Zn, Mn, and Ni respectively for the different seasons. In sediment, Cu had the lowest mean concentrations of 0.02±0.01 mg/l while iron had the highest mean concentrations of 6.86±3.06 mg/l. The obtained results were compared with Food and Agriculture Organization and the Department of Petroleum Resources standards for surface irrigation water and sediment respectively. The heavy metal distribution in water was Fe > Pb > Mn > Cd > Ni > Cu = Zn in dry and Zn > Fe > Pb > Ni > Mn > Cu > Cd rainy seasons respectively.  Overall, the heavy metals level in the water and sediment were low when compared to the standards. Computed contamination factors and pollution load index showed that the sediment were not polluted while in water, only Cu, Zn, Mn and Fe (in rainy season) showed low contamination, while Ni, Pb and Cd had moderate to very high contamination in both seasons. Hazard Index values for the heavy metals in adults and children via the water and sediment of this study is less than one (HI < 1). Hence the water and sediment from this site poses no health risk to the public. Correlation analysis for metals in water and sediment showed significant and positive relationships amongst the metals which indicated that the most of the metals originate from the same source while few originate from mixed sources mainly from agricultural activities, atmospheric deposition and runoff into the irrigation water.

The paper reveals the role of wastewaters in the spread of Coronavirus in cities and focuses on the need for collection, treatment, and management of wastewaters. While the focus of the fight against COVID-19 is on the production of vaccines, drugs and treatments, this article emphasizes the cleanliness of the environment with wastewater management. This paper is a novel work, since it presents a multi-side research concerning fighting against coronavirus through wastewater collection and treatment. Studies show that coronavirus exists in urban wastewaters and spread the COVID-19 everywhere. Coronavirus is attacking people globally and shrinking the economy. The question addressed by this paper is; will communities overcome the coronavirus without well-collected and treated wastewaters? The methods to achieve the goals are theoretical surveys, case study strategy, mathematical modeling, statistical procedures, forecasting the future, and discussions. A mathematical model will be built to calculate the number of deaths caused by the coronavirus with the help of registered statistics and predict the future trend of the disease pandemic in Iran. Since Coronavirus has been seen in wastewaters, results of this research demonstrate the need for carefully collected and treated wastewaters to overcome the coronavirus. This paper gives suitable techniques to treat wastewater as stabilization ponds, bacterial reactors, and anaerobic ponds. Concluding, this paper suggests indicators to select a wastewater treatment technique in every city, and its outcome will assist the global community in fighting the coronavirus more successfully.