Particulate matter exposure and non-cancerous inhalation health risk assessment of major dumpsites of Oerri metropolis, Nigeria.

Numerous particulates are released from the dumpsites in Owerri metropolis and later dispersed to other areas in the environment where they cause adverse health challenges to the inhabitants. To analyze the PM concentration, field measurements were carried out at seven major dumpsites in the Owerri Metropolis. Estimates of the possible health risks as the result of exposure to airborne particulate matter (PM2.5, PM10, etc.) were performed using the US Environmental Protection Agency human health risk assessment framework. A scenario assessment approach in which normal exposure and worst-case scenario were adopted for acute and chronic exposure periods for infants, children, and adults. The concentrations of PM 2.5 which ranged from 122.30-501.76 µg/m3 at the dumpsites exceeded the WHO 24hr annual mean maximum exposure limit. The Nigerian National Ambient Air Quality Standard allowable limit for PM10 was exceeded by most of the dumpsites. Hazard quotient > 1 was exceeded for PM 2.5 by nearly all dumpsites and is likely to cause health challenges. The results showed that under monthly conditions, both PM2.5 and PM10 concentration levels at the dumpsites have the potential to cause adverse health effects when for infants, children, and adults on acute or chronic bases. Actions should be taken to regulate such PM exposure and to raise public awareness for the inhabitants of the affected areas. In conclusion, regular monitoring is therefore needed to decrease the ambient particulate matter (PM) concentrations in the study area.

Assessment of the geo-environmental effects of activities of auto-mechanic workships at Alaoji Aba and Elekahia Port Harcourt, Niger Delta, Nigeria.

Geo-environmental assessment of activities of auto-mechanics at Alaoji Aba and Elekahia Port Harcourt, both in the Niger Delta region, Southern Nigeria were carried out with the main objective of determining the extent of soil contamination arising from anthropogenic activities within mechanic villages (MVs). Geochemical analysis of soil samples from the study area revealed that the concentrations of the trace metals ranged from <1 mg/kg for chromium (Cr) to 1,925 mg/kg for the lead (Pb). Soil analysis for polycyclic aromatic hydrocarbon (PAH) and total petroleum hydrocarbon (TPH) across the area revealed concentrations ranging from <0.02 to 1.80 mg/Kg and from <1.00 to 38,327 mg/kg respectively. Elevated levels of the heavy metals and TPH were observed at MV in Alaoji Aba when compared to MV in Elekahia Port Harcourt, and the control sites. These could be attributed to contamination due to the presence of these auto-mechanics in the area for over thirty years. The concentration of Pb and Cd recorded in some sample points were above USEPA (United State Environmental Protection Agency) and the National Environmental Standards and Regulations Enforcement Agency (NESREA) permissible limits. Results of PAH analysis showed the presence of naphthalene, phenanthrene, pyrene, fluorene, benzo(a)anthracene, acenaphthene, methylnaphthalene. Risk assessment analysis showed significant geo-accumulation values for Cd and Pb indicating heavy contamination. The monomial risk factor of the heavy metals in the MVs are in the order Cd>Pb>Cr, while potential ecological risk index analysis showed values indicating very high risk, considerable risk and a moderate risk to the area under study as well as the surrounding environment. These results suggest that the soils from the MVs which represent the mechanic workshops at Alaoji Aba and Elekahia Port Harcourt are considered to be of pollution concern due to elevated Pb and Cd levels. Hence, there is a serious need to regularly monitor the activities of auto-mechanics in the study area.

Application of assessment models for pollution and health risk from effluent discharge into a tropical stream: case study of Inyishi River, Southeastern Nigeria.

Pollution and health risk assessment models were used to study the effects of effluents discharged into the Inyishi River, Ikeduru LGA, Imo State, Nigeria. The study aims at investigating the environmental health effects of wastewater effluent discharge from the aluminum extrusion company on the Inyishi River. Samples were collected from both the aluminum extrusion company and Inyishi River and analyzed for physicochemical and trace metal parameters. Models adopted for assessment include transfer factor (TF), contamination factor (Cf), pollution load index (PLI), ecological risk factor (Er), water quality index (WQI), hazard quotient (HQ), and hazard index (HI). The results of the study revealed that pH and TH were within the Nigerian Standard for Drinking Water Quality (NSDWQ) and World Health Organization (WHO) standards. EC values at 2235 ± 0.001 and 105 ± 0.03 µS/cm for S3 and S4 respectively were higher than the permissible standards, while the values of EC at 24.04 ± 0.03, 5.26 ± 0.005, and 0.05 ± 0.01 µS/cm respectively for S1, S2, and SR are within the WHO standard. Very high concentration of SO42- was recorded at S3, while low concentration was measured at S2. Mean values of heavy metal ions studied were within NSDWQ and WHO standards for safe drinking water except for Al, Zn, Cd, Fe, and Mn, with the mean values of metal concentrations observed in the order Al > Fe > Zn > Mn > Cd > Cr. Positive linear correlation based on heavy metal contamination was observed for samples S1 and S2 with SR. High TF values were observed in decreasing order Mn > Cd > Cr > Fe > Zn. Similarly, very high CF was observed for Cd and Al while the PLI was generally high for all the samples. Low Er values were observed for all metals except for Cd, with the mean value of Er observed in the decreasing order Cd ˃ Mn ˃ Zn ˃ Cr. The river water sample generally revealed high WQI and was thus categorized as poor quality. HQ and HI values were below unity (< 1), but might pose health risk to children in cases of prolonged dermal adsorption. In conclusion, the quality of the Inyishi River has been negatively impacted by the wastewater effluent from the aluminum extrusion company. Proper treatment of the river water is therefore recommended before use for domestic purposes as prolonged usage of the untreated water might likely pose serious environmental health risks.

Airborne microplastics: a review study on method for analysis, occurrence, movement and risks.

Microplastics (of size < 5 mm) pollution in our environment is of current concern by researchers, public media and non-governmental organizations. Implications by their presence in aquatic and soil ecosystems have been well studied and documented, but less attention has been paid on airborne microplastics (MPs). Studies concerning airborne microplastics started from 2016 and only a few (n = 13) have been published to date. Although, studies may increase in the following years, since air is very important for human survival. Microplastics have been observed in atmospheric fallouts in indoor and outdoor environments using a sampling or vacuum pump, rain sampler, and/or particulate fallout collector. Identification and quantification have been carried out by visual, spectroscopic, and spectrometric techniques. Factors such as meteorological, climatic, and anthropogenic influence the distribution and movement of airborne MP. Human exposure may be through inhalation, dermal, and open meal during fallout, with their potential biopersistence and translocation. Ingestion may cause localized inflammation and cancer due to responses by the immune cells, especially in individuals with compromised metabolism and poor clearance mechanisms. Ecological risks involve possible contamination of the ecosystem through a dynamic relationship of MPs in soil, water, and air forming a MP contamination cycle. The present review aimed at providing a comprehensive overview of current knowledge or information regarding microplastics in air, identifying gap in knowledge, and giving suggestions for future research.

Environmental and health implications of trace metal concentrations in street dusts around some electronic repair workshops in Owerri, Southeastern Nigeria.

Assessment of trace metal concentrations in street-deposited sediments around some selected electronic repair workshops in Owerri, Imo State, Nigeria, was carried out. The objective of the study was to determine the concentrations of trace metals, namely nickel (Ni), chromium (Cr), lead (Pb), copper (Cu), cadmium (Cd), and zinc (Zn), in surface dusts from streets within some electronic repair workshops in Owerri, Imo State, Nigeria. Dust samples were collected from seven locations within the month of January 2014 during the dry season when the onset of dust was high in the area. The samples were air-dried, sieved, and digested in aqua regia, with the concentrations of trace metals determined with atomic absorption spectroscopy, Agilant FS 240AA model (USA). Results of the study revealed all the trace metals assessed except Cr in dust sample from Aladinma (ALA). Though elevated concentrations of Zn and Cu were observed in all the sampled locations, the concentrations did not exceed the Dutch intervention values. Risk assessment of the heavy metals showed high average daily dose (ADD) of the heavy metals for children and adults at New Market 2 (NMK2), New Market 1 (NMK1), and Tetlow (TEL), which could be attributed to the presence of electronic repair workshops and activities of electronic scrap dealers within these areas. It was observed that the values of hazard quotient (HQ) were less than 1, while that of hazard index (HI) were all below 1-5, indicating that the heavy metals pose no health risk to adults and children in the environment. However, there may be potential danger if the waste generated from the electronic repair workshops and electronic scrap dealers are not properly disposed and managed.