A geospatial assessment of human exposure pathways to chemical contaminants in the environment: a cause for action in Owerri, Imo State, Nigeria

The indiscriminate dumping of refuse and its potential threat to groundwater in Owerri, Nigeria remain a public health concern. This thesis applied multi-disciplinary techniques (environmental chemistry, health studies, geospatial statistics, social sciences, soil science and horticulture) to assess various pathways through which humans can be exposed to contaminants. A bi-seasonal random geospatial sampling of environmental matrices (groundwater, river water, dumpsites leachates, soil, and plant samples) impacted by urbanisation and anthropogenic activities was carried out between 2015 and 2017. Laboratory analysis reveals that concentration of nitrate in groundwater is above the maximum concentration limit (MCL) of 50μg/mL stipulated by the Nigerian Standard for Drinking Water Quality (NSDWQ) in approximately 12% of sampled wells. This presents nitrate as a critical contaminant in groundwater. Concentrations of Pb and Cd exceeded the MCL by about 1.6% and 0.25% respectively. All measured parameters in the river samples were within the acceptable threshold limits, whereas Pb concentration in soil measured above the 85 μg/g target value stipulated by the Nigeria Department of Petroleum Resources in about 0.9% of sampled soils. Pb measured above the thresholds of 0.3 μg/g and 0.1μg/g specified by the Food and Agricultural Organisation (FAO) in 99.8% of pumpkin leaf (Telfaiara occidentalis) and 51.6% of cassava tuber (Manihot occidentalis) samples respectively. Findings suggest review of groundwater risk evaluation techniques such as DRASTIC to incorporate more relevant soil and climatic attributes. In Owerri, urbanisation appears to have influenced groundwater nitrification as reflected in wells close to various contaminant sources, such as landfills and septic tanks. The wider implication of this study lies on the application of redox chemistry in the mini catchment assessment of contaminants behaviour that could help in the formulation of large-scale groundwater exploitation programmes and water management policies. Health risk assessment shows that children are significantly more vulnerable to contaminant exposure

Assessment of human exposure to food crops contaminated with lead and cadmium in Owerri, South-eastern Nigeria

Background: Food safety and security have remained an emerging global challenge amidst increasing human activities that potentially contaminate the food chain. With the rapid population growth, urbanisation and unrestrained emission of toxic substances, urban-dwelling Nigerians are particularly vulnerable to consuming contaminated food crops. Materials and method: This study presents a framework for critical analysis of human exposure patterns to potentially contaminated food crops using the city of Owerri (Nigeria) as case study. It systematically assessed the metal burden of soil and staple food crops and the potential health risk associated with dietary exposure of humans to contaminated food crops. Samples of soil, cassava (Manihot esculenta) tubers and fluted pumpkin (Telfairia occidentalis) leaves were collected from household gardens and analysed for concentration of selected metals (Al, As, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Ni, Pb and Zn) using ICP-OES. A risk assessment of human exposure to Pb contamination using both the Target Hazard Quotient (THQ) and Hazard Index (HI) was estimated. Results: The majority of metals measured below the respective health-based maximum concentration limits of the Nigerian Department of Petroleum Resources target value, except for Pb in soil, which was above the limit of 85 µg g−1 in 0.9 % of sampled soils. However, Pb measured above the threshold of 0.3 µg g−1 stipulated by the FAO/WHO Codex Alimentarius in 46 % of sampled pumpkin leaves with no correlation established with soil Pb concentrations. This suggests possible Pb contamination via atmospheric deposition, and that human ingestion of pumpkin leaves presents the greatest health risks. Conclusion: The findings revealed that children and toddlers are more prone to Pb contamination via food crop ingestion than adults based on the THQ and HI evaluations; hence need for relevant policies to ensure food safety. This study provides background data for epidemiological investigation of relationships between contaminated food crop ingestion and blood Pb

Correlates in Groundwater Quality Parameters and Textural Classes of Soils in a Peri-industrial District of the Nigerian Delta Region

This study investigated the physicochemical status of groundwaters of the oil-rich Ekakpamre community in Ughelli, Nigeria. Ten borehole water samples located about 1 km apart and soil samples around them were collected and analyzed by standard methods. Clay, sand and silt compositions in overlaying soils appeared to influence the DO (r=-0.999), TPH & toluene (r=0.998, each), and K+ ion (r=-0.999) levels in groundwaters at P<0.05. Three PCs which accounted for 100% variability in the original 27 variables formed the extraction solution and were most correlated with Cr (0.995), Pb (0.989) and PO42- ions (0.947). Though the high compositions of clay (72.67 ± 2.33%) and low compositions of sand (24.33 ± 2.60%) in the study indicates slight possibility of migration of surface pollutants to aquifers, the exceedances of Pb and Cd levels over regulatory limits portends public health hazards to consumers of groundwaters in the area. Keywords: Physiochemical status, Groundwater, Peri-industrial District, Niger Delta, Water contamination,    Textural compositions 

Effects of the Aqueous Root Extract of Vernonia amygdalina on the Haematological Profile of Rattus norvegicus

The effects of Vernonia amygdalina root extract on the haematological profile of 20 male albino rats (Wistar strain) were investigated for a period of 21 days. The rats were divided into three treatment groups A, B, and C and a control group D. The experimental groups A, B, and C were treated with 50mg.Kg-1, 150mg.Kg-1, and 300mg.Kg-1 body weight respectively while the control (group D) received equal volume of normal saline. The extracts were given to the animals orally for 21 days. Blood was collected through the orbital-plexus of rats to assay the effect of the extract on packed cell volume (PCV), white blood cell count (WBC), red blood cell count (RBC) and haemoglobin (Hb) level. The mean WBC, RBC, PVC and haemoglobin level ranged from 1560 ± 120 to 3200 ± 1200, 150.00 ± 40.00 to 276.00 ± 44.50, 38.00 ± 1.00 to 41.00 ± 3.00, and 16.00 ± 2.00 to 12.50 ± 0.50, respectively. There was no significant different (p>0.05) in the haematological profile of the treated groups when compared with the control. However, there was significant different (p<0.05) within each group from week one to week three except WBC in group D and PVC in all the groups. This suggested that the effect of the aqueous extract of V. amygdalina on the haematological profile of Rattus norvegicus was dependent on duration of consumption. Keywords: Vernonia amygdalina, Aqueous root extract, Haematological profile, Rattus norvegicu

Dynamism in plankton species occurrence and diversity of an impacted aquatic ecosystem, Southeastern Nigeria

Anthropogenic activities in rivers have been a major ecological problem affecting river morphology, water hydraulics, aquatic bio-systems and processes, and general water quality. This study established the diversity of planktons and physicochemical properties of dredging site of Otammiri River, Imo State. Water samples were collected from upstream, dredging site and downstream, with the aid of clean water sampling bottles and immediately transported to the laboratory for analysis. Plankton net of 55µm mesh was used to collect plankton samples and immediately transferred to plastic containers for microscopic examination, enumeration and classification. Occurrences of phytoplankton and zooplankton species were determined while Index of Diversity was computed using Margalef’s model. Multivariate redundancy analysis and biplot were used to show association among the planktons and the proportion of their occurrences at the sampling points. Phytoplankton was classified into Bacillariophyceae (Diatoms) (51.19%), Cyanophyceae (26.62%), Chlorophyceae (14.68%), Euglenophyceae (2.05%), Chrysophyceae (3.07%), and Xanthophyceace (2.39%); while zooplanktons were classified into Protozoa (47.06%), Rotifera (35.29%) and Cladocera (17.65%). Index of Diversity for phytoplankton species were: upstream (4.82), dredging site (5.19) and downstream (5.82); while for zooplankton were (1.86), (0.91) and (1.37) respectively. Physicochemical parameters showed significant variation (P<0.05) at the different sampling points. Dredging and other anthropogenic activities might be responsible for alterations in physicochemical characteristics and diversity of planktons in Otammiri River with consequences of ecological imbalance in the aquatic ecosystem

Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study

Summary Background Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally. Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income countries globally, and identified factors associated with mortality. Methods We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis, exomphalos, anorectal malformation, and Hirschsprung’s disease. Recruitment was of consecutive patients for a minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause, in-hospital mortality for all conditions combined and each condition individually, stratified by country income status. We did a complete case analysis. Findings We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal malformation, and 517 with Hirschsprung’s disease) from 264 hospitals (89 in high-income countries, 166 in middleincome countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male. Median gestational age at birth was 38 weeks (IQR 36–39) and median bodyweight at presentation was 2·8 kg (2·3–3·3). Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups). Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in lowincome countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries; p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88–4·11], p<0·0001; middle-income vs high-income countries, 2·11 [1·59–2·79], p<0·0001), sepsis at presentation (1·20 [1·04–1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention (ASA 4–5 vs ASA 1–2, 1·82 [1·40–2·35], p<0·0001; ASA 3 vs ASA 1–2, 1·58, [1·30–1·92], p<0·0001]), surgical safety checklist not used (1·39 [1·02–1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed (ventilation 1·96, [1·41–2·71], p=0·0001; parenteral nutrition 1·35, [1·05–1·74], p=0·018). Administration of parenteral nutrition (0·61, [0·47–0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65 [0·50–0·86], p=0·0024) or percutaneous central line (0·69 [0·48–1·00], p=0·049) were associated with lower mortality. Interpretation Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between lowincome, middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger than 5 years by 2030

Water Quality Index and Human Health Risk Assessment of Class B Swimming Pools in Owerri Municipal, Nigeria

Assessments of public swimming pools in Owerri municipal, Imo state, Nigeria was carried out for the purpose of determining the suitability of water for swimming in this fun loving town of Nigeria. Five public pools were selected by purposive sampling from more than 30 pools in the area. Water samples were collected in the morning and evening from pools and analyzed in triplicates for physicochemical properties and heavy metals content by using standard method for water analysis and Atomic Absorption Spectrometer. Data obtained were compared with WHO and EPA standards for drinking and recreational water and modeled on the Water Quality Index (WQI). Results revealed that pH ranged from 7.10±0.02 to 8.1±1.27 pH units, EC ranged from 40 ±3.11 µS/cm to 80±3.44 µS/cm, COD value ranged from 0.08±0.07 to 1.02 ±0.91, BOD value ranged from 0.03±0.02 to 3.14±0.13, dissolved oxygen (DO) ranged 3.9±1.77 mg/kg to 9.3±2.41 mg/kg, suspended solids ranged from 6.43±8.21 mg/l to 42.44±7.00 mg/l, total dissolved solids (TDS) ranged from 22±2.90 mg/l to 97.98±8.79 mg/l. The major cations were below the standard. Nitrate ranged from 0.91±0.02 mg/l to 0.96 mg/l, sulphate ranged from 2.34±0.10 mg/l to 2.81±0.11mg/l, phosphate ranged from 0.34±0.02 mg/l to 0.65±0.02 mg/l while chloride ranged from 12.75±1.89 mg/l to 31.89±2.04 mg/l with mean 24.23 mg/l. Except for chloride, all other studied anions were lower than the permissible limit set by WHO/EPA. Concentration of lead (Pb), iron (Fe), Copper (Cu) were also below the permissible limit. The individual WQ indexes showed A (3.32), B (5.44), C (10.08), D (12.40) and E (9.77) with average WQI of 8.20 suggesting that the swimming pools are of “Excellent water quality”, thereby suggesting safe swimming pools for recreational activities in the study area. Values of exposure pathways for all metals at all swimming pools were less than one. Therefore there were no risks of heavy metals from the swimming pools