Health risk assessment of pesticide residue in freshly harvested Vigna subterranea (Bambara nut) in Nsukka South Eastern Nigeria.

Two species of freshly harvested Bambara nut were analyzed for organophosphate and organochlorine pesticide residue using GC-FID and GC-ECD. The risk associated with the consumption of the Bambara nut was evaluated using the health risk index (HRI) and the probable cancer risk (PCR). A maximum of thirteen (13) organochlorines and eight (8) organophosphate pesticides were determined from both species respectively. The results revealed that almost all the quantified pesticides exceeded their respective FAO maximum residue levels (MRLs). The health risk index (HRI) values of the organochlorines and organophosphates were below 1 in adults indicating little or no risk to adults. While the HRI of the organophosphates and a few values in the organochlorines were above 1 in children indicating that organophosphate pesticides in the freshly harvested white and mixed Bambara nut could pose a great health risk to children within these areas. The Hierarchical Cluster Dendrogram indicated similar sources of the assessed organochlorine and organophosphate pesticides.

Relative distribution of rare-earth metals alongside alkaline earth and alkali metals in rhizosphere of agricultural soils in humid tropical environment.

The study of trace and major elements in the biosphere has traditionally focused on the transition and basic metals; the rare earth (REMs), alkaline earth (AEMs) and alkali metals (AMs) that equally constitute environmental contaminants are rarely considered especially in the tropics. The levels and spatial variation of some REMs, AEMs and AMs in the 0-50-cm layer of agricultural soils of Ikwo in southeastern Nigeria typing a humid tropical environment were studied. Soil sampling was undertaken at five zones namely north, south, east, west and centre (covering over 60% of the land area) in the 2017 dry season. Four soil samples were collected from each of the four cardinal points (with evidence of mining and agricultural activities), and two from the centre (serving as reference zone), totalling 18. Metal concentrations were determined using inductively coupled plasma atomic emission spectroscopy. The metals were grouped into REMs (Ce, La, Sm), AEMs (Ba, Ca, Mg, Sr) and AMs (Cs, K, Na, Rb). All metals increased in concentration from the north, or the south (for Ce and Sm only), towards the centre. Overall, they were reasonably similar in distribution pattern among the five zones. Cationic ratios did not vary markedly, reflecting the greater role of pedogenesis than anthropogenic activities in the area. Nevertheless, their variations showed more K, Ca, Sr and La enrichments over the other metals. Enrichment factor and pollution index of the REMs showed healthy levels of these elements in the soils. The data from this preliminary study may add to the data pool on levels and occurrence of REMs, AEMs and AMs in largely disturbed ecosystems of the humid tropics.

Pollution status of major rivers in an agricultural belt in Eastern Nigeria.

The physico-chemical and bacteriological analyses of four rivers namely: Ajali, Obinna, Karawa and Adada in Ezeagu and Uzo-uwani Local Government Areas (LGAs) of Enugu State, South-eastern Nigeria, were carried out to evaluate their suitability for consumption. Water samples from Ajali River were taken from a point where the river receives brewery effluents and other two points that were impacted by non-point pollution sources. A total of 54 water samples were collected during the dry season, early rainy season and rainy season proper for 2 years. For each trip, nine samples were collected from three sampling points in Ajali and two each in Adada, Obinna and Karawa. The water quality index (WQI) was calculated using the arithmetic index method. Significant seasonal and spatial variations (p < 0.05) were evident for sulphate, phosphate, sodium, magnesium, pH, total alkalinity, nitrate and total dissolved solids. Mean values of WQI were 71.75 ± 16.07 57.26 ± 5.39, 60.47 ± 13.12, and 66.75 ± 15.30 for Adada, Obinna, Karawa and Ajali, respectively.

Geoaccumulation assessment of heavy metal pollution in Ikwo soils, eastern Nigeria.

An imbalance in the environment's composition leads to significant effect on human activities such as farming. Of importance are heavy metals which are introduced anthropogenically or naturally. This calls for environmental monitoring and subsequent remediation if needed. An environmental monitoring exercise was conducted on Ikwo soils of Ebonyi State, eastern Nigeria with the aim of determining concentration levels for possible remediation. A total of 18 soil composite samples taken at 0-50 cm below soil surface from fallowed and cultivated soils not fertilized were subjected to heavy metal analyses and fertility indices like: organic matter (OM), cation exchange capacity (CEC), % total nitrogen (%TN), organic carbon (OC), and salinity. A correlation at 95% confidence level between geo-accumulations (Igeo) of the various heavy metals with salinity, OM, and CEC of the sampled soils reveals that Igeo could be a contributing factor to the fertility status of the soils. With the aid of inductively coupled plasma atomic emission spectrophotometer (ICP-AES), the distribution pattern was determined as Mn> Fe> Zn>Cu> Mo> Cd> V>Hg>Ti> Ni>Bi> Pb> Co>Ag>Au> Cr>Pd>Pt. The Igeo of the heavy metals in the study area varied from heavily to extremely contaminated levels. A remediation exercise was recommended on Ikwo soils due to their high salinity level and low CEC.

Contamination levels, toxicity profiles, and emission sources of polycyclic aromatic hydrocarbons (PAHs) in the soils of an emerging industrial town and its environs in the Southeastern Nigeria.

Polycyclic aromatic hydrocarbon (PAH) concentrations in Nnewi and its environs were determined. Soil samples were extracted by sonication using hexane:dichloromethane (3:1) mixture and determined by gas chromatography-flame ionization detection. The total PAHs concentrations (µg/kg) were 16.681 to 46.815, being three orders of magnitude lower than the maximum permissible level recommended by the Agency for Toxic Substances and Disease Registry (ATSDR). These concentrations followed this order: industrial ˃ farmlands ˃ commercial ˃ residential. Industrialized areas showed higher concentrations (p Ë‚ 0.05) than the other areas. Diagnostic ratios show that the major source of PAHs was the open burning of industrial and agricultural wastes, as shown by the occurrence of highest concentrations in the industrial areas, followed by agricultural areas. Benzo[a]pyrene equivalent values showed non-pollution and very low toxicity. Nevertheless, it was clear that industrialization has had some impact on the PAHs levels in soils and the total environment in this area and could be problematic with time, except with proper environmental management.

Health risk assessment of zinc, chromium, and nickel from cow meat consumption in an urban Nigerian population.

BACKGROUND: Meat consumption is increasingly becoming a larger part of diets worldwide. However, the bioaccumulation of toxic metals from anthropogenic pollution is a potential health risk to human health. OBJECTIVE: To measure the daily intake of zinc, chromium, and nickel from cow meat consumption and assess the possible health risks in an urban population in Nigeria. METHODS: Dried meat samples were digested with 3 : 2HNO3 : HClO4 v/v. Zinc, chromium, and nickel concentrations were determined with atomic absorption spectrophotometer. Daily intakes of meat were obtained using a food frequency questionnaire (FFQ). RESULTS: The estimated daily intakes (EDI) (µg/person/day) ranges were: zinc (10 496-13 459), chromium (310·90-393·73), and nickel (26·72-34·87). Estimated daily intake for zinc was 15-30% of provisional maximum tolerable daily intake (PMTDI) and for nickel it was 8-15% of tolerable daily intake (TDI). CONCLUSION: Chromium intakes were above recommended daily intake (RDI). Target hazard quotient (THQ) for nickel and zinc were within WHO/FAO limit. There was no evidence of possible health risk to consumers with regard to zinc and nickel. However, chromium intake should be of utmost concern, while disposal of tanning waste should be checked.