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Potential Human Health Risk Assessment of Heavy Metals in Road Dusts Collected From Three Urban Roads of Enugu State, Nigeria

100%

Nnamani A. R. , Nduka J. K. , Ukamaka A. A.

tom 54

83-101

Dust samples from roads classified based on traffic volumes (low, medium and high traffic) were collected from three different urban roads in Enugu South LGA, Enugu State, Nigeria followed by assessment of human health risks of each heavy metals. The concentrations of heavy metals in road dust were determined using computerized Agilent FS240AA Atomic Absorption Spectrophotometer. The heavy metal concentrations were dominated by Fe and Mn with mean concentration of 247.03 mg/kg and 26.43 mg/kg respectively. Other dominant elements were Cu and K with mean concentrations of 121.85 mg/kg and 73.39 mg/kg, respectively. The results revealed that the highest heavy metals in road are highest in industrial road site and commercial road while the dust from residential area has the lowest heavy metal concentration. Contrary to most metals detected, mercury (Hg) shows no detection. The health risk assessment through ingestion, dermal and inhalation contact was conducted according to the United States Environmental Protection Agency’s (USEPA) model for children and adults. The assessment of health risk indicated that there were mainly three exposure pathways for people: ingestion, dermal contact and inhalation. The main exposure pathway of heavy metals to both children and adults is ingestion. The values of HQ and HI are lower than the safe level (HI< 1), indicating no health risk exists in present condition. The cancer risk (CR) for children and adults from exposure to Pb, As, Ni, and Cr was found to be negligible (≤ 1 × 10−6). Meanwhile, the HI value for children is higher than that for adults, indicating that children have higher potential health risk than adults in the studied areas in Enugu state.

Performance Evaluation of Horizontal Flow Constructed Wetland for Removal of Pharmaceuticals from Synthetic Wastewater

84%

Mumtaj Z. A. , Khan A. R. , Alsubih M. , Khan S.

Rocznik Ochrona Środowiska

2024

tom Tom 26

322--334

The removal efficiency of pharmaceutical compounds in wastewater treatment can be significantly influenced by seasonal variations and the presence of vegetation. This study evaluates the removal efficiencies of five pharmaceutical compounds – Cefadroxil (CFL), Ciprofloxacin (CIP), Cefpodoxime (CFD), Atenolol (ATN) and Avil-25 (AVL) – in non-planted (CW2) and planted (CW1) constructed wetlands across various parameters including Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD), Total Suspended Solids (TSS), Alkalinity, Nitrate, and Phosphate during winter and summer seasons. Results indicate that CW1 consistently outperforms CW2 in all parameters and seasons. For example, CW1 achieved 54.28% BOD removal for CFL in winter compared to CW2's 39.67%, with summer values reaching 79.6% and 69.7%, respectively. The superior performance of CW1 was also observed for COD and other parameters, with phosphate removal reaching 94% in summer. The results of HPLC analysis indicated that CW1 showed better removal efficiencies of Cefadroxil (56.94%), Ciprofloxacin (90%), and Avil-25 (99.7%) than CW2. Even though Cefpodoxime showed low removal efficiency in both systems, CW1 still performed slightly better (13.99% vs. 0.7%). Atenolol removal was particularly notable in CW1 (93.79%), significantly outperforming CW2. Hazard quotient assessments revealed lower risks associated with pharmaceutical residues in CW1. For example, Ciprofloxacin's hazard quotient was reduced from 16% in CW2 to 10% in CW1, underscoring the effectiveness of vegetation in mitigating environmental risks. Atenolol showed a significant hazard quotient reduction from 2% in CW2 to less than 0.5% in CW1, while Avil-25's hazard quotient was negligible in CW1 compared to 4% in CW2. It was also concluded that vegetation positively influenced the treatment efficacy of constructed wetlands for pharmaceuticals with reduced eco-toxicity and the associated risks.