RESUMEN
Anthropogenic activities around the sea ports are capable of causing changes on the physicochemical and microbiological quality of water bodies along the port terminals. Such activities can cause an ecological imbalance in the water quality /ecosystem resulting in extinction of aquatic resources. The aim of this study therefore was to investigate the physicochemical and microbiological quality of surface water along the busy port terminals. Surface water samples were collected from Onne port terminal using sterile containers. The samples were collected during the wet and dry seasons between January to June 2021. The sterile bottles were filled with surface water samples and transported in an ice packed container to the Department of Microbiology Laboratory of the Rivers State University for analyses using standard analytical methods. Statistical analyses were carried out using ANOVA and All pairs tukey-kramer. Results of the physicochemical parameters showed that temperature, total dissolved solids, total suspended solids, nitrate and heavy metals were significantly higher during the dry season than the wet season at P ? 0.05 levels of significance. Seasonal variation with respect to microbial counts shows that Total Heterotrophic Bacteria, Total Heterotrophic Fungi, Total coliforms and Faecal coliforms had a mean value of 3.9±1.77 x 106; 0.8 ±0.05 x 104 ; 7.4 ±1.3 x 104 and 3.6 ±0.17 x 104 colony forming unit per millilitre respectively for wet season while the dry season had 1.6±0.77 x 106 , 0.5 ±0.01 x 104 , 4.6 ±0.17 x 104 and 2.7 ±1.03 x 104 cfu/ml respectively. In this study, the predominant bacterial isolates belonged to the genera of Vibrio, Pseudomonas, Klebsiella, Bacillus, Shigella, Staphylococcus, Salmonella, Proteus, Bacillus and Escherichia. coli. The results of physicochemical and microbiological characteristics including the heavy metals, were detected at concentrations on or below detection limits.. It is therefore suggested that relevant environmental regulatory bodies should maintain regular check to ensure that appropriate standards are maintained around seaports due to beehive of activities.
RESUMEN
Objective To investigate the content of thorium (Th) in surface water in Sichuan Province, China, and to evaluate Th-associated health risk via water intake for residents. Methods Twenty-three monitoring sections were set in main surface water bodies in Sichuan Province. From 2016 to 2021, the Th radioactivity level in the water bodies was measured during dry and normal-water seasons. The health risk of residents was evaluated by calculating radioactive Th intake from the surface water bodies combined with the use of a health risk assessment model. Results The Th radioactivity level of the surface water bodies in Sichuan Province was 0.02-0.67 μ./L. There was no significant difference in the Th radioactivity level of different years or different surface water bodies (P > 0.05). A significant difference was observed in the Th radioactivity level of different water seasons (P < 0.05). The total mean annual committed effective doses of Th in all age groups caused by drinking water and water immersion ranged from 3.14 × 10−8 to 8.75 × 10−7 Sv, all lower than the World Health Organization (WHO)-recommended reference level of 0.1 mSv. The overall carcinogenic risks for residents in all age groups ranged from 3.93 × 10−10 to 1.09 × 10−8, all below the most rigorous control limits issued by WHO and International Commission on Radiological Protection. Conclusion The Th-associated health risk via direct water intake and water immersion in main surface water bodies of Sichuan Province is at an acceptable level. Th in main surface water bodies of Sichuan Province is safe for all age groups.