Status of trace metals and arsenic in sediments and catfish muscles (Clarias gariepinus) from the Eastern Tanzanian basin
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Date
2024-08-29
Journal Title
Journal ISSN
Volume Title
Publisher
PLOS ONE
Abstract
Trace metals and metalloids are groups of chemical elements that naturally occur in low
concentrations and cycle in the environment driven by natural processes and human activi-
ties. They have a persistent and bio-accumulative tendency in the environment, and certain
trace metals and metalloids have become a public health concern. This study assesses the
concentration of eleven trace metals and a metalloid in sediments and catfish muscle from
five study sites in the Eastern Tanzanian River basin. Forty catfish tissues and fifteen sedi-
ment samples were collected and analyzed using ICP-MS. Concentrations of As, Cd, Co,
Pb, and Zn did not exceed the United States Environmental Protection Agency (USEPA)
guideline for pollution of sediments, while Al Cr, Al, Mn, and V with values ranging from
(118.54 to 70154.55) indicating moderately polluted. The stations Java-Sadaani and
Matandu showed the highest Cr, Ni, and Cu concentrations, but the potential ecological risk
index (RI) was low (RI < 95). In the catfish muscle tissue, the levels of Cd, Pb, Cu, and Zn
did not surpass the EU and FAO/WHO limits and results ranged from 2.22 to 35.22mg/kg.
Low levels of accumulation of Cd, Pb, and As were found in this study compared to catfish
muscles from other studies, whereas the concentrations of other trace metals and metal-
loids analyzed had comparable results. Biota/sediment accumulation factors (BSAF) were
all < 1. The weekly metal intake (MWI) results ranged from 6.89E-04 to 2.43E+01 μg/know-
1week-1, indicating a low risk as the value did not exceed the FAO/WHO established Per-
missible Tolerable Weekly Intake (PTWI). The non-carcinogenic health risk result THQ was
4.43E-02 and the carcinogenic health risks result HI was 4.42E-05 which indicated tolerable
levels of risks as both the values of the Target Hazard Quotient (THQ) and the Hazard Index
(HI) was < 1, and the carcinogenic target risk (TR) is < 0.0001. The highest TR values were
observed for Cr and Ni. We recommend a continued monitoring of the changes in trace
metal levels in the environment and biota together with continuous public health education
on the dangers of high levels of trace metals.
Description
Trace metals in sediments and catfish muscles
Keywords
Catfish, Sediment, Cancer risk factors, Ecological risk, Pollution, Metalloids, Arsenic, Rivers
Citation
https://doi.org/10.1371/journal.pone.0306335