Evaluation of sources, distribution and human bio-accessibility burden of heavy metals pollution in surface sediment and catfish Arius maculatus Thunberg (1792) from Langat and Bernam Rivers, Malaysia

The present study was conducted to identify the spatial distribution and sources concentrations of heavy metal from eighteen surface sediment samples of Langat and Bernam rivers using multivariate techniques and pollution indices with their geochemical partitioning in different solid phases and to investigate factors influencing these partitioning on bioaccessibility of metals contamination from geochemical perspectives. The in vitro digestion model in fish tissue are dependent on pH and solid-liquid factors. Results indicated that the concentrations of metals in surface sediment of Langat River decreased in the order of Sn> Cr >Ni > Fe> Cd> Hg and for heavy metals in surface sediment of Bernam River decreased in the order of Sn> Cr >Ni >Fe> Cd> Hg. Pearson’s correlation indicated that effectiveness of total organic matter and cation exchange capacity were effecting heavy metals distribution more than grain size and pH. In addition, cluster analysis results had divided Bernam River into three clusters namely; stations of Selisek, Tanjong Malim and Bagan Tepi sungai which were grouped into cluster one representing considerable degree of contamination; cluster two represents moderately high degree of contamination at Ulu Bernam, Kampung Bagan, Bandar Behrang and Kampung Tanjung while cluster three represents moderately medium degrees of contamination at Slim River and Sabak Bernam. Meanwhile for the Langat river, cluster one represents considerably high degree of contamination at UKM, Jalan Hulu Langat and Pangsun; cluster two represents considerably medium degree of contamination at Kajang, Batu Hulu Langat and Cheras; cluster three represents considerably low degree of contamination at Jugra, Banting and Jenjarom. The PCA showed that the main factors influencing the bioaccessibility of Hg in surface sediments of Langat River were the sediment TOM, F1 (EFLE) while mercury bioaccessibility in Bernam River were more affected by F1 (EFLE), CEC and TOM. The factor influencing bioaccessibility of cadmium from Langat River sediment were T-Cd and F3 (oxidation-organic), whereas, cadmium bioaccessibility in Bernam River sediment were influenced by F1 (EFLE). Tin bioaccessibility were influenced by CEC and pH in surface sediment of Langat River while F4 (resistance) was the most influencing factor for bioaccessibility of tin in surface sediment of Bernam River. The rank of biota-sediment accumulation factor (BSAF) for catfish (Arius maculatus) were in the descending order of Hg> Cr> Cd> Ni> Fe> Sn in Langat River while biota-sediment accumulation factor for catfish in Bernam River were in the decreasing order of Cd> Ni> Cr> Fe> Sn. Mercury was greater than one in terms of BSAF indicating an intensive accumulation of this metal from sediment of Langat River in tissues of catfish (Arius maculatus). Results showed that the bioaccessibility and chemicals forms of heavy metal in surface sediment were significantly correlated with catfish organs in Bernam and Langat Rivers. The results of bioaccessibility of heavy metals varied significantly with different in vitro assays in different stations along Langat and Bernam Rivers. The highest relative bioaccessibility of Ni (93.1%), Cr (46.9%), and Sn (23.2%) were observed in the IVG (gastric phase) compared with other in vitro assays of Bernam River. Meanwhile, the highest relative bioaccessibility of Ni (13.2%), Cr (42.3%), Sn (5.8%) and Hg (23.8%) were also noted in the IVG (gastric phase) of Langat River. The results of heavy metals accumulation within the different organs are as follows (in descending order): muscle Cr > Ni > Hg > Cd > Fe > Sn; liver Cr > Ni > Hg > Fe > Sn > Cd, and kidney Cr > Ni >Hg > Sn > Cd > Fe for Langat River. While, in Bernam River the highest metal concentrations was mostly in muscle and the pattern of metal concentration in the muscle was in the decreasing order of Ni > Cr > Fe > Cd > Sn> Hg Meanwhile for liver, heavy metals were found in the order of Cr> Sn> Ni > Fe> Cd> Hg and for kidney, was found in the descending order of Sn > Cr > Fe> Ni > Cd> Hg. A human health risk assessment of these metals was performed based on total and bioaccessibility concentrations of tissue. The hazard quotient (HQ) of total and bioaccessibility of heavy metals in catfish (Arius maculatus) from Langat and Bernam Rivers were calculated based on risk levels and results indicated that consumption could posed a serious threat to human health