No abstract

Polychlorinated biphenyls (PCBs) assessment in sediments of Turag River, Dhaka, Bangladesh has been conducted for the first time. This River provides critical ecological services to agriculture, industry, and transportation. However, the Turag River is one of the most industrially polluted rivers surrounding Dhaka in Bangladesh. In this study, six PCB congeners namely PCB 10, PCB 28, PCB 52, PCB 138, PCB 153, and PCB 180, were analyzed in surface sediments by GC-ECD at 9 sampling sites. Pre-monsoon and post-monsoon season sampling were collected in this study.The total concentrations of PCBs varied from 344.49 to 0.22 ng/g dw and 10.6 to 1.68 ng/g dw in pre-monsoon and post-monsoon, respectively. The paramount contributor congener to the total PCBs was PCB 180 and was found at all sites. The ecological risk assessment indicated a high potential risk in pre-monsoon ( = 277.32) and low potential risk in post-monsoon ( = 25.69).Sediment quality guideline quotients (SQGQs) showed that PCBs in pre-monsoon would cause no or moderate biological effects on organisms at most sampling sites except in surface sediments of site S5 (high biological effects), while no adverse ecotoxicological effect was observed in postmonsoon. Considering both probable effect level (PEL) and threshold effect level (TEL), the new sediment quality guideline quotient (NSQGQ) showed that in post-monsoon PCBs contamination would cause moderate biological effects, while in pre-monsoon the findings remained consistent with the findings of SQGQ. This study gave a quick look at the PCB contamination scenario in the Turag River sediments and also allowed for a comparison between the investigated River and other rivers worldwide.

Polychlorinated biphenyls (PCBs) assessment in sediments of Turag River, Dhaka, Bangladesh has been conducted for the first time. This River provides critical ecological services to agriculture, industry, and transportation. However, the Turag River is one of the most industrially polluted rivers surrounding Dhaka in Bangladesh. In this study, six PCB congeners namely PCB 10, PCB 28, PCB 52, PCB 138, PCB 153, and PCB 180, were analyzed in surface sediments by GC-ECD at 9 sampling sites. Pre-monsoon and post-monsoon season sampling were collected in this study. The total concentrations of PCBs varied from 344.49 to 0.22 ng/g dw and 10.6 to 1.68 ng/g dw in pre-monsoon and post-monsoon, respectively. The paramount contributor congener to the total PCBs was PCB 180 and was found at all sites. The ecological risk assessment indicated a high potential risk in pre-monsoon (Eri = 277.32) and low potential risk in post-monsoon (Eri = 25.69). Sediment quality guideline quotients (SQGQs) showed that PCBs in pre-monsoon would cause no or moderate biological effects on organisms at most sampling sites except in surface sediments of site S5 (high biological effects), while no adverse ecotoxicological effect was observed in post-monsoon. Considering both probable effect level (PEL) and threshold effect level (TEL), the new sediment quality guideline quotient (NSQGQ) showed that in post-monsoon PCBs contamination would cause moderate biological effects, while in pre-monsoon the findings remained consistent with the findings of SQGQ. This study gave a quick look at the PCB contamination scenario in the Turag River sediments and also allowed for a comparison between the investigated River and other rivers worldwide.