RESUMO
Despite well documented studies on metal pollutants in aquatic ecosystems, knowledge on the combined effects of catchment characteristics, sediment properties, and emerging pollutants, such as microplastics (MPs) on the presence of metals in urban river sediments is still limited. In this study, the synergistic influence of MPs type and hazard indices, catchment characteristics and sediment properties on the variability of metals present in sediments was investigated based on a typical urban river, Brisbane River, Australia. It was noted that the mean concentrations of metals in Brisbane River decreases in the order of Al (94,142 ± 12,194 µg/g) > Fe (62,970 ± 8104 µg/g) > Mn (746 ± 258 µg/g) > Zn (196 ± 29 µg/g) > Cu (50 ± 19 µg/g) > Pb (47 ± 25 µg/g) > Ni (25 ± 3 µg/g) while the variability of metals decreases in the order of Pb > Cu > Mn > Al > Ni > Zn > Fe along the river. According to enrichment factor (Ef) contamination categories, Mn, Cu and Zn exert a moderate level of contamination (Ef > 2), while Fe, Ni, and Zn show slight sediment pollution (1
Assuntos
Metais Pesados , Poluentes Químicos da Água , Rios , Microplásticos , Sedimentos Geológicos , Plásticos , Metais Pesados/análise , Monitoramento Ambiental , Poluentes Químicos da Água/análise , Ecossistema , Chumbo , Medição de RiscoRESUMO
The presence of microplastics (MPs) has been recognized as a significant environmental threat due to adverse effects spanning from molecular level, organism health, ecosystem services to human health and well-being. MPs are complex environmental contaminants as they bind to a wide range of other contaminants. MPs associated contaminants include toxic chemical substances that are used as additives during the plastic manufacturing process and adsorbed contaminants that co-exist with MPs in aquatic environments. With the transfer between the water column and sediments, and the migration within aquatic systems, such contaminants associated MPs potentially pose high risk to aquatic systems. However, only limited research has been undertaken currently to link the environmental risk associated with MPs occurrence and movement behaviour in aquatic systems. Given the significant environmental risk and current knowledge gaps, this review focuses on the role played by the abundance of different MP species in water and sediment compartments as well as provides the context for assessing and quantifying the multiple risks associated with the occurrence and movement behaviour of different MP types. Based on the review of past literature, it is found that the physicochemical properties of MPs influence the release/sorption of other contaminants and current MPs transport modelling studies have primarily focused on virgin plastics rather than aged plastics. Additionally, risk assessment of contaminants-associated MPs needs significantly more research. This paper consolidates the current state-of-the art knowledge on the source to sink movement behaviour of MPs and methodologies for assessing the risk of different MP species. Moreover, knowledge gaps and emerging trends in the field are also identified for future research endeavours.