Ecological risk assessment and corrective actions for dioxin-polluted sediment in a chemical plant's brine water storage pond

Polychlorinated dibenzodioxins/furans and dioxin-like polychlorinated biphenyls in fish and crustaceans of a recreationally fished estuary, following targeted remediation

Polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (dl-PCBs) are a suite of harmful chemicals (hereafter collectively referred to as 'dioxins'), and their emission into aquatic habitats leads to persistent contamination of sediments, aquatic food-webs, and seafoods. Quantifying contaminant levels in seafood species is important for the ongoing management of exposure risk by fishers, particularly after any remediation actions. We present dioxin concentrations in four seafood species (Yellowfin Bream Acanthopagrus australis, Sea Mullet Mugil cephalus, Eastern School Prawn Metapenaeus macleayi, and Eastern King Prawn Penaeus plebejus) in a recreationally fished estuary, in relation to a contaminated site that has undergone a remediation process, partially removing contaminated sediments (Homebush Bay, Port Jackson, New South Wales, Australia). Dioxin concentrations in these species were measured before (2005/6) and after (2015/16) remediation at a range of locations in and around the remediated site. Dioxin concentrations and congener profiles differed substantially among taxa, and concentrations were frequently higher than Australian screening criteria. The two prawn species showed evidence of a decline in dioxin concentrations after remediation, but the fish species only showed a declining dioxin concentration with distance from the contaminated site (not between periods). There were some minor changes in the congener profile for some species following remediation. While there was evidence for greatly reduced dioxin concentrations in prawn species following remediation, the complex patterns for fish were likely affected by environmental changes, species-specific and temporal changes in lipid content, and animal movement patterns. Future monitoring may aid interpretation of the patterns and modelling of exposure risk associated with seafood consumption into the future.

Exploiting fungi in bioremediation for cleaning-up emerging pollutants in aquatic ecosystems

Aquatic pollution negatively affects water bodies, marine ecosystems, public health, and economy. Restoration of contaminated habitats has attracted global interest since protecting the health of marine ecosystems is crucial. Bioremediation is a cost-effective and eco-friendly way of transforming hazardous, resistant contaminants into environmentally benign products using diverse biological treatments. Because of their robust morphology and broad metabolic capabilities, fungi play an important role in bioremediation. This review summarizes the features employed by aquatic fungi for detoxification and subsequent bioremediation of different toxic and recalcitrant compounds in aquatic ecosystems. It also details how mycoremediation may convert chemically-suspended matters, microbial, nutritional, and oxygen-depleting aquatic contaminants into ecologically less hazardous products using multiple modes of action. Mycoremediation can also be considered in future research studies on aquatic, including marine, ecosystems as a possible tool for sustainable management, providing a foundation for selecting and utilizing fungi either independently or in microbial consortia.