Steroidal estrogens, originating principally from human excretion, are likely to play a major role in causing widespread endocrine disruption in wild populations of the roach (Rutilus rutilus), a common cyprinid fish, in rivers contaminated by treated ...

Nanotechnology is a rapidly growing industry of global economic importance, exploiting the novel characteristics of materials manufactured at the nanoscale. The properties of engineered nanoparticles (ENPs) that make them useful in a wide range of industrial applications, however, have led to concerns regarding their potential impact on human and environmental health. The aquatic environment is particularly at risk of exposure to ENPs, as it acts as a sink for most environmental contaminants. This paper critically evaluates what is currently known about sources and discharge of ENPs to the aquatic environment and how the physicochemical characteristics of ENPs affect their fate and behaviour and thus availability for uptake into aquatic organisms, and assesses reported toxicological effects. Having reviewed the ecotoxicological information, the conclusion is that whilst there are data indicating some nanoparticles have the potential to induce harm in exposed aquatic organisms, there is insufficient evidence for harm, for known/modelled environmental concentrations for almost all ENPs considered. This conclusion, however, must be balanced by the fact that there are significant gaps in our understanding on the fate and behaviour of ENPs in the aquatic environment. Greater confidence in the assessments on ENP impacts in aquatic systems to enable effective comparisons across studies urgently requires more standardised approaches for ENP hazard identification, and critically, more thorough characterisations on the exposed particles. There is also an urgent need for the advancement of tools and techniques that can accurately quantify and visualise uptake of nanoparticles into biological tissues.

Despite increasing application of silver nanoparticles (NPs) in industry and consumer products, there is still little known about their potential toxicity, particularly to organisms in aquatic environments. To investigate the fate and effects of silver NPs in fish, rainbow trout (Oncorhynchus mykiss) were exposed via the water to commercial silver particles of three nominal sizes: 10 nm (N₁₀), 35 nm (N₃₅), and 600–1600 nm (N_Bulk), and to silver nitrate for 10 days. Uptake into the gills, liver, and kidneys was quantified by inductively coupled plasma-optical emission spectrometry, and levels of lipid peroxidation in gills, liver, and blood were determined by measurements of thiobarbituric acid reactive substances. Expression of a suite of genes, namely cyp1a2, cyp3a45, hsp70a, gpx, and g6pd, known to be involved in a range of toxicological response to xenobiotics was analyzed in the gills and liver using real-time PCR. Uptake of silver particles from the water into the tissues of exposed fish was low but nevertheless occurred for current estimated environmental exposures. Of the silver particles tested, N₁₀ were found to be the most highly concentrated within gill tissues and N₁₀ and N_Bulk were the most highly concentrated in liver. There were no effects on lipid peroxidation in any of the tissues analyzed for any of the silver particles tested, and this is likely due to the low uptake rates. However, exposure to N₁₀ particles was found to induce expression of cyp1a2 in the gills, suggesting a possible increase in oxidative metabolism in this tissue.

Since its emergence in the 1990s, White Spot Disease (WSD) has had major economic and societal impact in the crustacean aquaculture sector. Over the years shrimp farming alone has experienced billion dollar losses through WSD. The disease is caused by the White Spot Syndrome Virus (WSSV), a large dsDNA virus and the only member of the Nimaviridae family. Susceptibility to WSSV in a wide range of crustacean hosts makes it a major risk factor in the translocation of live animals and in commodity products. Currently there are no effective treatments for this disease. Understanding the molecular basis of disease processes has contributed significantly to the treatment of many human and animal pathogens, and with a similar aim considerable efforts have been directed towards understanding host–pathogen molecular interactions for WSD. Work on the molecular mechanisms of pathogenesis in aquatic crustaceans has been restricted by a lack of sequenced and annotated genomes for host species. Nevertheless, some of the key host–pathogen interactions have been established: between viral envelope proteins and host cell receptors at initiation of infection, involvement of various immune system pathways in response to WSSV, and the roles of various host and virus miRNAs in mitigation or progression of disease. Despite these advances, many fundamental knowledge gaps remain; for example, the roles of the majority of WSSV proteins are still unknown. In this review we assess current knowledge of how WSSV infects and replicates in its host, and critique strategies for WSD treatment.