Brian Priestly

Health Risk Assessment for Cyanobacterial Toxins in Seafood

Cyanobacteria (blue-green algae) are abundant in fresh, brackish and marine waters worldwide. When toxins produced by cyanobacteria are present in the aquatic environment, seafood harvested from these waters may present a health hazard to consumers. Toxicity hazards from seafood have been internationally recognised when the source is from marine algae (dinoflagellates and diatoms), but to date few risk assessments for cyanobacterial toxins in seafood have been presented. This paper estimates risk from seafood contaminated by cyanobacterial toxins, and provides guidelines for safe human consumption.

Issues raised by the reference doses for perfluorooctane sulfonate and perfluorooctanoic acid

On 25th May 2016, the U.S. EPA released reference doses (RfDs) for Perfluorooctane Sulfonate (PFOS) and Perfluorooctanoic Acid (PFOA) of 20ng/kg/day, which were much more conservative than previous values. These RfDs rely on the choices of animal point of departure (PoD) and the toxicokinetics (TK) model. At this stage, considering that the human evidence is not strong enough for RfD determination, using animal data may be appropriate but with more uncertainties. In this article, the uncertainties concerning RfDs from the choices of PoD and TK models are addressed. Firstly, the candidate PoDs should include more critical endpoints (such as immunotoxicity), which may lead to lower RfDs. Secondly, the reliability of the adopted three-compartment TK model is compromised: the parameters are not non-biologically plausible; and this TK model was applied to simulate gestation and lactation exposures, while the two exposure scenarios were not actually included in the model structure.

Toxicology in Australia: a key component of environmental health.

Managing public concerns relating to chemical exposures can consume substantial public health resources, particularly as the scientific basis around these issues is often contentious. Toxicology remains underrecognized as a public health discipline in Australia, although Australian toxicologists are making significant contributions from academia, government, and the commercial sector toward assessing the level of risk and protecting the community from environmental hazards. Internationally, the growth of environmental toxicology and the promotion of sound science in risk assessment as a basis for making regulatory decisions have been, to some extent, driven by the outcomes of the 1992 UNCED Conference on Sustainable Development (Rio Summit) and its Chapter 19 Agenda 21 activities. The promotion of safe chemical management practices and the need for global strengthening of capabilities in toxicology are among the initiatives of the Intergovernmental Forum on Chemical Safety (IFCS), which was formed after the Rio Summit to manage these programs. This article describes some of the initiatives in capacity building that marked the development of environmental toxicology in Australia since 1992 in response to these international environmental health initiatives.

Immunological effects among workers who handle engineered nanoparticles

Objective To determine whether exposure of workers handling engineered nanoparticles (ENPs) may result in increased inflammation and changes in lung function. Methods A prospective panel study compared changes in several markers of inflammation for ENP handling and non-ENP handling control workers. Nanoparticle exposure was measured during ENP handling and for controls. Lung function, fraction of exhaled nitric oxide (FeNO), C-reactive protein (CRP), blood cell counts and several serum cytokines were measured at baseline, at the end of the shift and at the end of the working week. Results Nanoparticle exposure was not higher when ENPs were being handled; nanoparticle counts were higher in offices and in ambient air than in laboratories. There were no differences at baseline in lung function, FeNO, haemoglobin, platelet, white cell counts or CRP levels between those who handled nanoparticles and those who did not, with or without asthmatic participants. There were statistically significant increases in sCD40 and sTNFR2 over the working day for those who handled ENPs. The changes were larger and statistically significant over the working week and sCD62P also showed a statistically significant difference. The changes were slightly smaller and less likely to be statistically significant for atopic than for non-atopic participants. Conclusions Even at low ENP exposure, increases in three cytokines were significant over the week for those who handled nanoparticles, compared with those who did not. However, exposure to low and transient levels of nanoparticles was insufficient, to trigger measurable changes in spirometry, FeNO, CRP or blood cell counts.

Risk perception and risk communication: Is nanotechnology at the crossroads in Australia?

This presentation addresses the potential for nanotechnology development to be derailed, or at least delayed, by unresolved concerns about health and safety issues. Findings from surveys of risk perception indicate that availability of knowledge about health risks can both inform and fuel concerns. Trust in regulatory systems is one factor which can influence community perceptions of risk, and there remain some issues about whether the regulatory systems are fully capable of identifying and managing these risks.