Integrated Risk Framework for Onsite Wastewater Treatment Systems

Onsite wastewater treatment systems (OWTS) are becoming increasingly important for the treatment and dispersal of effluent in new urbanised developments that are not serviced by centralised wastewater collection and treatment systems. However, the current standards and guidelines adopted by many local authorities for assessing suitable site and soil conditions for OWTS are increasingly coming under scrutiny due to the public health and environmental impacts caused by poorly performing systems, in particular septic tank-soil adsorption systems. In order to achieve sustainable onsite wastewater treatment with minimal impacts on the environment and public health, more appropriate means of assessment are required. This paper highlights an integrated risk based approach for assessing the inherent hazards associated with OWTS in order to manage and mitigate the environmental and public health risks inherent with onsite wastewater treatment. In developing a sound and cohesive integrated risk framework for OWTS, several key issues must be recognised. These include the inclusion of relevant stakeholders throughout framework development, the integration of scientific knowledge, data and analysis with risk assessment and management ideals, and identification of the appropriate performance goals for successful management and mitigation of associated risks. These issues were addressed in the development of the risk framework to provide a generic approach to assessing risk from OWTS. The utilisation of the developed risk framework for achieving more appropriate assessment and management techniques for OWTS is presented in a case study for the Gold Coast region, Queensland State, Australia.     

A comparison of two techniques for studying sediment desorption kinetics of hydrophobic pollutants

A comparison of two techniques (gaseous purge and vial desorption) for studying the kinetics of desorption of hydrophobic pollutants from natural sediments was conducted using identical, pre-equilibrated pollutant-sediment suspensions. Desorption profiles for the two techniques [for Lindane, Aldrin, 2,2'-dichlorobiphenyl (2,2'-DCB), 4,4'-dichlorobiphenyl (4,4'-DCB), and 2,2',6,6'-tetrachlorobiphenyl (TCB)] were then compared, based on the distribution of pollutant mass between the labile (fast) and non-labile (slow) desorption phases and the release rate constants for each phase of release. The vial desorption technique shows many practical advantages over the gaseous purge technique, including its more realistic mixing conditions, the use of an independent sample for each data point (as opposed to a calculation of a cumulative mass purged at each time point), the fact that the vials constitute a closed system and are therefore less subject to ambient contamination, and the relatively low demands of time and money for the vial technique. No consistent trends in labile rate constants or in pollutant distribution between the labile and non-labile phase were observed between the two techniques. A comparison of kinetic parameters shows much faster non-labile rate constants for the gaseous purge technique, attributed to the violent, continuous agitation employed, which likely disrupted sediment aggregates and oxidized the natural organic matter associated with the sediment. Non-labile rate constants have implications for the long-term fate of compounds adsorbed to repetitively disturbed sediments. This study suggests that the traditionally less popular vial desorption technique may yield more realistic non-labile desorption rate constants.     

Are you okay to drive? Commuting behavior and blood alcohol concentrations among restaurant diners

Objective: Drink driving is widely recognized as a major road safety problem. In Australia, health promotion messages encourage monitoring the number of standard drinks consumed prior to driving. This pilot research aimed to investigate commuting behavior and blood alcohol concentration (BAC) of diners, including intended drivers, at Sunshine Coast restaurants.

Methods: Five hundred and forty-four diners (n = 260 males) consented to participate in a brief interview and to use a breathalyzer device to measure their BAC.

Results: Forty percent of participants advised they don't drink and drive (34% of males, 45% of females; 67.25% of <17–20 years, 30.5% of 50–59 years), and of the remaining participants, 75% advised they count the number of their drinks (69% of males, 84% of females; 32% of <17–20 years, 82% of 50–59 years), while 10% of participants monitored their BAC by how they were feeling (12% of males, 6% of females). Thirty-seven percent of participants said it was easy/very easy to estimate their BAC (41% of males; 33% of females; 21% of <17–20 years, 43% of 50–59 years). The actual BAC was less than expected for 56% of participants, with one-third underestimating BAC and some intended drivers having an actual BAC in excess of the 0.05 limit.

Conclusions: Given the proportion of diners who reported they count the number of drinks, or use feelings as a way to gauge BAC, coupled with the considerable proportion who underestimated their BAC, a safer public health message is to avoid driving if you intend to drink. In addition, targeted intervention for experienced drivers (and, arguably, drinkers) appears warranted, as every participant aged less than 21 years who stated he or she would drive home indeed had a zero BAC. Interestingly every female driver who stated she would be driving home also had a legal BAC, suggesting gender-specific intervention.     

Exposure,epidemiology, and mechanism of the environmental toxicant manganese

It has become increasingly apparent that global manganese (Mn) pollution to air and water is a significant threat to human health. Despite this recognition, research is only beginning to comprehend the detrimental effects of exposure. Mn, while essential, is particularly harmful to the central nervous system, and overexposure is symptomatic of several neurological disorders. At-risk populations have been identified, but it is still unclear whether typical exposure levels have any long-term consequences. Those at an elevated risk have diminished intellectual function, learning and memory, and mental development. While the overall mechanism of toxicity is undetermined, Mn has been found to induce oxidative stress, exacerbate mitochondrial dysfunction, dysregulate autophagy, and promote apoptosis, ultimately enhancing neurodegeneration. Extrapolation of this in vitro and in vivo data to humans is difficult. There is a definite need to correlate epidemiological studies with causative effects. It is imperative that research efforts endure, so threats are appropriately identified and exposure properly regulated.     

Spatial and social connectivity of fish-eating “Resident” killer whales (Orcinus orca) in the northern North Pacific

The productive North Pacific waters of the Gulf of Alaska, Aleutian Islands and Bering Sea support a high density of fish-eating “Resident” type killer whales (Orcinus orca), which overlap in distribution with commercial fisheries, producing both direct and indirect interactions. To provide a spatial context for these interactions, we analyzed a 10-year dataset of 3,058 whale photo-identifications from 331 encounters within a large (linear ~4,000 km) coastal study area to investigate the ranging and social patterns of 532 individually identifiable whales photographed in more than one encounter. Although capable of large-scale movements (maximum 1,443 km), we documented ranges generally <200 km, with high site fidelity across summer sampling intervals and also re-sightings during a winter survey. Bayesian analysis of pair-wise associations identified four defined clusters, likely representing groupings of stable matrilines, with distinct ranging patterns, that combined to form a large network of associated whales that ranged across most of the study area. This provides evidence of structure within the Alaska stock of Resident killer whales, important for evaluating ecosystem and fisheries impacts. This network included whales known to depredate groundfish from longline fisheries, and we suggest that such large-scale connectivity has facilitated the spread of depredation.     

Reflecting on progress since the 2005 NARSTO emissions inventory report

Emission inventories are the foundation for cost-effective air quality management activities. In 2005, a report by the public/private partnership North American Research Strategy for Tropospheric Ozone (NARSTO) evaluated the strengths and weaknesses of North American emissions inventories and made recommendations for improving their effectiveness. This paper reviews the recommendation areas and briefly discusses what has been addressed, what remains unchanged, and new questions that have arisen. The findings reveal that all emissions inventory improvement areas identified by the 2005 NARSTO publication have been explored and implemented to some degree. The U.S. National Emissions Inventory has become more detailed and has incorporated new research into previously under-characterized sources such as fine particles and biomass burning. Additionally, it is now easier to access the emissions inventory and the documentation of the inventory via the internet. However, many emissions-related research needs exist, on topics such as emission estimation methods, speciation, scalable emission factor development, incorporation of new emission measurement techniques, estimation of uncertainty, top-down verification, and analysis of uncharacterized sources. A common theme throughout this retrospective summary is the need for increased coordination among stakeholders. Researchers and inventory developers must work together to ensure that planned emissions research and new findings can be used to update the emissions inventory. To continue to address emissions inventory challenges, industry, the scientific community, and government agencies need to continue to leverage resources and collaborate as often as possible. As evidenced by the progress noted, continued investment in and coordination of emissions inventory activities will provide dividends to air quality management programs across the country, continent, and world.

Implications: In 2005, a report by the public/private partnership North American Research Strategy for Tropospheric Ozone (NARSTO) evaluated the strengths and weaknesses of North American air pollution emissions inventories. This paper reviews the eight recommendation areas and briefly discusses what has been addressed, what remains unchanged, and new questions that have arisen. Although progress has been made, many opportunities exist for the scientific agencies, industry, and government agencies to leverage resources and collaborate to continue improving emissions inventories.