Modelling nutrient loads to Sydney estuary (Australia)

Sydney estuary (Australia) catchment is substantially urbanised (80%) and small (480 km²) with a large population (2.5 million) and is therefore highly sensitive to anthropogenic influence. The Model for Urban Stormwater Improvement Conceptualisation used to model nutrient export to the estuary determined an average annual load of 475 t total nitrogen, 63.5 t total phosphorus and 343,000 t total suspended solids. Model verification included intense, short-term water sampling and analysis undertaken in the current project and use of published data spanning 10 years. Under high-rainfall conditions (>50 mm day^???1), the estuary becomes stratified and nutrients are either removed from the estuary directly in a plume or indirectly by advective/dispersive remobilisation. The majority of the nutrient load is delivered during moderate rainfall (5–50 mm day^???1) conditions and accumulates close to discharge points and remains in the estuary. To significantly reduce nutrient load, management strategies should aim to minimise low and moderate rainfall pollutant loads.     

The mismatch of bioaccumulated trace metals (Cu,Pb and Zn) in field and transplanted oysters (<Emphasis Type="Italic">Saccostrea glomerata</Emphasis>) to ambient surficial sediments and suspended particulate matter in a highly urbanised estuary (Sydney estuary,Australia)

A significant correlation between sedimentary metals, particularly the ‘bio-available’ fraction, and bioaccumulated metal concentrations in the native Sydney rock oyster (Saccostrea glomerata) tissues has been successfully demonstrated previously for Cu and Zn in a number of estuaries in New South Wales, Australia. However, this relationship has been difficult to establish in a highly modified estuary (Sydney estuary, Australia) where metal contamination is of greatest concern and where a significant relationship would be most useful for environmental monitoring. The use of the Sydney rock oyster as a biomonitoring tool for metal contamination was assessed in the present study by investigating relationships between metals attached to sediments and suspended particulate matter (SPM) to bioaccumulated concentrations in oyster tissues. Surficial sediments (both total and fine-fraction), SPM and wild oysters were collected over 3 years from three embayments (Chowder Bay, Mosman Bay and Iron Cove) with each embayment representing a different physiographic region of Sydney estuary. In addition, a transplant experiment of farmed oysters was conducted in the same embayments for 3 months. No relationship was observed between sediments or SPM metals (Cu, Pb and Zn) to tissue of wild oysters; however, significant relationship was observed against transplanted oysters. The mismatch between wild and farmed, transplanted oysters is perplexing and indicates that wild oysters are unsuitable to be used as a biomonitoring tool due to the involvement of unknown complex factors while transplanted oysters hold strong potential.     

Enhanced biodegradation of pentachlorophenol in unsaturated soil using reversed field electrokinetics

This study investigated the use of electrokinetics in unsaturated soil to promote biodegradation of pentachlorophenol through increased contact between bacteria and contaminant. Soil microcosms, contaminated with approximately 100 mg kg⁻¹ pentachlorophenol (containing [¹⁴C]-PCP as a tracer), and inoculated with a specific pentachlorophenol-degrading bacterium (Sphingobium sp. UG30–1 × 10⁸ cfu g⁻¹) were subjected to constant and regularly reversed electric currents (10 mA). The former caused large pH and moisture content changes due to water electrolysis and electroosmotic effects, with subsequent negative impacts on biodegradation parameters including enzyme activity and contaminant mineralisation (as measured by ¹⁴CO₂ evolution rate). The reversed field caused little change in pH and moisture content and led to more rapid contaminant mineralisation, lower soil contaminant concentration in the majority of the microcosms and increased soil enzyme activity (with the exception of soil immediately adjacent to the anode). The presence of an electric field, if suitably applied, may therefore enhance contaminant biodegradation in unsaturated soil.     

Use of Sediment Risk and Ecological/Conservation Value for Strategic Management of Estuarine Environments: Sydney Estuary,Australia

Sediment mantling the floor of Sydney estuary contains a wide range of chemicals at highly elevated concentrations over extensive areas. Appropriate sediment management decisions are urgently required to prevent further degradation of sediment quality and to minimize resulting adverse ecological effects. The objective of the present work was to provide a systematic, estuary-wide assessment of sediment risk and ecological/conservation value throughout the harbor to guide sediment management decisions. Sediment risk is the likelihood of sediment chemistry causing adverse biological effects to bottom-dwelling animals and was conducted using national sediment quality guidelines (SQGs) for single contaminants and the mean SQG quotient approach to assess chemical mixtures. Sediment risk was negligible at the mouth of the estuary, but increased strongly landwards. The ecological/conservation value assessment was conducted to identify sites that warrant different levels of protection and was conducted using the value of ecological communities and priority waterway use. Consideration of these two parameters combined enabled the estuary to be prioritized for management attention. The prioritization and identification of appropriate management strategies were determined through the use of management matrices also based on sediment risk and ecological/conservation value. A computer package is being developed to provide managers with information on sediment risk, ecological/conservation value, the urgency and the type of management intervention required for any location in Sydney estuary, in real-time. This approach to estuarine management is unique and will greatly improve effective management of Sydney estuary, and other harbors in urgent need of management action and protection.     

Polybrominated diphenyl ethers and polybrominated biphenyls in Australian sewage sludge

This paper presents a brief review of the international scientific literature of polybrominated diphenyl ethers (PBDEs) and polybrominated biphenyls (PBBs) in sewage sludge and a survey of these compounds in sewage sludge from 16 Australian wastewater treatment plants (WWTPs). The SigmaPBDE mean concentration in the Australian study was 1137microgkg(-1) dry weight (d.w.) (s.d. 1116) and ranged between 5 and 4 230microgkg(-1)d.w. The urban mean of 1308microgkg(-1) (s.d. 1320) and the rural mean of 911microgkg(-1) (s.d. 831) are not statistically different and are similar to levels in European sludges. Principal components analysis was performed on the data set and revealed that 76% of the data variation could be explained by two components that corresponded to overall concentration of the pentaBDE and the decaBDE commercial formulations. An analysis of variance was performed comparing PBDEs levels at three WWTPs over the years 2005 and 2006, finding differences between treatment plants (BDE-47) but no significant difference in PBDE levels in the years 2005 and 2006. Low levels of BB-153 were detected in all samples of this survey (n=16); mean 0.6microgkg(-1)d.w. (s.d. 0.5). This compound has rarely been reported in any other study of sewage sludges undertaken outside Australia. This work highlights the need for a risk assessment of PBDEs in sewage sludge when used for land application, taking into account typical levels found in Australian sludges and soils.     

Adaptation of a Canadian culpability scoring tool to Alberta police traffic collision report data

Objective: The objective of this study was to adapt a previously validated Canadian Culpability Scoring Tool (CCST) to Alberta police report data.

Methods: Police traffic collision reports from motor vehicle (MV) collisions in Calgary and Edmonton (Alberta, Canada) from 2010 to 2014 were used. Adaptation of the CCST was completed with input from personnel within Alberta Transportation, contributing to face and content validity. Two research assistants, given only the information necessary for scoring, evaluated 175 randomly selected MV–MV collisions. Interrater agreement was estimated using kappa (k) and reported with 95% confidence intervals (CIs). Discussion of disagreements between the research assistants and consultation from Alberta Transportation informed the algorithm used in the Alberta Motor Vehicle Collision Culpability Tool (AMVCCT). The AMVCCT was automated and applied to all motorists involved in collisions. Binary logistic regression was used to examine characteristics of the culpable and nonculpable drivers and their effects were reported using odds ratios (ORs) with 95% CIs.

Results: Interrater agreement for the random sample was excellent (k = 0.95; 95% CI, 0.92–0.99). Of those drivers hospitalized, 1,130 (37.54%) were rated not culpable and 1,880 (62.46%) were rated culpable. The odds of being culpable were higher for males than for females (OR = 1.43; 95% CI, 1.23–1.66). The odds of being culpable were higher in those impaired by alcohol than those considered “apparently normal” (OR = 61.10; 95% CI, 22.66–164.75). The odds of being deemed culpable, when compared with drivers >54 years old, were higher for those <25 years old (OR = 1.72; 95% CI, 1.35–2.20) and lower for those in the 40- to 54-year-old age group (OR = 0.78; 95% CI, 0.63–0.96). Driving between 12 a.m. and 6 a.m. resulted in higher odds of being culpable compare with all other 6-h time blocks. Direction and statistical significance remained consistent when applying the tool to all MV collisions. Sensitivity analysis including the removal of single vehicle collisions did not affect the direction or statistical significance of the main results.

Conclusions: The AMVCCT identified a culpable group that exhibited characteristics expected in drivers who are at fault in collisions. The age groups 25–39 and 40–54 demonstrated different results than the CCST. However, this is the only difference that exists in the findings of the AMVCCT compared to the CCST and could exist due to differences between the driving populations in Alberta and British Columbia. It is possible to adapt the CCST to provinces outside British Columbia and, in doing so, we can identify risk factors for collision contribution and not-at-fault drivers who represent the driving population.     

Perinatal dioxin exposure, cytochrome P-450 activity, liver functions and thyroid hormones at follow-up after 7-12 years

OBJECTIVES: Prenatal and lactational exposure to Dutch "background" dioxin levels may cause health effects spanning many years. In addition, perinatal studies have shown a relationship between dioxin exposure and thyroid disturbance. To assess the later health effects of prenatal and lactational dioxin exposure on liver function we measured plasma ALAT and ASAT levels amongst our longitudinal cohort, as was done perinatally and at 2(1/2) years. The children underwent a caffeine loading test to determine CYP1A2 activity. To assess the later effects on thyroid function we measured plasma TSH and FT4. STUDY DESIGN: A longitudinal cohort of 37 healthy children (age 7-12, mean 8.2 years), with documented prenatal and lactational dioxin exposure, ingested 3mg caffeine/kg BW 6h prior to blood withdrawal. Paraxanthine/caffeine molar ratio, ALAT, ASAT, TSH and FT4 were determined in venous blood. RESULTS: Linear regression of ASAT and ALAT revealed no relation with prenatal and lactational dioxin exposure. No correlation was found between the paraxanthine/caffeine molar ratio and prenatal and lactational dioxin exposure. Linear regression of TSH and FT4 revealed no relation with prenatal and lactational dioxin exposure. CONCLUSION: This follow-up has shown a normalisation of previously abnormal ALAT and ASAT levels, indicating a transient effect. CYP1A2 activity, measured by means of a caffeine-loading test, revealed no correlation with the prenatal and lactational exposures. A normalisation of previously abnormal thyroid hormone homeostasis was seen, also possibly indicating a transient effect. This study provides new data on long-term follow-up after perinatal dioxin exposure to background levels of dioxins.     

Climate Skepticism in British Newspapers, 2007–2011

Climate skepticism in the UK media has not been a major focus of recent research. This paper aims to help fill the gap by looking at the incidence of skeptical voices in UK newspapers across three periods: 2007, 2009/2010, and 2010/2011. After analyzing more than 3200 articles, it finds that skeptical voices increased their presence markedly across all newspapers and all types of articles in the second period, and maintained a significant presence in many in the third. Uncontested skeptical voices were particularly prevalent in opinion pieces and editorials in right-leaning newspapers in the second. It also finds that skeptical voices or opinions were more likely to be included in pieces written by in-house non-specialist columnists than by environment editors or correspondents. The negative implications of the results for public understanding and the quality of public debate are then explored.