Identifying heavy metal levels in historical flood water deposits using sediment cores.

When designing mitigation and restoration strategies for aquatic systems affected by heavy metal contamination, we must first understand the sources of these pollutants. In this study, we introduce a methodology that identifies the heavy metal levels in floodplain lake sediments deposited by one source; fluvial floods. This is done by comparing sediment core heavy metal profiles (i.e., historical pollution trends) to physical and chemical properties of sediments in these cores (i.e., historical flooding trends). This methodology is applied to Willsmere and Bolin Billabongs, two urban floodplain lakes (billabongs) of the Yarra River (South-East Australia). Both billabongs are periodically inundated by flooding of the Yarra River and one billabong (Willsmere Billabong) is connected to an urban stormwater drainage network. 1-2-m long sediment cores (containing sediment deposits up to 500 years old) were taken from the billabongs and analysed for heavy metal concentrations (arsenic, chromium, copper, lead, nickel, zinc). In cores from both billabongs, arsenic concentrations are high in the flood-borne sediments. In Bolin Billabong, absolute metal levels are similar in flood and non-flood deposits. In Willsmere Billabong, absolute copper, lead and zinc levels were generally lower in fluvial flood-borne sediments in the core compared to non-fluvial sediments. This suggests that heavy metal concentrations in Bolin Billabong sediments are relatively similar regardless of whether or not fluvial flooding is occurring. However for Willsmere Billabong, heavy metal concentrations are high when overland runoff, direct urban stormwater discharges or atmospheric deposition is occurring. As such, reducing the heavy metal concentrations in these transport pathways will be of great importance when trying to reduce heavy metal concentrations in Willsmere Billabong sediments. This study presents a proof-of-concept that can be applied to other polluted aquatic systems, to understand the importance of river floods in the contamination of the bed sediments of aquatic systems. As a cost effective and less time consuming alternative to extensive field monitoring, our proposed method can be used to identify the key sources of pollution and therefore support the development of effective management strategies.

Sediment cores as archives of historical changes in floodplain lake hydrology.

Anthropogenic activities are contributing to the changing hydrology of rivers, often resulting in their degradation. Understanding the drivers and nature of these changes is critical for the design and implementation of effective mitigation strategies for these systems. However, this can be hindered by gaps in historical measured flow data. This study therefore aims to use sediment cores to identify historical hydrological changes within a river catchment. Sediment cores from two floodplain lakes (billabongs) in the urbanised Yarra River catchment (Melbourne, South-East Australia) were collected and high resolution images, trends in magnetic susceptibility and trends in elemental composition through the sedimentary records were obtained. These were used to infer historical changes in river hydrology to determine both average trends in hydrology (i.e., coarse temporal resolution) as well as discrete flood layers in the sediment cores (i.e., fine temporal resolution). Through the 20th century, both billabongs became increasingly disconnected from the river, as demonstrated by the decreasing trends in magnetic susceptibility, particle size and inorganic matter in the cores. Additionally the number of discrete flood layers decreased up the cores. These reconstructed trends correlate with measured flow records of the river through the 20th century, which validates the methodology that has been used in this study. Not only does this study provide evidence on how natural catchments can be affected by land-use intensification and urbanisation, but it also introduces a general analytical framework that could be applied to other river systems to assist in the design of hydrological management strategies.

Maximizing the aesthetic result in panniculectomy after massive weight loss.

BACKGROUND: Plastic surgical consultation for abdominal contouring following massive weight loss is becoming increasingly prevalent, especially with the popularity of surgical weight loss procedures. The authors reviewed their experience with a novel panniculectomy technique that generally combines horizontal and vertical tissue excision to generate the best contour possible while providing effective relief of symptoms related to a dependent abdominal panniculus. METHODS: A retrospective chart review was conducted of 100 consecutive patients who underwent panniculectomy using the authors' technique over a 5-year period. Demographic and procedural data were collected, and outcome measures were analyzed. RESULTS: Eighty-seven women and 13 men with an average weight loss of 133 lb underwent abdominal panniculectomy. A total of 37 ventral hernias were repaired concomitantly. Mean clinical follow-up was 16 months. Hospital length of stay averaged 4 days, and the most common complications were blood transfusion requirement (n = 39), fluid collections (n = 32), tissue necrosis requiring debridement (n = 18), and contour irregularities requiring revision (n = 15). Overall, 56 patients had a completely uncomplicated recovery. Greater amounts of tissue resection were associated with higher rates of transfusion (p < 0.01). CONCLUSIONS: The panniculectomy technique described can be performed safely and reproducibly. It yields an excellent abdominal contour and is effective in alleviating many symptoms of the dependent abdominal panniculus. It also provides exposure for improved evaluation and repair of concomitant ventral hernia defects.

Biologic enhancement of wound healing.

Manipulation of the healing process through wound supplementation with agents that are natural contributors to the healing process is an appealing concept. Early experimental studies evaluating wounds supplemented with inflammatory mediators used materials extracted from cell preparations and generated encouraging results. Recombinant technology has allowed the production of larger volumes of these mediators that can be used more practically and safely in the clinical setting. Several clinical trials involving inflammatory mediators as wound supplements are reviewed, and the results of many of the studies are encouraging. Wound supplements are considered drugs, and therefore, they must be demonstrated to be safe and efficacious before they can receive approval for human use by the FDA. It is extremely expensive to carry out the experimental studies required for FDA approval. Because of the expense involved, Regranex is the only supplement that has been tested thoroughly enough to receive FDA approval for use in humans. It is hoped that additional agents will be demonstrated to be safe and efficacious in human trials so that they might become available in the United States in the near future.