Enhanced biological phosphorus removal using thermal alkaline hydrolyzed municipal wastewater biosolids

This study reports the feasibility of using municipal wastewater biosolids as an alternative carbon source for biological phosphorus removal. The biosolids were treated by a lowtemperature, thermal alkaline hydrolysis process patented by Lystek International Inc.(Cambridge, ON, Canada) to produce short-chain volatile fatty acids and other readily biodegradable organics. Two sequencing batch reactors(SBRs) were operated with synthetic volatile fatty acids(Syn VFA) and readily biodegradable organics produced from the alkaline hydrolysis of municipal wastewater biosolids(Lystek) as the carbon source, respectively.Municipal wastewaters with different strengths and COD:N:P ratios were tested in the study. The reactors' performances were compared with respect to nitrogen and phosphorus removal. It was observed that phosphorus removal efficiencies were between 98%–99% and 90%–97% and nitrogen removal efficiencies were 78%–81%, and 67% for the Syn VFA and Lystek, respectively. However, the kinetics for phosphorus release and uptake during the anaerobic and aerobic stages with Lystek were observed to be significantly lower than Syn VFA due to the presence of higher order VFAs(C4 and above) and other fermentable organics in the Lystek.     

Monitoring Fish Contaminant Responses to Abatement Actions: Factors that Affect Recovery

Monitoring of contaminant accumulation in fish has been conducted in East Fork Poplar Creek (EFPC) in Oak Ridge, Tennessee since 1985. Bioaccumulation trends are examined over a twenty year period coinciding with major pollution abatement actions by a Department of Energy facility at the stream’s headwaters. Although EFPC is enriched in many contaminants relative to other local streams, only polychlorinated biphenyls (PCBs) and mercury (Hg) were found to accumulate in the edible portions of fish to levels of human health concern. Mercury concentrations in redbreast sunfish were found to vary with season of collection, sex and size of individual fish. Over the course of the monitoring, waterborne Hg concentrations were reduced >80%; however, this did not translate into a comparable decrease in Hg bioaccumulation at most sites. Mercury bioaccumulation in fish did respond to decreased inputs in the industrialized headwater reach, but paradoxically increased in the lowermost reach of EFPC. As a result, the downstream pattern of Hg concentration in fish changed from one resembling dilution of a headwater point source in the 1980s to a uniform distribution in the 2000s. The reason for this remains unknown, but is hypothesized to involve changes in the chemical form and reactivity of waterborne Hg associated with the removal of residual chlorine and the addition of suspended particulates to the streamflow. PCB concentrations in fish varied greatly from year-to-year, but always exhibited a pronounced downstream decrease, and appeared to respond to management practices that limited episodic inputs from legacy sources within the facility.     

Genetic structure of the southeastern United States loggerhead turtle nesting aggregation: evidence of additional structure within the peninsular Florida recovery unit

The southeastern United States supports one of two large loggerhead turtle (Caretta caretta) nesting aggregations worldwide and is therefore critical to global conservation and recovery efforts for the species. Previous studies have established the presence of four demographically distinct nesting populations (management units) corresponding to beaches from (1) North Carolina through northeastern Florida, (2) peninsular Florida, (3) the Dry Tortugas, and (4) northwest Florida. Temporal and geographic genetic structure of the nesting aggregation was examined utilizing partial mitochondrial control region haplotype frequencies from 834 samples collected over the 2002 through 2008 nesting seasons from 19 beaches as well as previously published haplotype data. Most rookeries did not exhibit interannual genetic variation. However, the interannual variation detected did significantly impact the interpretation of spatial genetic structure in northeastern Florida. Based on pairwise F _ST comparisons, exact tests of population differentiation, and analysis of molecular variance, the present study upholds the distinctiveness of the four currently recognized management units and further supports recognition of discrete central eastern, southern (southeastern and southwestern), and central western Florida management units. Further subdivision may be warranted, but more intensive genetic sampling is required. In addition, tools such as telemetry and mark-recapture are needed to complement genetic data and overcome limitations of genetic markers in resolving loggerhead turtle rookery connectivity in the southeastern USA.     

An assessment of persistent organic pollutants in Scottish coastal and offshore marine environments

Concentrations of persistent organic pollutants (POPs), including polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) were determined in sediment and biota (fish liver) from around Scotland. The concentrations were investigated using assessment criteria developed by OSPAR and ICES. Organic contaminant concentrations, PAHs, PCBs and PBDEs in sediment, and PCBs and PBDEs in fish liver, were significantly higher in the Clyde compared to all other sea areas. This is mainly due to historic industrial inputs. Highest PCB and PAH concentrations were found in the strata furthest up the Clyde estuary, with concentrations of POPs in these strata being at levels such that there is an unacceptable risk of chronic effects occurring in marine species. Furthermore, for PAHs in Clyde sediment there was a significant negative gradient going from north to south towards the open sea. PAH and PCB concentrations in sediment and biota in all other Scottish sea areas (except for PCBs in sediment from East Scotland) were unlikely to give rise to pollution effects, being below relevant assessment criteria. Although no assessment criteria are available for PBDEs, the concentrations observed in Scottish sediments were low with all congeners below the limit of detection (LoD; 0.03 μg kg(-1) dry weight) in 140 out of a total of 307 samples analysed. Where PBDEs were detected, the dominant congeners were BDE47 and BDE99. PBDEs were detected in fish livers, although concentrations were less than 150 μg kg(-1) lipid weight in all sea areas except the Clyde where concentrations ranged between 8.9 and 2202 μg kg(-1) lipid weight. Few trends were detected in contaminant concentrations in biota or sediment at any Scottish site with more than five years data. Downward trends were detected in PAHs in sediment from the Clyde, Irish Sea and Minches and Malin Sea and PCBs in fish liver from the Moray Firth. Rules were developed for the aggregation of the contaminant data across a sea area. An overall assessment for each sea area was then assigned, looking at the frequency of sites or strata within each sea area that were above or below the relevant assessment criteria. Overall the status of the various sea areas, with respect to the assessed POPs, can be considered to be acceptable in that they were below concentrations likely to result in chronic effects for all sea areas except the Clyde.     

Burial survival of benthic macrofauna following deposition of simulated dredged material

In many coastal regions, the disposal of dredged material constitutes the largest (albeit often localised) anthropogenic disturbance to the seabed. Impacts can be minimised by reducing the amount of sediment overburden on the bed at any one time allowing short-term recovery to proceed via the vertical migration of resident species. However, there is currently a limited understanding of the ability of such species to successfully vertically migrate. This study presents the findings of a field experiment to investigate the vertical migratory capability of temperate macroinvertebrate species following the placement of simulated dredged material. The relationships between vertical migration success with sediment characteristics (organic carbon and sand content) and placement depth were explicitly examined. While the polychaete worms Tharyx sp. A. and Streblospio shrubsolii showed poor vertical migration with only 6 cm of sediment overburden, the oligochaete Tubificoides benedii showed some recovery while the gastropod mollusc Hydrobia ulvae exhibited good migratory success, even with 16 cm of sediment overburden. While increases in sand content from 16% to 38% had no noticeable effect on vertical migration, increased sediment organic content from 0.8% to 3.3% detrimentally affected vertical migratory activity. The results support the theory that species' survival following sediment burial is trophic group-related. The relevance of these findings with respect to dredged material disposal management is discussed.     

Open space index: a GIS-based tool for assessing human penetration of a landscape

In light of the rapid and continuous growth of the built environment worldwide and its attendant ecological impact, increasing the size and distribution of open space in urban areas is recognised as one effective way to reconcile the social and ecological objectives of society. However, there is no simple and objective indicator to measure open space that can be used for creating and maintaining sustainable landscapes. The paper introduces a metric, open space index (OSI), that measures the amount of space unpenetrated by the built environment. The metric is calculated by measuring the shortest distance between any location and the nearest built environment using a Geographic Information System. The metric is illustrated using two counties of the greater Twin Cities Metropolitan Region of Minnesota. The sensitivity of OSI to the size, shape, and spatial configuration of the built environment suggests that the metric can serve as an important planning tool for reconciling conservation and development in a wide range of contexts.     

Moving beyond “mitigation and adaptation”: examining climate change responses in New Zealand

Despite the apparent failure of international negotiations and renewed criticism of the accuracy of climate science, responses to climate change continue in households, cities, fields, and meeting rooms. Notions of “doing something about”, or “taking action on” or “mitigating and adapting” to climate change inform practices of carbon trading, restoring native forests, constructing wind turbines, insulating houses, using energy efficient light bulbs, and lobbying politicians for more or less of these actions. These expressions of agency in relation to climate change provide the focus of our enquiry. We found that relationships or social networks linked through local government are building capabilities to respond to climate change. However, the framework of “mitigation–adaptation” will need to be supplemented by a more diverse suite of mental models for making sense of climate change. Use of appropriate languages, cultural reference points, and metaphors embedded in diverse histories of climates and change will assist actors in their networked climate change responses.     

Effects of veterinary fences on Wildlife conservation in Zimbabwe

In Zimbabwe, veterinary fences are used to control trypanosomiasis and foot- and-mouth disease, two important diseases that threaten cattle production and beef exports. Wildlife is implicated in both instances and the effects of fences on wildlife conservation and land use are discussed in relation to these two diseases. Advantages and disadvantages related to direct and indirect fence effects are outlined. Although the maintenance of fences for trypanosomiasis control is likely to become obsolete, control of foot- and-mouth disease will rely on fences for the foreseeable future. Most of Zimbabwe's protected wildlife areas are located in marginal agricultural land around the periphery of the country where cattle productivity is low. This land should be excluded from any involvement in the beef export industry rather than attempting its inclusion through cordoning and isolating individual protected areas. Within such land, the need for rigid veterinary restrictions should then disappear and allow more flexible strategies for disease control, including adaptive and imaginative approaches to land-use planning.     

Respiratory effects of household exposures to tobacco smoke and gas cooking on nonsmokers

The records of 708 nonsmoking white adult residents of Washington County, MD, who had participated in two of respiratory symptoms were analyzed to evaluate the effects of exposure at home to two potential sources of indoor air pollution: cigarette smoking by other household members, and use of gas as a cooking fuel. After adjustment for the effects of age, sex, socioeconomic level, occupational exposure to dust, and years of residence in household, the presence of one or more smokers in the household was only suggestively associated with a higher frequency of chronic phlegm and impaired ventilatory function defined as FEV₁ < 80% predicted. The use for cooking was associated with a significantly increased frequency of chronic cough and a significantly greater percentage with impaired ventilatory function as measured both by FEV₁ < 80% predicted and by FEV₁/FVC < 70%.