Reconstructed Stream Flow for the Salt and Verde Rivers From Tree-Ring Data1

ABSTRACT: The Salt and Verde Rivers of central Arizona provide the water supply for metropolitan Phoenix and a considerable acreage of irrigated agriculture. Rapid urbanization has caused concern over future water supply and aggravated flooding in the already flood-prone Salt River Valley. Tree-ring data were used as a proxy source to extend the annual and seasonal runoff records back to A.D. 1580 and thus to determine whether the period of record for annual discharge adequately represents the long term flow characteristics of the two rivers. Results show that several periods of extended low flow have occurred during the past 400 years, many of which were more severe then any comparable period since 1890. The low flow periods appear to have a recurrence interval of about 22 years. Also the gaged records contain an above average number of high seasonal and annual flows when compared to the entire 400 years. The reconstructions contain important implications for future water supply and flood potentials in the Salt River Valley.     

An Ombudsman for Humanitarian Assistance?

The early phases of a project to design and make operational an ombudsman for humanitarian assistance (HAO) are described in this paper. Beginning with a brief historical overview of the ombudsman concept, it then outlines seven key features of a potential HAO that were identified in the initial feasibility study. The main conclusion from the feasibility study was that, in principle, it is possible to design an HAO by adapting the operational frameworks of existing ombudsman schemes so as to match the needs of the humanitarian sector. Although this seems possible in theory, there still remain some major challenges requiring practical testing in a pilot phase. The most fundamental of these is how to enable the beneficiaries of aid to make their voices heard and register their views on the management of the emergency that is affecting them. Important also, are the issues of ensuring an international jurisdiction and finding sustainable ways of financing the scheme. Finally, the paper alludes to the framework of the pilot itself and how to address the main challenges ahead.     

Triple tracks in CR-39 as the result of Pd–D Co-deposition: evidence of energetic neutrons

Since the announcement by Fleischmann and Pons that the excess enthalpy generated in the negatively polarized Pd–D-D₂O system was attributable to nuclear reactions occurring inside the Pd lattice, there have been reports of other manifestations of nuclear activities in this system. In particular, there have been reports of tritium and helium-4 production; emission of energetic particles, gamma or X-rays, and neutrons; as well as the transmutation of elements. In this communication, the results of Pd–D co-deposition experiments conducted with the cathode in close contact with CR-39, a solid-state nuclear etch detector, are reported. Among the solitary tracks due to individual energetic particles, triple tracks are observed. Microscopic examination of the bottom of the triple track pit shows that the three lobes of the track are splitting apart from a center point. The presence of three α-particle tracks outgoing from a single point is diagnostic of the ¹²C(n,n′)3α carbon breakup reaction and suggests that DT reactions that produce ≥9.6 MeV neutrons are occurring inside the Pd lattice. To our knowledge, this is the first report of the production of energetic (≥9.6 MeV) neutrons in the Pd–D system. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Elevated concentrations of primordial radionuclides in sediments from the Reedy River and surrounding creeks in Simpsonville, South Carolina

A gamma-ray survey and analysis of 16 riverbed samples from the Reedy River watershed near Simpsonville, SC were conducted and compared with national and international studies of primordial radionuclides. The study reported here follows on a recent discovery of anomalously high uranium concentrations in several private well waters in the area. An HPGe spectrometer was used for quantification of gamma emitting radionuclides in the sediments. All sediments contained radionuclides from the uranium and thorium series as well as (40)K. Uranium-238 concentrations in sediment samples ranged from 11.1 to 74.2Bqkg(-1). The measured radionuclide concentrations were compared with data from UNSCEAR and NURE reports. The river and stream sediment data were augmented by in situ NaI(Tl) gamma-ray spectrometer measurements. Comparisons between the ex situ and in situ measurements indicate equivalently distributed uranium in the surface soils and stream sediments, the source of which is likely attributed to the monazite belts that are known to exist in the area.     

Levels of community participation and satisfaction with decentralized wildlife management in Idodi-Pawaga Wildlife Management Area,Tanzania

Participatory approaches to conservation are viewed as a plausible alternative to the old ‘fortress conservation’ approach. The design and implementation of these approaches in developing countries have tended to embrace community participation through decentralized governance mechanisms in the past three decades. However, sustainable conservation approaches that maintain community livelihoods while conserving biodiversity are challenged with meeting both objectives. In addressing this challenge, little attention has been given to an empirical analysis of community’s satisfaction levels on how they participated in the design and implementation of this approach. In this article, we use a mixed method approach using both quantitative and qualitative data to examine levels of satisfaction and participation of local communities in the Idodi-Pawaga Wildlife Management Area (WMA), south-western Tanzania. We find that social economic factors (e.g. age, household size, gender, number of years living in the same location and participation/non-participation) influence, in different ways, the satisfaction levels of community’s participation towards the WMA creation. Due to inadequate participation, we find that the WMA design and implementation process failed from the beginning to actively involve the local communities and this has resulted in the near absence of the promised economic benefits from wildlife conservation. We suggest that participation should go beyond the simple information sharing to actively engage the local communities in key planning activities from the beginning of any WMA programme. It is also important to take into consideration their levels of satisfaction with the process of decision-making if meaningful decentralized governance is to be achieved.     

Fate of turbid glacial inflows in a hydroelectric reservoir

Environmental Fluid Mechanics - Turbidity from glacial meltwater limits light penetration with potential ecological consequences. Using profiles of temperature, conductivity, and turbidity, we...     

Atrazine toxicity to Handroanthus heptaphyllus,a nontarget species from a Brazilian biome threatened by agriculture

The economic basis of the Brazilian midwest is agriculture, concentrating most of the grain production in the country. With the purpose of increasing yield, farmers have intensified land use and the use of atrazine among other pesticides, which can supposedly compromise human health and photosynthetic metabolism of plant species from Cerrado, such as Handroanthus heptaphyllus. The aim of this study was to determine experimentally the sensitivity level of H. heptaphyllus to atrazine, by measuring gas exchange, chlorophyll a fluorescence, chloroplastidic pigments, and membrane permeability. The experiment was conducted in a factorial scheme. Nine‐month‐old H. heptaphyllus plants were treated with six realistic doses of atrazine: 0, 25, 50, 100, 200, and 400 g a.i. ha^–1 (corresponding to 10, 20, 40, 80, and 100% of the commercial dose recommended for corn crops, respectively), with five replications. Evaluations were performed at 12, 36, 84, 180, and 276 h after treatment application. Photosynthesis, the effective quantum yield of photosystem II, and electron transport rate were gradually reduced by the action of atrazine. On the other hand, the nonphotochemical quenching increased gradually, which indicates that this mechanism was not sufficient to avoid oxidative stress and cellular damage in H. heptaphyllus treated plants. Based on these results, we concluded that the action of the herbicide in the photosynthetic reduction occurs by the electron transport rate limitation. Therefore, H. heptaphyllus trees are at risk in Cerrado areas next to agricultural lands.     

Nitrate in shallow groundwater in typical agricultural and forest ecosystems in China, 2004-2010

The nitrate-nitrogen(NO 3-N) concentrations from shallow groundwater wells situated in 29 of the Chinese Ecosystem Research Network field stations,representing typical agroand forest ecosystems,were assessed using monitoring data collected between 2004 and 2010.Results from this assessment permit a national scale assessment of nitrate concentrations in shallow groundwater,and allow linkages between nitrate concentrations in groundwater and broad land use categories to be made.Results indicated that most of the NO 3--N concentrations in groundwater from the agroand forest ecosystems were below the Class 3 drinking water standard stated in the Chinese National Standard:Quality Standard for Ground Water(≤ 20 mg/L).Over the study period,the average NO 3--N concentrations were significantly higher in agro-ecosystems(4.1 ± 0.33 mg/L) than in forest ecosystems(0.5 ± 0.04 mg/L).NO 3-N concentrations were relatively higher(> 10 mg N /L) in 10 of the 43 wells sampled in the agricultural ecosystems.These elevated concentrations occurred mainly in the Ansai,Yucheng,Linze,Fukang,Akesu,and Cele field sites,which were located in arid and semiarid areas where irrigation rates are high.We suggest that improvements in N fertilizer application and irrigation management practices in the arid and semi-arid agricultural ecosystems of China are the key to managing groundwater nitrate concentrations.     

Removal of PFOS, PFOA and other perfluoroalkyl acids at water reclamation plants in South East Queensland Australia

This paper examines the fate of perfluorinated sulfonates (PFSAs) and carboxylic acids (PFCAs) in two water reclamation plants in Australia. Both facilities take treated water directly from WWTPs and treat it further to produce high quality recycled water. The first plant utilizes adsorption and filtration methods alongside ozonation, whilst the second uses membrane processes and advanced oxidation to produce purified recycled water. At both facilities perfluorooctane sulfonate (PFOS), perfluorohexane sulfonate (PFHxS), perfluorohexanoic acid (PFHxA) and perfluorooctanoic acid (PFOA) were the most frequently detected PFCs. Concentrations of PFOS and PFOA in influent (WWTP effluent) ranged up to 3.7 and 16 ng L⁻¹ respectively, and were reduced to 0.7 and 12 ng L⁻¹ in the finished water of the ozonation plant. Throughout this facility, concentrations of most of the detected perfluoroalkyl compounds (PFCs) remained relatively unchanged with each successive treatment step. PFOS was an exception to this, with some removal following coagulation and dissolved air flotation/sand filtration (DAFF). At the second plant, influent concentrations of PFOS and PFOA ranged up to 39 and 29 ng L⁻¹. All PFCs present were removed from the finished water by reverse osmosis (RO) to concentrations below detection and reporting limits (0.4-1.5 ng L⁻¹). At both plants the observed concentrations were in the low parts per trillion range, well below provisional health based drinking water guidelines suggested for PFOS and PFOA.