Influence of sanitization on the physico-chemical and microbiological quality of organic and conventional broccoli

The present study was carried out in order to evaluate the effect of chlorinated and ozonized water on the physico-chemical characteristics of broccoli, produced under organic and conventional cultivation procedures. Organic and conventional broccolis were subjected to two sanitation treatments, using chlorine and ozone, and were kept under cold storage for seven days. Analyses of pH, titrable acidity, soluble solids and weight loss were performed and the content of Cu, Mn and Zn was determined. In addition, the presence of pesticides was verified. The results show no influence of the cultivation method or the sanitation treatment on sample weight loss. Cultivation methods and sanitizing treatments affected broccoli pH, titratable acidity, and soluble solids during the evaluation period. No differences regarding the metal content on organic and conventional broccoli were observed. Furthermore, the presence of organochlorine compounds, nor other pesticides, was not detected both in organic and conventional vegetables.

A study of high solids anaerobic digestion of Bucknell University food waste followed by aerobic curing

Anaerobic digestion of food scraps has the potential to accomplish waste minimization, energy production, and compost or humus production. At Bucknell University, removal of food scraps from the waste stream could reduce municipal solid waste transportation costs and landfill tipping fees, and provide methane and humus for use on campus. To determine the suitability of food waste produced at Bucknell for high-solids anaerobic digestion (HSAD), a year-long characterization study was conducted. Physical and chemical properties, waste biodegradability, and annual production of biodegradable waste were assessed. Bucknell University food and landscape waste was digested at pilot-scale for over a year to test performance at low and high loading rates, ease of operation at 20% solids, benefits of codigestion of food and landscape waste, and toprovide digestate for studies to assess the curing needs of HSAD digestate. A laboratory-scale curing study was conducted to assess the curing duration required to reduce microbial activity, phytotoxicity, and odors to acceptable levels for subsequent use ofhumus. The characteristics of Bucknell University food and landscape waste were tested approximately weekly for one year, to determine chemical oxygen demand (COD), total solids (TS), volatile solids (VS), and biodegradability (from batch digestion studies). Fats, oil, and grease and total Kjeldahl nitrogen were also tested for some food waste samples. Based on the characterization and biodegradability studies, Bucknell University dining hall food waste is a good candidate for HSAD. During batch digestion studies Bucknell University food waste produced a mean of 288 mL CH4/g COD with a 95%confidence interval of 0.06 mL CH4/g COD. The addition of landscape waste for digestion increased methane production from both food and landscape waste; however, because the landscape waste biodegradability was extremely low the increase was small.Based on an informal waste audit, Bucknell could collect up to 100 tons of food waste from dining facilities each year. The pilot-scale high-solids anaerobic digestion study confirmed that digestion ofBucknell University food waste combined with landscape waste at a low organic loading rate (OLR) of 2 g COD/L reactor volume-day is feasible. During low OLR operation, stable reactor performance was demonstrated through monitoring of biogas production and composition, reactor total and volatile solids, total and soluble chemical oxygendemand, volatile fatty acid content, pH, and bicarbonate alkalinity. Low OLR HSAD of Bucknell University food waste and landscape waste combined produced 232 L CH4/kg COD and 229 L CH4/kg VS. When OLR was increased to high loading (15 g COD/L reactor volume-day) to assess maximum loading conditions, reactor performance became unstable due to ammonia accumulation and subsequent inhibition. The methaneproduction per unit COD also decreased (to 211 L CH4/kg COD fed), although methane production per unit VS increased (to 272 L CH4/kg VS fed). The degree of ammonia inhibition was investigated through respirometry in which reactor digestate was diluted and exposed to varying concentrations of ammonia. Treatments with low ammoniaconcentrations recovered quickly from ammonia inhibition within the reactor. The post-digestion curing process was studied at laboratory-scale, to provide a preliminary assessment of curing duration. Digestate was mixed with woodchips and incubated in an insulated container at 35 °C to simulate full-scale curing self-heatingconditions. Degree of digestate stabilization was determined through oxygen uptake rates, percent O2, temperature, volatile solids, and Solvita Maturity Index. Phytotoxicity was determined through observation of volatile fatty acid and ammonia concentrations.Stabilization of organics and elimination of phytotoxic compounds (after 10–15 days of curing) preceded significant reductions of volatile sulfur compounds (hydrogen sulfide, methanethiol, and dimethyl sulfide) after 15–20 days of curing. Bucknell University food waste has high biodegradability and is suitable for high-solids anaerobic digestion; however, it has a low C:N ratio which can result in ammonia accumulation under some operating conditions. The low biodegradability of Bucknell University landscape waste limits the amount of bioavailable carbon that it can contribute, making it unsuitable for use as a cosubstrate to increase the C:N ratio of food waste. Additional research is indicated to determine other cosubstrates with higher biodegradabilities that may allow successful HSAD of Bucknell University food waste at high OLRs. Some cosubstrates to investigate are office paper, field residues, or grease trap waste. A brief curing period of less than 3 weeks was sufficient to produce viable humus from digestate produced by low OLR HSAD of food and landscape waste.

Chemical composition and elemental oxide ratios to AI2O3 of bulk solids at DSDP Leg 64 Holes

Analyses of sediments from Leg 64 sites reveal a diverse and in one case unique geochemistry. Sites are characterized by high heat flow along an active, divergent plate boundary, or rapid accumulation of diatom muds, or both. The geochemical trends of Sites 474-476 at the tip of Baja California reflect changes4n the percentages of sedimentary components - particularly biogenous matter and mineralogy - that support interpretations of sedimentary environments inferred to be present since the commencement of subsidence along this young, passive continental margin. The sediments below dolerite sills in Holes 477, 477A, 478, and 481 show major mineralogic and chemical deviations from "average" hemipelagic sediments. The sills appear to have two functions: (1) they allow hydrothermal circulation and metamorphism in a partially closed system by trapping heat and fluids emanating from below, and (2) they expel heated interstitial fluids at the moment of intrusion and mobilize elements, most likely leading to the formation of metalliferous deposits along the surface traces of normal faults in the basin. The hydrothermal system as a whole appears to be localized and ephemeral, as is indicated by the lack of similar geochemical trends and high heat flow at Sites 478 and 481. Site 479 illustrates sedimentation in an oxygen-minimum zone with anoxic sediments and concomitant geochemical trends, especially for MnO. With few exceptions, geochemical trends are remarkably constant with depth, suggesting that Site 479 can serve as an "internal" standard or average sediment against which the magnitude of hydrothermal alteration at the basinal Sites 477, 478, and 481 can be measured.

Calcium isotope ratios of pore fluids and solid phase of organic rich sediments

Pore fluid calcium isotope, calcium concentration and strontium concentration data are used to measure the rates of diagenetic dissolution and precipitation of calcite in deep-sea sediments containing abundant clay and organic material. This type of study of deep-sea sediment diagenesis provides unique information about the ultra-slow chemical reactions that occur in natural marine sediments that affect global geochemical cycles and the preservation of paleo-environmental information in carbonate fossils. For this study, calcium isotope ratios (d44/40Ca) of pore fluid calcium from Ocean Drilling Program (ODP) Sites 984 (North Atlantic) and 1082 (off the coast of West Africa) were measured to augment available pore fluid measurements of calcium and strontium concentration. Both study sites have high sedimentation rates and support quantitative sulfate reduction, methanogenesis and anaerobic methane oxidation. The pattern of change of d44/40Ca of pore fluid calcium versus depth at Sites 984 and 1082 differs markedly from that of previously studied deep-sea Sites like 590B and 807, which are composed of nearly pure carbonate sediment. In the 984 and 1082 pore fluids, d44/40Ca remains elevated near seawater values deep in the sediments, rather than shifting rapidly toward the d44/40Ca of carbonate solids. This observation indicates that the rate of calcite dissolution is far lower than at previously studied carbonate-rich sites. The data are fit using a numerical model, as well as more approximate analytical models, to estimate the rates of carbonate dissolution and precipitation and the relationship of these rates to the abundance of clay and organic material. Our models give mutually consistent results and indicate that calcite dissolution rates at Sites 984 and 1082 are roughly two orders of magnitude lower than at previously studied carbonate-rich sites, and the rate correlates with the abundance of clay. Our calculated rates are conservative for these sites (the actual rates could be significantly slower) because other processes that impact the calcium isotope composition of sedimentary pore fluid have not been included. The results provide direct geochemical evidence for the anecdotal observation that the best-preserved carbonate fossils are often found in clay or organic-rich sedimentary horizons. The results also suggest that the presence of clay minerals has a strong passivating effect on the surfaces of biogenic carbonate minerals, slowing dissolution dramatically even in relation to the already-slow rates typical of carbonate-rich sediments.

A dynamic mathematical model for sequential leach bed anaerobic digestion of organic fraction of municipal solid waste

A mathematical model that describes the operation of a sequential leach bed process for anaerobic digestion of organic fraction of municipal solid waste (MSW) is developed and validated. This model assumes that ultimate mineralisation of the organic component of the waste occurs in three steps, namely solubilisation of particulate matter, fermentation to volatile organic acids (modelled as acetic acid) along with liberation of carbon dioxide and hydrogen, and methanogenesis from acetate and hydrogen. The model incorporates the ionic equilibrium equations arising due to dissolution of carbon dioxide, generation of alkalinity from breakdown of solids and dissociation of acetic acid. Rather than a charge balance, a mass balance on the hydronium and hydroxide ions is used to calculate pH. The flow of liquid through the bed is modelled as occurring through two zones-a permeable zone with high flushing rates and the other more stagnant. Some of the kinetic parameters for the biological processes were obtained from batch MSW digestion experiments. The parameters for flow model were obtained from residence time distribution studies conducted using tritium as a tracer. The model was validated using data from leach bed digestion experiments in which a leachate volume equal to 10% of the fresh waste bed volume was sequenced. The model was then tested, without altering any kinetic or flow parameters, by varying volume of leachate that is sequenced between the beds. Simulations for sequencing/recirculating 5 and 30% of the bed volume are presented and compared with experimental results. (C) 2002 Elsevier Science B.V. All rights reserved.

Sensitivity of organic matter decomposition to warming varies with its quality

The relationship between organic matter (OM) lability and temperature sensitivity is disputed, with recent observations suggesting that responses of relatively more resistant OM to increased temperature could be greater than, equivalent to, or less than responses of relatively more labile OM. This lack of clear understanding limits the ability to forecast carbon (C) cycle responses to temperature changes. Here, we derive a novel approach (denoted Q(10-q)) that accounts for changes in OM quality during decomposition and use it to analyze data from three independent sources. Results from new laboratory soil incubations (labile Q(10-q)=2.1 +/- 0.2; more resistant Q(10-q)=3.8 +/- 0.3) and reanalysis of data from other soil incubations reported in the literature (labile Q(10-q)=2.3; more resistant Q(10-q)=3.3) demonstrate that temperature sensitivity of soil OM decomposition increases with decreasing soil OM lability. Analysis of data from a cross-site, field litter bag decomposition study (labile Q(10-q)=3.3 +/- 0.2; resistant Q(10-q)=4.9 +/- 0.2) shows that litter OM follows the same pattern, with greater temperature sensitivity for more resistant litter OM. Furthermore, the initial response of cultivated soils, presumably containing less labile soil OM (Q(10-q)=2.4 +/- 0.3) was greater than that for undisturbed grassland soils (Q(10-q)=1.7 +/- 0.1). Soil C losses estimated using this approach will differ from previous estimates as a function of the magnitude of the temperature increase and the proportion of whole soil OM comprised of compounds sensitive to temperature over that temperature range. It is likely that increased temperature has already prompted release of significant amounts of C to the atmosphere as CO2. Our results indicate that future losses of litter and soil C may be even greater than previously supposed.

How can soil monitoring networks be used to improve predictions of organic carbon pool dynamics and CO2 fluxes in agricultural soils?

Abstract As regional and continental carbon balances of terrestrial ecosystems become available, it becomes clear that the soils are the largest source of uncertainty. Repeated inventories of soil organic carbon (SOC) organized in soil monitoring networks (SMN) are being implemented in a number of countries. This paper reviews the concepts and design of SMNs in ten countries, and discusses the contribution of such networks to reducing the uncertainty of soil carbon balances. Some SMNs are designed to estimate country-specific land use or management effects on SOC stocks, while others collect soil carbon and ancillary data to provide a nationally consistent assessment of soil carbon condition across the major land-use/soil type combinations. The former use a single sampling campaign of paired sites, while for the latter both systematic (usually grid based) and stratified repeated sampling campaigns (5–10 years interval) are used with densities of one site per 10–1,040 km². For paired sites, multiple samples at each site are taken in order to allow statistical analysis, while for the single sites, composite samples are taken. In both cases, fixed depth increments together with samples for bulk density and stone content are recommended. Samples should be archived to allow for re-measurement purposes using updated techniques. Information on land management, and where possible, land use history should be systematically recorded for each site. A case study of the agricultural frontier in Brazil is presented in which land use effect factors are calculated in order to quantify the CO2 fluxes from national land use/management conversion matrices. Process-based SOC models can be run for the individual points of the SMN, provided detailed land management records are available. These studies are still rare, as most SMNs have been implemented recently or are in progress. Examples from the USA and Belgium show that uncertainties in SOC change range from 1.6–6.5 Mg C ha−1 for the prediction of SOC stock changes on individual sites to 11.72 Mg C ha−1 or 34% of the median SOC change for soil/land use/climate units. For national SOC monitoring, stratified sampling sites appears to be the most straightforward attribution of SOC values to units with similar soil/land use/climate conditions (i.e. a spatially implicit upscaling approach). Keywords Soil monitoring networks - Soil organic carbon - Modeling - Sampling design

An Investigation of Organic Factors in the Neuropsychological Functioning of Patients with Borderline Personality Disorder

The hypothesis to be tested in this study was that the cognitive deficits that have been documented in patients with Borderline Personality Disorder (BPD) are largely the consequence of organic insult, either developmental or acquired. Using a cross–sectional design, 80 subjects (males and females) who met the criteria for BPD participated in the study. They completed a battery of neuropsychological tests and a comprehensive interview assessing organic status as well as measures of the potentially confounding factors of current levels of depression and anxiety. It was expected that BPD-patients with a probable history of organic insult would perform significantly worse than would BPD patients without such a history. Analyses of the results provided partial support for the hypothesis. Subjects with both BPD and a history of organic insult were significantly more impaired on several measures including measures of attention than were BPD only subjects. The results suggested that the impaired cognitive performance of persons diagnosed with BPD may, in part, be attributed to organic factors.

Preliminary results on the characterisation of organic aerosols in urban schools by Aerosol Mass Spectrometry

Vehicle emissions have been linked to detrimental health effects with children thought to be more susceptible (See e.g., Ryan et al 2005). In an urban environment a major source of organic aerosols (OA) are vehicle emissions. The ambient concentration of OA is dynamic in nature and the use of an aerosol mass spectrometer can achieve the necessary temporal resolution to capture the daily variation of OA (Jimenez et al 2009). Currently there is a limited understanding of effects of long term exposure to traffic emissions on children’s health. In the present study, we used an aerosol mass spectrometer to monitor OA and determine children’s potential exposure at school to traffic emissions.In this paper, we present the preliminary results of this investigation. The study is a part of a larger project aimed at gaining a holistic picture of the exposure of children to traffic related pollutants, known as UPTECH (www.ilaqh.qut.edu.au/Misc/ UPTECH%20Home.htm).