Minimal pesticide-primed soil inoculum density to secure maximum pesticide degradation efficiency in on-farm biopurification systems

Addition of pesticide-primed soil containing adapted pesticide degrading bacteria to the biofilter matrix of on farm biopurification systems (BPS) which treat pesticide contaminated wastewater, has been recommended, in order to ensure rapid establishment of a pesticide degrading microbial community in BPS. However, uncertainties exist about the minimal soil inoculum density needed for successful bioaugmentation of BPS. Therefore, in this study, BPS microcosm experiments were initiated with different linuron primed soil inoculum densities ranging from 0.5 to 50 vol.% and the evolution of the linuron mineralization capacity in the microcosms was monitored during feeding with linuron. Successful establishment of a linuron mineralization community in the BPS microcosms was achieved with all inoculum densities including the 0.5 vol.% density with only minor differences in the time needed to acquire maximum degradation capacity. Moreover, once established, the robustness of the linuron degrading microbial community towards expected stress situations proved to be independent of the initial inoculum density. This study shows that pesticide-primed soil inoculum densities as low as 0.5 vol.% can be used for bioaugmentation of a BPS matrix and further supports the use of BPS for treatment of pesticide-contaminated wastewater at farmyards.     

Methodological and Practical Considerations for Developing Multiproject Baselines for Electric Power and Cement Industry Projects in Central America

The Lawrence Berkeley National Laboratory (Berkeley Lab) and the Center for Sustainable Development in the Americas (CSDA) conducted technical studies and organized two training workshops to develop capacity in Central America for the evaluation of climate change projects. This paper describes the results of two baseline case studies conducted for these workshops, one for the power sector and one for the cement industry, that were devised to illustrate certain approaches to baseline setting. Multiproject baseline emission rates (BERs) for the main Guatemalan electricity grid were calculated from 2001 data. In recent years, the Guatemalan power sector has experienced rapid growth; thus, a sufficient number of new plants have been built to estimate viable BERs. We found that BERs for baseload plants offsetting additional baseload capacity ranged from 0.702 kgCO2/kWh (using a weighted average stringency) to 0.507 kgCO2/kWh (using a 10th percentile stringency), while the baseline for plants offsetting load-following capacity is lower at 0.567 kgCO2/kWh. For power displaced from existing load-following plants, the rate is higher, 0.735 kgCO2/kWh, as a result of the age of some plants used for meeting peak loads and the infrequency of their use. The approved consolidated methodology for the Clean Development Mechanism yields a single rate of 0.753 kgCO2/kWh. Due to the relatively small number of cement plants in the region and the regional nature of the cement market, all of Central America was chosen as the geographic boundary for setting cement industry BERs. Unfortunately, actual operations and output data were unobtainable for most of the plants in the region, and many data were estimated. Cement industry BERs ranged from 205 kgCO2 to 225 kgCO2 per metric ton of cement.     

Characterizing pesticide sorption and degradation in macro scale biopurification systems using column displacement experiments

The efficiency of biopurification systems to treat pesticide-contaminated water was previously studied in microcosms. To validate the obtained results, macrocosm systems were set-up. Four pesticides (linuron, isoproturon, bentazone, and metalaxyl) were continuously applied to ten different organic substrate mixes. Retention of the pesticides was similar and in some cases slightly lower in the macrocosms compared to the microcosms. Differences in retention between the different mixes were however minimal. Moreover, the classification of the retention strength of the pesticides was identical to that observed in microcosms: linuron > isoproturon > metalaxyl > bentazone. Monod kinetics were used to describe delayed degradation, which occurred for isoproturon, metalaxyl and bentazone. No breakthrough of linuron was observed, thus, this pesticide was appointed as the most retained and/or degraded pesticide, followed by isoproturon, metalaxyl and bentazone. Finally, most of the matrix mixes efficient in degrading or retaining pesticides were mixes containing dried cow manure.     

Biosphere II: Meeting ground for ecology and technology

Summary Biosphere II is a new project to build a self-contained ecological system containing humans, plants, and as many other living organisms as necessary for long-term sustenance. Soviet space scientists have already designed Bios 3, simulating conditions on board a flight to Mars. In building Biosphere II, the Institute of Ecotechnics (IE), in collaboration with Space Biospheres Ventures, Decisions Teams Limited, The Environmental Research Laboratory associated with The University of Arizona, and Sarbid Limited, plan to build the prototype of an artificial world in which environmental and ecological processes can be observed closely; An educational, scientific, and ethical laboratory, Biosphere II will raise public consciousness of the interdependence of all life. It will also serve as a control world where possibly harmful environmental effects can be modelled before they reach a crisis stage. Eventually the biospheres are to be marketed and set up in space as the biosphere, no longer in conflict with but aided by human technology, puts forth its young upon other celestial bodies.Dorion Sagan's most recent books areMicrocosmos andOrigins of Sex, both co-authored with Lynn Margulis. He is working onBiospheres, a book on closed ecological systems which is to be published shortly.