Use of Preservative Agents and Antibiotics for Increased Poliovirus Survival on Positively Charged Filters

Environmental surveillance of poliovirus (PV) and other non-enveloped viruses can help identify silent circulation and is necessary to certify eradication. The bag-mediated filtration system is an efficient method to filter large volumes of environmental waters at field sites for monitoring the presence of viruses. As filters may require long transit times to off-site laboratories for processing, viral inactivation or overgrowth of bacteria and fungi can interfere with virus detection and quantification (Miki and Jacquet in Aquatic Microb Ecol 51(2):195–208, 2008). To evaluate virus survival over time on ViroCap^? filters, the filters were seeded with PV type 1 (PV1) and/or MS2 and then dosed with preservatives or antibiotics prior to storage and elution. These filters were stored at various temperatures and time periods, and then eluted for PV1 and MS2 recovery quantification. Filters dosed with the preservative combination of 2% sodium benzoate and 0.2% calcium propionate had increased virus survival over time when stored at 25 °C, compared to samples stored at 25 °C with no preservatives. While elution within 24 h of filtration is recommended, if storage or shipping is required then this preservative mixture can help preserve sample integrity. Addition of an antibiotic cocktail containing cephapirin, gentamicin, and Proclin^? 300 increased recovery after storage at 4 and 25 °C, when compared to storage with no antibiotics. The antibiotic cocktail can aid sample preservation if access to appropriate antibiotics storage is available and sample cold chain is unreliable. This study demonstrated that the use of preservatives or antibiotics is a simple, cost-effective method to improve virus detection from ViroCap cartridge filters over time.     

REUSE OF DOMESTIC WASTEWATER FOR IRRIGATION IN ARID ZONES: A CASE STUDY1

ABSTRACT: The domestic sewage of the city of Beer-Sheva, Israel, which is located in an arid region, is treated in a series of facultative ponds. The treated effluent is stored temporarily in an open surface earthen reservoir (about 0.5 ± 10⁶ m³ in volume) and then used for irrigation. The effluent is applied via sprinkler and trickle irrigation systems. The main crops irrigated are cotton, wheat, alfalfa, and corn. Total cotton yield is over 5500 kg/ha, and the wheat grain yield is over 7500 kg/ha. The amount of effluent applied is about 6500 m³/ha for cotton (including preplant irrigation), and the wheat receives about 4500 m³/ha via irrigation and an additional 2000 m³/ha from precipitation. Due to the nutrient content in the effluent, the above yields are obtained without any additional fertilization.     

THE OPTIMAL TIME TO START THE OPERATION OF A DESALTING PLANT IN ISRAEL1

The study contains the methodology of finding the optimal time to start the operation of a desalting plant or any other non conventional source of water for agricultural use in Israel. The essence of the methodology is the moving equilibrium price and quantity of agricultural products. The market of agricultural products is represented by a single demand curve and a supply curve which is derived from the agricultural sector production function. Both the demand for and the supply of agricultural products functions are shifting over time. The marginal value product of water is the critical value that determines the optimal time of a desalting plant. The study is static in the sense that dynamic aspects per se are not dealt with-e.g. learning by doing of building and operating desalting plants. The empirical results although used for illustrative purposes can be used as reference points for other detailed and more ‘exact’ studies on water desalination.     

New international long-term ecological research on air pollution effects on the Carpathian Mountain forests,Central Europe

An international cooperative project on distribution of ozone in the Carpathian Mountains, Central Europe was conducted from 1997 to 1999. Results of that project indicated that in large parts of the Carpathian Mountains, concentrations of ozone were elevated and potentially phytotoxic to forest vegetation. That study led to the establishment of new long-term studies on ecological changes in forests and other ecosystems caused by air pollution in the Retezat Mountains, Southern Carpathians, Romania and in the Tatra Mountains, Western Carpathians on the Polish-Slovak border. Both of these important mountain ranges have the status of national parks and are Man & the Biosphere Reserves. In the Retezat Mountains, the primary research objective was to evaluate how air pollution may affect forest health and biodiversity. The main research objective in the Tatra Mountains was to evaluate responses of natural and managed Norway spruce forests to air pollution and other stresses. Ambient concentrations of ozone (O(3)), sulfur dioxide (SO(2)), nitrogen oxides (NO(x)) as well as forest health and biodiversity changes were monitored on densely distributed research sites. Initial monitoring of pollutants indicated low levels of O(3), SO(2), and NO(x) in the Retezat Mountains, while elevated levels of O(3) and high deposition of atmospheric sulfur (S) and nitrogen (N) have characterized the Tatra Mountains. In the Retezat Mountains, air pollution seems to have little effect on forest health; however, there was concern that over a long time, even low levels of pollution may affect biodiversity of this important ecosystem. In contrast, severe decline of Norway spruce has been observed in the Tatra Mountains. Although bark beetle seems to be the immediate cause of that decline, long-term elevated levels of atmospheric N and S depositions and elevated O(3) could predispose trees to insect attacks and other stresses. European and US scientists studied pollution deposition, soil and plant chemistry, O(3)-sensitive plant species, forest insects, and genetic changes in the Retezat and Tatra Mountains. Results of these investigations are presented in a GIS format to allow for a better understanding of the changes and the recommendations for effective management in these two areas.     

Emission control policies under uncertainty

The paper deals with the problem of optimal environmental policy under uncertainty. Usually, when an environmental policy is considered, only the expected values of the parameters of the marginal benefit and marginal cost functions associated with the policy are known. Thus a relevant question is: In the presence of uncertainty, what is the optimal policy mean for achieving the environmental objective? The study addresses itself to the specific objective of improving air quality although the analysis is generally applicable. The policy means are emission taxes and emission quotas. It is shown that under uncertainty neither of these means is generally optimal, and that specific parameter values of the costs and benefits relations and their distributions determine the optimal policy for each situation.     

Trichloroacetic acid cycling in Sitka spruce saplings and effects on sapling health following long term exposure

Trichloroacetic acid (TCA, CCl(3)COOH) has been associated with forest damage but the source of TCA to trees is poorly characterised. To investigate the routes and effects of TCA uptake in conifers, 120 Sitka spruce (Picea sitchensis (Bong.) Carr) saplings were exposed to control, 10 or 100 microg l(-1) solutions of TCA applied twice weekly to foliage only or soil only over two consecutive 5-month growing seasons. At the end of each growing season similar elevated TCA concentrations (approximate range 200-300 ng g(-1) dwt) were detected in both foliage and soil-dosed saplings exposed to 100 microg l(-1) TCA solutions showing that TCA uptake can occur from both exposure routes. Higher TCA concentrations in branchwood of foliage-dosed saplings suggest that atmospheric TCA in solution is taken up indirectly into conifer needles via branch and stemwood. TCA concentrations in needles declined slowly by only 25-30% over 6 months of winter without dosing. No effect of TCA exposure on sapling growth was measured during the experiment. However at the end of the first growing season needles of saplings exposed to 10 or 100 microg l(-1) foliage-applied TCA showed significantly more visible damage, higher activities of some detoxifying enzymes, lower protein contents and poorer water control than needles of saplings dosed with the same TCA concentrations to the soil. At the end of each growing season the combined TCA storage in needles, stemwood, branchwood and soil of each sapling was <6% of TCA applied. Even with an estimated half-life of tens of days for within-sapling elimination of TCA during the growing season, this indicates that TCA is eliminated rapidly before uptake or accumulates in another compartment. Although TCA stored in sapling needles accounted for only a small proportion of TCA stored in the sapling/soil system it appears to significantly affect some measures of sapling health.     

Process hazards review applied to the use of anhydrous ammonia in agriculture: an example of chemical process safety for small business

Process hazards review (PHR) techniques have generally been applied by large, sophisticated companies in the nuclear, aerospace, and chemical process industries. There remains, however, a large population of smaller distributors and consumers of hazardous materials which could benefit equally from the application of PHR. These consumers unfortunately are generally less sophisticated and individually lack the necessary resources required to apply such state-of-the-art safety techniques.

Where common processes can be identified, it is possible to conduct a more generic PHR that will provide a sound technical basis for recognizing and preventing the development of hazards wherever these processes are used. Some facility-specific issues will always need to be considered, but the existence of the generic PHR should make the conduct of a PHR by each facility considerably easier and less costly.

Researchers from the National Institute for Occupational Safety and Health (NIOSH) contracted with DNV Technica Inc. to lead a hazard and operability study (HAZOP) of agricultural handling of anhydrous ammonia, from the receipt of ammonia at the retail distribution centre to the application of the ammonia by farmers to the fields. The multidisciplinary HAZOP team consisted of representatives from NIOSH, an agricultural chemical trade association, an ammonia producer, state ammonia facility inspectors, a retail distributor, and an equipment manufacturer. Several participants were part-time farmers with ammonia application experience.

Some specific aspects of applying the HAZOP technique in the context of this study, the findings obtained, and the plans to disseminate the important safety information developed during the course of the PHR are discussed. Finally, it is suggested that this approach could prove to be a useful addition to the product stewardship activities of chemical producers.