Studies on the effects of 21 fungicides and five pyrethroid insecticides on growth of
, emergence and survival of alfalfa seed and the efficacy of the chemicals in control of Verticillium wilt pathogens were conducted. 相似文献
Despite the ban on persistent organochlorines (OCs) in most of the developed nations, their usage continued until recently in many Asian developing countries including Vietnam, for agricultural purposes and vector-borne disease eradication programs. In this study, we collected human breast milk samples from the two big cities in Vietnam: Hanoi (n=42) and Hochiminh (n=44) and determined the concentrations of persistent OCs such as PCBs, DDT and its metabolites (DDTs), hexachlorocyclohexanes (HCHs), hexachlorobenzene (HCB), chlordane compounds (CHLs) and tris-4-chlorophenyl-methane (TCPMe). The contamination pattern of OCs was in the order of DDTs > PCBs > HCHs > CHLs approximately HCB approximately TCPMe. Compilation of available data indicated that DDT residue levels in human breast milk from Vietnam were among the highest values reported for Asian developing countries as well as developed nations. This result suggests recent usage of DDTs in both north and south Vietnam. Interestingly, in both cities, the p,p'-DDT portion was higher in multiparas than those in primiparas. Considering the fact that the interval between the first and the second child of a mother in Vietnam is usually short, this result probably indicates continuous intake of DDTs in the population. Analysis of infant exposure to DDTs via breast milk suggested that the daily intake rates for number of individuals are close to or above the threshold for adverse effects which may raise concern on children health. 相似文献
This paper concerns the incineration of isopropyl alcohol (IPA) using the ferrospinel catalyst MnFe2O4. It covers the preparation of the ferrospinel catalyst, the screening of catalytic activity, catalytic incineration testing, and 72-hr decay testing of the catalyst. The experimental results of catalyst screening reveal that the Mn/Fe catalyst is the best of five prepared catalysts (chromium/iron [Cr/Fe], manganese/iron [Mn/Fe], zinc/iron [Zn/Fe], nickel/iron [Ni/Fe], and pure magnetite [Fe3O4]). In tests of the catalytic incineration system used to convert IPA, 98% conversion was obtained at a space velocity of 24,000 hr(-1), an oxygen (O2) content of 21%, 1700 ppm of IPA, and a reaction temperature of 200 degrees C. 相似文献
Airborne microorganisms, especially the pathogenic microorganisms, emitted from animal feeding operations (AFOs) may harm the environment and public health and threaten the biosecurity of the farm and surrounding environment. Electrolyzed water (EW), which was considered to be an environmentally friendly disinfectant, may be a potential spraying medium of wet scrubber for airborne microorganism emission reduction. A laboratory test was conducted to investigate the airborne bacteria (CB) removal efficiency of the wet scrubber by EW spray with different designs and operating parameters. Both the available choline (AC) initial loss rate and AC traveling loss rate of acidic electrolyzed water (AEW; pH = 1.35) were much higher than those of slightly acidic electrolyzed water (SAEW; pH = 5.50). Using one spraying stage with 4 m sec?1 air speed in the duct, the no detect lines (NDLs) of SAEW (pH = 5.50) for airborne Escherichia coli, Staphylococcus aureus, and Salmonella enteritidis removal were all 50 mg L?1, whereas the NDLs of AEW (pH = 1.35) for airborne E. coli, S. aureus, and S. enteritidis removal increased to 70, 90, and 90 mg L?1, respectively. The NDLs of SAEW (pH = 5.50) for airborne E. coli, S. aureus, and S. enteritidis were lower than those of AEW (pH = 1.35) at single spraying stage. Increase in the number of stages lowered the NDLs of both SAEW (pH = 5.50) and AEW (pH = 1.35) for airborne E. coli, S. aureus, and S. enteritidis. EW with a higher available chlorine concentration (ACC) was needed at air speed of 6 m sec?1 to reach the same airborne CB removal efficiency as that at air speed of 4 m sec?1. The results of this study demonstrated that EW spray wet scrubbers could be a very effective and feasible airborne CB mitigation technology for AFOs.
Implications: It is difficult to effectively reduce airborne bacteria emitted from animal feeding operations (AFOs). Electrolyzed water (EW) with disinfection effect and acidity is a potential absorbent for spray in wet scrubber to remove microorganisms and ammonia. Based on the field test results, a laboratory experiment we conducted this time was to optimize the design and operation parameters to improve the airborne bacteria removal efficiency. A better understanding of the EW application in the wet scrubber can contribute to the mitigation of airborne bacteria from animal houses and improve the atmosphere air quality. 相似文献