Rice field water

About 1000 pg/L (as judged by 280 g/ha in rice field water 10 cm deep) Significant reductions in immature populations of the rice water weevil (Lissorhopterus oryzophilus) 4-5 days after rice emergence in a continuously flooded field 12... 

Solid Phase Extraction. DEAE-anion exchange chromatography was employed to concentrate BT israelensis toxin from a large volume of very diluted solution. A liter of rice field water was spiked with 250 ng of the toxin (final concentration 250 pg/ml). This solution was then passed through a 1 ml DEAE-column (Sephacel Pharmacia). The toxin was eluted with 1 ml of 0.15 M NaCl solution and then assayed with the ELISA and the Immuno-Blot procedures. The assay,... 

Herbicide solutions were prepared by dilution of a concentrated aqueous stock solution with distilled deionized water or rice field water. Solutions or suspensions in gas-tight pyrex vessels were stirred eind irradiated in a photoreactor ( 2), a 150 x 36 cm chrome-lined cylinder fitted with six F40BL fluorescent lamps. A 4-nitroanisole/pyridine actlnometer (3) had a half-life of 50 min in the reactor, equivalent to spring sunlight in the Sacr uaento Valley. 

Harrison, R. O. Braun, A. Gee, S. J. O Brian, D. J. Hammock, B. D. Evaluation of an enzyme-linked immunosorbent assay (ELISA) for the direct analysis of molinate (ordram) in rice field water. Fo Agric. Immunol. 1 37-52. 1989. 

Fenthion, temephos and their degradation products were determined by HPLC-DAD and APCl-LC-MS in rice field water samples after SPE (Empore Cjg). Four fenthion transformation products could be identified in the positive or negative modes whereas the degradation of temephos resulted in six products. For both pesticides the oxo-analogue products predominate [366]. After rice fields had been treated with fenitrothion, crop waters were sampled and analysed by ELISA, LC-DAD and MS coupled by APCI interface. Eenitrothion, fenitrooxon, 3-methyl-4-nitrophenol and the s-Me isomer of fenitrothion were identified by LC-MS [367]. 

The sensitivity of the proposed method for each of the tin species examined is summarized in Table 109. These limits could be decreased either by increasing the sample size, avoiding some of the sub-analyses, or both. While the method has mainly been used for samples generated during laboratory studies (e.g., photodecompositon), none of the natural water samples analyzed have contained materials which interfered with the determination of any of the tin compounds of interest. For example, a 1-L rice-field water sample was analyzed for Ph3Sn at 1.0 yg/1 with 60% recovery. 

Virtually anywhere water contacts organic matter in the absence of air is a suitable place for methanoarchaea to thrive—at the bottom of ponds bogs and rice fields for example Marsh gas (swamp gas) IS mostly methane Methanoarchaea live inside termites and grass eating animals One source quotes 20 L/day as the methane output of a large cow... 

Sass RL, Fisher FM, Wang YB, Turner FT, Jund MF. Methane emissions from rice fields The effect of flood water management. Global Biogeochem. Cyc. 1992 6 249-262. 

Myttenaere, C., Bordeau, P. and Bittel, R. (1969a). Relative importance of water and soil in the indirect radiocaesium and radiocobalt contamination of irrigated rice fields, page 175 in Agricultural end Public Health Aspects of Environmental Contamination by Radioactive Materials, IAEA Publication No. STI/PUB/226 (International Atomic Energy Agency, Vienna). 

The relative importance of both activities is well reflected on the population labor distribution per activity 70% is dedicated to agriculture and 15% to shellfish production [14] however, these two activities are not very compatible. Aquatic organisms are currently being exposed to multiple chemical and environmental stressors with different mechanisms of toxicity, each contributing to a final overall adverse effect [16]. Recently, the shellfish farmers in the Ebro River delta have complained about a loss of production in the periods of rice cultivation that they attribute to the heavy pesticide loads discharged after rice field treatment, and this has raised also public concern about the quality of the water in this area. 

This high agriculture activity compromises the chemical and ecological status of the Ebro delta. Pesticides used in the area migrate into the delta building up, together with the pollution produced by some industries, a contamination that can be dangerous to its both fauna and flora, and this contamination increases when water from the rice fields is drained into the delta [17]. 

Siddaramappa, R., A.C. Tirol, J.N. Seiber, E.A. Heinrichs, and I. Watanabe. 1978. The degradation of carbofuran in paddy water and flooded soil of untreated and retreated rice fields. Jour. Environ. Sci. Health B 13 369-380. 

Smith, K.A., A.A. Grigarick, and M.J. Oraze. 1988. Field evaluations of diflubenzuron and triflumuron for control of the rice water weevil in California rice fields. Jour. Agricul. Entomol. 5 121-126. 

Spraying of PCP to control populations of water snails in rice fields of Surinam resulted in the death of fish and birds, including snail kites (Rostrhamus sociabilis), certain egrets and herons, and wattled jacanas (Jacana jacana). Levels of PCP in these birds and their food items suggested that PCP-contaminated food probably caused the deaths (Vermeer et al. 1974) (Table 23.5). 

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