Photochemical nitro-nitrite rearrangement in methyl parathion decay under tropical conditions

Two pilot-scale studies were comparatively conducted under tropical conditions during December 1992 to September 1993. One study involved facultative ponds(FP) and the others water spinach ponds(SP). Four rectangular concrete ponds, 0.8 m × 2.4 m × 1.1 m (width × length × depth), were employed to treat the Chiang Mai University campus wastewater. Water spinach (Ipomoea aquatica) was planted in two of the ponds. The influent characteristics noted showed a low organic content, i.e. BOD 25.4-29.9 mg/l, with BOD:N ratio around 1:1. The investigations were conducted using the following hydraulic retention times (HRT): 1.6, 2, 2.7, 4, 8 and 16 d. The results showed that the BOD, COD and SS mass removal rates increased as the mass loading rates increased and the SP was significantly more effective in reducing the organic content than the FP. No relationship was found between TN mass removal and the loading rates. However, the TP mass removal rates in the SP and the FP were rather low and were considered to be insignificant. It was observed that SS accumulated in the water spinach root systems which tended to act as a strainer. This process led to plant growth inhibition and finally die-off. The average water spinach growth rates varied from 37 to 107 g wet wt./(m2.d) and no relationship was established between the growth rates and the HRT.

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A simple design and operation for the anaerobic treatment of highly concentrated swine waste in the tropics

Water Science & Technology ◽

10.2166/wst.1995.0466 ◽

1995 ◽

Vol 32 (12) ◽

pp. 91-97 ◽

Cited By ~ 1

Author(s):

P. Y. Yang ◽

M. Kuroshima

Keyword(s):

Treatment Process ◽

Total Solid ◽

Anaerobic Treatment ◽

Solid Content ◽

Total Solid Content ◽

Treatment Processes ◽

Tropical Conditions ◽

Biological Reaction ◽

The Tropics ◽

Small Producers

In order to develop a simple operation for an anaerobic treatment process for highly concentrated pig wastewater for small producers, a three-stage anaerobic treatment process was investigated. The system provided a series of mixing, homogenization, biological reaction and final stabilization of concentrated pig waste (total solid content of 8–10%). The process provided a stable operational performance, simple operational procedure and well stabilized sludge effluent. It was also found that the system is economically feasible in Hawaii. Compared to the other treatment processes for highly concentrated pig waste, this process is considered as an appropriate alternative for the application of the small producers in land limited and tropical conditions. Also, the present treatment system can be easily developed into a prefabricated package plant which can minimize the on-site labor and building costs.

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Interactive toxic effects of agrochemicals on aquatic organisms

Water Science & Technology ◽

10.2166/wst.1999.0067 ◽

1999 ◽

Vol 40 (1) ◽

pp. 357-364 ◽

Cited By ~ 8

Author(s):

A. Kungolos ◽

P. Samaras ◽

A. M. Kipopoulou ◽

A. Zoumboulis ◽

G. P. Sakellaropoulos

Keyword(s):

Daphnia Magna ◽

Marine Bacterium ◽

Methyl Parathion ◽

Vibrio Fischeri ◽

Interactive Effect ◽

Algal Growth ◽

Aquatic Organisms ◽

Interactive Effects ◽

Selenastrum Capricornutum ◽

Toxic Compound

The effects of three common agrochemicals, lindane, methyl parathion and atrazine, on crustacean Daphnia magna, alga Selenastrum capricornutum and marine bacterium Vibrio fischeri were investigated in this study. Methyl parathion was the most toxic compound towards all three organisms, while lindane was more toxic to Daphnia magna and Vibrio fischeri than atrazine, and atrazine was more toxic to Selenastrum capricornutum than lindane. Among the three aquatic organisms, Selenastrum capricornutum was most sensitive in detecting lindane and atrazine toxicity, while Daphnia magna was most sensitive in detecting methyl parathion toxicity. The interactive effects of the pesticides were also investigated. The interactive effect between lindane and methyl parathion on survival of Daphnia magna was synergistic, while the ones between lindane and atrazine and between methyl parathion and atrazine were generally additive. The interactive effect of the three pesticides applied together on Daphnia magna was synergistic. The interactive effect of the three pesticides on the growth of Selenastrum capricornutum was antagonistic with few cases of addition, while the effect of all the three pairs of pesticides on algal growth was also antagonistic. The interactive effect of lindane and methyl parathion on Vibrio fischeri was additive.

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A Kinetic Spectrophotometric Method to Determine the Insecticide Methyl Parathion in Commercial Formulations and the Aqueous Environment

International Journal of Environmental & Analytical Chemistry ◽

10.1080/03067319008026953 ◽

1990 ◽

Vol 38 (4) ◽

pp. 513-523 ◽

Cited By ~ 5

Author(s):

C. Cruces Blanco ◽

F. Garcia Sanchez

Keyword(s):

Spectrophotometric Method ◽

Methyl Parathion ◽

Aqueous Environment ◽

Kinetic Spectrophotometric

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Lunar Cycle Influences Reproductive Performance of Crossbred Brahman Cows Under Tropical Conditions

Journal of Biological Rhythms ◽

10.1177/0748730420983638 ◽

2021 ◽

pp. 074873042098363

Author(s):

Alejandro A. Aguirre ◽

Roberto A. Palomares ◽

Aitor D. De Ondiz ◽

Eleazar R. Soto ◽

Mariana S. Perea ◽

...

Keyword(s):

Reproductive Performance ◽

Full Moon ◽

Lunar Cycle ◽

The Moon ◽

Crossbred Cows ◽

Lunar Phases ◽

Tropical Conditions ◽

Service Conception ◽

New Moon ◽

Postpartum Estrus

Evidence has accumulated over the years indicating that the moon influences some aspects of the reproductive activity in animals and humans. However, little is known about the influence of the lunar cycle on the reproductive performance of cows under tropical conditions, where the environment strongly affects reproduction. This retrospective study was conducted with the aim of assessing the influence of the lunar cycle on some reproductive traits of tropical crossbred cows managed in a pasture-based system. Data from 5869 reproductive records from two commercial farms localized in the Maracaibo Lake Basin of Zulia State, Venezuela, were analyzed. Variables studied were first service conception rate, calving frequency, first postpartum estrous frequency, and pregnancy frequency. In addition to the lunar cycle, the effects of farm, season, and predominant breed were also considered. Data were analyzed using logistic regression and general linear model from SAS. First service conception was affected by lunar phases and predominant breed, but not by farm or season. For frequencies of calving, first postpartum estrus, and pregnancy, there was no main effect of farm, season, and predominant breed, whereas the effect of lunar phases was highly significant. First service conception was significantly greater in waning than in crescent phase of the lunar cycle. Frequencies of calving, first estrus, and pregnancy were highly correlated and showed greater figures around full moon and new moon. In conclusion, lunar cycle influenced first service conception, attaining greater values in the waning phase of the moon cycle. Frequencies of calving, first postpartum estrus, and pregnancy in crossbred cows showed a clear bimodal rhythm, whose greatest values coincided with new moon and full moon.

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