Rice Field Water Research Articles

Rice Pesticide Concentrations in the Colusa Basin Drain and the Sacramento River, California, 1990–1993

AbstractThe pesticides molinate, thiobencarb, and carbofuran are applied to rice (Oryza sativa L.) fields in the Sacramento Valley, California, each year during April through June. These pesticides are of concern because of their adverse effects on water quality and their potential adverse effects on aquatic life. Therefore, the California Regional Water Quality Control Board (CRWQCB) mandated the holding of irrigation‐return water in rice fields to increase pesticide degradation and dissipation before the water is released to the Sacramento River. The CRWQCB also established performance goals to maintain drinking water quality for the city of Sacramento and to protect the habitat for aquatic life. The objectives of this study were to determine the effects of increased irrigation‐return water holding times on rice pesticide concentrations and loads in the Colusa Basin Drain and the Sacramento River. Dissolved pesticide concentrations were measured in water samples collected in May through July during 1990–1993 at the Colusa Basin Drain at Road 99E near Knights Landing (Colosa Basin Drain) and at the Sacramento River at Sacramento. Pesticide concentrations and loads at both sites showed a decrease from 1990–1992 and an increase in 1993. This trend cannot be explained by the yearly holding time regulations but can be explained by the amount of yearly emergency releases. The yearly changes in pesticide concentration detected demonstrate that continued monitoring and management of pesticides is necessary to maintain water quality.

Influence of fertilizer management and water regime on methane emission from rice fields

Experiments were conducted to determine methane emission from a rainfed lowland rice field (water depth about 3–30 cm) and an irrigated shallow rice field (4–6 cm), both planted to the same cultivar, cv. ‘Gayatri,’ as influenced by fertilizer management practices. Methane emission peaked from 100 to 125 days after transplanting followed by a decline in rainfed lowland field plots. Application of prilled urea did not enhance methane emission significantly over that of the untreated control. Subsurface application of urea supergranules was, however, effective in reducing the methane flux over that of the control. Methane emission was lowest in plots treated with the mixture of prilled urea and Nimin (a nitrification inhibitor). Under irrigated shallow conditions, the application of prilled urea and green manure ( Sesbania rostrata), singly and in combination, significantly increased methane emission over that of the control. Cumulative methane efflux from control and prilled urea treated lowland rice field was about 4–10 times higher than that in irrigated shallow fields. These results suggest that by virtue of their readily mineralizable carbon and ninhydrin reactive nitrogen, these substrates can serve as positive indicators of methane emission potential of rice fields.

Copper (II) complexation in northern California rice field waters: an investigation using differential pulse anodic and cathodic stripping voltammetry

Differential pulse anodic stripping voltammetry (DPASV) and competitive ligand equilibration-cathodic stripping voltammetry (CLE-CSV) demonstrated that≥99% of the dissolved copper in five rice field waters, one river water and a catchment basin water collected at sites in northern California is complexed by natural organic matter. Concentrations of natural copper complexing ligands (C L) ranged from 81 to 426 nM determined by CLE-CSV using the competitive ligand 8-hydroxyquinoline and from 156 to 1374 nM using DPASV. Experimental values for conditional stability constants (with respect to free Cu 2+) of natural copper–organic ligand complexes (log K′ CuL) fell in the range 10.2–11.2 using DPASV and 11.1–11.5 using CLE-CSV. DPASV analyses revealed evidence of organic matter adsorption to the electrode surface at low dissolved organic carbon (DOC) concentrations (i.e. 200 μg l −1 DOC for a 10-min deposition period), for some but not all water samples. Examination of lyophilized, filtered rice field water using scanning electron microscopy (SEM) and pyrolysis gas chromatography mass spectrometry (pyr-GC/MS) did not reveal differences that could be associated with surface active material. Uncomplexed copper accounts for only minor amounts of total copper in rice field waters and natural ligands are expected to influence its effectiveness as an agrochemical.

SWAGMAN Options: A hierarchical multicriteria framework to identify profitable land uses that minimize water table rise and salinization

In irrigation areas of southeastern Australia, recharge from rice cultivation is contributing to water table rise. The presence of a shallow water table exacerbates the damage potential of waterlogging and soil salinization, and threatens the long-term productivity of irrigated agriculture. By minimizing farm net recharge, water table rise and the damage potential of waterlogging and salinization can be minimized. A hierarchical multicriteria framework, SWAGMAN Options (Salt Water And Groundwater MANagement), is developed to identify profitable nonriceland uses which complement rice growing and induce discharge from shallow water tables without exceeding critical levels of soil salinity. The framework is multidisciplinary in its approach. Fundamentals of agronomy, irrigation, economics, hydrogeology, and operations research are used to formulate this framework. SWAGMAN Options is applied to the Camarooka Project Area in New South Wales, Australia, to study the sensitivity of maximum rice area per farm, rice field water use limit, rainfall conditions, optimal depth, critical salinity, initial piezometric levels, and weights associated with the objective functions on subsurface drainage and farm net returns. Results indicate that complementing rice production with maize and canola and restricting rice to fields where rice field water use is less than 14 ML ha −1, will minimize the water table rise and improve farm profitability. A description of the framework, SWAGMAN Options, and the results from sensitivity analyses are presented in this paper.

Fate and disposition of diflubenzuron in rice fields

AbstractLaboratory and field investigations were undertaken to determine the fate, disposition, and persistence of the insecticide diflubenzuron in California rice culture. Water solubility was similar in distilled/deionized water (88.8 ± 4.0 μg/L) and rice field water (92.6 ± 3.5 μg/L), while the measured Henry's law constant was 2.34 ± 0.02 × 10−1 Pa.m3/mole. Diflubenzuron was rapidly photodegraded in field water primarily to the more stable chlorophenylurea and difluorobenzoic acid; field water photolysate was equally toxic to Daphnia magna as pure insecticide solutions. Applications to experimental rice field plots resulted in rapid dissipation of diflubenzuron (half‐life 27.3 h), nonpersistent sediment residues, and significant partitioning into the surface microlayer.

Changes in sex ratio of chironomid imagines from rice field waters

A survey was made of the sex ratios of chironomids emerging from three rice fields to investigate the sexual difference of response to pesticide application in the immature stage. In a field without pesticides, Ablabesmyia monilis showed a preponderance of female imagines. A field with herbicide application showed male preponderance for Chironomus kiiensis, Polypedilum nubifer and Tanytarsus oyamai. This trend was even more pronounced for T. oyamai in a field with insecticide-herbicide-fungicide application. The sex ratio increases associated with pesticide application may be due to different responses of the sexes to decreased predation pressure as a secondary effect of pesticide toxicity or pesticide toxicity itself in the immature stage.

FATE AND DISPOSITION OF DIFLUBENZURON IN RICE FIELDS

Laboratory and field investigations were undertaken to determine the fate, disposition, and persistence of the insecticide diflubenzuron in California rice culture. Water solubility was similar in distilled/deionized water (88.8 ± 4.0 μg/L) and rice field water (92.6 ± 3.5 μg/L), while the measured Henry's law constant was 2.34 ± 0.02 × 10−1 Pa.m3/mole. Diflubenzuron was rapidly photodegraded in field water primarily to the more stable chlorophenylurea and difluorobenzoic acid; field water photolysate was equally toxic to Daphnia magna as pure insecticide solutions. Applications to experimental rice field plots resulted in rapid dissipation of diflubenzuron (half-life 27.3 h), nonpersistent sediment residues, and significant partitioning into the surface microlayer.

Aqueous sample preparation for bioassay using supercritical fluid extraction

AbstractSupercritical fluid extraction (SFE) has become a valuable tool in the preparation of environmental samples for analysis. Most applications to date have been to extract compounds from solid matrices for later analysis by gas chromatographic or high‐performance liquid chromatographic methods. The objective of this research was to extend SFE applications to aqueous samples extracted on EmporeTM (C18) solid‐phase extraction disks. This technique, which essentially eliminated the use of conventional solvents in preparing the filtered samples, yielded extracts that were compatible with bioassay. The method included aqueous sample extraction onto C18 Empore disks and subsequent elution with supercritical CO2 to isolate and concentrate analytes of interest, using glass beads as an off‐line trapping matrix. Analytes were then redissolved in reconstituted water and evaluated for toxicity using the larval medaka, Oryzias latipes, 96‐h static toxicity bioassay. Tests with water spikes of molinate, thiobencarb, methyl parathion, and malathion extracted on disks and eluted by SFE gave quantitative recoveries (>90%). Samples of a mixture of these compounds prepared using SFE produced an LC50 of 2.88 mg/L, compared with an LC50 of 2.60 mg/L produced by a water sample directly spiked with equivalent concentrations. Extracts of rice‐field water prepared for bioassay and gas chromatographic analysis using the SFE method gave good recoveries without loss of biological activity.

Mass rearing, larval behaviour and effects of plant age on the rice caseworm, Nymphula depunctalis (Guenée) (Lepidoptera: Pyralidae)

The mass-rearing method for efficient production of rice caseworm Nymphula depunctalis (Guenée) was improved. Moths oviposit most in ventilated cages on the undersides of floating cut rice leaves aged 4–8 weeks after transplanting (WT). There was no effect of leaf width on oviposition. Greatest egg production occurs with a 12 h scotophase. Moths are highly tolerant of crowding in oviposition cages, as up to 40 females averaged 86–115 eggs per female in 0.14 m 3 cages. Honey as a carbohydrate energy source increases the rate of oviposition but not total oviposition. Larvae require standing water to fill their cases as respiration occurs with tracheal gills. Larval survival was equal when reared in distilled water, pesticide-free ricefield water, or chlorinated tap water, whether aerated or not. Larvae survive better, grow larger, mature more rapidly, and become more fecund adults when reared on plants 2–6 WT. Pupae are non-aquatic. The caseworm's inability to develop satisfactorily on post-vegetative rice may be attributed to poor nutrition and less favourable oviposition substrates. Females prefer to oviposit on dropping leaves floating on the water surface. As the crop matures, fewer leaves touch or float on the water surface. Eggs desiccate if laid on aerial portions of plants and are more exposed to natural enemies.

Stable isotope ratios in irrigation water can estimate rice crop evaporation

Irrigated crops provide about one third of world food production, and the total area under irrigation has increased by more than a factor of three since 1950 [Brown, 1988]. Possibilities for further geographical expansion are limited; therefore future production increases are likely to require higher efficiency of water use. Of the major grain crops, lowland rice requires the most water, with total demand per unit area at least twice that for wheat and maize. Stable isotope abundance changes in irrigation water can provide direct indication of integrated evaporation losses exclusive of transpiration and thus provide a new tool to monitor a key parameter relevant to water use efficiency. Large enrichments of deuterium and oxygen‐18 in rice field water compared to initial input water in a semi‐arid region of southeastern Australia indicate high evaporation rates (7 mm day−1) during the first month following flooding. This contrasts with semi‐mature rice crops which had small heavy isotope enrichments of field water, indicating low evaporation (<1 mm day−1), compared to transpiration (6 to 7 mm day−1). Over the entire rice‐cropping season, evaporation accounted for about 40 per cent of total losses to the atmosphere, with transpiration providing the remainder.

Infectivity of Lagenidium giganteum to Culex tarsalis (Diptera: Culicidae) in Rice Field Waters: Laboratory Evaluation

Effects of rice field water quality and host age on the infectivity of Lagenidium giganteum Couch to Culex tarsalis Coquillett were investigated in the laboratory for 3 yr. Selected water chemistry parameters were quantified to determine their influence on the corresponding infection rates. Large variation in dose-response was obtained among different water samples. When individual instars were exposed to a concentration of 10 zoospores/ml in different water samples, infection for the first through fourth instars respectively averaged 49, 42, 56, and 47%, with 78% of the variation in larval mortality significantly correlating with changes in common water chemistry parameters. Singly, none of the water chemistry variables accounted for >35% of the variation in infection rates. The causal relationships between changes in water chemistry and infectivity were unclear. When all instars were bioassayed in the same container to remove variation caused by different water samples, the first three instars were equally susceptible to infection, and the fourth instar was less susceptible. With exposure to 100 zoospores per ml, the period of lethal infection increased from 18 to 48 h as host age increased from the first to the fourth stadium.

Effects of cadmium on the biochemical composition of the freshwater crayfishProcambarus clarkii (Girard, 1852)

Lake Albufera of Valencia (Spain) and the surrounding rice field waters are subjected to very heavy loads of sewage and toxic residues. Among these residues include heavy metals which have been deposited from the many urban and waste waters in this area. The American red crayfish, Procambarus clarkii from Albufera Lake has high resistance to heavy metals. The authors have also found that P. clarkii shows a high capacity for cadmium accumulation in experimental conditions and natural conditions since crayfish collected in this area contained considerable amounts of cadmium in several tissues even after 15 days of depuration in clean water. Since the physiological changes that take place when organisms are exposed to sublethal levels of stress could include rate of feeding as well as respiration and excretion, the net result could be a change in energy available for growth and reproduction. In this work, the authors have studied the biochemical energy composition of hepatopancreas, muscle and gills of P. clarkii after short term sublethal exposure to cadmium.

Bensulfuron methyl dissipation in california rice fields, and residue levels in agricultural drains and the Sacramento River

Herbicides applied to rice fields in the Sacramento Valley, CA, are released into agricultural drains via runoff water. Major agricultural drains then empty into the Sacramento River where contaminants may affect the quality of drinking water and aquatic wildlife habitat. Bensulfuron methyl (BSM) (Londax| methyl 2-[[[[[(4,6-dimethoxypyrimidin-2-yl)amino]carbonyl]amino]sulfonyl] methyl]benzoate), a highly active sulfonylurea, was registered for use in California in 1989 as a rice herbicide. Although toxicity of BSM is low for mammals and fish (rat oral LDso >5000 mg/kg; rainbow trout 96-hr LCso >150 mg/L) (Beyer et al. 1988), the effect of residues on the aquatic environment, in particular plant life, is unknown. Persistence of BSM in rice paddy water has been examined in the laboratory (Yuyama et al. 1987b) but not in the field. According to label recommendations, rice paddy water should be held on the field for at least 5 days after application of BSM. Residue levels of BSM in agricultural drains and rivers, resulting from runoff releases after this holding time, have not been determined. This study examines dissipation of BSM from paddy water of commercial rice fields and measures residue levels in major agricultural drains and the Sacramento River. MATERIALS AND METHODS Three commercial rice fields located in Colusa and Glenn Counties, CA, were selected to examine dissipation of BSM in paddy water. Fields 1, 2 and 3 had total areas of 24, 16 and 17 ha, respectively. Only the last paddy of each of these fields was sampled. Paddy areas were 1.3, 1.2 and 3.1 ha, for Fields 1, 2 and 3, respectively. A 60% dry flowable formulation of BSM was aerially applied to Fields 1, 2 and 3 on May 2, 12 and 16, respectively, in 1989. Applications were made to standing water, 8 to 12 d after seeding, at the nominal rate of 0.07 kg/ha, for all three fields. Water

Effect of saline water on rice yields and soil properties in the Murrumbidgee Valley

Rice was grown on a transitional redbrown earth for 3 consecutive seasons and irrigated with saline groundwater of salinities 0.25, 0.5, 1.0, 1.5 and 2.0 dS/m. A 4.0 dS/m treatment was applied in the final year. Grain yield was only affected by the 4.0 dS/m treatment, where a 25% yield reduction occurred. Soil salinities increased with increasing salinity of applied treatments, reaching equilibrium after 3 years. The higher salinity treatments resulted in significantly increased rice field water consumption, attributed to increased infiltration rates. The presence of high electrolyte levels in the soil surface prevented any detrimental effect of increased soil sodium levels on soil properties. However, the communal supply system with potential cultivation of salt-sensitive species such as soybean, along with the potential for higher groundwater accessions, suggests that the salinity of irrigation water should be maintained as low as possible.

Gill ATPase activity inProcambarus clarkii as an indicator of heavy metal pollution

Lake Albufera and the surrounding rice field waters are subjected to very heavy loads of sewage and toxic industrial residues, including heavy metals, from the many urban and waste waters of this area. The American red crayfish, Procambarus clarkii have a high resistance to toxic effects of heavy metals. The sublethal effects of heavy metals on gills of fish and aquatic invertebrates have been extensively studied. Some metabolic disturbances and histologic damages have been reported, as well as osmoregulation alterations. However, little work has been done about the effect of heavy metals on Na,K and Mg-ATPases of freshwater invertebrate gills. Na,K-ATPase is the prime mediator of ion transport across cellular membranes and plays a central role in whole body ion regulation in marine and estuarine animals. Na,K-ATPase has been reviewed and assessed as a potentially useful indicator of pollution stress in aquatic animals. The purpose of this study is look for the relation, if any, between crayfish gill ATP-ase activity changes and metal exposure in laboratory. This find would allow the authors to assay this potential indicator in the field.

Evaluation of an enzyme‐linked immunosorbent assay (ELISA) for the direct analysis of molinate (Ordram®) in rice field water

A direct ELISA for the thiocarbamate herbicide molinate was used to study distribution and dissipation of the compound in a treated rice field. No sample preparation other than buffering and dilution was required for the analysis of field water samples. Analyses were performed in 96‐well microplates and required less than 0–5 man‐hour per sample (three dilutions per sample, four replicate wells per dilution). Spiked samples and selected field samples were split for analysis by ELISA and gas chromatography. Two control samples of 92 and 93 ppb (after dilution) had between run coefficients of variation of 13.8 and 13.9% for 37 ELISA runs. A nested ANOVA analysis revealed that the largest source of error for the ELISA was due to within replicate variability, partly attributable to interwell variability of the 96‐well plates. Practical aspects of reducing assay error and handling ELISA data are discussed. Quality control data showed that reliability of the direct ELISA is comparable to the gas chromatography ...

Determination of lead in treated crayfish Procambarus clarkii: accumulation in different tissues.

The continual loading of trace metals into our environment represents a water pollution problem due to their toxic effects on aquatic biota. In addition, metal ions can be incorporated into food chains and concentrated by aquatic organisms to a level that affects their physiological state. There are several investigations on the toxic effects and bioaccumulation of lead in fishes, molluscs, and crustaceans. Lake Albufera (Valencia, Spain) and the surrounding rice-field waters are subjected to large loads of sewage and toxic industrial residues (including heavy metals) from many urban wastewaters in the area. In 1978, the American red crayfish Procambarus clarkii (Girard) appeared in Lake Albufera. The crayfish have reached a high density producing ecological and agricultural economic problems in rice crops. The crayfish is being fished commercially for human consumption without adequate protection to human health. The purpose of the present study was to investigate the accumulation of lead in tissues of the crayfish P. clarkii following short term lead exposure at several sublethal concentrations. The gills, midgut glands, antennal glands and muscle were analyzed by atomic absorption spectrophotometry.

Effects of temperature on the acute toxicity of heavy metals (Cr, Cd, and Hg) to the freshwater crayfish, Procambarus clarkii (Girard).

Chromium, an essential trace element for humans and animals is involved in normal carbohydrate metabolism; however, it is toxic at high concentrations. There is no evidence that cadmium and mercury are biologically essential but their toxicity for organisms is well known. Both cause toxic effects at low concentrations to most organisms, especially in combination with other environmental variables such as temperature. Lake Albufera and the surrounding rice field waters are subjected to very heavy loads of sewage and toxic industrial residues (including heavy metals) from the many urban and waste waters in this area. In 1978, the American red crayfish Procambarus clarkii appeared in lake Albufera and in the surrounding rice fields. Without adequate sanitary control, the crayfish is presently being fished commercially for human consumption. The purpose of the present study is to evaluate the degree of toxicity of various heavy metals (chromium, cadmium and mercury) to freshwater crayfish Procambarus clarkii at various temperatures.

Uptake of nutrients by rice under rice-cum-fish culture in intermediate deep water situation (upto 50-cm water depth)

In a lowland rice field, under controlled (cement tank) and uncontrolled (earthen tank) water situations the uptake of Fe by rice was two times higher under rice-cum-fish culture than in rice alone. Uptake of N by rice recorded 10% increase when fish was reared in the field in association with paddy. However, concentration and uptake of K, Ca, Mg and Mn did not show any definite trend.

Cadmium accumulation in the crayfish, Procambarus clarkii, using graphite furnace atomic absorption spectroscopy.

Lake Albufera and the surrounding rice-field waters are being subject to very heavy loads of sewage and toxic industrial residues (including heavy metals and pesticides) from the many urban and wastewaters in this area. The American red crayfish Procambarus clarkii is native to the Louisiana marshes (USA). In 1978, the crayfish appeared in Lake Albufera near Valencia (Spain), and presently, without adequate sanitary controls, the crayfish is being fished commercially for human consumption. In view of this interest, it is important to have accurate information on concentrations of cadmium in natural waters and cadmium levels of tissues of freshwaters animals used as human food, as well as the accumulation rates of this metal in this animal. In the present study, the authors investigated the accumulation of cadmium in several tissues of the red crayfish, P clarkii (Girard) from Lake Albufera following cadmium exposure. Determinations of cadmium were made by flameless atomic absorption spectroscopy and the standard additions method. Digestion of samples was made by wet ashing in open flasks with concentrated HNO/sub 3/ at 80-90/sup 0/C.