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PubMedDate not supplied

Nitrate leaching beneath a containerized nursery crop receiving trickle or overhead irrigation.

Container production of nursery crops is intensive and a potential source of nitrogen release to the environment. This study was conducted to determine if trickle irrigation could be used by container nursery producers as an alternative to standard overhead irrigation to reduce nitrogen release into the environment. The effect of overhead irrigation and trickle irrigation on leachate nitrate N concentration, flow-weighted nitrate N concentration, leachate volume, and plant growth was investigated using containerized rhododendron (Rhododendron catawbiense Michx. 'Album') supplied with a controlled-release fertilizer and grown outdoors on top of soil-monolith lysimeters. Leachate was collected over two growing seasons and overwinter periods, and natural precipitation was allowed as a component of the system. Precipitation accounted for 69% of the water entering the overhead-irrigated system and 80% of the water entering the trickle-irrigated system. Leachate from fertilized plants exceeded the USEPA limit of 10 mg L(-1) at several times and reached a maximum of 26 mg L(-1) with trickle irrigation. Average annual loss of nitrate N in leachate for fertilized treatments was 51.8 and 60.5 kg ha(-1) for the overhead and trickle treatments, respectively. Average annual flow-weighted concentration of nitrate N in leachate of fertilized plants was 7.2 mg L(-1) for overhead irrigation and 12.7 mg L(-1) for trickle irrigation. Trickle irrigation did not reduce the amount of nitrate N leached from nursery containers when compared with overhead irrigation because precipitation nullified the potential benefits of reduced leaching fractions and irrigation inputs provided under trickle irrigation.

Agriculture↗
PubMed2005

[Intracanal aspiration technique for root canal irrigation: evaluation of smear layer removal].

A new irrigation technique (intracanal aspiration technique, IAT) was developed to minimize the extrusion of root canal irrigant. Fifteen instrumented canals of extracted canines were divided into one control and four experimental groups of 3 teeth each. Each root was fixed in a case and surrounded with colored saline agar to measure the meter value of the Root ZX and to evaluate the extrusion of the irrigant. In control teeth, no irrigation was performed. In Groups 1 and 2, the root canal was irrigated using IAT with an aspiration needle placed 2 or 3 mm short of the apex. In Groups 3 and 4, the root canal was irrigated in a conventional manner with a washing needle placed 2 or 3 mm short of the apex. The file folder of a Root ZX was attached to the aspiration needle in Groups 1 and 2, and to a washing needle in Groups 3 and 4. Each canal was irrigated with 9 ml of 14% EDTA solution and 6 ml of 6% NaClO in experimental groups, and the meter value of the Root ZX during irrigation was recorded. After the irrigation, cleanliness of the canal was evaluated using a SEM and extrusion of NaClO by discoloration of the agar. Irrigation using IAT was more effective for removing smear layer compared to the conventional method and extrusion of the irrigant was minimized. In addition, the Root ZX measurement during IAT could monitor the extent of the irrigant in the apical canal.

Dental Pulp Cavity↗
PubMed2003

Epithelial iris cyst treatment with intracystic ethanol irrigation.

PURPOSE: To report the therapeutic effects of ethanol (ETOH) irrigation into epithelial iris cysts (EIC). STUDY DESIGN: Retrospective noncomparative interventional case series. PARTICIPANTS: 102 eyes of 102 patients aged between 4 and 71 years with EIC, with 4 months to 15 years follow-up. INTERVENTION: Under local or general anesthesia, cyst fluid was drained gently via a 27-gauge needle. Without changing the position of the needle, the syringe was replaced with one containing an equal amount of ETOH to the drained cyst fluid, and ETOH was gently irrigated into the cyst. The ETOH was left inside until the cyst wall turned white (about one minute). The ETOH was aspirated and the needle removed. After the irrigation, patients were treated with atropine 1% and dexamethasone 5 ml eye drops. RESULTS: Pretreatment findings suggest that the bases of all the cysts were connected either to incisions made during previous operations or to sites of laceration from penetrating trauma. Three types of cysts were identified: single in 88 patients, double in 11 patients, and triple in 3 patients. The cyst wall contained keratic precipitates in three cases, and was vascularized in two cases. Of the 102 cases, 3 were excluded from the study because the EIC was connected to the anterior chamber. Follow-up indicated that 93 cysts resolved after the first irrigation, 3 after the second irrigation and 2 after the third irrigation and 1 case did not respond after third irrigation. The cysts clinically shrank in 78 cases by 1 day after ETOH irrigation and in 20 cases by 2 weeks after ETOH irrigation. Anterior chamber reaction was observed the day after ETOH irrigation in two cases, probably as a result of ETOH leakage, and in nine cases without apparent ETOH leakage. All were treated with dexamethasone 10 ml eye drop for 2 weeks. Intraocular pressure (IOP) normalized in 11 out of 21 cases who had IOP>20 mmHg before ETOH irrigation. CONCLUSION: Ethanol irrigation is a cost-effective and safe procedure, and we recommend consideration of the procedure for treatment of iris epithelial cysts.

Adolescent↗
PubMed2000

Visually-guided irrigation in patients with early knee osteoarthritis: a multicenter randomized, controlled trial.

OBJECTIVE: To determine if visually-guided arthroscopic irrigation is an effective therapeutic intervention in patients with early knee osteoarthritis. DESIGN: Ninety patients with knee osteoarthritis were randomized in a double-blind fashion to receive either arthroscopic irrigation with 3000 ml of saline (treatment group) or the minimal amount of irrigation (250 ml) required to perform arthroscopy (placebo group). The primary outcome variable was aggregate WOMAC score. RESULTS: The study did not demonstrate an effect of irrigation on arthritis severity as measured by aggregate WOMAC scores, the primary outcome variable; the mean change in aggregate WOMAC score at 12 months was 15.5 (95% CI 7.7, 23.4) for the full irrigation group compared to 8.9 (95% CI 4.9, 13.0) for the minimal irrigation group (P=0.10). Full irrigation did have a statistically significant effect on patients' self-reported pain as measured by the WOMAC pain subscale and by a visual analog scale (VAS) (the secondary outcome variables). Mean change in WOMAC pain scores decreased by 4.2 (95% CI -0.9, 9.4) for the full irrigation group compared with a mean decrease of 2.3 (95% CI -0.1, 4.7) in the minimal irrigation group (P=0.04). Mean VAS pain scores decreased by 1.47 (95% CI -1.2, 4.1) in the full irrigation group compared to a mean decrease of 0.12 (95% CI 0.0, 0.3) in the minimal irrigation group (P=0.02). A hypothesis-generating post-hoc analysis of the effect of positively birefrigent intraarticular crystals showed that patients with and without intraarticular crystals had statistically significant improvements in pain assessments and aggregate WOMAC scores at 12 months; patients with crystals had statistically greater improvements in pain. CONCLUSIONS: Visually-guided arthroscopic irrigation may be a useful therapeutic option for relief of pain in a subset of patients with knee OA, particularly in those who have occult intraarticular crystals.

Adult↗
PubMed1988

Optimal irrigation pressures in operative choledochoscopy.

A prospective study was conducted on 20 consecutive patients who underwent elective exploration of common bile-ducts for stones to determine the optimal irrigation pressures in choledochoscopy. Ten patients had rigid choledochoscopy and 10 patients had flexible choledochoscopy. Choledochoscopic views were assessed at low irrigation pressure (irrigant delivered at hydrostatic pressure of 1 m of water or 80 mmHg) and high irrigation pressure (irrigant delivered at cuff pressure of 300 mmHg plus hydrostatic pressure of 80 mmHg). Choledochoscopic views were better with high than low irrigation pressures for rigid choledochoscopy. However, there was little difference in the views for flexible choledochoscopy. Common bile-duct pressures were measured with irrigant delivered at pressures 80-380 mmHg at intervals of 50 mmHg. With increasing irrigation pressures, the common duct pressures rose and they were consistently higher in flexible than rigid choledochoscopy. The common duct pressures in rigid choledochoscopy never exceeded the recommended safety limit, even at the high irrigation pressure of 380 mmHg. With flexible choledochoscopy, the common duct pressure was below the recommended safety limit only with low irrigation pressure of 80 mmHg. Therefore, it is recommended that a high irrigation pressure of 380 mmHg for rigid choledochoscopy and a low irrigation pressure of 80 mmHg for flexible choledochoscopy be used.

Common Bile Duct↗
PubMed1998

Clinical and antimicrobial effects of a single episode of subgingival irrigation with tetracycline HCl or chlorhexidine in deep periodontal pockets.

15 adults, each providing 4 non-adjacent untreated periodontal pockets with a probing depth (PD) exceeding 6 mm, volunteered for a randomized, split-mouth, double-blind, clinical study evaluating subgingival irrigation with chlorhexidine (CHX) or tetracycline HCl (TTC). The study protocol included oral hygiene instructions followed by scaling and root planing. Experimental and immediately adjacent teeth did not receive instrumentation. The 4 deep periodontal pockets in each patient were assigned to be irrigated with 150 ml CHX (0.12%), TTC (10 or 50 mg/ml; TTC10, TTC50), or sterile saline (control) in a single episode. Post-irrigation mechanical plaque control was supported by 2x daily CHX rinses throughout the 12-week observation interval. Recordings of oral hygiene (P1I), gingival health (GI), bleeding on probing (BoP), probing depth (PD), clinical attachment level (CAL), and microbial morphotypes from subgingival paper point samples were performed pre-irrigation, and at 1, 2, 4, 6, 8, 10, and 12 weeks post-irrigation. Mean post-irrigation P1I was low, fluctuating between 0.0 and 0.4, without significant differences between experimental groups. Mean pre-irrigation GI approximated 1.4 and reached 0.8 at the exit of study without significant differences between experimental groups. All experimental sites exhibited BoP pre-irrigation. BoP was significantly reduced in TTC50 compared to TTC10, CHX and control sites from week 8 post-irrigation. PDs were reduced for the experimental groups with TTC50 exhibiting the strongest reduction. CALs remained unaltered from pre-irrigation for TTC10, CHX and control sites over the 12-week observation interval, whereas TTC50 sites consistently improved to significantly differ from all other groups at week 10 and 12 post-irrigation. The distribution of bacterial morphotypes was significantly altered towards one of periodontal health for all experimental groups with a profound effect for TTC50 sites. Our results suggest that subgingival irrigation with TTC solutions at high concentrations may have a role in the management of adult periodontitis.

Adult↗
PubMed2006

Alkali burns of the eye: effect of immediate copious irrigation with tap water on their severity.

PURPOSE: To examine the effect of immediate irrigation on ocular alkali burn. METHODS: Information on the injury, immediate irrigation, and ocular findings was retrospectively obtained from each patient's record. RESULTS: 36 patients (49 eyes) irrigated their eyes with tap water (the irrigation group) and 17 patients (29 eyes) did not (no irrigation group). The mean age of patients in the irrigation and no irrigation groups was 30 and 53 years, respectively. According to Hugher's classification, 76% of eyes in the irrigation group had grade 1 injury, while 86% of eyes in the no irrigation group had grade 2 injuries. Mean time from the injury until healing was 8 days in the irrigation group and 29 days in the no irrigation group, respectively. CONCLUSION: Immediate copious irrigation with tap water reduced the severity in alkali burns of the eye and shortened the healing time.

Adult↗
PubMed1995

Comparison of in vivo tissue temperature profile and lesion geometry for radiofrequency ablation with a saline-irrigated electrode versus temperature control in a canine thigh muscle preparation.

BACKGROUND: It is thought that only a thin layer of tissue adjacent to the electrode is heated directly by electrical current (resistive heating) during radiofrequency ablation. Most of the thermal injury is thought to result from conduction of heat from the surface layer. The purpose of this study was to determine whether lesion depth could be increased by producing direct resistive heating deeper in the tissue with higher radiofrequency power, allowed by cooling the ablation electrode with saline irrigation to prevent the rise in impedance that occurs when the electrode-tissue interface temperature reaches 100 degrees C. METHODS AND RESULTS: In 11 anesthetized dogs, the thigh muscle was exposed and bathed with heparinized canine blood (36 degrees C to 37 degrees C). A 7F catheter, with a central lumen, a 5-mm tip electrode with six irrigation holes, and an internal thermistor, was positioned perpendicular to the thigh muscle and held at a constant contact weight of 10 g. Radiofrequency current was delivered to 145 sites (1) at high constant voltage (66 V) without irrigation (CV group, n = 31), (2) at variable voltage (20 to 66 V) to maintain tip-electrode temperature at 80 degrees C to 90 degrees C without irrigation (temperature-control group, n = 39), and (3) at high CV (66 V) with saline irrigation through the catheter lumen and ablation electrode at 20 mL/min (CV irrigation group, n = 75). Radiofrequency current was applied for 60 seconds but was terminated immediately in the event of an impedance rise > or = 10 omega. Tip-electrode temperature and tissue temperature at depths of 3.5 and 7.0 mm were measured in all three groups (n = 145). In 33 CV irrigation group applications, temperature was also measured with a separate probe at the center (n = 18) or edge (n = 15) of the electrode-tissue interface. In all 31 CV group applications, radiofrequency energy delivery was terminated prematurely (at 11.6 +/- 4.8 seconds) owing to an impedance rise associated with an electrode temperature of 98.8 +/- 2.1 degrees C. All 39 temperature-control applications were delivered for 60 seconds without an impedance rise, but voltage had to be reduced to 38.4 +/- 6.1 V to avoid temperatures > 90 degrees C (mean tip-electrode temperature, 84.5 +/- 1.4 degrees C). In CV irrigation applications, the tip-electrode temperature was not > 48 degrees C (mean, 38.4 +/- 5.1 degrees C) and the electrode-tissue interface temperature was not > 80 degrees C (mean, 69.4 +/- 5.7 degrees C). An abrupt impedance rise with an audible pop and without coagulum occurred in 6 of 75 CV irrigation group applications at 30 to 51 seconds, probably owing to release of steam from below the surface. In the CV and temperature-control group applications, the temperatures at depths of 3.5 (62.1 +/- 15.1 degrees C and 67.9 +/- 7.5 degrees C) and 7.0 mm (40.3 +/- 5.3 degrees C and 48.3 +/- 4.8 degrees C) were always lower than the electrode temperature. Conversely, in CV irrigation group applications, electrode and electrode-tissue interface temperatures were consistently exceeded by the tissue temperature at depths of 3.5 mm (94.7 +/- 9.1 degrees C) and occasionally 7.0 mm (65.1 +/- 9.7 degrees C). Lesion dimensions were smallest in CV group applications (depth, 4.7 +/- 0.6 mm; maximal diameter, 9.8 +/- 0.8 mm; volume, 135 +/- 33 mm3), intermediate in temperature-control group applications (depth, 6.1 +/- 0.5 mm; maximal diameter, 11.3 +/- 0.9 mm; volume, 275 +/- 55 mm3), and largest in CV irrigation group applications (depth, 9.9 +/- 1.1 mm; maximal diameter, 14.3 +/- 1.5 mm; volume, 700 +/- 217 mm3; P < .01, respectively). CONCLUSIONS: Saline irrigation maintains a low electrode-tissue interface temperature during radiofrequency application at high power, which prevents an impedance rise and produces deeper and larger lesions. A higher temperature in the tissue (3.5 mm deep) than at the electrode-tissue interface indicates that direct resistive heating occurred deeper

Animals↗
PubMed1990

Supragingival irrigation with 0.06% chlorhexidine in naturally occurring gingivitis. I. 6 month clinical observations.

The purpose of this study was to assess the efficacy of supragingival irrigation with 0.06% chlorhexidine gluconate (CHX) on naturally occurring gingivitis. The relative benefit of CHX irrigation in comparison with CHX rinsing, water irrigation, and normal oral hygiene was evaluated. In a blind, placebo-controlled 6-month study 222 patients were assigned to one of four groups: Group 1: Once daily irrigation with 300 ml water followed by irrigation with 200 ml 0.06% chlorhexidine gluconate (experimental); Group 2: Twice daily rinsing with 15 ml 0.12% chlorhexidine (positive control); Group 3: Once daily irrigation with 500 ml water (irrigation control) and Group 4: Sodium fluoride dentifrice for normal oral hygiene only (negative control). All groups used the same sodium fluoride dentifrice for tooth brushing. At baseline, 3 months, and 6 months patients were examined for Gingival Index (GI), Bleeding on Probing (BOP), Plaque Index (PLI), Pocket probing depth (PD), Calculus Index (CI), and stain. After the baseline visit all patients received a supra- and subgingival oral prophylaxis. At 6 months GI and BOP were significantly (P less than or equal to 0.05) reduced by adjunctive CHX irrigation (42.5% and 35.4%, respectively), CHX rinse (24.1% and 15.0%), and water irrigation (23.1% and 24.0%) compared to tooth brushing alone. Plaque was significantly (P less than or equal to 0.05) reduced only by CHX irrigation (53.2%) and CHX rinse (43.3%) while calculus and staining were significantly (P less than or equal to 0.05) increased in the two chlorhexidine groups (276.4% (irrigation) and 273.2% (rinse)). Although significant (P less than or equal to 0.05), pocket probing depth reduction was minimal after CHX irrigation (4.6%).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Effectiveness of adjunctive irrigation in early periodontitis: multi-center evaluation.

The purpose of this study was to determine the effect of daily water irrigation versus regular oral hygiene alone on gingival and periodontal health in periodontitis patients receiving supportive periodontal treatment. The study also sought to determine if there are enhanced benefits from using an antiplaque zinc sulfate rinse as an irrigant. One hundred fifty-five patients who have had periodontitis and had been treated either surgically or non-surgically completed the 6-month multi-center multi-national study. Patients with at least two 5 mm sites demonstrating bleeding on probing were assigned to 3 equal groups by balanced randomization. In all centers Group A (n = 57) performed regular oral hygiene only, and Group B (n = 58) irrigated with 500 ml water once daily after regular oral hygiene. Group C (n = 40) patients irrigated with a total of 500 ml once daily; following irrigation with 300 ml water, the patients then irrigated with an additional 200 ml with a zinc sulfate solution. The irrigants were diluted to provide the manufacturer's recommended daily dosage. The supragingival irrigation was performed with a commercially available oral irrigator. Bacterial measurements at baseline, 3 months, and 6 months were taken to determine the effect of irrigation on the target organisms and will be reported elsewhere. Gingival index: irrigation with water (Group B) was significantly better than normal oral hygiene (Group A) and irrigation with zinc sulfate (Group C) (P < 0.05) in reducing gingival inflammation. Bleeding on probing: significant reductions in bleeding on probing occurred for water (Group B) compared to normal oral hygiene (Group A) (P < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed2006

On-farm management practices to minimise off-site movement of pesticides from furrow irrigation.

Off-site movement of pesticides from furrow-irrigated agriculture has been a concern in the Ord River Irrigation Area, Western Australia. This paper reports on the effectiveness of incorporation of pesticides by cultivator or power harrows before irrigating, and spraying pesticides only onto beds to minimise off-site transport. Incorporation of pesticides by power harrows prior to irrigation was found to be more effective in decreasing the off-site transport of a more strongly sorbed pesticide, endosulfan. The average load of total endosulfan (alpha + beta + sulfate) decreased by 74% (P < 0.01) from 11.41 g ha(-1) from the conventionally treated bays to 2.96 g ha(-1) from the incorporated irrigation bays. The total average load of atrazine leaving the irrigation bays was decreased by 81% (P < 0.05) from 87.82 g ha(-1) under the conventional practice of spraying the whole field to 16.95 g ha(-1) by spraying the beds only. A reduction of 52% in total average load of metolachlor was observed following incorporation with power harrows, but this was not significant. Incorporation by cultivator or by power harrows decreased the total load of atrazine or metolachlor leaving the irrigation bays over the whole irrigation period, but these treatments were not shown to be statistically significant, which may have been due to the limited number of field replicates. Incorporation of strongly sorbed pesticides (e.g. endosulfan) prior to irrigation significantly decreased the off-site transport of these pesticides in a furrow irrigation system and may be a useful practice to minimise off-site transport of other similar pesticides. Minimising off-site transport of weakly sorbed pesticides (e.g. atrazine and metolachlor) from a furrow irrigation system is more difficult. The nature of furrow irrigation makes it highly conducive to pesticide transport, particularly of weakly sorbed pesticides, and further work is needed to develop strategies to minimise the movement of this group of pesticides to water bodies.

Acetamides↗
PubMed2001

Irrigation water as a source of drinking water: is safe use possible?

BACKGROUND: In arid and semi-arid countries there are often large areas where groundwater is brackish and where people have to obtain water from irrigation canals for all uses, including domestic ones. An alternative to drawing drinking water directly from irrigation canals or village water reservoirs is to use the water that has seeped from the irrigation canals and irrigated fields and that has formed a small layer of fresh water on top of the brackish groundwater. The objective of this study was to assess whether use of irrigation seepage water for drinking results in less diarrhoea than direct use of irrigation water and how irrigation water management would impact on health. METHODS: The study was undertaken in an irrigated area in the southern Punjab, Pakistan. Over a one-year period, drinking water sources used and diarrhoea episodes were recorded each day for all individuals of 200 households in 10 villages. Separate surveys were undertaken to collect information on hygiene behaviour, sanitary facilities, and socio-economic status. RESULTS: Seepage water was of much better quality than surface water, but this did not translate into less diarrhoea. This could only be partially explained by the generally poor quality of water in the in-house storage vessels, reflecting considerable in-house contamination of drinking water. Risk factors for diarrhoea were absence of a water connection and water storage facility, lack of a toilet, low standard of hygiene, and low socio-economic status. The association between water quality and diarrhoea varied by the level of water availability and the presence or absence of a toilet. Among people having a high quantity of water available and a toilet, the incidence rate of diarrhoea was higher when surface water was used for drinking than when seepage water was used (relative risk 1.68; 95% CI 1.31-2.15). For people with less water available the direction of the association between water quality and diarrhoea was different (relative risk 0.80; 95% CI 0.69-0.93). This indicates that good quality drinking water provides additional health benefits only when sufficient quantities of water and a toilet are available. In a multivariate analysis no association was found between water quality and diarrhoea but there was a significant effect of water quantity on diarrhoea which was to a large extent mediated through sanitation and hygiene behaviour. CONCLUSIONS: Increasing the availability of water in the house by having a household connection and a storage facility is the most important factor associated with reduced diarrhoea in this area. Safe use of canal irrigation water seems possible if households can pump seepage water to a large storage tank in their house and have a continuous water supply for sanitation and hygiene. Irrigation water management clearly has an impact on health and bridging the gap between the irrigation and drinking water supply sectors could provide important health benefits by taking into account the domestic water availability when managing irrigation water.

Adolescent↗
PubMed2006

Deficit irrigation for reducing agricultural water use.

At present and more so in the future, irrigated agriculture will take place under water scarcity. Insufficient water supply for irrigation will be the norm rather than the exception, and irrigation management will shift from emphasizing production per unit area towards maximizing the production per unit of water consumed, the water productivity. To cope with scarce supplies, deficit irrigation, defined as the application of water below full crop-water requirements (evapotranspiration), is an important tool to achieve the goal of reducing irrigation water use. While deficit irrigation is widely practised over millions of hectares for a number of reasons - from inadequate network design to excessive irrigation expansion relative to catchment supplies - it has not received sufficient attention in research. Its use in reducing water consumption for biomass production, and for irrigation of annual and perennial crops is reviewed here. There is potential for improving water productivity in many field crops and there is sufficient information for defining the best deficit irrigation strategy for many situations. One conclusion is that the level of irrigation supply under deficit irrigation should be relatively high in most cases, one that permits achieving 60-100% of full evapotranspiration. Several cases on the successful use of regulated deficit irrigation (RDI) in fruit trees and vines are reviewed, showing that RDI not only increases water productivity, but also farmers' profits. Research linking the physiological basis of these responses to the design of RDI strategies is likely to have a significant impact in increasing its adoption in water-limited areas.

Agriculture↗
PubMedDate not supplied

Nitrate exported in drainage waters of two sprinkler-irrigated watersheds.

Nitrate contamination of surface waters has been linked to irrigated agriculture across the world. We determined the NO3-N loads in the drainage waters of two sprinkler-irrigated watersheds located in the Ebro River basin (Spain) and their relationship to irrigation and N management. Crop water requirements, irrigation, N fertilization, and the volume and NO3-N concentration of drainage waters were measured or estimated during two-year (Watershed A; 494 irrigated ha) and one-year (Watershed B; 470 irrigated ha) study periods. Maize (Zea mays L.) and alfalfa (Medicago sativa L.) were grown in 40 to 60% and 15 to 33% of the irrigated areas, respectively. The seasonal irrigation performance index (IPI) ranged from 92 to 100%, indicating high-quality management of irrigation. However, the IPI varied among fields and overirrigation occurred in 17 to 44% of the area. Soil and maize stalk nitrate contents measured at harvest indicated that N fertilizer rates could be decreased. Drainage flows were 68 mm yr(-1) in Watershed A and 194 mm yr(-1) in Watershed B. Drainage NO3-N concentrations were independent of drainage flows and similar in the irrigated and nonirrigated periods (average: 23-29 mg L(-1)). Drainage flows determined the exported mass of NO3-N, which varied from 18 (Watershed A) to 49 (Watershed B) kg ha(-1) yr(-1), representing 8 (Watershed A) and 22% (Watershed B) of the applied fertilizer plus manure N. High-quality irrigation management coupled to the split application of N through the sprinkler systems allowed a reasonable compromise between profitability and reduced N pollution in irrigation return flows.

Agriculture↗
PubMed2006

Environmental impact of irrigation in la violada district (Spain): I. Salt export patterns.

Salt loading in irrigation return flows contributes to the salinization of the receiving water bodies, particularly when originated in salt-affected areas as frequently found in the middle Ebro River basin (Spain). We determined the salt loading in La Violada Gully from the total dissolved solids (TDS) and flows (Q) during the 1995 to 1998 hydrological years. Since this gully collects flows from various sources, an end-member mixing analysis (EMMA) was performed to quantify the drainage flow from La Violada Irrigation District (VID). Three flow components were identified in La Violada Gully: drainage waters from VID (Qd); tail-waters from irrigation ditches, spill-over, and seepage from the Monegros Canal (Qo); and ground water inflows (Qg) originating in the dryland watershed. Gypsum in the soils of VID was the main source for salts in La Violada Gully (flow-weighted mean TDS=1720 mg L-1, dominated by sulfate and calcium). The contribution of Qg to the total gully flow during the 1996 irrigation season was low (6.5% of the total flow). The 1995 to 1998 annual salt load average in La Violada Gully was 78 628 Mg, 71% of which was exported during the irrigation season. The 1995 to 1998 irrigation season salt load average in Qd was 43 015 Mg (77% of the total load). Thus, irrigated agriculture in VID was the main source of salt loading in this gully, with a yield of 11.1 Mg of salts per hectare of irrigated land for the irrigation season. Efficient irrigation systems and irrigation management practices that reduce Qd are key factors for controlling off-site salt pollution of these gypsum-rich irrigated areas.

Environment↗
PubMed1998

Prospective trial of catheter irrigation and muscle flaps for sternal wound infection.

BACKGROUND: Sternal wound infection is a relatively rare but potentially devastating complication of open heart operations. The most common treatments after debridement are rewiring with antibiotic irrigation and muscle flaps. Here we present the results of a prospective trial to determine the appropriate roles of closed-chest catheter irrigation and muscle flap closure for sternotomy infection and to assess the effect of internal mammary artery bypass grafting on the outcome of each treatment modality. METHODS: Between 1990 and 1994, 5,658 sternotomies were performed at the University of Washington Medical Center. Sternal dehiscence occurred in 43 patients, 25 of whom had infection (overall incidence, 0.44%). Because of the infrequency of this complication, a prospective, randomized trial was developed in which the initial approach to sternal dehiscence was rewiring and catheter irrigation. Muscle flaps were used as the primary treatment if the sternum could not be restabilized or as secondary treatment if catheter irrigation failed. Wound resolution, length of hospital stay, and complications were evaluated. RESULTS: Sterile dehiscences were successfully closed with irrigation in 17 of 18 patients; the other patient required flap closure. Of the 25 patients with infection, 19 had irrigation and 6, closure with flaps primarily. In the group of infected patients, 17 of the 19 who received irrigation also had internal mammary artery bypass grafting. Irrigation failed in 15 (88.2%) of these 17 patients, and salvage was accomplished with muscle flap closure. All 6 patients with infection who were closed primarily with muscle flaps had a successful outcome. Hospitalization averaged 10.2 days when muscle flaps were used primarily and 14.3 additional days for unsuccessful irrigation. When irrigation was successful, the hospital stay averaged 11.2 days. CONCLUSIONS: Catheter irrigation should be reserved for patients without infection or patients with infection but without internal mammary artery bypass grafts in whom dehiscence occurs less than 1 month after sternotomy. All others should have closure with muscle flaps.

Anti-Bacterial Agents↗
PubMed1999

Effect of calcium hydroxide and four irrigation regimens on instrumented and uninstrumented canal wall topography.

The topography of instrumented and uninstrumented canal walls exposed to calcium hydroxide and four different irrigation regimens was observed by scanning electron microscopy. After chemomechanical debridement, one tooth in each matched pair was medicated with calcium hydroxide. One week later, the teeth were irrigated and split longitudinally for evaluation. When no calcium hydroxide was used, predentin and pulpal debris covered the dentinal tubules of the uninstrumented surfaces in specimens irrigated with water or EDTA, but was absent on uninstrumented surfaces in specimens irrigated with NaOCl or NaOCl and EDTA. A typical smear layer was absent in instrumented specimens irrigated with NaOCl and EDTA, but covered the dentinal tubules of the instrumented surfaces of the EDTA irrigated specimens (partially) and the water or NaOCl irrigated specimens (completely). Calcospherites or their remnants were seen on the uninstrumented canal walls of specimens irrigated with NaOCl or NaOCl and EDTA, respectively. Calcium hydroxide use did not alter the surface topography in specimens irrigated with water, EDTA, or NaOCl, but seemed to erode the intertubular dentin in specimens irrigated with NaOCl and EDTA. All irrigants seemed to effectively remove most of the calcium hydroxide.

Calcium Hydroxide↗
PubMed1999

Effect of endodontic irrigation solutions on microhardness of root canal dentine.

OBJECTIVES: This study was undertaken to evaluate the effect of several endodontic irrigation solutions on the microhardness of root canal dentine. METHODS: Eighteen freshly extracted maxillary incisors were used in this experiment. The crowns of teeth were sectioned at the cemento-enamel junction. The root canals were instrumented to an apical size #50 file, and irrigated with saline solution. The prepared roots were divided equally into two groups each of nine roots. Each root was sectioned transversely into cervical, middle and apical segments. The three sections of each root were separately mounted in a metal chuck with acrylic resin. The coronal dentine surfaces of the root segments were polished. The microhardness of the dentine was measured for the purposes of control data at 500 microns and 1 mm from the pulpo-dentinal interface. The canal portions in the root segments included in the first group were irrigated with 3% H2O2 and 5% NaOCl solutions used alternatively, while 17% EDTA solution was the irrigation used in the second group. One millilitre of each solution/segment was applied for 60 s exposure time. After irrigation, dentine microhardness was re-assessed and compared with the control values obtained before the irrigation treatment. Data were statistically analysed using ANOVA and Scheffe's test. RESULTS: The results showed that, irrigation with either H2O2/NaOCl or EDTA decreased the microhardness value of root dentine. Irrigation with EDTA gave more reduction of dentine hardness compared to H2O2/NaOCl irrigation. The reduction of KHN of dentine following the irrigation treatment was statistically significant (p < 0.05) at both levels of hardness measurement. CONCLUSIONS: Both H2O2/NaOCl and EDTA irrigating solutions significantly reduced the microhardness of root canal dentine.

Adult↗