A study on pesticide runoff from paddy fields to a river in rural region--2: development and application of a mathematical model

A mathematical model was developed to predict the runoff of pesticides from paddy fields to a river in a rural region. The model comprises three submodels: (1) submodel for river flow, (2) submodel for pesticide behavior in paddy fields, (3) submodel for pesticide behavior in a river. The tank model was applied to predict the river flow and the paddy water. In order to reproduce the actual behavior of pesticides in paddy fields, the kinetics of the transport and reaction mechanisms of pesticides applied to paddy fields were considered in the model. The model was applied to the Kozakura River Basin where the detailed field survey was conducted. The model reflected well the runoff characteristics of pesticides obtained from the detailed field survey.     

Removal of pesticide mixtures in a stormwater wetland collecting runoff from a vineyard catchment

Wetlands can collect contaminated runoff from agricultural catchments and retain dissolved and particle-laden pesticides. However, knowledge about the capacity and functioning of wetland systems with respect to the removal of pesticides is very limited. Here we show that stormwater wetlands can efficiently remove pesticides in runoff from vineyard catchments during the period of pesticide application, although flow and hydrochemical conditions of the wetland largely vary over time. During the entire agricultural season, the inflowing load of nine fungicides, six herbicides, one insecticide and four degradation products was 8.039 g whereas the outflowing load was 2.181 g. Removal rates of dissolved loads by the wetland ranged from 39% (simazine) to 100% (cymoxanil, gluphosinate, kresoxim methyl and terbuthylazine). Dimethomorph, diuron, glyphosate, metalaxyl and tetraconazole were more efficiently removed in spring than in summer. More than 88% of the input mass of suspended solids was retained, underscoring the capability of the wetland to trap pesticide-laden particles via sedimentation. Only the insecticide flufenoxuron was frequently detected in the wetland sediments. Our results demonstrate that stormwater wetlands can efficiently remove pesticide mixtures in agricultural runoff during critical periods of pesticide application, although fluctuations in the runoff regime and hydrochemical characteristics can affect the removal rates of individual pesticides.     

Phosphorus purification in a paddy field watershed using a circular irrigation system and the role of iron compounds

In a paddy field watershed using a circular irrigation system, it was clear that the watershed tended to purify phosphorus by an analysis on the mass balance of pollutants. A reasonable hypothesis was that the phosphorus precipitation with iron compounds in a river may affect the purification. To verify this, an investigation on phosphorus and iron in the river water and sediments were conducted. Total iron (T-Fe) concentration in the river ranged from 3 to 10 mg/L, and the concentration increased with the river flowing down, whereas dissolved iron (D-Fe) concentrations tended to decrease. The concentrations of total phosphorus (T-P) and phosphate phosphorus (PO4-P) also tended to decrease as the river flowing down. From the analysis of mass balance, the study watershed was considered to be a substantial iron source, having 307 and 206 kg/ha of annual outflow loads. In the sediment of the river, T-P ranged from 834 to 2440 microg/g, and most of the inorganic compound was Fe-P. In addition, The Bray No.2 phosphorus (441-1030 microg/g) was much higher than in paddy soils. Therefore, the sediment contained a large amount of phosphorus and was fertile. From the results of laboratory-based experiments, it can be said that iron compounds in the river were sufficient for the precipitation of phosphorus. Since the accumulated sediment in the river was conventionally dredged up and transported to adjacent paddy fields, it was considered to be that this operation played a significant role in phosphorus resource recycling.     

Ammonia volatilization from a paddy field following applications of urea: rice plants are both an absorber and an emitter for atmospheric ammonia

Ammonia (NH(3)) volatilization from a paddy field following applications of urea was measured. Two lysimeters of Gray Lowland soil with a pH (H(2)O) of 5.7 were used for the experiment. Urea was applied at a rate of 50 kg N ha(-1) by incorporation as the basal fertilization (BF) and at rates of 30 and 10 kg N ha(-1) by top-dressing as the first (SF1) and second (SF2) supplemental fertilizations, respectively. Two wind tunnels per lysimeter were installed just after BF; one was transplanted with rice plants (PR plot), and the other was without rice plants (NR plot). Weak volatilization was observed at the PR plots after BF. By contrast, strong volatilization was observed at the PR plots after SF1 with a maximum flux of 150 g N ha(-1) h(-1); however, almost no volatilization was observed after SF2. The NH(3) volatilization loss accounted for 2.1%, 20.9%, 0.5%, and 8.2% of the applied urea at each application, BF, SF1, SF2, and the total application, respectively, for which only the net fluxes as volatilization were accumulated. The NH(3) volatilization fluxes from the paddy water surface (F(vol)) at the NR plots were estimated using a film model for its verification. After confirmation of good correlation, the film model was applied to estimate F(vol) at the PR plots. The NH(3) exchange fluxes by rice plants (F(ric)) were obtained by subtracting F(vol) from the observed net NH(3) flux. The derived F(ric) showed that the rice plants emitted NH(3) remarkably just after SF1 when a relatively high rate of urea was applied, although they absorbed atmospheric NH(3) in the other periods. In conclusion, rice plants are essentially an absorber of atmospheric NH(3); however, they turn into an emitter of NH(3) under excess nutrition of ammoniacal nitrogen.     

Some observations from a field survey of the Irpinia (Italy) earthquake of 23 November 1980

This paper reports a field survey carried out 4 months after the Irpinia earthquake of 23 November 1980. The factors influencing the scale of damage are noted and the correspondence between damage levels and ground motions recorded by the ENEL network of strong motion instruments is briefly discussed.     

Assessment of the influence of a cable TV channel on a local community: A case study of a small rural town in Japan

This article describes a study of how a cable TV channel, run by a small rural town in Japan, influences the awareness and behaviour of its residents. The study is based on a postal survey. Results indicate that the TV programmes increase residents interests in the community, communication among residents, and resident participation in public activities. They also show that such effects on the community are influenced by the usefulness of the programmes, viewing frequency, amount of community participation, and certain personal attributes of residents, such as gender, age and household type.Received: 2 May 2001, Accepted: 26 February 2003, JEL Classification: L82, R29, R58Kazufumi Ueno: I would like to thank 21st Century Research Organization for Human Care, formally the 21st Century Hyogo Project Association, for permission to use the survey data for this study.     

Impact of chemical amendment of dairy cattle slurry on phosphorus, suspended sediment and metal loss to runoff from a grassland soil

Emerging remediation technologies such as chemical amendment of dairy cattle slurry have the potential to reduce phosphorus (P) solubility and consequently reduce P losses arising from land application of dairy cattle slurry. The aim of this study was to determine the effectiveness of chemical amendment of slurry to reduce incidental losses of P and suspended sediment (SS) from grassland following application of dairy cattle slurry and to examine the effect of amendments on metal concentrations in runoff water. Intact grassed-soil samples were placed in two laboratory runoff boxes, each 200-cm-long by 22.5-cm-wide by 5-cm-deep, before being amended with dairy cattle slurry (the study control) and slurry amended with either: (i) alum, comprising 8% aluminium oxide (Al₂O₃) (1.11:1 aluminium (Al):total phosphorus (TP) of slurry) (ii) poly-aluminium chloride hydroxide (PAC) comprising 10% Al₂O₃ (0.93:1 Al:TP) (iii) analytical grade ferric chloride (FeCl₂) (2:1 Fe:TP), (iv) and lime (Ca(OH)₂) (10:1 Ca:TP). When compared with the study control, PAC was the most effective amendment, reducing dissolved reactive phosphorus (DRP) by up to 86% while alum was most effective in reducing SS (88%), TP (94%), particulate phosphorus (PP) (95%), total dissolved phosphorus (TDP) (81%), and dissolved unreactive phosphorus (DUP) (86%). Chemical amendment of slurry did not appear to significantly increase losses of Al and Fe compared to the study control, while all amendments increased Ca loss compared to control and grass-only treatment. While chemical amendments were effective, the reductions in incidental P losses observed in this study were similar to those observed in other studies where the time from slurry application to the first rainfall event was increased. Timing of slurry application may therefore be a much more feasible way to reduce incidental P losses. Future work must examine the long-term effects of amendments on P loss to runoff and not only incidental losses.     

Evaluating demand management aspects of urban water policy—A field survey in the city of Thessaloniki, Greece

The objective of the paper is to investigate the attitudes and preferences of the residential water users of the city of Thessaloniki, in order to evaluate the demand management aspects of the urban water policy. A field survey has been conducted in the city of Thessaloniki and investigated among others the reliability of the utility’s services and infrastructure, the acceptability of various water demand options, the willingness to pay of the consumers and the level of public awareness. Straightforward comparisons with the results of a similar survey five years ago help extract useful remarks and conclusions concerning the shift of the urban water policy towards integrated and therefore more sustainable directions.     

Effects of land use change on hydrological cycle from forest to upland field in a catchment,Japan

Understanding the effects of land use change on the hydrological cycle is very important for development of sustainable water resource in an upland field catchment. In this study, soil and hydrological properties in an upland field catchment, which was reclaimed partially from a forest catchment, were compared with another forest catchment. The soil properties of surface and subsurface layers were investigated in the two catchments. The soil was compacted and water-holding capacity of soil in the upland field catchment became smaller after the reclamation from forest to upland field, which decreased infiltration rate and water storage in the soil layers. We found that peak discharge and direct runoff in the upland field catchment increased compared with the forest catchment. Annual evapotranspiration from the upland field catchment tended to be lower due to the change in vegetation type and soil properties. Furthermore, a semi-distributed hydrological model was applied in the upland field catchment to understand the integrated effects of reclamation on the hydrological cycle. The model parameters, which were determined using a nonlinear optimization technique—the Shuffled Complex Evolution method (SCE), were compared between the two catchments. The Nash and Sutcliffe coefficient was used to evaluate the model performance. The simulated results indicated that evapotranspiration was decreased and change in discharge was more obvious in the surface layer. We considered that declined infiltration and water storage and increased peak discharge and direct runoff have a negative impact on water resources in the upland field catchment. This study will provide information for forest managers in planning and making decisions for land and water resource management.     

Status of the indoor air chemical pollution in Japanese houses based on the nationwide field survey from 2000 to 2005

This paper describes the present state and the changes in indoor air pollution levels by Volatile Organic Compounds (VOCs) in houses in Japan, as revealed through measurements of indoor VOC concentrations and investigations on the actual conditions in the residential environment by means of a questionnaire survey covering a total of more than 10,000 newly built houses over six years (from 2000 to 2005). The VOCs initially measured were formaldehyde, toluene, xylene, and ethylbenzene, followed by the subsequent inclusion of styrene and acetaldehyde.     

Fate of effluent organic matter and DBP precursors in an effluent-dominated river: A case study of wastewater impact on downstream water quality

The impact of treated wastewater discharges on downstream water quality was evaluated in an effluent-dominated stream in the Southwest USA. The fate and transport of effluent organic matter (EfOM) and disinfection by-product (DBP) precursors was studied. Nitrification and biodegradation were important mechanisms. Changes in DBP formation potential along the river appeared to correlate with dissolved organic carbon (DOC) and organic nitrogen concentrations and specific ultraviolet absorbance. The mean oxidation state of carbon (MOC) decreased in value along the river. MOC decreases paralleled decreases in the biodegradability of residual DOC (i.e., lower biodegradable DOC/DOC ratio). The EfOM was biodegradable by up to 40 percent, both in the stream and in a laboratory reactor, and many DBP precursors (e.g., haloacetonitriles, certain nitrosamines) decreased in concentration. Alternatively, the DBP yields for trihalomethanes or haloacetic acids either remained the same or increased slightly, suggesting that these precursors were part of the recalcitrant organic matter (OM).     

Effects of wind on the transmission heat loss in duo-pitched insulated roofs: A field study

This article presents measuring results of the thermal performance of duo-pitched tiled woodframe roof designs. The roofs have been monitored in a test building, exposed to the outside climate. The experiment was part of a programme to study the hygrothermal performance of highly insulated envelope parts in situ, in order to investigate whether a good thermal quality (U = 0.2 W/(m² K)) is achievable with current residential construction practices in Belgium. The results show the effect of wind on the thermal performance of duo-pitched roofs. The measured thermal properties of the roof components are compared to the design values, and related to the wind speeds and directions registered near the test building. The established thermal effects are explained using tracer gas tests to show the pattern of wind driven air flow in the roofs.     

River restoration: what are we restoring to? a case study of the Ravensbourne river, London

State of the art techniques are now being developed to restore our rivers to improve their ecological and conservation value, as well as enhancing their amenity and recreation potential. This study focuses upon the restoration of a small section of the Ravensbourne River in a suburban park near London (Queen's Mead Recreation Ground), which was channelized in the 1970s for the purposes of flood control. As well as reviewing the current status and progress in river restoration, and the feasibility of carrying out such works, the paper asks “what are we restoring to"? Is it to a rural pre twentieth century river character, or are we creating a controlled version of nature? The history of the river is examined along with possible options for restoration. Finally, results from two public perception surveys are outlined which indicate substantial support for restoration. The paper also raises the question of whether the term 'restoration' is an appropriate one to use.     

全站仪中间法在矿山高程测量中的应用——以河南镇平县地形测量为例

随着社会经济的发展,各行各业对重要地理信息数据的需求不断增长。在矿山测量中高程测量是一项非常重要的工作。传统高程测量主要有水准测量、三角高程测量、GNSS高程测量等方法。全站仪三角高程测量法是最常用的技术手段,但是人们对全站仪中间法测量高程代替三、四等水准测量的使用研究还在不断探索中。用全站仪进行三角高程测量代替传统的三、四等水准测量,已被生产实践证明是完全可行的测量方法和手段。本文结合工作实例通过理论分析探讨了在矿山高程测量中应用全站仪中间法的可行性。     

Using the adaptive model of thermal comfort for obtaining indoor neutral temperature: Findings from a field study in Hyderabad,India

There is a dearth of thermal comfort studies in India. It is aimed to investigate into the aspects of thermal comfort in Hyderabad and to identify the neutral temperature in residential environments. This was achieved through a thermal comfort field study in naturally ventilated apartment buildings conducted during summer and monsoon involving over 100 subjects. A total of 3962 datasets were collected covering their thermal responses and the measurement of the thermal environment. The comfort band (voting within –1 and +1), based on the field study, was found to be 26–32.45°C, with the neutral temperature at 29.23°C. This is way above the indoor temperature standards specified in Indian Codes. It was found that the regression neutral temperature and the globe temperature recorded when voting neutral converged when mean thermal sensation of the subjects was close to 0. This happened during the period of moderate temperature when the adaptive measures were adequate. The indoor temperatures recorded in roof-exposed (top floor) flats were higher than the lower floors. The thermal sensation and preference votes of subjects living in top floors were always higher. Consequently, their acceptance vote was also lower. It was found that the subjects living in top floor flats had a higher neutral temperature when the available adaptive opportunities were sufficient. This was due to their continuous exposure to a higher thermal regime due to much higher solar exposure. This study calls for special adaptive measures for roof-exposed flats to achieve neutrality at higher temperature.     

A study of the weathering of the bukit timah granite part a: Review,field observations and geophysical survey

The Bukit Timah granite exhibits a full range of weathering grades. Examination of these exposures shows that the weathering has been rapid. Field observations and geophysical surveys show that the rock has been weathered up to 70 meters depth, and that the main mechanisms of weathering is chemical decomposition. The humid tropical condition in Singapore with high annual precipitation has produced secondary weathering of the residual soil. The weathering profiles suggest that the weathering of the Bukit Timah granite is stratified with weathered layers and a sharp boundary between the residual soil and the slightly to moderately weathered granite. This paper (Part A) is a review of current weathering classification systems for weathered rock. Some results from field observations and geophysical surveys are also presented in the paper. A weathering classification and determination method is proposed for the Bukit Timah granite. Results from field and laboratory investigations of the weathering of the granite and material properties will be presented in Part B.     

A field study on 8 pharmaceuticals and 1 pesticide in Belgium: Removal rates in waste water treatment plants and occurrence in surface water

Only recently, attention has been drawn towards the occurrence of pharmaceuticals in the environment. In recent years many reports have been made on the occurrence of the large, differentiated group of pharmaceuticals in waste water, surface water, ground water and in soil. In this study, we demonstrate the applicability of a previously developed LC-MS/MS method by evaluating in waste water and surface water samples from Belgium the occurrence of 8 pharmaceuticals and 1 pesticide (flubendazole, pipamperone, rabeprazole, domperidone, ketoconazole, itraconazole, cinnarizine, miconazole and propiconazole). Removal rates in five public waste water treatment plants were assessed. Introduction of several compounds into the aquatic environment by discharge of effluent could be demonstrated. For several compounds, the highest concentrations (up to 35.6 μg/l for pipamperone) were observed in the effluent of a WWTP receiving water from chemo-pharmaceutical and other industrial companies. The occurrence of these compounds in the aquatic environment was assessed by analyzing 16 surface water samples, taken from various locations. Four pharmaceuticals (flubendazole, pipamperone, domperidone and cinnarizine) could be detected in at least one sample at low concentrations (up to 26.4 ng/l). The pesticide propiconazole was found in comparable concentrations (up to 85.9 ng/l) as in effluent, suggesting potential introduction by direct seepage of water from rural grounds. The highest concentrations of flubendazole, pipamperone, domperidone, propiconazole and cinnarizine (up to 961.3 ng/l) were observed in a sample, taken near the discharge of a WWTP receiving water from chemo-pharmaceutical and other industries. An initial environmental risk assessment was done based on these results.     

Influence of eco‐hydrological factors on aquatic plant succession in a regulated river: a case study of the Petchburi River,Thailand

Monitoring of aquatic plant biomass in the Petchburi River, a regulated river system in Thailand, was carried out together with the examination of eco‐hydrological characters and the sedimentary organic content. The surveys were performed during May, August and November of 2010 and 2011. The results indicated temporal variation in water velocity (0.08–2.51 m/s) and medium to low organic levels (0.58–4.68%) of the benthic substrates. Dominant aquatic plants were Hydrilla verticillata (L.F.) Royle and Potamogeton malaianus Miq. with the highest biomass of 70.84 and 182.72 g/m², respectively. The biomass was substantially decreased during the flood‐induced discharge period. This study indicates that Potamogeton has more adaptive potential to high water velocities than Hydrilla, while Hydrilla prefers lower water velocities. Discharge velocities of less than 0.5 m/s could provide positive growth rates of such submerged plants. Approaching the discharge control from this ecological point of view can further contribute to river habitat conservation.     

基于学习效果调研的工科专业课教学探索——以山东建筑大学钢结构教学为例

大学专业课教学既是传授专业知识的过程,也是陪伴学生迈向优秀工程师的重要环节。工科院校专业课教学的最终落脚点是学生的学习效果,立足一线教学实践,从教学效果入手,分析专业教学中存在的问题,通过课堂教学内容、工程实践能力和科学研究素养等多方面改革,激发学生学习专业知识的兴趣,完善知识结构,提升人才培养质量,努力培养适应新时期社会需求的高级工程技术人员。