NO2 and SO2 dispersion modeling and relative roles of emission sources over Map Ta Phut industrial area, Thailand

Map Ta Phut industrial area (MA) is the largest industrial complex in Thailand. There has been concern about many air pollutants over this area. Air quality management for the area is known to be difficult, due to lack of understanding of how emissions from different sources or sectors (e.g., industrial, power plant, transportation, and residential) contribute to air quality degradation in the area. In this study, a dispersion study of NO2 and SO2 was conducted using the AERMOD model. The area-specific emission inventories of NOx and SO2 were prepared, including both stack and nonstack sources, and divided into 11 emission groups. Annual simulations were performed for the year 2006. Modeled concentrations were evaluated with observations. Underestimation of both pollutants was Jbund, and stack emission estimates were scaled to improve the modeled results before quantifying relative roles of individual emission groups to ambient concentration overfour selected impacted areas (two are residential and the others are highly industrialized). Two concentration measures (i.e., annual average area-wide concentration or AC, and area-wide robust highest concentration or AR) were used to aggregately represent mean and high-end concentrations Jbfor each individual area, respectively. For AC-NO2, on-road mobile emissions were found to be the largest contributor in the two residential areas (36-38% of total AC-NO2), while petrochemical-industry emissions play the most important role in the two industrialized areas (34-51%). For AR-NO2, biomass burning has the most influence in all impacted areas (>90%) exceptJor one residential area where on-road mobile is the largest (75%). For AC-SO2, the petrochemical industry contributes most in all impacted areas (38-56%). For AR-SO2, the results vary. Since the petrochemical industry was often identified as the major contributor despite not being the largest emitter, air quality workers should pay special attention to this emission group when managing air quality for the MA.     

Metal distributions in soil receiving urban pavement runoff and snowmelt.

Wet and dry deposition of anthropogenic metals and particulates generated from urban and traffic activities can result in contamination of urban-land-use soils. These particulate residuals encompass a wide size gradation, from 1 to greater than 10 000 microm. This study hypothesized that such contamination of surficial soils can be analyzed and explained as a function of the soil/residual granulometry. This study analyzed the gradation-based physical characteristics for 10 urban transportation land-use sites with soil/residual complexes (SRCs) located throughout metropolitan Cincinnati, Ohio, and an urban residential reference site. Particle density (rho(s)) of SRCs ranged from 2.8 to 2.1 g/cm3, with the lower particle density associated with particles less than 100 microm. For each site, specific surface area generally increased with decreasing particle size, while the predominance of total surface area was associated with the coarser size fractions, except for the clayey glacial till reference site not influenced by traffic. Cumulative analysis for lead, copper, cadmium, and zinc associated with SRCs indicated that more than 50% of the metal mass was associated with particles greater than 250 microm, with more than 80% associated with particles greater than 106 microm. Study results are similar to rainfall-runoff and snowmelt distributions. Results provide guidance when considering potential fate and control of metals transported by urban drainage and are distributed across the SRC size gradation.     

A Comprehensive Strategy to Reduce Residential Wood Burning Impacts in Small Urban Communities

Paniculate control strategies in the U.S. have historically focused on the reduction of industrial emissions. In recent years, however, area sources such as residential wood combustion have been recognized as significant and rapidly increasing sources of particulate emissions. In some areas of the country it will be necessary to substantially reduce residential wood burning emissions in order to attain or maintain acceptable levels of total and respirable particulate matter. A comprehensive strategy to reduce residential wood burning impacts has been developed for the Medford-Ashland area, 1 a community of about 100,000 population situated in a poorly ventilated valley in Oregon. Portions of this strategy will be applied in other areas of Oregon. The strategy may be applicable to urban communities in other states as well.     

Nitrogen,Phosphorus, Carbon,and Suspended Solids Loads from Forest Clear-Cutting and Site Preparation: Long-Term Paired Catchment Studies from Eastern Finland

The long-term impacts of current forest management methods on surface water quality in Fennoscandia are largely unexplored. We studied the long-term effects of clear-cutting and site preparation on runoff and the export of total nitrogen (total N), total organic nitrogen (TON), ammonium (NH₄-N), nitrate (NO₃-N), total phosphorus (total P), phosphate (PO₄-P), total organic carbon, and suspended solids (SS) in three paired-catchments in Eastern Finland. Clear-cutting and soil preparation were carried out on 34 % (C34), 11 % (C11), and 8 % (C8) of the area of the treated catchments and wide buffer zones were left along the streams. Clear-cutting and soil preparation increased annual runoff and total N, TON, NO₃-N, PO₄-P, and SS loads, except for SS, only in C34. Runoff increased by 16 % and the annual exports of total N, TON, NO₃-N, and PO₄-P by 18, 12, 270, and 12 %, respectively, during the 14-year period after clear-cutting. SS export increased by 291 % in C34, 134 % in C11, and 16 % in C8 during the 14, 6, and 11-year periods after clear-cutting. In the C11 catchment, NO₃-N export decreased by 12 %. The results indicate that while current forest management practices can increase the export of N, P and SS from boreal catchments for many years (>10 years), the increases are only significant when the area of clear cutting exceeds 30 % of catchment area.     

Ambient air concentrations of polycyclic aromatic hydrocarbons,fluoride, suspended particles and particulate carbon in areas near aluminum production plants

Concentrations of airborne polycyclic aromatic hydrocarbons (PAH), fluoride, suspended particles and particulate carbon were determined in four different residential areas near aluminum industries. Two of the areas were exposed to pollutants from primary aluminum production, the third area was close to a plant manufacturing electrodes for the aluminum industry while the fourth area received pollutants from the production of aluminum as well as electrodes. The sampling time was 24 h and the samples were collected every eighth day for about 16 months. The concentrations of PAH were high compared to levels in other polluted areas with industry and dense traffic. The average concentrations for benzo(a)pyrene (BaP) were above 10 ngm⁻³, which has been proposed as a guideline in some countries, at all sites. The highest air concentration of BaP measured in the present study was 160 ng m⁻³. At two of the stations the fluoride concentrations exceeded the 24-h national guideline of 25 μgm⁻³, which has been set to protect human health. In a few cases the concentrations of suspended particles were high while the levels of carbon agreed with concentrations reported in urban and residential areas in U.S.A. The concentrations varied with time and the variation was caused mainly by the changes of the meteorological conditions. The frequency distributions were skew for all components and close to logarithmic normal. PAH were well correlated with fluoride, which is an aluminum production tracer, indicating that they are of the same origin. The aluminum industry did not seem to be the main source of particulate matter and carbon in air. Apportionment studies of the organic pollutants were carried out by cluster analysis, and the results showed that the aluminum production is the main source to the PAH in ambient air in these areas.     

NO2 and SO2dispersion modeling and relative roles of emission sources over Map Ta Phut industrial area,Thailand

Map Ta Phut industrial area (MA) is the largest industrial complex in Thailand. There has been concern about many air pollutants over this area. Air quality management for the area is known to be difficult, due to lack of understanding of how emissions from different sources or sectors (e.g., industrial, power plant, transportation, and residential) contribute to air quality degradation in the area. In this study, a dispersion study of NO₂ and SO₂ was conducted using the AERMOD model. The area-specific emission inventories of NO_x and SO₂ were prepared, including both stack and nonstack sources, and divided into 11 emission groups. Annual simulations were performed for the year 2006. Modeled concentrations were evaluated with observations. Underestimation of both pollutants was found, and stack emission estimates were scaled to improve the modeled results before quantifying relative roles of individual emission groups to ambient concentration over four selected impacted areas (two are residential and the others are highly industrialized). Two concentration measures (i.e., annual average area-wide concentration or AC, and area-wide robust highest concentration or AR) were used to aggregately represent mean and high-end concentrations for each individual area, respectively. For AC-NO₂, on-road mobile emissions were found to be the largest contributor in the two residential areas (36–38% of total AC-NO₂), while petrochemical-industry emissions play the most important role in the two industrialized areas (34–51%). For AR-NO₂, biomass burning has the most influence in all impacted areas (>90%) except for one residential area where on-road mobile is the largest (75%). For AC-SO₂, the petrochemical industry contributes most in all impacted areas (38–56%). For AR-SO₂, the results vary. Since the petrochemical industry was often identified as the major contributor despite not being the largest emitter, air quality workers should pay special attention to this emission group when managing air quality for the MA.

Implications: Effective air quality management in Map Ta Phut Industrial Area, Thailand requires better understanding of how emissions from various sources contribute to the degradation of ambient air quality. Based on the dispersion study here, petrochemical industry was generally identified as the major contributor to ambient NO₂ and SO₂. By accounting for all stack and non-stack sources, on-road mobile emissions were found to be important in some particular areas.     

Exposure to PCBs, through inhalation, dermal contact and dust ingestion at Taizhou, China--a major site for recycling transformers

Air samples containing gaseous and particulate phases were collected from e-waste workplaces and residential areas of an intensive e-waste recycling area and compared with a reference site. The highest total concentration of PCBs was detected at transformer recycling workshops (17.6 ng m(-3)), followed by the residential area (3.37 ng m(-3)) at Taizhou, and the lowest was obtained at the residential area of the reference site, Lin'an (0.46 ng m(-3)). The same trend was also observed with regards to PCB levels in dust samples. The highest average PCBs level of 2824 ng g(-1) (dry wt) was found in the transformer recycling workshops, and was significantly higher than that of residential areas of Taizhou (572 ng g(-1) dry wt) and Lin'an (42.4 ng g(-1) dry wt). WHO-PCB-TEQ level in the workshops of Taizhou was 2216 pg TEQ(1998)g(-1) dry wt or 2159 pg TEQ(2005)g(-1) dry wt, due to the high abundance of PCB 126 (21.5 ng g(-1) dry wt), which contributed 97% or 99% of WHO-PCB-TEQs. The estimated intake of PCBs via dust ingestion and dermal absorption by transformer recycling workers were 77.5×10(-5) and 36.0×10(-5) pg WHO-PCB-TEQ(1998)kg(-1)d(-1), and 67.3×10(-5) and 31.3×10(-5) pg WHO-PCB-TEQ(2005)kg(-1)d(-1), respectively.     

Lake eutrophication at the urban fringe,Seattle region,USA

Nutrient pollution and associated eutrophication of freshwaters threaten the ecological integrity and the services provided to humans by lakes. We examined how human residential development influenced the level of lake eutrophication in the Seattle, WA, USA, region. We surveyed 30 lakes and measured 3 indicators of eutrophication: concentrations of chlorophyll-a and phosphorus, and the proportion of algae that are inedible to zooplankton. We classified lakes based on the waste-treatment method for shoreline homes: septic, sewer, and undeveloped lakes. Septic lakes occurred along the urban-rural fringe while sewer lakes occurred near urban centers. Septic lakes were more eutrophic than sewer lakes and undeveloped lakes, as indicated by higher levels of phosphorus and chlorophyll-a. These results suggest that septic systems contribute to the high levels of eutrophication in lakes at the urban-rural fringe. Lakes at the urban-rural fringe represent an opportunity for proactive management of urban expansion to minimize lake eutrophication.     

Nitrogen removal from urban stormwater runoff through layered bioretention columns.

Bioretention is a low-impact technology used for the treatment of stormwater runoff in developed areas. The fates of mineral nitrogen compounds in two bioretention columns (RP1 and RP2) with different media-layering characteristics were investigated under multiple loadings of simulated urban runoff. The immediate capture of nitrogen was evaluated, with nitrogen transformation reactions that occurred during the drying periods between rainfall events. A greater proportion of ammonium was removed from runoff in RP2 (68 +/- 16%), which had a high permeability layer over a lower permeability layer, than in RP1 (12 +/- 6%), which had the inverse configuration. Both column systems demonstrated nitrate export (9 +/- 32% and 54 +/- 22% greater than input for RP1 and RP2, respectively), attributed to washout of nitrate resulting from nitrification processes between runoff loading events. Bioretention media with a less permeable bottom soil layer could form an anoxic/anaerobic zone for promoting nitrification/denitrification processes.     

Foliar washoff of pesticides (FWOP) model: Development and evaluation

Abstract

The Foliar Washoff of Pesticides (FWOP) Model was developed to provide an empirical simulation of pesticide washoff from plant leaf surfaces as influenced by rainfall amount. To evaluate the technique, simulations by the FWOP Model were compared to those by the foliar washoff algorithm of the Chemical, Runoff and Erosion from Agricultural Management Systems (CREAMS) Model. The two algorithms were linked individually to the Pesticide Runoff Simulator (PRS) for the comparison. Five years of test data from a Mississippi watershed were used to evaluate six insecticides (carbaryl, profenofos, methyl parathion, permethrin, phorate, and toxaphene).

Initially, the FWOP model was used to evaluate the relative impact of chemical distribution (foliage versus soil) on the subsequent foliar washoff and soil surface contributions to runoff losses. Results indicated that runoff losses were low If all of the insecticide was applied to the foliage whereas high losses occurred if applied only to the soil. When an assumed application was distributed between the plant and soil (i.e., 90% to foliage and 10% to soil), predicted runoff losses compared well with observed field data (<3% of the application rate).

Except for toxaphene, the FWOP model generally predicted less washoff and subsequent runoff losses than the CREAMS approach. Simulated toxaphene washoff losses were in good agreement with observed field data. Statistical comparisons of the two modeling approaches using the Kolmogorov‐Smirnov test showed differences in the two cumulative frequency distributions for washoff but smaller differences for runoff. Average 5‐year runoff losses, however, were greater using the CREAMS approach—by factors of 2, 3, and 3 for profenofos, methyl parathion and phorate, respectively.

Results from this study will be useful for upgrading current exposure assessment models to more accurately address foliar washoff losses of pesticides as well as for assessing the impact of foliar‐applied chemicals on environmental quality.     

Spatial characterization of the Baltic sea drainage basin and its unmonitored catchments

We present an updated, harmonized hydrologic base map of the entire Baltic Sea Drainage Basin (BSDB), including 634 subdrainage basins. The updated map has a level of detail approximately 5 to 10 times higher than the current standard and includes various spatial-aggregation possibilities of relevance for water management. All 634 subdrainage basins and their various spatial aggregations are characterized in terms of population, land cover, drainage density, and slope. We identify, quantify, and characterize, in particular, drainage basins that are unmonitored with regard to the combination of water-flow and nutrient-concentration measurements needed to monitor coastal nutrient and pollutant loading. Results indicate that out of a total BSDB population of 84 239 000 in 2002, 24% lived in unmonitored coastal drainage basins that cover 13% of the total BSDB area. A more detailed analysis of Swedish catchments indicates that Sweden has a particularly large proportion of unmonitored coastal catchment areas (20% of the total Swedish area) with high population pressures (55% of the total Swedish population), when compared with average conditions for the whole BSDB. In general, the investigated characteristics of unmonitored coastal basins vary and differ largely from those in adjacent monitored drainage basins within the BSDB.     

Spatial and temporal variability of outdoor coarse particulate matter mass concentrations measured with a new coarse particle sampler during the Detroit Exposure and Aerosol Research Study

The Detroit Exposure and Aerosol Research Study (DEARS) provided data to compare outdoor residential coarse particulate matter (PM_10–2.5) concentrations in six different areas of Detroit with data from a central monitoring site. Daily and seasonal influences on the spatial distribution of PM_10–2.5 during Summer 2006 and Winter 2007 were investigated using data collected with the newly developed coarse particle exposure monitor (CPEM). These data allowed the representativeness of the community monitoring site to be assessed for the greater Detroit metro area. Multiple CPEMs collocated with a dichotomous sampler determined the precision and accuracy of the CPEM PM_10–2.5 and PM_2.5 data.CPEM PM_2.5 concentrations agreed well with the dichotomous sampler data. The slope was 0.97 and the R² was 0.91. CPEM concentrations had an average 23% negative bias and R² of 0.81. The directional nature of the CPEM sampling efficiency due to bluff body effects probably caused the negative CPEM concentration bias.PM_10–2.5 was observed to vary spatially and temporally across Detroit, reflecting the seasonal impact of local sources. Summer PM_10–2.5 was 5 μg m^?3 higher in the two industrial areas near downtown than the average concentrations in other areas of Detroit. An area impacted by vehicular traffic had concentrations 8 μg m^?3 higher than the average concentrations in other parts of Detroit in the winter due to the suspected suspension of road salt. PM_10–2.5 Pearson Correlation Coefficients between monitoring locations varied from 0.03 to 0.76. All summer PM_10–2.5 correlations were greater than 0.28 and statistically significant (p-value < 0.05). Winter PM_10–2.5 correlations greater than 0.33 were statistically significant (p-value < 0.05). The PM_10–2.5 correlations found to be insignificant were associated with the area impacted by mobile sources during the winter. The suspected suspension of road salt from the Southfield Freeway, combined with a very stable atmosphere, caused concentrations to be greater in this area compared to other areas of Detroit. These findings indicated that PM_10–2.5, although correlated in some instances, varies sufficiently across a complex urban airshed that that a central monitoring site may not adequately represent the population's exposure to PM_10–2.5.     

Mitigation of methane and nitrous oxide emissions from drained irrigated rice fields

One of the important cultural practices that affect methane and nitrous oxide emissions from tropical rice plantations is the water drainage system. While drainage can reduce methane emissions, it can also increase nitrous oxide emissions, as well as reduce yields. In this experiment, four different water drainage systems were compared in a rice field in central Thailand including: (1) continuous flooding, (2) mid-season drainage, (3) multiple drainage and (4) a local method (drainage was done according to local cultural practice) in order to find a system of drainage that would optimize yields while simultaneously limiting methane and nitrous oxide emissions. Methane and nitrous oxide emission were observed and compared with rice yield and physical changes of rice plants. It was found that drainage during the flowering period could reduce methane emission. Interestingly, nitrous oxide emission was related to number of drain days rather than the frequency of draining. Fewer drain days can help reduce nitrous oxide emission. The mid-season drainage and the multiple drainage, with 6.9% and 11.4% reduction in rice yield, respectively, had an average methane emission per crop 27% and 35% lower when compared to the local method. Draining with fewer drain days during the flowering period was recommended as a compromise between emissions and yield. The field drainage can be used as an option to reduce methane and nitrous oxide emissions from rice fields with acceptable yield reduction. Mid-season drainage during the rice flowering period, with a shortened drainage period (3 days), is suggested as a compromise between the need to reduce global warming and current socio-economic realities.     

Rapid multiresidue determination for currently used pesticides in agricultural drainage waters and soils using gas chromatography–mass spectrometry

An efficient and sensitive method for simultaneous determination of 38 pesticides in agricultural drainage waters and soils has been developed and validated. Water samples were extracted using solid-phase extraction with C18 cartridges while solid samples (suspended particle matter and soil) were extracted by using the quick, easy, cheap, effective, rugged and safe (QuEChERS) extraction method. The target pesticides were analyzed by using gas chromatography-mass spectrometry with electron impact ionization. The proposed method allowed a simultaneous determination and confirmation of a large number of pesticides in agricultural drainage waters, suspended particle matters and soils/sediments with a good reproducibility and low detection limits. The developed method was applied to a survey of pesticides in a vegetable growing area of Guangzhou, China. The pesticides commonly found in the area were butachlor, carbofuran, dichlorvos, fipronil, isocarbophos and pyridaben.     

Regional measurements of PCDD/PCDF concentrations in Korean atmosphere and comparison with gas-particle partitioning models

The current investigation was aimed at determining the levels of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/PCDFs) in the Korean atmosphere along with their estimation using gas-particle partitioning. Samples collected from six cites showed that large cities were polluted with a concentration of 0.593 pg TEQ/m3. Samples were also collected from residential (nine sites), commercial (five sites), and industrial (seven sites) districts in each city. Higher levels of PCDDs/PCDFs were observed in industrial area than other areas, since it includes many sources. Higher chlorinated 2,3,7,8-substituted congeners were predominantly found in the particulate phase. HpCDD/Fs and OCDD/Fs shared 97-99% of the particulate phase, whereas TCDD/Fs, which dominated the gaseous phase, shared 34.8% and 42.8% in 2,3,7,8-substituted congeners. The regression dataset was transformed due to the relationship between log K(P) and log P(L)o. A wide variation was observed in the slopes for the residential areas when compared with the slopes for the commercial and industrial areas. The Junge-Pankow model and K(oa) adsorption model were both found to be helpful in describing the gas-particle partitioning in the current study.     

Polynuclear Hydrocarbon Emissions from Selected Industrial Processes

A number of selected industrial processes considered as potential sources of benzo{a)- pyrene and other polynuclear hydrocarbons were surveyed. Polynuclear hydrocarbon emission levels were measured directly for asphalt hot road mix preparation and asphalt airblowing. Emissions of other pollutants, including particulate matter, carbon monoxide, and total gaseous hydrocarbons were also measured, and are reported together with pertinent data on process design and operation. Results are discussed with reference to the type of process; the type of equipment used, including control devices; and other factors. The significance of some additional processes as contributors of polynuclear hydrocarbons was examined indirectly by collecting atmospheric samples of polynuclear hydrocarbons in residential areas in the vicinity of (1) a carbon black manufacturing area, (2) a steel and coke manufacturing area, (3) an organic chemical industry complex, and (4) a residential and small-industry coal burning area.     

Gaseous carbon dioxide and methane, as well as dissolved organic carbon losses from a small temperate wetland under a changing climate

Temperate forests can contain large numbers of wetlands located in areas of low relief and poor drainage. These wetlands can make a large contribution to the dissolved organic carbon (DOC) load of streams and rivers draining the forests, as well as the exchange of methane (CH4) and carbon dioxide (CO2) with the atmosphere. We studied the carbon budget of a small wetland, located in Kejimkujik National Park, Nova Scotia, Canada. The study wetland was the Pine Marten Brook site, a poor fen draining a mixed hardwood-softwood forest. We studied the loss of DOC from the wetland via the outlet stream from 1990 to 1999 and related this to climatic and hydrologic variables. We added the DOC export information to information from a previously published model describing CH4 and CO2 fluxes from the wetland as a function of precipitation and temperature, and generated a new synthesis of the major C losses from the wetland. We show that current annual C losses from this wetland amount to 0.6% of its total C mass. We then predicted that under climate changes caused by a doubling of atmospheric CO2 expected between 2040 and 2050, total C loss from the wetland will almost double to 1.1% of total biomass. This may convert this wetland from what we assume is currently a passive C storage area to an active source of greenhouse gases.     

道路径流SS和COD污染特征及出流规律

选择芜湖市火车站点进行长期监测,采集降雨7次;同时选择5个不同功能区,采集典型降雨1次。探讨了道路径流中总固体悬浮物(SS)和化学需氧量(COD)的污染特征、影响因素及出流规律,结果表明,7次降雨事件SS和COD平均值范围分别为198～1 529 mg/L和66～367 mg/L。SS和COD污染较为严重。SS在不同功能区中大小顺序为:工业区>居民区>商业区>交通区>文教区,总COD大小顺序为:工业区>交通区>居民区>商业区>文教区,溶解态COD大小顺序为:工业区>交通区>商业区>文教区>居民区,颗粒态COD大小顺序为:工业区>居民区>交通区>文教区>商业区。工业活动对地表径流SS和COD含量影响最大。SS受降雨历时影响较大,溶解态COD受平均雨强影响较大,颗粒态COD受最大雨强影响较大。不同降雨强度下,SS、溶解态COD及颗粒态COD的出流规律不同,降雨强度对径流初期效应的影响显著。     

Effect of soil-use on deep groundwater quality in Southern Chile

This study evaluated the effects of farming activities on the quality of deep well water in Southern Chile. In this area, the use of fertilisers is becoming more widespread and the accumulation and poor management of cattle slurry and silage sub-products increases the risk of contamination. The study was carried out in the province of Osorno, where rainfall occurs all year round (maximum in winter); total annual rainfall exceeds 1300 mm. The soil is of volcanic origin and this province includes areas used for intensive farming and cattle raising activities, residential and recreational purposes and extensive farming practices. Water quality was analysed over a 15 month period in deep wells in either intensive farming areas and residential/recreational zones or extensive farming land. Although levels of nitrate were higher in deep wells located in intensive farming areas, levels of phosphor and pH were lower than those of wells located in extensive farming areas. Nevertheless, the range of nutrient concentration (nitrite, iron, manganese and phosphor) revealed significant statistical differences between both types of farming land; nitrite dominated in well samples located in intensive farming areas, while iron and manganese dominated in extensive farming areas. Seasonal differences were registered in temperature, nitrate, total coliforms and Escherichia coli. Maximum levels of nitrate and bacteria were reached in spring and autumn, respectively. No significant relationships were established between nutrient and bacterial levels with meteorological factors such as temperature, rainfall and number of days when rainfall occurred. Variations in nutrients and bacteria, both temporal and between locations (spatial), are associated to soil use and proximity to septic well wastewaters. Iron and manganese concentrations exceeded permitted drinking-water standards in a considerable percentage of samples, which may be due to soil composition. Bacterial pollution occurred infrequently in autumn and winter. The quality of deep-well waters in Southern Chile is generally good. Nevertheless, evidence indicates that intensive farming practices, slurry, silage and poor management of rural residential areas, constitute a significant potential risk.     

Export of nutrients from golf courses on the Precambrian Shield

Annual export rates, or fluxes, of total nitrogen (TN), nitrate, total phosphorus (TP) and potassium from four streams on two golf courses on the Precambrian Shield were compared with those from forested reference locations. Overall, the mean annual fluxes of K, TN, NO(3) and TP from golf courses were greater than from forested areas by 10, 2, 6 and 2 times, respectively. The overall mean export coefficients (kg/ha/yr) were 16 for K, 5.2 for TN, 2.1 for NO(3) and 0.14 for TP. For TN and TP, these are similar to those reported from cropland in Canada by Chambers and Dale.