National Assessment of Pesticide Runoff Loads from Grass Surfaces

Pesticide runoff loads from grass surfaces were estimated through simulation experiments for 37 chemicals registered for use on U.S. lawns and golf courses. Simulation runs were made for each chemical and surface (lawns, greens, fairways) using 100-year weather records generated for nine U.S. cities. Results were summarized as mean annual and 1-in-10?year annual maximum daily pesticide loads. These loads varied greatly with pesticide, grass surface, and city, ranging from less than one to over 400??g/ha for mean annual loads and from less than one to over 500??g/ha for 1-in-10?year maximum daily loads. Mean annual loads averaged over the 37 chemicals and three grass surfaces were found to be closely related to growing season precipitation. Variations among the nine cities were well-captured by three general climate categories: humid, represented by Atlanta and Houston; mesic, as with Albany, Columbus, Madison, and Olympia; and dry, represented by Bismarck, Fresno, and Roswell. Mean annual pesticide runoff was 19, 6, and 2??g/ha in the humid, mesic, and dry regions, respectively.     

Reduced-Runoff Irrigation of Sudan Grass Hay, Imperial Valley, California

Sudan grass is a moderately salt-tolerant annual that is capable of substantial osmotic adjustment under high soil salinity conditions, but little is documented about its actual water use and yield under saline conditions. We estimate water use and evaluate the effects of “reduced-runoff” irrigation on soil salinity associated with Sudan grass hay production during a three-year field study (1996–98) in the Imperial Valley, California. The reduced-runoff irrigation method relies on the application of a simplified volume-balance surface irrigation model, and can result in negligible surface runoff; however, its use may have adverse impacts on soil salinity. Despite an anticipated salinity-induced yield reduction of about 15% associated with an average soil salinity of 6 dS∕m (0–0.6 m depth), use of the reduced-runoff method resulted in satisfactory crop yields, practically no tailwater runoff, and a slight decrease from the initial average profile soil salinity. The average applied water depth and estimated consumptive use (ETc) during the project were 1,019 and 935 mm, respectively, resulting in an average hay yield of 14.4 Mg∕ha versus the 1996–98 county average of 12.6 Mg∕ha. The project average ETc/ET0 and yield∕ETc ratios of 0.73 and 15.5 kg∕ha?mm, respectively, were approximately 15% less than those estimated from water-use-efficiency studies, probably as a result of salinity-induced hay yield reduction.     

Design and Performance of Multipurpose Constructed Wetland and Flow Equalization Basin

Stormwater runoff from a portion of a 273?ha (675?acres) Midwestern rail yard contacts industrial facilities including fuel storage tanks and fueling and servicing operation areas. Stormwater draining from a smaller 64?ha (159?acres) sub-basin containing the industrial facilities previously flowed into a retention pond within the rail yard. The retention pond had a surface area of 607?m2 (0.15?acre) and a maximum storage capacity of 1.4?million?L (370,000?gal). Given the large drainage area of the pond the retention time within the pond was shorter than optimal, limiting its potential effectiveness for improving water quality. To address these issues the pond was redesigned to have a 6.25?million?L (1.65?million?gal) storage capacity and configured into a constructed wetland to control a 50-year storm event and increase its ability to treat stormwater runoff. A network of riparian plants (5,700) was placed within the stormwater wetland to treat runoff prior to discharge off-site. Evaluating the performance of both the former and current retention basins revealed significant improvements in the retention and treatment ability when comparing the two structures. Mean total suspended solid concentrations and oil and grease concentrations were reduced approximately 45% when comparing pre- and postconstruction flow analysis. This innovative multiuse approach has demonstrated effectiveness in controlling storm flows and treating runoff from the rail yard.     

Actual and Reference Evaporative Losses and Surface Coefficients of a Maize Field during Nongrowing (Dormant) Periods

Effective water resources planning, allocation, management, and use in agroecosystems require accurate quantification of actual evapotranspiration (ETc) during growing and nongrowing (dormant) periods. Prediction of ETc for a variety of vegetation surfaces during the growing season has been researched extensively, but relatively little information exists on evaporative losses during nongrowing periods for different surfaces. The objectives of this research were to evaluate ETc in relation to available energy, precipitation, and grass and alfalfa-reference ET (ETo and ETr) for a maize (Zea mays. L) field and to analyze the dynamics of surface coefficients (Kc) during the nongrowing period (October 15–April 30). The evaporative losses were measured using a Bowen ratio energy balance system (BREBS) on an hourly basis and averaged over 24?h for three consecutive nongrowing periods: 2004–2005 (Season I), 2005–2006 (Season II), and 2006–2007 (Season III). BREBS-measured ETc was approximately 50% of available energy (Rn?G; Rn is net radiation and G is soil heat flux density) during normal and wet seasons (Seasons I and III) and 41% of available energy during a dry season (Season II). Cumulative ETc ranged from 133?mm in Season II to 167?mm in Season III and exceeded precipitation by 21% during the dry season. The ratio of ETc to precipitation was 0.85 in Season I, 1.21 in Season II, and 0.41 in Season III. ETc was approximately 50% of ETo and 36% of ETr in both Seasons I and III, whereas in Season II, ETc was 32% of ETo and 23% of ETr. Overall, measured ETc during the dormant season was generally most strongly correlated with radiation terms, particularly Rn, albedo, incoming shortwave radiation, and outgoing longwave radiation. Average surface coefficients over the three seasons were 0.44 and 0.33 for grass and alfalfa-reference surfaces, respectively. Using geometric mean Kc values to calculate ETc using a KcETref approach over the entire nongrowing season yielded adequate predictions with overall root mean square deviations of 0.64 and 0.67?mm?day?1 for ETo and ETr, respectively. Estimates of ETc using a dual crop coefficient approach were good on a seasonal basis, but performed less well on a daily basis. Regression equations that were developed (accounting for serial autocorrelation in the ETc and ETref time series) yielded good estimates of ETc. Considering nongrowing period evaporative losses in water budget calculations would enable water regulatory agencies to better account for water use in hydrologic balance calculations over the entire year rather than only for the growing season and to better assess the progression and availability of water resources for the next growing season.     

A qualitative field method for monitoring pesticides in the edge-of-field runoff

A field method is described, which allows the qualitative estimation of pesticide contamination in the edge-of-field runoff. The method employs cheap and easy-to-use runoff sampling bottles, which were installed in an agricultural stream catchment over a period of three growing seasons. During this time 18 runoff events were detected, in nine of which insecticide contamination was measured (maximum concentrations: lindane 0.7 microgram l-1 and 12.7 micrograms kg-1, parathion 20 micrograms l-1 and 728 micrograms kg-1, fenvalerate 18.4 micrograms l-1 and 924 micrograms kg-1). These insecticides were detected mainly as particle-bound chemicals. On about 80% of the occasions the presence or absence of runoff measured in the field was in agreement with a simulation of runoff presence or absence using the runoff model KINEROS.     

Subirrigation Systems to Minimize Nitrate Leaching

Nitrate leaching from corn production systems and the subsequent contamination of ground and surface waters is a major environmental problem. In field plots 75 m long by 15 m wide, the writers tested the hypothesis that subirrigation and intercropping will reduce leaching losses from cultivated corn and minimize water pollution. Nitrate leaching under subirrigation at a depth of either 0.7 m or 0.8 m below the soil surface was compared with leaching under free drainage. The cropping systems investigated were corn (Zea mays L.) monoculture and corn intercropped with annual Italian ryegrass (Lolium multiflorum Lam. cv. Barmultra). The effects of three fertilizer application rates (0, 180, and 270 kg N ha?1) on leaching were investigated in the freely drained plots. The greatest annual loss of NO3?-N in tile drainage water (21.9 kg N ha?1) occurred in freely draining, monocropped plots fertilized with 270 kg N ha?1. Monocropped plots fertilized with 270 kg N ha?1, with subirrigation at 0.7 m depth, resulted in annual nitrate losses into tile drainage of 6.6 kg N ha?1, 70% less than under free drainage. Annual soil denitrification rates (60 kg N ha?1) with subirrigation at 0.7 m were about three-fold greater than under free drainage. Intercropping under free drainage resulted in a 50% reduction in tile drainage loss of NO3?-N compared with monocropping. Off-season (November 1, 1993, to May 31, 1994) tile drainage losses of NO3?-N (7.8 kg N ha?1) from freely draining monocropped plots accounted for 30% of the annual tile drainage losses.     

Physically Based Coupled Model for Simulating 1D Surface–2D Subsurface Flow and Plant Water Uptake in Irrigation Furrows. II: Model Test and Evaluation

A physically based seasonal Furrow Irrigation Model was developed, which comprises three modules: The one-dimensional surface flow, the two-dimensional subsurface flow, and a crop model. The modeling principles of these modules, their simultaneous coupling, and the solution strategies were described in a companion paper (W?hling and Schmitz 2007). In the current contribution, we present the model testing with experimental data from five real-scale laboratory experiments [Hubert-Engels Laboratory (HEL)], two field experiments in Kharagpur, Eastern India (KGP), one literature data set [Flowell-wheel (FW)], and data from three irrigations during a corn growing season in Montpellier, Southern France [Lavalette experiments (LAT)]. The simulated irrigation advance times match well with the observations of the HEL, FW, and KGP experiments, which is confirmed by coefficients of determination R2 ≥ 0.99 and coefficients of efficiency Ce ≥ 0.7. Predicted recession times also match with the observations of the HEL runs, however, the values of R2 ≥ 0.9 and Ce ≥ 0.6 are lower for predicted recession times as compared to predicted advance times. In contrast to the other experiments in the study, advance times are underpredicted for the experiments in France. The established soil hydraulic parameters for this site lead to an underestimation of the actual initial infiltration capability of the soil. In the long-term simulation, however, the overall change in soil moisture storage is correctly predicted by the model and the calculated yield of 12.8?t?ha?1 is in very good agreement with the observations (12.7?t?ha?1). We evaluated the sensitivity of the input parameters with regards to predicted advance time and runoff in both a 26.4?m long furrow and a long 360?m long furrow. The analysis revealed that calculated runoff is four to five times more sensitive to the inlet flow rate than to infiltration parameters. Furrow geometry parameters are most sensitive to calculated advance times in the short furrow with low infiltration opportunity time, whereas the inflow rate and infiltration parameters are more sensitive to calculated advance times in the long furrow with larger infiltration opportunity time.     

Exposure to pesticides and cryptorchidism: geographical evidence of a possible association

Synthetic hormone-disrupting chemicals may play a role in the increased frequency of cryptorchidism observed in some studies. We used a spatial ecological design to search for variations in orchidopexy rates in the province of Granada in Spain and to search for relationships between these differences and geographical variations in exposure to pesticides. Orchidopexy rates were estimated for the period from 1980 to 1991 in all municipalities and health care districts served by the University of Granada Hospital. A random sample of males of the same age (1-16 years) admitted for any reason during the same period was used to estimate inpatient control rates. Each municipality was assigned to one of four levels of pesticide use. We used Poisson homogeneity tests to detect significant differences in rates of orchidopexy between districts and between levels of pesticide use. Poisson and logistic regression models were also used to estimate the strength of association between orchidopexy and level of pesticide use. Orchidopexy rates tended to be higher in districts near the Mediterranean coast where intensive farming is widespread. The city of Granada, where the reference hospital is located, also had higher figures both for orchidopexy and inpatient control rates. Regression models showed that the strength of association between orchidopexy and level of pesticide use tended to increase with higher levels of use, with the exception of level 0 (mainly in the city of Granada). Our results are compatible with a hypothetical association between exposure to hormone-disruptive chemicals and the induction of cryptorchidism. Several methodological limitations in the design make it necessary to evaluate the results with caution.     

Including Source-Specific Phosphorus Mobility in a Nonpoint Source Pollution Model for Agricultural Watersheds

Most widely used nonpoint source models associate pollutant loads almost exclusively with land use via pollutant export coefficients and some kind of runoff coefficient. Not surprisingly, the range of management options suggested by such models’ simulations are largely linked to changes in land use. This problem is addressed by developing models of dissolved phosphorus (DP) mobility for specific agricultural sources: manure, fertilizers, soil/plant complexes, and impervious surfaces and those associated with baseflow P loads. These models are coupled with a spatially distributed hydrologic model, the variable source loading function model. The model was applied to a small (164?ha), upstate New York watershed and tested against 1996–2000 stream flow and DP data. The source-specific model required no direct calibration of parameters compared to eight parameters needed in a similar export coefficient type model. Both models predicted stream DP loads well but the source-specific model provided additional insights into, for example, how much DP in the stream was derived from accumulated soil P as opposed to direct leaching from manure. This type of information is necessary to develop and assess a full range of options for best management practices, especially those that involve nonstatic activities such as manure spreading.     

Thermal Mitigation of Urban Storm Water by Level Spreader–Vegetative Filter Strips

A study was conducted in Louisburg, North Carolina, to determine the effect of level spreader–vegetative filter strip (LS-VFS) storm-water control measures (SCMs) on runoff temperature and thermal loading. Two LS-VFS systems draining an urban catchment were monitored during the summers of 2008 and 2009. The first VFS was 7.6?m wide and entirely grassed. The second was 15.2?m wide, with the first-half grassed and the second-half wooded. Runoff temperatures and thermal loads from the urban catchment tended to peak toward the beginning of a storm event. Median and maximum storm temperatures were significantly reduced across both the 7.6-m and 15.2-m LS-VFSs. However, median and maximum effluent temperatures for both filter strip lengths were significantly greater than the 21°C trout threshold. Mean and median effluent temperatures from the 15.2-m LS-VFS were slightly lower (<1°C) than those from the 7.6-m LS-VFS, which may show the impact of increased filter strip width and/or the shading from wooded vegetation on effluent temperatures. Expected differences between influent and effluent temperatures (both median and maximum) were greater as the influent temperature increased. Substantial and statistically significant (α = 0.05) thermal load reductions were observed in both LS-VFSs because of measured reductions in both temperature and flow volume. Thermal load was eliminated in seven of 38 storm events because of infiltration of the entire runoff volume in the filter strips. The ability of LS-VFS systems to reduce storm-water temperatures and thermal loads supports their use in thermally sensitive watersheds.     

Evaluation of Four Permeable Pavement Sites in Eastern North Carolina for Runoff Reduction and Water Quality Impacts

Four permeable pavement applications in North Carolina’s Coastal Plain were constructed and monitored to determine their effectiveness of reducing runoff quantity and improving water quality. Sites were either constructed of permeable interlocking concrete pavers (2), porous concrete (1), or concrete grid pavers (1). One site of each pavement type was monitored for runoff reduction for periods ranging from 10 to 26 months. Measured runoff depths from rainfall events over 50?mm were used to determine permeable pavement equivalent curve numbers for the sites, which ranged from 45 to 85. Only the two permeable interlocking concrete pavement (PICP) sites were monitored for water quality. Runoff and exfiltrate samples were intended to be collected, in addition to runoff monitoring, from the Swansboro PICP site. However, no runoff was produced during this study from the Swansboro PICP site for rainfall events up to 88?mm. From exfiltrate concentrations, nutrient retention was estimated to be 3.4 and 0.4?kg/ha/year for total nitrogen and total phosphorus, respectively. For the Goldsboro PICP site, water quality of asphalt runoff and PICP exfiltrate were compared. Analysis of water quality samples from the second site determined that concentrations of total Kjeldahl nitrogen, ammonia, total phosphorus, and zinc were significantly (p ? 0.05) lower in permeable pavement exfiltrate than asphalt runoff.     

Retention of Sediment and Nutrient Loads with Peak Runoff Control

The purpose of this research was to evaluate peak runoff control as a water protection method to reduce sediment and nutrient loads. Increased eutrophication of surface waters and risk of floods demands cost effective methods to reduce pollutant input and risks of flooding. With the peak runoff control it is possible to cut the main peaks and store the runoff water temporarily in ditches. The method decreases the suspended solids (SS) and nutrient loads by reducing flow velocities, and improving the settling of sediment particles. The method was tested in two heavily drained adjacent peat harvesting areas suffering considerable erosion. The peak flows were cut by 27–87%, the SS load by 61–94%, the total nitrogen (Ntot) by 45–91%, and the total phosphorus (Ptot) load by 47–88%. The peak runoff control method operated most effectively during extreme events when most of the SS load is transported. A detailed particle analysis of runoff water showed that water detention reduced the median particle size of SS load as the largest particles settle. The results clearly indicate that the peak runoff control is an effective method to control the sediment loads and peak flows from peatland drainage.     

Postoperative pain therapy following total endoprosthetic surgery on the hip using a continuous 3-in-1 blockade

40 patients who had undergone total hip replacement were included in a randomised prospective study. Postoperative pain management was performed with a continuous 3-in-1 block combined with demand-adapted intravenous meperidine titration (3-in-1 catheter group; n = 20) or by demand-adapted intravenous meperidine titration alone (control group; n = 20). The 3-in-1 catheter was placed before the start of anesthesia, and the patients received 30 ml 0.5% bupivacaine via this catheter. A second dose of 30 ml 0.5% bupivacaine was injected 10 min after postanaesthetic recovery. In the control group intravenous meperidine titration was initiated if the patients required pain relief. Subjective pain intensity was evaluated over a 6-hour period by means of the visual analogue scale. Bupivacaine plasma concentrations were determined in 18 patients at 30, 60, 120, and 180 min after the first postoperative injection of bupivacaine. Good pain control was achieved in both groups. The patients in the control group required a mean of 80.8 +/- 49.9 mg meperidine. The 3-in-1 block group required significantly less meperidine (54.3 +/- 44.5 mg). Mean bupivacaine plasma levels ranged between 0.75 and 1.33 micrograms/ml. Placement of the 3-in-1 catheters was without complications. For the management of postoperative pain following total hip replacement a continuous 3-in-1 block alone was often insufficient but postoperative meperidine requirements were significantly reduced (p < 0.05). Toxic bupivacaine plasma concentrations were not measured.     

Feasibility of a Dune Infiltration System to Protect North Carolina Beaches from Fecal Bacteria Contaminated Storm Water

Storm water ocean outfalls discharging into recreational waters pose a human health threat because of increased potential exposure to bacteria and other pathogens. The dune infiltration system (DIS) was designed and implemented at two ocean outfall sites in response to concerns by the North Carolina Department of Transportation and the town of Kure Beach, North Carolina The systems were designed to divert storm water runoff from 1.9?ha (4.7 acre) and 3.2?ha (8.0 acre) watersheds into the beach dunes. Following construction, data were collected from 25 storms during March through October 2006. The systems captured a combined total of nearly 1,800??m3 (63,500??ft3), or 95% of the influent storm water runoff—a significant reduction of runoff volume and peak flow discharging directly onto the beach (p<0.0001). Fecal coliform and enterococci concentrations were measured in the inflowing storm water runoff and groundwater downslope of the systems. Both groundwater bacteria concentrations near the systems were significantly lower than the bacteria concentrations in the inflowing storm water (p<0.001). Furthermore, groundwater fecal coliform concentrations after implementing the DISs were statistically similar to preconstruction levels (p<0.05). The initial results are promising, and the system should be considered for more widespread use. However, further comprehensive research is recommended to more thoroughly understand the viability of the DIS as a storm water best management practice and the fate and transport of the bacteria within the dunes.     

Groundwater Mounding at a Storm-Water Infiltration BMP

This research presents an initial study of the impacts of storm-water infiltration on a shallow unconfined aquifer at a bioinfiltration best management practice (BMP) on the campus of Villanova University. The study site is a vegetated infiltration basin with a 0.52?ha drainage area consisting of parking areas and recreational fields and features approximately 35% directly connected impervious area. The research utilized continuous monitoring of precipitation, groundwater elevation, and groundwater temperature in conjunction with surface water hydrologic modeling to assess the duration, magnitude, and extent of groundwater mounding at a storm-water infiltration BMP. Results indicate that precipitation greater than 1.80?cm causes increased mounding at wells adjacent to the site. In addition, it was found that precipitation less than approximately 1.80?cm leads to larger increases in groundwater elevation at an upgradient control well located near the edge of a large grass field. The extent of groundwater mounding is observed to be localized to the BMP and does not extend a significant distance downgradient. In addition, the magnitude and duration of groundwater mounding is related to both infiltration rate and groundwater temperature, such that cooler temperatures correlate to increased mounding. This study demonstrates the utility of groundwater monitoring for the purpose of BMP hydraulic performance assessment, and recommends that additional research be conducted in the future and that groundwater monitoring be considered for site monitoring plans.     

Urban Runoff Quality Characterization and Load Estimation in Saskatoon, Canada

The improvement in the effluent quality of the treated sanitary sewage entering the South Saskatchewan River at Saskatoon, Canada, and the impending change in provincial legislation governing urban runoff, provided the impetus for Saskatchewan Environment to initiate the stormwater runoff quality study reported in this paper. Among others, the study involved a field program for characterizing the urban runoff water quality from four catchments, each representing a different type of land use. Both a site mean concentration approach and a multiple variable regression analysis approach were used to quantify the pollutant load contained within the runoff. Thereafter, using the runoff water quality characterizations developed in the study, rainfall–runoff pollutant loads from the entire city were estimated and compared with two local point sources to the receiving stream. On the basis of this analysis, it was found that urban runoff contributes more total suspended solids and total Kjeldahl nitrogen load, similar chemical oxygen demand load, and slightly less total phosphorus load than the two local point sources.     

HSPF Simulation of Runoff and Sediment Loads in the Upper Changjiang River Basin, China

To evaluate the performance of a computer model simulating runoff and sediment load in the upper region of the Changjiang (Yangtze River) basin over a relatively short time interval, including examining the applicability of the input precipitation data generated from global circulation models and satellite data, we used a spatially distributed model, HSPF with the International Satellite Land Surface Climatology Project (ISLSCP) precipitation data for 1987 and 1988 as input data. The Nash–Sutcliffe coefficient (R2) for 5-day average streamflow was 0.94 in the calibration period and 0.95 in the verification period for the whole upper region. Moreover, the model simulated the 5-day average streamflow well in each main tributary, as shown by R2 values of 0.46–0.96, except that it underestimated the peak flow rates during the flood season over 2 years by up to 71% in Tuojiang and 61% in Jialingjiang. The model simulated the 5-day concentrations of suspended solids (SS) fairly well in the headwaters and upper regions of the Jinshajiang, Yalongjiang, and Minjiang watersheds, as shown by R2 values of 0.31–0.65. In the other regions, however, the model underestimated the SS load by up to 72%, and rarely simulated the fluctuation of SS concentration in each river channel during the flood season. These errors led to the underestimation of sediment runoff volume from the whole upper region during the flood season, as shown by the ratio of the simulated sediment load to the observed data at Yichang: 0.69 in the calibration period and 0.68 in the verification period. The ISLSCP precipitation tended to be more frequent and less intense than the measured precipitation. This was probably the main reason why the HSPF did not perform well in all regions at all times.     

酸浸出-沉矾湿法炼锌工业优化实践

分析内蒙古赤峰某锌冶炼厂酸浸出-沉矾工艺中沉矾渣、高酸渣渣锌偏高以及沉矾后液铁含量偏高的问题。通过采用相应的技改优化措施,不仅降低了沉矾渣与高酸渣的锌含量,同时通过调整辅料加入方式,使沉矾分梯度进行,也降低了除铁后液铁浓度,减少了辅料用量,优化措施实施后产生了可观的经济效益。     

DHEA as physiological replacement therapy at menopause

BACKGROUND: We report on a case of combined sciatic nerve block and 3-in-1 block for amputation of lower limb in an ASA IV-V patient 6 days after intraoperative cardiopulmonary resuscitation following induction of general anaesthesia. CASE REPORT: A 54-year old male patient was admitted for necrosectomy of a crural ulcer due to end-stage peripheral vascular disease and non-insulin dependent diabetes mellitus. The patient also suffered from toxic cardiomyopathy. After induction for general anaesthesia the haemodynamic situation deteriorated progressively and ended up in cardiac arrest with consequent successful cardiopulmonary resuscitation. The operation was cancelled and the patient was admitted to the intensive-care unit, where he was extubated after 2 days of further haemodynamic stabilisation. Following development of a septic situation of the lower limb the patient was again admitted for amputation six days after the cardiopulmonary resuscitation. Regional anaesthesia was conducted with a combination of a sciatic nerve block via the posterior approach and a 3-in-1 block facilitated by ultrasonographic guidance. For each of the blocks we used 20 mL mepivacaine 1%. Sensory blockade was sufficient and the patient remained haemodynamic and respiratorily stable. DISCUSSION AND CONCLUSIONS: The combined sciatic and 3-in-1 block is a rarely used technique, but for haemodynamically unstable patients it is a safe method for surgery of the lower limb.     

Pollutant Mass Flushing Characterization of Highway Stormwater Runoff from an Ultra-Urban Area

Water quality of highway stormwater runoff from an ultra-urban area was characterized by determining the event mean concentration (EMC) for several pollutants and by evaluating pollutant flushing. Thirty-two storm events were monitored between June 2002 and October 2003. Mean EMCs in mg/L were 0.035, 0.11, 0.22, 1.18, 420, 3.4, 0.14, 1.0, and 0.56 for Cd, Cu, Pb, Zn, total suspended solids (TSS), total Kjeldahl nitrogen (TKN), NO2–N, NO3–N, and TP. First flush as defined by flushing of 50% of the total pollutant mass load in the first 25% of the event runoff volume occurred in 33% of the storm events for NO2?, 27% for TP, 22% for NO3? and TKN, 21% for Cu, 17% for TSS, 14% for Zn, and 13% for Pb. Median values for the mass flushed in the first 25% of runoff volume were greater than the mass flushed in any 25% portion beyond the first for all pollutants. The mass in later 25% volume portions were greater than in the first 25% volume in at least 17% of the events for all pollutants, indicating that a significant amount of the pollutant load can be contained in later portions of the runoff volume. Nonetheless, management of the first 1.3?mm (1/2?in.) of runoff was able to capture 81–86% of the total pollutant mass.