[en] At a seminar on chemical spills, papers were presented on spill countermeasures such as steam stripping and enhanced oxidation, the fate and behavior of spilled materials, environmental impacts of spills, emergency planning, risk assessment, spill decision support systems, spill reporting requirements, analytical instrumentation and methods, and remote sensing. Separate abstracts have been prepared for 17 papers from this seminar

[en] We present a novel UV-curable patch system that can be used to repair the cracked surfaces of chemical reservoirs. When a crack occurs in a chemical reservoir, the patch can be quickly attached to the damaged area, and then cured with a portable UV source in order to prevent the further spread of toxic chemicals. Crosslinked acrylated epoxidized soy bean oil (AESO) materials with various compositions and crosslinking densities were prepared by reacting AESO with the triethylenetetramine (TETA) crosslinker and tested as UV-curable pressure sensitive adhesives (PSAs). The optimum curing behavior and adhesion performance of the UV-curable patch system were found by using various analytical methods, namely oscillatory rheology, and peel, tack strength, and tensile tests. Finally, an optimized patch was applied to a laboratory scale chemical reservoir in order to assess its performance as a UV-curable crack repairing patch system for the prevention of chemical spills from cracked reservoirs.

[en] The performance of a mixed population of hydrocarbon-degrading microbes in removing hydro-carbon contaminant in water was investigated using a fixed bed bioreactor system. The hydrocarbon-degrading microbes used for the study were isolated from oil-contaminated soil and further cultured in a nutrient medium. Sample concentrations of 500 mg/L, 1000 mg/L, 2000 mg/L and 6000 mg/L were studied. Each sample concentration was studied at loading rates of 0.5 L/min, 1.0 L/min, and 2.0 L/min for a week. Total petroleum hydrocarbon (TPH), pH, temperature, dissolved oxygen (DO), conductivity and the microbial population density were measured to ascertain the progress of microbial degradation of the oil contaminant in the water. A minimum degradation rate of 36. 83 ± 0.00% was achieved at the least administered loading rate of 0.5 L/min at 1000 mg/L oil concentration. Maximum degradation rate of 93.85 ± 0.00% was also achieved at loading rate of 1.0 L/min at the highest oil concentration of 6000 mg/L. The minimum and maximum degradation rates were achieved at microbial populations of 1. 53E + 13 ± 0.00 and 1.50E+13 ± 0.00, respectively. The hydrocarbon degradation occurred in an optimum pH range of 6.63 ± 0.20 and 7.32 ± 0.11 and a temperature range of 27.3 ± 0. 76 and 29.9 ± 0.41 degrees celsius. (au)

[en] Environment Ontario's Spills Action Center (SAC) receives and initiates response to spills and other urgent environmental incidents on a 24 h per day basis. The center documented 14,588 occurrence reports in 1992. Two thirds of these involved a range of ministry notification requirements and environmental complaints, while one third involved spills. Information on spills reported in 1992 are summarized. The 5,014 spills reported to SAC in 1992 represent a 5% decrease from 1991. Fewer spills to air accounted for this decrease, while the number of spills to land and water remained unchanged. Oil and fuel spills accounted for 59% of spilled material. Chemical or chemical solutions accounted for ca 15%, wastes or wastewaters 18%, gaseous emissions 6% and unknown for the remainder. Around 20% of spills were less than 10 liters, 57% were less than 100 liters, and 86% were less than 1000 liters. About 28% of the spills had a confirmed environmental impact or adverse affect, two thirds involving soil contamination and around one fifth involving surface water contamination. Twenty-three spills resulted in human health and safety concerns. Around 45% of all spills were completely cleaned up, and an additional 22% were partially cleaned up. Industrial sectors with the largest proportion of reported spills were: transportation, 16%; petroleum, 13%; metallurgical, 6%; general manufacturing, 5%; and chemical, 5%. Public sector spills accounted for 18% of reported spills. Motor vehicles were the largest sources of spills accounting for over 28% of reported spills. 14 figs., 14 tabs

[en] A project was initiated to protect the health of people living in the St-Lawrence basin from contaminants associated with an oil or chemical spill. Between 1980 and 1990, more than 240 chemical spills and 300 oil spills were recorded in the region which has prompted concerns regarding the possible contamination of drinking water sources. 45% of Quebec's population relies on the St-Lawrence River as a source of drinking water. Thus far, the project has identified the major chemical and oil products transported on the St-Lawrence River, and the main health risks associated with these products. Computerized dispersion models which can determine the migration of the contaminants in water, are available. Simulation exercises have been carried out to train personnel in the event of an actual spill. 1 ref

[en] The St. Lawrence River is the source of drinking water for some 45 per cent of the population in the Province of Quebec, hence contamination of the river by oil or chemical spills is a matter of great public health importance. Project SHORES was developed by the Quebec Environmental Health Committee through the St. Lawrence 'Vision 2000' Action Plan. As part of this project, a simulation exercise involving phenol and diesel fuel was carried out. The exercise included development of a computerized dispersion model which was then used to evaluate the migration of phenol in critical areas of the St. Lawrence River. Main public health risks to nearby populations, with emphasis on drinking water contamination, were assessed based on the simulation results. 18 refs., 2 tabs. 1 fig

[en] In order to mitigate the detrimental effects that contaminants such as petrochemical and chemical spills may have on the environment it is critical to understand their transport. This paper presented an assessment of travel time for spills management using HEC-RAS water quality analysis on the Credit River Watershed. It is a 1000 km2 area of urban and rural landscapes drained by 90 km of the main Credit River. The study focused on the mixing characteristics of 5 stream reaches in the Credit River watershed. Dye tracing was done under three different flow conditions to obtain a longitudinal dispersion coefficient, which is a necessary parameter for predicting and modelling time concentration curves downstream of a spill. The longitudinal dispersion coefficient was input into the US Army Corp of Engineers, Hydrologic Engineering Centers River Analysis System (HEC RAS) to predict time concentration curves. The HEC RAS model produced average travel time close to those measured in the field after final calibration was completed.

[en] The seasonal soil compartment model SESOIL, a one-dimensional vertical transport code for chemicals in the unsaturated soil zone, has been coupled with the Monte Carlo computer code PRISM, which utilizes a Latin hypercube sampling method. Frequency distributions are assigned to each of 64 soil, chemical, and climate input variables for the SESOIL model, and these distributions are randomly sampled to generate N (200, for example) input data sets. The SESOIL model is run by PRISM for each set of input values, and the combined set of model variables and predictions are evaluated statistically by PRISM to summarize the relative influence of input variables on model results. Output frequency distributions for selected SESOIL components are produced. As an initial analysis and to illustrate the PRISM/SESOIL approach, input data were compiled for the model for three sites at different regions of the country (Oak Ridge, Tenn.; Fresno, Calif.; Fargo, N.D.). The chemical chosen for the analysis was trichloroethylene (TCE), which was initially loaded in the soil column at a 60- to 90-cm depth. The soil type at each site was assumed to be identical to the cherty silt loam at Oak Ridge; the only difference in the three data sets was the climatic data. Output distributions for TCE mass flux volatilized, TCE mass flux to groundwater, and residual TCE concentration in the lowest soil layer are vastly different for the three sites

[en] Atmospheric modeling of accidental toxic chemical releases requires accurate simulation of wind flows on the 1 to 25 km (meso-γ) scale. Complex meteorological fields have been a challenge to real-time emergency response models for decades especially when,wind observations are sparse. 'ne Gaussian model is a reasonable tool for the first few kilometers if the terrain is relatively flat, the wind flow is simple (no vertical structure), and meteorological data are available at the source. Most other situations demand three-dimensional models. Three-dimensional diagnostic wind field models depend on available meteorological observations which are subsequently adjusted by mass conservation to create a wind field over the terrain. Even in urban areas with multiple meteorological stations, 3-D diagnostic models may suffer from a lack of sufficient real-time observations. Deterministic models are stressed even more during variable low wind speed or stable atmospheric conditions, especially if the release is denser-than-air. Furthermore, typical wind direction measurement errors of 5 to 10 degrees extrapolated 10 or 20 km cause significant dislocations of downwind concentrations. This paper presents a recent case study that illustrates the difficulty of modeling accidental toxic releases in urban areas

[en] A loss of ca 15,000 liters of gasoline from underground storage tanks resulted in contamination of ca 3,000 m³ of soil and formation of a liquid gasoline plume which occupied over 1,000 m² of an aquifer at Carberry, Manitoba. A remediation program was implemented to recover the gasoline from the soils and aquifer in order to contain the gasoline plume and return the aquifer to a usable state. Following installation of several monitoring wells and computer modelling of the plume, a remediation plan was devised. A recovery system was designed and implemented which comprises two water table depression and recovery wells, a hydrocarbon vapor extraction system, and an air stripping tower. Since the start of recovery operations, the subsurface liquid gasoline plume has been reduced to isolated pockets. However, following rain events, gasoline continues to leach from the contaminated soils and move down to the water table, resulting in intermittent floating liquid plumes. The reduction in size of the plume is chiefly attributed to the operation of the recovery system. The vapor extraction system had removed ca 4,000 liters of gasoline, and the ground water system was then able to remove ca 3,000 liters of gasoline from the aquifer. Continued use of the recovery ssystem is expected to remove the recoverable gasoline contamination from the subsurface within the next two years. Residual amounts which cannot practicably be removed will remain and continue to biodegrade over time. 17 refs., 12 figs., 1 tab