ISSN:1069-3629    

DOI:10.1111/j.1745-6592.1993.tb00419.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

ISSN:1069-3629    

DOI:10.1111/j.1745-6592.1993.tb00420.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

ISSN:1069-3629    

DOI:10.1111/j.1745-6592.1993.tb00421.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

ISSN:1069-3629    

DOI:10.1111/j.1745-6592.1993.tb00422.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

ISSN:1069-3629    

DOI:10.1111/j.1745-6592.1993.tb00423.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

ISSN:1069-3629    

DOI:10.1111/j.1745-6592.1993.tb00424.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

ISSN:1069-3629    

DOI:10.1111/j.1745-6592.1993.tb00425.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractPassive measurements of volatile organic compounds (VOCs) provide a method for early detection and long‐term monitoring of potential leaks from underground storage tanks (USTs) and associated fuel service lines. A diffusive sampler was constructed of a sorbent tube that fits inside a specially designed sampling chamber. VOCs in the soil enter the chamber by molecular diffusion and are collected by the sorbent. The sorbent is easily retrieved for laboratory analyses by thermally desorbing into a gas chromatograph/mass spectrometer (GC/MS), or qualitative concentrations can be determined directly in the field with specific‐indicator detectors.The diffusive samplers were evaluated in an exposure chamber under controlled conditions. Laboratory measurements of the sorbed mass of organic vapor were found to be in close agreement with theoretical values and indicate the passive sampling approach is viable for detecting relatively low concentrations of organic vapors in the vadose zone over a one‐day sampling period, as well as providing relatively long‐term monitoring periods up to 58 days. A field test found the sampling approach successful in identifying an area where the vadose zone was contaminated by leaking petrole

ISSN:1069-3629    

DOI:10.1111/j.1745-6592.1993.tb00426.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractTwo borehole geophysical methods—electromagnetic induction and natural gamma radiation logs—were used to vertically delineate landfill leachate plumes in a glacial aquifer. Geophysical logs of monitoring wells near two land‐fills in a glacial aquifer in west‐central Vermont show that borehole geophysical methods can aid in interpretation of geologic logs and placement of monitoring well screens to sample landfill leachate plumes.Zones of high electrical conductance were delineated from the electromagnetic log in wells near two landfills. Some of these zones were found to correlate with silt and clay units on the basis of drilling and gamma logs. Monitoring wells were screened specifically in zones of high electrical conductivity that did not correlate to a silt or clay unit. Zones of high electrical conductivity that did not correlate to a silt or clay unit were caused by the presence of ground water with a high specific conductance, generally from 1000 to 2370 μS/cm (microsiemens per centimeter at 25 degrees Celsius). Ambient ground water in the study area has a specific conductance of approximately 200 to 400 μS/cm. Landfill leachate plumes were found to be approximately 5 to 20 feet thick and to be near the water tabl

ISSN:1069-3629    

DOI:10.1111/j.1745-6592.1993.tb00427.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractIn the BAT ground water sampling system, a stainless steel probe with a porous filter element is pushed vertically to the desired sampling depth. An evacuated glass sampling tube is then lowered down the penetration rods where it makes contact with the filter via a hypodermic needle and draws a pore fluid sample.An investigation of the system was carried out at a number of sites contaminated by leaking underground gasoline storage tanks. Ground water samples obtained using the BAT system and adjacent monitoring wells were analyzed for volatile organic compounds (VOCs).Because the BAT system is an in situ penetration device with a small filter length, it is possible to determine variations in contaminant concentration with depth. BAT samples in general exhibited higher recovery of VOCs than did bailer samples from adjacent monitoring wells screened over large intervals.Much higher levels of VOCs were recovered when the probe was used with its 316 stainless steel filter than when using the high‐density polyethylene (HDPE) filter. Significant sorption apparently occurred on the latter filter.Because the BAT sample tubes are sealed and remain a closed system, the in situ water pressure is maintained. No significant loss of VOCs was found in sampling tubes containing headspace. Samples from the upper tube in the cascaded setup with headspace recovered levels of VOCs as high, or in a few cases higher, than the lower, no‐headspace tu

ISSN:1069-3629    

DOI:10.1111/j.1745-6592.1993.tb00428.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY