If the native clay in our area is so impermeable, why doesn't rainwater stay trapped on the surface?
Following a rainfall event, a portion of the rainfall runs directly off the ground surface into local drainage ways, creeks, rivers and lakes. Another portion infiltrates into soil primarily through fractures in the upper weathered portion of the native clay. The weathered zone of the clay is approximately five metres (16 feet) thick and is underlain by un-weathered clay of very low permeability. The un-weathered clay acts as a barrier to the downward movement of infiltration and thereby promotes lateral movement in the weathered zone from topographically high areas to adjacent surface drainage features (ditches, streams etc.). A very small portion of the infiltration (approximately 2 mm/per year) moves down through the un-weathered clay to the bedrock. The landfill cells at the Lambton Facility are constructed in the un-weathered clay, where groundwater movement is extremely slow.
If your facility is closed down, won't industry be forced to manage its own hazardous wastes?
Such an action would serve no practical purpose and could put the public and the environment at risk. Hundreds of generators send their hazardous waste to the Lambton Facility each year, because they know it has the capability to manage it safely in accordance with all associated government regulations. While some generators might have the resources and technical know-how to manage their wastes, most would not.
With the assistance of waste management specialists, like Clean Harbors, generators can provide the products consumers demand while meeting their environmental obligations. At the same time, the overall volume of waste is being reduced-in some cases by as much as 90 per cent-through a variety of practical measures initiated by waste generators, governments, consumers and service companies, like Clean Harbors.
In daily application, hazardous waste management is a complex issue, closely bound to our modern standards and styles of living. Closing the Lambton Facility is not a viable alternative since it would not halt the production of hazardous wastes.
If you don't regularly test the quality of the drinking water wells in the surrounding area, how can you be sure you're not adversely affecting them?
The monitoring program at the Lambton Facility involves the twice annual sampling of 47 monitoring wells. These wells are located around the perimeter of the Lambton facility property and are installed in the two zones of ‘active’ groundwater movement, namely the shallow weathered clay and a thin zone immediately at the bedrock surface, referred to as the Interface Aquifer. The Interface Aquifer includes a thin layer of sand and sandy till where present, and a metre or two of fractured shale bedrock. The monitoring program, which provides full coverage of the facility, is intended as an ‘early warning system’ that would flag any movement of contamination from the Facility. The results of the monitoring program are released annually in a comprehensive report, which is distributed to the Ministry of the Environment and other interested parties. The monitoring data have demonstrated that the site remains secure. As such, there is no reason to believe that the Facility is having any effect on drinking water wells located farther away.
Is the groundwater aquifer around the Lambton Facility linked by an underground stream to Lake Huron?
No. Scientific knowledge about the mechanism by which groundwater moves refutes such a claim.
The subsurface geography of western Lambton County, an area called the St. Clair Clay Plain. The plan is characterized by a clay till layer approximately 38-45 metres (130-150 feet) thick, which overlies shale bedrock. A thin layer [0.5 metre (1.5 feet)] of sand, silt and gravel is occasional present overlying the bedrock. This material, where present, combined with the upper metre or two of bedrock is moderately permeable and has historically been used as source of water supply for area farms and residences. The narrow zone is called the ‘Interface Aquifer’.
University of Waterloo researchers have studied groundwater movement in Lambton County and have determined that movement occurs through two zones, namely a thin surface layer of weathered clay and the aforementioned Interface Aquifer. Water that infiltrates into the weathered clay moves lateral to nearby water courses (stream and roadside ditches). Movement in the thin Interface Aquifer occurs very slowly in a westerly direction towards the St. Clair River. Available information has established that the Interface Aquifer is primarily recharged in the upland areas located east of Lambton County where the overlying clay is relatively thin. .
In the vicinity of the Lambton Facility, the thick layer of clay till impedes the downward the movement of groundwater. Movement in the Interface Aquifer is consistent with the regional pattern of flow and is towards the west. The slow rate of groundwater movement in the aquifer is reflected in the age of the water. Specifically, radiocarbon dating of water samples collected from the aquifer in the vicinity of the Facility by the University researchers has established that the water in the aquifer is about 15,000-year-old (glacial in age).
Are there measures designed into your landfill operation to ensure the protection of the area's groundwater?
Yes. The landfill design entombs the waste in a thick layer of un-weathered clay till. The clay attenuates contaminant movement and provides for the long-term protection of the area's groundwater. During the facility's Environmental Assessment completed in 1997, it was determined that the rate of contaminant movement was extremely slow (measured in millimeters per year) and that it would take hundreds to thousands of years for the most mobile constituents in the waste, such as chloride, to reach the underlying Interface Aquifer. Should it ever be necessary, a contingency program has been developed and approved by the Ministry of Environment, which if activated will ensure that landfill contaminants are controlled and collected on site, with no adverse effect on the groundwater beyond the Facility property. The monitoring program, which has been in place since 1974 at the facility has verified that the landfill provides for the secure storage of contaminants.
Does the Landfill Pollute Local Groundwater Resources?
There is no evidence of contamination in samples collected from the Facility’s monitoring wells installed to the perimeter of the Facility property in the regional Interface Aquifer. The monitoring program is completed twice per year and the results are presented in the Annual Landfill Report, copies of which are available to the Ministry of Environment and other interested parties. Learn more »
Does the Operation of the Landfill Contaminate Local Crops?
Clean Harbors has maintained a phytotoxicology monitoring program since 1991 to track potential impacts on surrounding farms within approximately two km of the Lambton Facility. Foliage, soil and crop samples are collected and analyzed for a broad range of trace organic compounds and metals. There has been no evidence of any impact on the quality of local crops. Learn more »