Glossary

Glossary

DATA COLLECTORS:

Any of a variety of devices that provide quantitative physical descriptions of the site and activities (thermometer, PID, pressure transducer, etc.)

DATALOGGER:

Recording device usually connected to a computer that automatically records data from devices on a site (i.e. pressure transducer).

DE MINIMIS RISK:

A level of risk that the scientific and regulatory community asserts is too insignificant to regulate.

DEBT SERVICE RATIO:

Also called the debt coverage ration (DCR), is a measure with which lenders can evaluate the potential for risk of an income property loan.  It is a measure of financial risk and indicates the project’s ability to cover debt service payments.  It is the “buffer” or “cushion” between the net operating income (NOI) and the debt service (NOI divided by the debt service).  Generally, the lower the DCR, the higher the risk to the lender and vice versa. When lenders perceive that a project is high risk, they will require a higher DCR to lessen the potential for risk of the loan.

DEBT SERVICE:

In simple terms, the debt service is the amount or service “fee” that the lender requires for a loan advance. This amount is of crucial importance to the borrower because it will often absorb the largest portion of the cash flow from the property. The amount of the debt service, along with the loan term, is also a determining factor in setting the amount of the loan itself. Naturally, the higher the interest rate on a loan, the higher the debt service (other things being equal).  Also, the shorter the loan term, the faster the loan principal must be repaid and, consequently, the higher the debt service and vice versa.

DECONTAMINATION UNIT (STEAM CLEANER):

Device that sprays high pressure water (may be hot or cold) to wash soil and contamination off equipment. Required to prevent cross contamination.

DEED RESTRICTION:

A private legal restriction on the use of land contained in the deed to the property or otherwise formally recorded.

DENSE NONAQUEOUS PHASE LIQUID (DNAPL):

One of a group of organic substances that are relatively insoluble in water and more dense than water.  DNAPLs tend to sink vertically through sand and gravel aquifers to the underlying layer.

DETECTION LIMIT:

 The lowest concentration of a chemical that can be distinguished reliably from a zero concentration.

DIFFUSION:

The movement of a substance from an area of high concentration to an area of low concentration. (See DISPERSION.)

DIOXIN:

Any of a family of compunds known chemically as dibenzo-p-dioxins.  They are chemicals released during combustion.  Concern about them arises from their potential toxicity and the risk posed by contamination in commercial products.  Boilers and industrial furnaces are among the sources of dioxins.

DIRECT PUSH SAMPLING:

A technique in which a sampling tube is hydraulically pushed or driven into the subsurface, collecting material as it advances.  This technique can be used when sampling for constituents, including VOCs SFOCs, PCBs, and PAHs.

DISCHARGE:

The volume of water that passes a given location within a given period of time. Usually expressed in cubic feet per second.

DISPERSION:

The process by which a substance or chemical spreads and dilutes in flowing groundwater or soil gas. (See DIFFUSION.)

DISPOSAL:

Disposal is the final placement or destruction of toxic, radioactive or other wastes; surplus or banned pesticides or other chemicals; polluted soils; and drums containing hazardous materials from removal actions or accidental release.  Disposal may be accomplished through the use of approved secure landfills, surface impoundments, land farming, deep well injection, or ocean dumping.

DISSOLVED OXYGEN METER:

Device that measures the amounts of dissolved oxygen in water. Used as an indicator of biological activity.

DOMESTIC WATER USE:

 Water used for household purposes, such as drinking, food preparation, bathing, washing clothes, dishes, and dogs, flushing toilets, and watering lawns and gardens. About 85% of domestic water is delivered to homes by a public-supply facility, such as a county water department. About 15% of the Nation's population supply their own water, mainly from wells.

DOWNGRADIENT:

In the direction of decreasing static head (potential). The direction water and contaminants will most likely flow without other influences.

DRAINAGE BASIN:

Land area where precipitation runs off into streams, rivers, lakes, and reservoirs. It is a land feature that can be identified by tracing a line along the highest elevations between two areas on a map, often a ridge. Large drainage basins, like the area that drains into the Mississippi River contain thousands of smaller drainage basins. Also called a "watershed."

DRAWDOWN:

Lowering the water table due to withdrawal of groundwater.

DRAWDOWN:

Lowering the water table due to withdrawal of groundwater.

DRILLING RIG:

Equipment used for drilling borings and monitor wells.

DUAL-PHASE EXRACTION:

Also known as multi-phase extraction, it is a technology that uses a vacuum system to remove various combinations of contaminated groundwater, separate-phase petroleum product, and vapors from the subsurface.  The system lowers the water table around a well, exposing more of the formation.  Contaminants in the newly exposed vadose zone then are accessible to soil vapor extraction.  Once above ground the extracted vapors or liquid-phase organics and groundwater are separated and treated.

DUE DILIGENCE:

The process of evaluating the environmental condition of a parcel of land, usually in connection with a real estate transaction.