A dam is a barricade built across a waterway such as a stream or river, to block and control the flow of water.

DDT (Dichloro-diphenyl-trichloroethane) is a synthetic pesticide that was widely used during the 1940's.  It was banned in 1973 by the United States due to the discovery of how highly toxic it was to fish, bird species and water supplies. DDT is still commonly used in some developing countries.

The term deciduous refers to perennial plants whose leaves die at the end of each growing season (usually in autumn), and are replaced by new leaves at the start of the next growing season (spring). A deciduous forest contains deciduous vegetation with a climate of mild temperatures and abundant rainfall.

Decommissioning refers to the destruction or recycling of a system or product. For example, in Victoria when energy saving light bulbs are installed in homes, the old light bulbs must be decommissioned in order for the installation company to claim Victorian Energy Efficiency Certificates (VEECs).

The term decompose refers to the breakdown of materials by bacteria and fungi, causing the chemical makeup and physical appearance of the materials to change.

The term deep (or dark) green refers to a person who believes that society needs a radical transformation to become more sustainable. It is also the belief that environmental sustainability should have priority over economic and social issues. These characteristics differ to light green and bright green individuals.

Deforestation refers to the logging and removal of most of the trees from forested land, generally so that the land can be used for agriculture or urban development.  Land clearing is the cause for approximately 20 percent of global greenhouse gas emissions. Key locations for deforestation include South America, central Africa, and Indonesia.

Degradability refers to a materials ability to break down by bacterial (biodegradable) or ultraviolet processes.

Depletion refers to the use or consumption of a resource, particularly a natural resource, faster than it can be replenished.

Desalination is the process of removing salts from sea water or brackish water by using various technologies in order to make it suitable for drinking (creating freshwater). Desalination is a technical solution to freshwater shortage.

Desertification refers to the conversion of rain-fed cropland to desert-like land, with a decline in agricultural productivity of more than 10 percent. Desertification is commonly caused by a combination of overgrazing, soil erosion, extended drought, and climate change.

Designed for disassembly refers to products that are designed so that the components are easily disassembled for reuse or recycling, to reduce landfill waste and to save natural resources.

Diesel is a petroleum-based fuel (fossil fuel) which is commonly used for heavy duty engines including buses and trucks.

Diethanolamine is a softening agent which is commonly found in soaps, shampoos, cleansers, and cosmetics.

Diethanolamine can react with other ingredients in cosmetic formulas to form an extremely potent carcinogen called nitrosodiethanolamine (NDEA).  NDEA is readily absorbed through the skin and has been linked with stomach, esophagus, liver and bladder cancers. 

Disposable items are consumer products, material items and packaging that is used once or a few times and then thrown away.

Disposable Product Replacement is a sustainablity standard that an ekko.world trader might claim.

The trader would typically claim it when the product they make replaces another which is single or minimal use. An example might be a Reusable Bag replacing a Plastic Bag. Or a glass container replacing a disposable coffee cup.

Disposal refers to the final placement or destruction of a wide range of waste materials. This process commonly occurs through use of approved landfill sites or incineration.

Diversion rate refers to the percentage of waste materials that are diverted from landfill or incineration to be recycled, reused or composted.

The term dominant species refers to one or a few species of animals or plants that are most common in a particular natural environment. Dominant species of vegetation generally reflect the characteristics of their habitat such as soil type, water type, and climactic conditions.

Downcycling refers to turning waste material or unused items into new materials or products.  The process usually reduces the material back to its original components and is generally of a lower quality and functionality than the original material.

Dredging is a type of fishing practice where a net is attached to a frame that is pulled along the ocean floor to collect edible marine animals. Dredging can also refer to the removal of mud from the bottom of waterways. This practice can disturb the marine ecosystem and cause silting which may kill aquatic life. Dredging of contaminated mud can expose aquatic life to heavy metals and other toxins.

Drip irrigation is the practice of spraying water directly onto the base of plants so that less water is required for them to grow.

A drought is an extended period of lower than average rainfall.

Dry farming refers to the practice of farming semi-arid or dry grassland areas without irrigation. This farming method is achieved through the use of fallowing, maintaining a finely broken surface, and growing drought-tolerant crops.

Dryland salinity refers to salt accumulation in soils, soil water and groundwater. Salinity may be naturally occurring or caused by land clearing. Across Australia more than 5.7 million hectares of land are classified as having a high potential for dryland salinity. 

A dual flush toilet is a toilet with two flush options, including a half flush button for users to save water.

A dump is an area of land used to dispose of solid waste materials without environmental controls.

Dust pollution refers to airborne particles that contaminate indoor and outdoor environments. These particles may affect healthy breathing or allergies in some people.