Glossaire de A à Z
Obstacle to flow
Ocean
Oceanic current
Oceanography
Oligo-mesohaline lagoon
Lagune dont la salinité moyenne annuelle est située entre 0,5 et 5 PSU (oligo) et entre 5 - 18 PSU (méso).
oligochaete
On-site sanitation
All treatment processes that remove wastewater from an individual single-family home usually on the plot on which the house is built, without any wastewater conveyance. An extension (rarer) concerns the wastewater treatment of some neighbouring houses on private land. It is still on-site sanitation but it is regrouped. On the contrary, a group having a small collecting system and a treatment facility (spreading, filters, etc.) on community land is considered community sanitation. On-site sanitation is first defined as opposed to community sanitation.
Open data
Open sea
Operational monitoring
Control to establish, as part of the water status monitoring programme, the status of water bodies which are not fully guaranteed to achieve their environmental objectives, and assess the effectiveness of programmes of measures on them.
Operator of a classified facility
Opportunity cost
Option value
Order
Administrative decision of general interest (e.g. ministerial order of 29 February 1992 laying down a number of rules for all cattle farms subject to authorization) or individual (e.g. Prefect's order setting out the specific rules that the classified facility operated by Mr. X must comply with). Orders can be issued by ministers (ministerial or inter-ministerial orders), prefects (prefectural or prefect's orders) or mayors (municipal orders). The
Organic farming
Un Label. Méthode de production agricole excluant le recours aux produits chimiques de synthèse utilisés par l’agriculture industrielle et intensive. Les agriculteurs labellisés « bio » sont regroupés en fédérations avec des cahiers des charges à respecter. Ces derniers comprennent en général l’utilisation d’engrais d’origine naturelle, l’interdiction d’intrants d’origine chimique, la rotation des cultures et des élevages peu intensifs de manière à préserver les sols.
Organic matter
Organic micropollutant
Organic active ingredient, usually synthesized by the chemical industry, whose accumulation, even at low concentrations, can be toxic. The main organic micropollutants controlled are volatile organic compounds (VOC), hydrocarbons, andpolychlorinated biphenyl(PCB).