Risk Shark: Reunion Must Correct Treatment of its Wastewater

"The shark is risk-factor", evokes all the stakeholders such moneys months, the fisherman to the scientist. At a time when the role of the Marine Reserve is singled out, that of the wastewater treatment insistently reflections of the actors of the file. According to an inventory of the Office of Water Reunion published in August 2011, only 42% of homes in Reunion are connected to public sewerage. Everything else ends up in sewerage based on the principle of natural purifying capacity of the soil. Simply put, 58% of domestic wastewater end up in direct pipeline into the yard, soil absorption. Waiting for the mains drainage with a mesh size of the territory concerned primarily coastal areas, easier connection.

The sewerage inevitably ends up in the basement. The problem lies in the fact that "the island of Reunion is a volcanic island young (3 million years) and built on the collapse of volcanic formations," said the Water Board. The soils are "essentially basaltic who have the characteristic of being very porous." The soils of the Reunion are very permeable. The "transmissivity" of water in soils are "axes of infiltration and rapid vertical movement promoting the transfer of pollutants to groundwater."

In its report, the public sees a "strong involvement of health risks likely to drinking water wells, irrigation of crops consumed or bathing areas." In short, anyway, these waters are not collected and therefore untreated continue to cycle to the ocean.

To explain the approximation assumed sharks close to shore, the hypothesis of a variation of "water chemistry" is evoked by the specialist life of coral reefs, Pascale Chabanet. "Degree of salinity, temperature mean water, turbidity, organic matter composition from livestock activities and urban sanitation ...", these lines of inquiry are open, along with an explanation of shark risk waiting.

Pending the effectiveness of wastewater treatment plants such as new generation Cambaie St. Paul (2013) or St. Mary, Reunion Park is conditioned by a coverage rate of wastewater equivalent / capita negative. The current ratio shows a capacity to care in community sanitation for 380 000 inhabitants, where the Reunion into account 830 000. Regularly, the treatment plants are required to reject at sea