EFFECIENCY OF ZEA MAYS IN THE RETENTION OF NUTRIENTS IN THE INTERSTITIAL WATER FROM PORT-AU-PRINCE DREDGED SEDIMENTS

Many chemical substances rejected into the natural environment accumulate in the vases or muds constituting the sediments. Nowadays, in order to reduce human health and ecological risks, also to prevent the blockage of drainage channels and manage flood risks, operations of dredging are accomplished everywhere across the world. In European countries dredged sediments are used sometimes as manure to fertilizer agricultural soils. In Port-au-Prince, operations of dredging are usually realized on “Bois-de-Chêne” river or channel. The Channel sediments are exposed to wastewater from the Urban Community of Port-au-Prince. After the operations of dredging, the polluted sediments, including solid wastes, are deposited on a site very close to the bay of Port-au-Prince. This discharge allows to a transfer of pollutants to ocean. Indeed, these sediments mixed with solid and liquid wastes can contribute to an eutrophication hazard for the marine ecosystem of Port-au-Prince.

Terrestrial ecohydrology approaches, based on phytotechnology, are mostly used to reduce and manage hazards or risks linked to contaminated sediments. In order to eliminate pollutants containing in the polluted dredged sediments from drainage channel of Port-au-Prince, Zea mays L. has been used, as ecohydrological agent, in this study to reduce the toxicity of sediments chemical compounds on natural ecosystems.

The analysis of pore water of the sediments taken at three (3) points along the channel has allowed showing the Toxicity of the experimental material in nitrogen and phosphorus compounds. The nitrogen (nitrates, ammonia) and phosphorus (phosphate) pollutants were determined according to the french standards. The phosphate values, in particular, are higher of more than 7 times than the maximum limit (2 mg/L). The latter consisted in trapping the mineral compounds by the vegetable material. The measured physical parameters reveal that corn samples raised in the sediments had a better growth than those in the pilot ground from Damien farm. The analysis of collected plants samples shows the potentialities of Zea mays L in the phytoremediation of nitrogen and phosphorus.