Tracking major endocrine disruptors in coastal waters using an integrative approach coupling field-based study and hydrodynamic modeling.

Many of the world's large coastal cities discharge partially treated wastewater effluents containing various endocrine disrupting chemicals (EDCs) to coastal environments. Nonylphenols (NP) and bisphenol A (BPA) were found to be the most abundant EDCs in sewage effluents in Hong Kong. The environmental fate and ecological risk of these two EDCs remains largely unknown, particular for coastal systems with complex hydrodynamic flows. Based on a validated three-dimensional (3D) multiple-scale hydrodynamic model, a field-based study was conducted to track the two EDCs from potential sources to the only marine reserve in Hong Kong. The two compounds were detected in all seawater, suspended particle, and sediment samples, with higher aqueous concentrations in wet season than in dry season. High concentrations in sediments suggest sediment is a sink, posing an ecological risk to the benthos. The fate and transport of the two EDCs was predicted using a 3D near-field Lagrangian jet model seamlessly coupled with a 3D shallow water circulation model. The results suggested the NP and BPA in the marine reserve cannot be solely attributed to the nearby submarine sewage outfall, but likely concurrently contributed by other sources. This study calls for more effective measures of reducing the use and release of these EDCs, and research to investigate their impacts on the marine benthos.

Efeitos ambientais da disposição oceânica de esgotos por meio de emissários submarinos: uma revisão / Environmental effects of sewage oceanic disposal by submarine outfalls: a review

Os sistemas de disposição oceânica de esgotos domésticos, ou emissários submarinos, têm sido historicamente utilizados em todo o mundo como solução para destinação final de efluentes urbanos, principalmente devido aos aspectos econômicos.Porém, o descarte no oceano, seja em águas rasas ou mais profundas, pode induzir uma série de impactos ambientais negativos, dos quais se destacam a eutrofização, a floração de algas tóxicas, a introdução de microrganismos patogênicos e a contaminação por substâncias químicas capazes de produzir efeitos tóxicos sobre a biota e bioacumulação. Desse modo, o lançamento de esgoto não tratado no mar não constitui uma prática ambientalmente adequada, sendo necessário o tratamento dos efluentes de forma a remover nutrientes, contaminantes e organismos patogênicos e evitar a degradação ambiental.

Oceanic disposal systems of domestic sewage, or submarine sewage outfalls, have been historically used around the world as a solution for urban effluents, in special due to economic aspects. However, release into the ocean, in shallow or deepwaters, may induce a set of negative environmental impacts, as eutrophication, toxic algal blooms, pathogenic microorganisms introduction and contamination by chemical substances which are capable of causing toxic effects to the biota and bioaccumulation. Thus, the release of untreated sewage into the sea does not constitute an adequate environmental practice; then, urban effluents should be treated in order to remove nutrients, contaminants and pathogenic organisms and avoid environmental degradation.