Depuration of ingested C-labelled polystyrene nanospheres in the Atlantic scallop (Placopecten magellanicus).

The presence of nano-plastics in marine bivalves is well established and may represent a risk to human consumption. The main objective of our work was to study the detailed tissue distribution of 14C-radiolabelled polystyrene nanospheres (PSNP; 325 nm) following their ingestion by commercial-size Atlantic scallop (Placopecten magellanicus) using whole-body autoradiography to assess their translocation, bioaccumulation and depuration mechanisms over a short-term exposure (6h) and a long-term exposure (2 weeks). Results showed that the nanospheres (PSNP) did not accumulate in scallop tissues despite the fact they were ingested and transported all along the digestive system.

Distribution and Fate of Ultraviolet Absorbents and Industrial Antioxidants in the St. Lawrence River, Quebec, Canada.

Ultraviolet absorbents (UVAs) and industrial antioxidants (IAs) are contaminants of emerging concern. In this study, we investigated the distribution and partitioning of these contaminants in surface water, suspended particulate matter (SPM), sediment, and various tissues of lake sturgeon () and northern pike () from the St. Lawrence River (SLR), Quebec, Canada.

Origin of nitrate and sulfate sources in volcano-sedimentary aquifers of the East Africa Rift System: An example of the Ali-Sabieh groundwater (Republic of Djibouti).

Within the East African Rift System (EARS), the complex Ali-Sabieh aquifers system, located in the south of the Republic of Djibouti, was overexploited and subjected to anthropogenic and/or geogenic pollution with high concentrations of dissolved nitrate (up to 181 mg/l) and sulfates (up to 1540 mg/l). This study is the first undertaken on the hydrochemistry of this aquifer system, combining geochemical tools and multi-isotope - δH(HO), δO(HO), δO(SO), δS(SO), δN(NO), δO(NO), δC(DIC), and C- was used to decipher the origin and fate of different nitrate and sulfate sources to groundwater. The groundwater samples of the region show a chemical evolution from fresh Ca(Na)-bicarbonate to brackish Na-Cl , mainly due to water-rock interaction.

Radiolabeling of amide functionalized multi-walled carbon nanotubes for bioaccumulation study in fish bone using whole-body autoradiography.

Commercial and medicinal applications of functionalized carbon nanotubes (f-CNTs) such as amidated f-CNTs are expanding rapidly with a potential risk exposure to living organisms. The effects of amidated f-CNTs on aquatic species have received a limited attention. In this work, an easy wet method to prepare [C]-label amide multi-walled carbon nanotubes (MWNTs) is reported.

Sorption and competition of two persistent organic pesticides onto marine sediments: Relevance to their distribution in aquatic system.

Sorption is a key process in the distribution of substances between environmental compartments in marine ecosystems. Two persistent organic pesticides, also known as toxaphene congeners, namely B8-1413 (P26) and B9-1679 (P50), are of special interest because they are not detected in sediments while relatively concentrated in marine mammals. Sorption-desorption, entrapment and competition behaviors of these pesticides onto marine sediments were studied to explain their environmental distribution.

Sorption behaviors of a persistent toxaphene congener on marine sediments under different physicochemical conditions.

Sorptive processes are important parameters affecting the mobility, availability and fate of persistent organic pollutants (POPs), such as toxaphene, in aquatic systems. The sorption and desorption behaviors of the B7-1450, a stable toxaphene congener in environment, on marine sediment was studied under different temperature and salinity conditions to better understand the B-1450 distribution in estuarine systems. The data were fitted to different sorption models to characterize sorption behaviors by evaluating sorption coefficients and sequestrated fraction of B7-1450 on sediments.

Wastewater reclamation using discarded reverse osmosis membranes for reuse in irrigation in Djibouti, an arid country.

The purpose of this paper is to establish the feasibility of recovering discarded reverse osmosis (RO) membranes in order to reduce the salinity of domestic treated wastewater. This study shows that the reuse of RO membranes is of particular interest for arid countries having naturally high mineralized water such as Djibouti. The pilot desalination unit reduces the electrical conductivity, the turbidity and the total dissolved salt respectively at 75-85, 96.

Investigations on the sorption of a toxaphene model congener, the B7-1450, on marine sediments.

Sorption is a natural process that takes place in sediments or soils and changes the mobility and availability of hydrophobic organic compounds, such as toxaphene pesticide in the environment. The sorption of the 2-exo,3-endo,5-exo,8,9,10,10-heptachlorobornane (B7-1450), used as a model compound of the toxaphene heptachlorobornane congeners found in sediments, was investigated for the first time through a series of batch sorption experiments. The losses of B7-1450 due to adsorption onto glass walls and to evaporation occurring during analytical treatment steps were corrected.