Assessing glyphosate in water, marine particulate matter, and sediments in the Lagoon of Venice

Lagoon water, suspended particulate matter, and sediment samples from seven sites at Lagoon of Venice were collected from 2019 to 2021 in order to study the presence of the herbicide glyphosate (N-(phosphonomethyl)glycine), among the most widely used agricultural chemicals worldwide, but its occurrence in lagoon water environment has not been deeply investigated. The sites were selected considering a supposed diversity of inputs and of pollution levels. An analytical method based on ion chromatography coupled with tandem mass spectrometry was optimized and validated for lagoon water, marine particulate matter, and sediment samples. Maximum concentrations of glyphosate were 260 and 7 ng L−1 for lagoon water and suspended particulate matter, respectively, and 15 ng g−1 for sediment, with some spatial and temporal fluctuations. Our results demonstrate that glyphosate content in the Venice Lagoon mainly depends on external forcing from river inlets and agricultural lagoon activities.

Effect of ambient water conditions on microbial communities on the artificially produced aggregates: Evidence from experiments using two different seawater cultures

<p>Microbial communities on marine aggregates could be influenced by ambient water conditions; however, empirical data are scarce. In this study, we used fingerprint analysis of PCR-amplified 16S rRNA gene fragment to examine how microbial communities on aggregates change in response to different conditions of ambient water. We conducted two experiments using seawater cultures from surface waters of the lagoon and the anthropogenically influenced bay of Nouméa, New Caledonia: a transplant experiment in which the artificially produced aggregates from one station was added to ultra-filtered seawater culture of another station, and a water-flow experiment in which the artificially produced aggregates placed in the ultra-filtered seawater culture with or without water-flow. In a transplant experiment, bacterial community composition (BCC) on the bay and lagoon water aggregates were significantly different (<em>p < 0.05</em>, ANOSIM) at the beginning of experiment. After 11 days of incubation, BCC on the lagoon water aggregates were significantly different (<em>p < 0.05</em>) from transplanted communities. Transplantation effect was also observed in the bay water treatments. In a water-flow experiment, BCC on the bay and lagoon water aggregates were significantly different (<em>p < 0.05</em>) at the beginning of the experiment. BCC on the lagoon and bay water aggregates with and without water-flow treatments were significantly different (<em>p </em>< 0.05) at the end of incubation, and effect of water-flow on BCC were observed in the bay and lagoon water treatments. Our experimental studies suggest that changes in ambient water conditions potentially influence microbial communities on aggregates in the Bay of Nouméa.</p>

Modelling the variability of hydrological parameters of the Sasyk reservoir impoundment under various options of its operation

This paper highlights the results of adaptation and verification of the Delft3D Flexible Mesh numerical model under the conditions of the Sasyk reservoir. The objective of this work is to evaluate the expected spatio-temporal variability of water salinity in the Sasyk reservoir after completion of the Sasyk renaturalization project by means of establishing a constant water exchange with the sea through the artificial channel. The Sasyk Lagoon was separated from the sea and transformed into a freshwater reservoir in the late 1970s. However, due to the poor water quality in the Sasyk reservoir in the modern period, the solution of the problem of transforming the reservoir to its original coastal conditions, i.e. the renaturalization, has acquired particular importance. Model results, obtained under conditions of 2019, indicate the possibility of using a hydrodynamic model to evaluate the effectiveness and possible consequences of various scenario-based decisions to be implemented for the management of the hydrological regime of the reservoir under various options of its operation. The model runs were used to evaluate the flushing time of the Sasyk Lagoon and the pattern of the salinity fluctuations in the reservoir after the restoration of the artificial channel in the sand bar with a width of 100 m and a depth of 1.5 m and the establishment of the constant “sea-lagoon” interconnection. Applying the hydrometeorological conditions of 2019, a scenario-based modelling for two consecutive years was performed. For the first year of the simulation, a variant of water management under the absence of freshwater inflow from the Danube and the presence of sea water inflow throughout the year was considered. The model results at the end of the first year of the simulation were set as the initial conditions for the second year, and the rest of the external forcing remained unchanged. Additionally, the variant considering the Danube discharge into the lagoon during May-July for the second year of simulation was investigated. Based on the simulation results, it was found that in the case of a constant water exchange with the sea through the connecting “sea-lagoon” channel (with the abovementioned morphometric characteristics) and under the absence of the Danube freshwater inflow throughout the year: 1) the flushing time of the lagoon will be 1 year and 5 months; 2) stabilization of water salinity in the lagoon will not occur, i.e. the salinization of the lagoon water takes place in the long-term perspective; 3) the time period from the moment of initiating the water exchange with the sea, during which the lagoon reaches the water salinity limit of 7-8 ‰, that is critical for the existence of freshwater species of flora and fauna, is expected to amount to 4 months for the southern part and to 5.5 months for the northern part of the lagoon; after which the formation of the marine ecosystem of the reservoir will begin. It is shown that the stabilization of water salinity in the lagoon in the second year of the simulation can be achieved under conditions of ensuring the Danubian freshwater discharge in the period of significantly higher water level in the Danube River, compared to the lagoon water level (May-July 2019).

Radioactivity and Elements Measurements From Lagoon of Cocody Area District of Abidjan (Côte d'Ivoire)

The aim of this study was to assess radio activity and elements levels of Ebrié lagoon water in Abidjan, Côte d'Ivoire. Eight bottles of water from Ebrié lagoon were taken for the study. This study was achieved by measuring of the activity concentration of 238U, 40K, and 232Th in Ebrié lagoon water samples using gamma spectrometry. Elements contents were determined too by Absorption Atomic Spectrometry technique. The activity concentrations of these radionuclides show that populations in these townships-villages are permanently exposed to diseases caused by the ionizing rays. The elemental analysis showed that the potential source of the pollutants is anthropogenic, intrusion from industrial and agricultural activities, materials and lubricants used near the lagoon are important factors of the pollution in this lagoon.

Distribution and bioaccumulation of Endocrine Disrupting Chemicals (EDCS) in Lagos Lagoon water, sediment and fish

Toxic chemical contaminants released from industrial, agricultural, and municipal sources continues to threaten aquatic ecosystems. Aquatic ecosystems act as the final sinks accumulating and transporting numerous chemicals such as octylphenol (OP), nonylphenol (NP) and bisphenol-A (BPA). These chemicals are undesirable as they have been reported to possess endocrine disrupting properties. This study therefore assessesthe distribution and bioaccumulation of endocrine disrupting chemicals (EDCs) in Lagos Lagoon. Water and sediment samples were collected at nine different locations on the lagoon. Five different species of fishes were also collected, identified and homogenized prior to sample pre-treatment. Samples were extracted, clean-up, derivatized and analysed by gas chromatography–mass spectrometry. Physicochemical properties of the samples were also determined. In the water samples, BPA was not detected in all the samples collected at the different locations while the concentrations of NP and OP ranged from ND-102 ng/L and ND-127 ng/L, respectively. The concentrations of the targeted compounds in the sediment samples ranged from ND- 5.08 μg/g BPA, ND-1.90 μg/g NP, and ND- 2.51 μg/g OP while the concentrations ranged from ND-1139 ng/g BPA, ND-476 ng/g NP, and ND-643 ng/g OP in the fish samples. This study revealed the occurrence of EDCs in Lagos lagoon water and their accumulation in biota therein, which can have detrimental effects on other organisms across the food chain. Thus, the need to monitor these endocrine disrupting chemicals is imperative. Keywords: EDCs; BPA; OP; NP; Lagos lagoon