Marine mussels (Mytilus edulis) were exposed to seawater spiked with tritiated water (HTO) at a dose rate of 122 and 79 μGy h⁻¹ for 7 and 14 days, respectively, and tritiated glycine (T-Gly) at a dose rate of 4.9 μGy h⁻¹ over 7 days. This was followed by depuration in clean seawater for 21 days. Tissues (foot, gills, digestive gland, mantle, adductor muscle and byssus) and DNA extracts from tissues were analysed for their tritium activity concentrations. All tissues demonstrated bio-accumulation of tritium from HTO and T-Gly. Tritium from T-Gly showed increased incorporation into DNA compared to HTO. About 90% of the initial activity from HTO was depurated within one day, whereas T-Gly was depurated relatively slowly, indicating that tritium may be bound with different affinities in tissues. Both forms of tritium caused a significant induction of micronuclei in the haemocytes of mussels. Our findings identify significant differential impacts on Mytilus edulis of the two chemical forms of tritium and emphasise the need for a separate classification and control of releases of tritiated compounds, to adequately protect the marine ecosystem.

Recent EU legislation is directed to reverse the upward trends in the concentrations of agricultural pollutants in groundwater. However, uncertainty of the groundwater travel time towards the screens of the groundwater quality monitoring networks complicates the demonstration of trend reversal. We investigated whether trend reversal can be demonstrated by relating concentrations of pollutants in groundwater to the time of recharge, instead of the time of sampling. To do so, we used the travel time to monitoring screens in sandy agricultural areas in the Netherlands, determined by 3H/3He groundwater dating. We observed that concentrations of conservative pollutants increased in groundwater recharged before 1985 and decreased after 1990. Thereby, we demonstrated trend reversal of groundwater quality. From this research we concluded that 3H/3He dating can be used to facilitate (re)interpretation of existing groundwater quality data. The presented approach is widely applicable in areas with unconsolidated granular aquifers and large agricultural pressures on groundwater resources. Groundwater age dating reveals trends and trend reversal in groundwater quality.

Smoke from plastic waste incineration in an open air travels worldwide and is a major source of air pollution particulate matter (PM) that is very withstand to degradation and hazard to human health. Suspension of smoke aerosol components in water occurs during rains and fire extinguishing. Here, water-suspended plastic smoke aerosol (WPS) preparations suitable for biotesting were synthesized. It has been revealed using dynamic light scattering that WPS contained major nano-sized (∼30 nm) PM fraction, and this result was confirmed by electron microscopy. Optical absorption of WPS was in the UV region and an increase in λₑₓ led to a red-shift in fluorescence emission with a corresponding decrease in fluorescence intensity. WPS was analyzed in neurotoxicity studies in vitro using presynaptic rat cortex nerve terminals (synaptosomes). Generation of spontaneous reactive oxygen species (ROS) detected using fluorescent dye 2′,7-dichlorofluorescein in nerve terminals was decreased by WPS (10–50 μg/ml) in a dose-dependent manner. WPS also reduced the H₂O₂-evoked ROS production in synaptosomes, thereby influencing cellular oxidative processes and this effect was similar to that for carbon nanodots. WPS (0.1 mg/ml) decreased the synaptosomal membrane potential and synaptic vesicle acidification in fluorimetric experiments. WPS (1.0 mg/ml) attenuated the synaptosomal transporter-mediated uptake of excitatory and inhibitory neurotransmitters, L-[¹⁴C]glutamate and [³H]GABA, respectively. This can lead to an excessive increase in the glutamate concentration in the synaptic cleft and neurotoxicity via over activation of ionotropic glutamate receptors. Therefore, WPS was neurotoxic and provoked presynaptic malfunction through changes of oxidative activity, reduction of the membrane potential, synaptic vesicle acidification, and transporter-mediated uptake of excitatory and inhibitory neurotransmitters in nerve terminals. In summary, synthesis and emission to the environment of ultrafine PM occur during combustion of plastics, thereby polluting air and water resources, and possibly triggering development of neuropathologies.

From previous catastrophic fission nuclear accidents, such as the Chernobyl and Fukushima accidents, researchers learnt the lessons that external hazard beyond design basis or human errors could result in severe accidents and multi-failure of the confinements although they were considered as very-low-probability events and not requested to be paid much attention to according to the current nuclear safety regulations. Fusion energy is always regarded as a safe and clean energy. However, massive quantity of radioactivity still exists in the fusion reactor and is possible to be released into the environment. The environmental pollution and potential public consequences due to severe accidents of fusion reactor remain largely unexplored. In this contribution, we intended to investigate the hypothetical accident to envelop the worst but probable consequences of fusion reactor, and compare with historic Chernobyl and Fukushima accidents under assumed environmental conditions. It was demonstrated that, the radiation consequences of a hypothetical fusion accident would be much less severe than fission accidents, e.g. an INES 7 accident could not appear in a fusion reactor, as in the Chernobyl and Fukushima nuclear accidents. However, it would still be disastrous and the publics close to site might be exposed to “potentially lethal” radiation dose.

International audience | Groundwater aquifers in Morocco’s coastal regions are under serious threat as a result of climate change. This study was conducted to evaluate and map the quality of water resources, by evaluating the level of pollution of the groundwater in the Meskala-Ouazzi sub-basin, a coastal area of Essaouira based on the physico-chemical analysis of 58 samples using a geographic information system (GIS) technique, analytical analysis, nitrate pollution index (NPI), and groundwater pollution index (GPI). The diagram piper of the study area is dominated by Cl-Ca-Mg, Cl-Na, HCO3-Ca-Mg, and SO4-Ca types. The concentrations of nitrate ranged from 2 to 175 mg/L. It was discovered that 22% of the groundwater samples had nitrate amounts greater than the World Health Organization’s recommended maximum allowable level of 50 mg/L. The NPI ranged between − 0.9 and 7.8. According to the classification of NPI, 44.8% of the total groundwater samples represent clean water, indicating that the groundwater in the study area is suitable for irrigation. GPI values ranging from 0.6 to 3.7, with an average of 1.7, identifies 37.9% of all groundwater samples as low polluted. The inverse distance weighting (IDW) approach was used to generate a spatial distribution map, which indicates that appropriate groundwater is present in the sub-upstream basin’s part. Overall, the forte concentration in groundwater samples detected in western and central areas showed that the nitrate originated from large amounts of nitrogen fertilizer used by humans in agricultural activities during periods of irrigation. The low tritium (δ3H) content shows that the aquifer recharge is stale water and excessive use of fertilizers leads to groundwater pollution faster over time.

The dynamics of the coastal aquifers are well-expressed by geochemical and isotopic signatures. Coastal regions often exhibit complex groundwater recharge pattern due to the influence of depression in the Bay of Bengal, tidal variations on surface waters, saline water intrusion and agricultural return flows. In this research, groundwater recharge processes occurring in coastal Tamil Nadu, South India were evaluated using major ion chemistry and environmental isotopes. A total of 170 groundwater samples were collected from shallow and deep aquifers during both post-monsoon (POM) and pre-monsoon (PRM) seasons. The isotopic results showed a wide variation in the shallow groundwater, suggesting contribution from multiple recharge sources. But, the deeper groundwater recharge is mainly from precipitation. The northern part of the study area showed more depleted isotopic values, which rapidly changed towards south from −6.8 to −4.4‰. Alternatively, central and southern parts exhibited relatively enriched isotopic content with variation from −0.58 to −2.7‰. Groundwater was discerned to be brackish to saline with chloride content, 600–2060 mgL⁻¹ and δ¹⁸O ranging from −5.8 to −4.5‰, suggesting influence of the saline water sources. A minor influence of anthropogenic activities was also observed in the deeper groundwater during PRM, which was confirmed by tritium and Cl⁻ trends. The old groundwater with depleted isotopic content infer recharged by distant sources while modern groundwater with enriched isotopes points to the influence of evaporated recharge.

The decline of groundwater table and deterioration of water quality related to seawater have long been regarded as a crucial problem in coastal regions. In this work, a hydrogeologic investigation using combined hydrochemical and isotopic approaches was conducted in the coastal region of the South China Sea near the Leizhou peninsular to provide primary insight into seawater intrusion and groundwater circulation. Hydrochemical and isotopic data show that local groundwater is subjected to anthropogenic activities and geochemical processes, such as evaporation, water–rock interaction, and ion exchange. However, seawater intrusion driven by the over-exploitation of groundwater and insufficient recharge is the predominant factor controlling groundwater salinization. Systematic and homologic isotopic characteristics of most samples suggest that groundwater in volcanic area is locally recharged and likely caused by modern precipitation. However, very depleted stable isotopes and extremely low tritium of groundwater in some isolated aquifers imply a dominant role of palaeowater.

No baseline existed for the radionuclides in Kuwait territorial water. With changing trend in the region to embrace nuclear energy, the baseline study is imperative to create a reference and to record the influence-functioning of upcoming power plants. The first one in Bushehr, Iran is ready to start and several more are likely to come-up in UAE, Saudi Arabia and Kuwait. The present baseline concentration of the four considered radionuclide’s show low concentration of tritium, polonium, strontium and cesium; their concentration is comparable to most oceanic waters.

This study examined the distribution of virioplankton and bacterioplankton in two coral reef systems (Ahe and Takaroa atolls) in the Tuamotu Archipelago, in comparison with the surrounding oligotrophic ocean. Mean concentrations of 4.8×10⁵ and 6.2×10⁵cellsml⁻¹ for bacteria and 8.1×10⁶ and 4.3×10⁶VLP(virus-like particle) ml⁻¹ were recorded in Ahe and Takaroa lagoons, respectively. Chlorophyll-a concentrations and dissolved organic matter were higher in Ahe whereas ³H thymidine incorporation rates were higher in Takaroa. First data on lytic and lysogenic strategies of phages in coral reef environments were discussed in this paper. The fraction of visibly infected cells by viruses was negligible regardless of the lagoon station (mean=0.15%). However, the fraction of lysogenic cells ranged between 2.5% and 88.9%. Our results suggest that the distribution patterns of virioplankton are apparently not coupled to the spatial dynamics of the bacterioplankton communities.