Spatial uptake patterns of microplastics (MP) by marine species are largely unexplored under field conditions. A novel “biodeposit trap” that measure uptake and egestion of MP by suspension-feeders through the analysis of their biodeposits, was designed and used to estimate the spatial variation of these processes by mussels in field conditions. Traps containing wild or farmed mussels or control empty shells were deployed at three sites characterised by different MP concentrations and water flow conditions. A different MP dimensional composition was observed between MP pools present in biodeposit and control traps, with the latter shifted towards higher dimensional range (0.05–5 mm). Conversely, mussels accumulated small MP (0.02–0.05 mm) into their biodeposits without any significant difference between wild and farmed specimens. MP uptake rates were on average 4–5 times higher at the site where MP contamination was expected to be highest and where water flow conditions were considered moderate. | publishedVersion

Spatial uptake patterns of microplastics (MP) by marine species are largely unexplored under field conditions. A novel “biodeposit trap” that measure uptake and egestion of MP by suspension-feeders through the analysis of their biodeposits, was designed and used to estimate the spatial variation of these processes by mussels in field conditions. Traps containing wild or farmed mussels or control empty shells were deployed at three sites characterised by different MP concentrations and water flow conditions. A different MP dimensional composition was observed between MP pools present in biodeposit and control traps, with the latter shifted towards higher dimensional range (0.05–5 mm). Conversely, mussels accumulated small MP (0.02–0.05 mm) into their biodeposits without any significant difference between wild and farmed specimens. MP uptake rates were on average 4–5 times higher at the site where MP contamination was expected to be highest and where water flow conditions were considered moderate.

The livelihoods of poor people living in rural areas of Indus Basin Irrigation System (IBIS) of Pakistan depend largely on irrigated agriculture. Water duties in IBIS are mainly calculated based on crop-specific evapotranspiration. Recent studies show that ignoring the spatial variability of factors affecting the crop water requirements can affect the crop production. The objective of the current study is thus to identify the factors which can affect the water duties in IBIS, map these factors by GIS, and then develop the irrigation response units (IRUs), an area representing the unique combinations of factors affecting the gross irrigation requirements (GIR). The Lower Chenab Canal (LCC) irrigation scheme, the largest irrigation scheme of the IBIS, is selected as a case. Groundwater quality, groundwater levels, soil salinity, soil texture, and crop types are identified as the main factors for IRUs. GIS along with gamma design software GS + was used to delineate the IRUs in the large irrigation scheme. This resulted in a total of 84 IRUs in the large irrigation scheme based on similar biophysical factors. This study provided the empathy of suitable tactics to increase water management and productivity in LCC. It will be conceivable to investigate a whole irrigation canal command in parts (considering the field-level variations) and to give definite tactics for management.

International audience | We report lead (Pb) analyses in juvenile (n = 37; mean length = 24.7 ± 2.3 cm) and adult (n = 16; mean length = 52.3 ± 9.3 cm) Centroscymnus coelolepis Mediterranean deep-sea sharks that are compared to Pb content in bathy-demersal, pelagic and shallow coastal sharks. Median Pb concentrations of C. coelolepis muscle (0.009-0.056 wet ppm) and liver (0.023-0.061 wet ppm) are among the lowest encountered in shark records. Stable Pb isotope imprints in adult C. coelolepis muscles highlight that most of Pb in C. coelolepis is from human origin. Lead isotopes reveal the persistence of gasoline Pb emitted in the 1970s in low-turnover adult shark's muscle while associated liver imprints are in equilibrium with recent pollutant Pb signatures suggesting an efficient pollutant Pb turnover metabolism. The comparison of Pb distribution between adult and juvenile cohorts suggests the role of dietary exposure and possible maternal offloading of Pb during gestation, likely associated to vitellogenesis in this aplacental viviparous deep-sea shark.

We report lead (Pb) analyses in juvenile (n = 37; mean length = 24.7 ± 2.3 cm) and adult (n = 16; mean length = 52.3 ± 9.3 cm) Centroscymnus coelolepis Mediterranean deep-sea sharks that are compared to Pb content in bathy-demersal, pelagic and shallow coastal sharks. Median Pb concentrations of C. coelolepis muscle (0.009–0.056 wet ppm) and liver (0.023–0.061 wet ppm) are among the lowest encountered in shark records. Stable Pb isotope imprints in adult C. coelolepis muscles highlight that most of Pb in C. coelolepis is from human origin. Lead isotopes reveal the persistence of gasoline Pb emitted in the 1970s in low-turnover adult shark's muscle while associated liver imprints are in equilibrium with recent pollutant Pb signatures suggesting an efficient pollutant Pb turnover metabolism. The comparison of Pb distribution between adult and juvenile cohorts suggests the role of dietary exposure and possible maternal offloading of Pb during gestation, likely associated to vitellogenesis in this aplacental viviparous deep-sea shark.

International audience | During the last decades, the coastal areas of Morocco have witnessed an intense socioeconomic development associated with a continuous population growth and urban extension. This has led to an overexploitation of coastal aquifers leading to a degradation of their water quality. In order to obtain large scale overview on the quality status of Morocco's coastal aquifers (MCA) to assist national water managers to make informed decisions, a comprehensive scrutinization of the MCA against common indicators and using unified methods is essential. In this study, databases from thirteen MCA were analyzed, using multivariate statistical approaches and graphical methods in order to investigate the degree of mineralization in each aquifer and to identify the main salinization processes prevailing in groundwater. The results showed that the dominant groundwater types are Na–Cl, Ca–Mg–Cl, Ca–Mg–SO4, Ca–Mg–HCO3 and Ca–HCO3–Cl. The Gibbs diagram and the seawater contribution (0–37%) indicate that the mineralization is mainly due to the seawater intrusion and water-rock interaction. The salinity degree diagram illustrates that almost all groundwater samples are located in the moderate to very saline zone, indicating that MCA are recharged by water from variable sources. The groundwater quality assessment shows a deterioration, particularly by seawater intrusion and significant nitrate pollution. The temporal evolution confirm that the MCA are influenced by seawater namely in the Atlantic part. The Wilcox and USSL diagram indicate that the majority of sampled water are unsuitable for irrigation uses. In addition, and by referring to the WHO and the Moroccan standards for water potability, large number of samples from the groundwaters of the MCA is not fully adequate for drinking purposes. A set of management actions (e,g., artificial recharge) are proposed in order to mitigate the effect of groundwater overexploitation and seawater intrusion to ensure the sustainability of MCA.

During the last decades, the coastal areas of Morocco have witnessed an intense socioeconomic development associated with a continuous population growth and urban extension. This has led to an overexploitation of coastal aquifers leading to a degradation of their water quality. In order to obtain large scale overview on the quality status of Morocco's coastal aquifers (MCA) to assist national water managers to make informed decisions, a comprehensive scrutinization of the MCA against common indicators and using unified methods is essential. In this study, databases from thirteen MCA were analyzed, using multivariate statistical approaches and graphical methods in order to investigate the degree of mineralization in each aquifer and to identify the main salinization processes prevailing in groundwater. The results showed that the dominant groundwater types are Na–Cl, Ca–Mg–Cl, Ca–Mg–SO₄, Ca–Mg–HCO₃ and Ca–HCO₃–Cl. The Gibbs diagram and the seawater contribution (0–37%) indicate that the mineralization is mainly due to the seawater intrusion and water-rock interaction. The salinity degree diagram illustrates that almost all groundwater samples are located in the moderate to very saline zone, indicating that MCA are recharged by water from variable sources. The groundwater quality assessment shows a deterioration, particularly by seawater intrusion and significant nitrate pollution. The temporal evolution confirm that the MCA are influenced by seawater namely in the Atlantic part. The Wilcox and USSL diagram indicate that the majority of sampled water are unsuitable for irrigation uses. In addition, and by referring to the WHO and the Moroccan standards for water potability, large number of samples from the groundwaters of the MCA is not fully adequate for drinking purposes. A set of management actions (e,g., artificial recharge) are proposed in order to mitigate the effect of groundwater overexploitation and seawater intrusion to ensure the sustainability of MCA.

Partie B | International audience | Incidental zinc sulfide nanoparticles (nano-ZnS) are spread on soils through organic waste (OW) recycling. Here we performed soil incubations with synthetic nano-ZnS (3 nm crystallite size), representative of the form found in OW. We used an original set of techniques to reveal the fate of nano-ZnS in two soils with different properties. 68 Zn tracing and nano-DGT were combined during soil incubation to discriminate the available natural Zn from the soil, and the available Zn from the dissolved nano-68 ZnS. This combination was crucial to highlight the dissolution of nano-68 ZnS as of the third day of incubation. Based on the extended X-ray absorption fine structure, we revealed faster dissolution of nano-ZnS in clayey soil (82% within 1 month) than in sandy soil (2% within 1 month). However, the nano-DGT results showed limited availability of Zn released by nano-ZnS dissolution after 1 month in the clayey soil compared with the sandy soil. These results highlighted: (i) the key role of soil properties for nano-ZnS fate, and (ii) fast dissolution of nano-ZnS in clayey soil. Finally, the higher availability of Zn in the sandy soil despite the lower nano-ZnS dissolution rate is counterintuitive. This study demonstrated that, in addition to nanoparticle dissolution, it is also essential to take the availability of released ions into account when studying the fate of nanoparticles in soil.

Incidental zinc sulfide nanoparticles (nano-ZnS) are spread on soils through organic waste (OW) recycling. Here we performed soil incubations with synthetic nano-ZnS (3 nm crystallite size), representative of the form found in OW. We used an original set of techniques to reveal the fate of nano-ZnS in two soils with different properties. 68Zn tracing and nano-DGT were combined during soil incubation to discriminate the available natural Zn from the soil, and the available Zn from the dissolved nano-68ZnS. This combination was crucial to highlight the dissolution of nano-68ZnS as of the third day of incubation. Based on the extended X-ray absorption fine structure, we revealed faster dissolution of nano-ZnS in clayey soil (82% within 1 month) than in sandy soil (2% within 1 month). However, the nano-DGT results showed limited availability of Zn released by nano-ZnS dissolution after 1 month in the clayey soil compared with the sandy soil. These results highlighted: (i) the key role of soil properties for nano-ZnS fate, and (ii) fast dissolution of nano-ZnS in clayey soil. Finally, the higher availability of Zn in the sandy soil despite the lower nano-ZnS dissolution rate is counterintuitive. This study demonstrated that, in addition to nanoparticle dissolution, it is also essential to take the availability of released ions into account when studying the fate of nanoparticles in soil.