Compared responses to copper and increased temperatures of hybrid and pure offspring of two mussel species
SCIENCE OF THE TOTAL ENVIRONMENT
Authors: Mlouka, Rania; Cachot, Jerome; Boukadida, Khouloud; Clerandeau, Christelle; Gourves, Pierre-Yves; Banni, Mohamed
Abstract
This study investigates the combined effects of increased temperatures and copper on the early live stages of the Mediterranean mussel Mytilus galloprovincialis and the blue mussel Mytilus edulis as well as their hybrids. For this purpose, developmental abnormalities was measured after 48 h of exposure as well as a battery of oxidative stress markers such as, antioxidant enzyme activities, lipid peroxidation measured as malondialdehyde accumulation (MDA) and metallothionein contents (MT) and related gene expression pattern. Embryotoxicity and metal accumulation in tissues of mussel larvae exposed to a sublethal concentration of copper (10 mu g/L) along with a slight temperature increase from 18 degrees C to 22 degrees C were significantly increased after 48 h of exposure. Coexposure to Cu and elevated temperatures significantly increased the antioxidant enzyme activities termed as, glutathione-S-transferase (GST), catalase (CAT). superoxide dismutase (SOD) and being maintained at 22 degrees C only in pure M. galloprovincialis (PG) larvae and female galloprovincialis x male edulis hybrid larvae (HFG). A significant decrease in mRNA abundance of cat, sod, gst gene transcription levels was showed in the same species. Furthermore, metallothionein accumulation increased significantly in PG D-larvae exposed to copper at 22 degrees C. The same pattern was observed in term of gene expression of MTs cognates (mt-10 and mt-20). Significant increase of MDA levels in pure M. edulis (PE) larvae and their female M. edulis x male M. galloprovincialis hybrid larvae (HFE) combined with a low MTs content were observed. Overall, this study provides clues about the relatively higher resistance and resilience of M. galloprovincialis species compared to M. edulis species under environmental pollution and future climate change scenarios. (C) 2019 Elsevier B.V. All rights reserved.
Efficiencies and mechanisms of steel slag with ferric oxides for removing phosphate from wastewater using a column filter system
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
Authors: Ahmad, Siti Zu Nurain; Al-Gheethi, Adel; Hamdan, Rafidah; Othman, Norzila
Abstract
The current study aimed to investigate the efficiencies and mechanisms of slag filter media for removing phosphorus from synthetic wastewater. The steel slag with high ferric oxides (Fe2O3) was subjected for the electric arc furnace (EAF) and selected as the filter media (HFe). The chemical characteristics of HFe were determined using pH, point of zero charge (PZC) and XRF. The phosphorus removal efficiency was studied in a designed vertical steel slag column rock filters in unaerated HFe (UEF) and aerated HFe (AEF) system. The microstructure of HFe was analyzed by FTIR, XRD and SEM-EDX analysis. The results of XRF revealed that ferric oxide (Fe2O3) ranged from 26.1 to 38.2%. PZC for Filter HFe was recorded at pH 10.55 +/- 0.27. The highest efficiencies were recorded by UEF and AEF systems at pH 3 and pH 5 (89.97 +/- 4.02% and 79.95 +/- 6.25% at pH 3 and 72.97 +/- 8.38% and 66.00 +/- 12.85% at pH 5 for UEF and AEF, respectively). These findings indicated that AEF exhibiting higher removal than UEF systems might be due to presence high Fe concentration in AEF which play important role in the phosphorus removal. The main elements available on the surface of HFe included carbon, oxygen, iron, calcium, magnesium, silicon, platinum, sulphur, manganese, titanium and aluminium. The XRD analysis indicated that the precipitation of orthophosphate as calcium and iron-phosphates was the removal mechanism as confirmed using FT-IR analysis. These findings demonstrated the efficiency of HFe in removing of phosphorus from wastewater.