ABSTRACT
The aquatic environment is continuously under threat because it is the final receptor and sink of waste streams. The development of industry, mining activities and agriculture gave rise to an increase in metal pollution in the aquatic system. Thus a wide occurrence of metal mixtures exists in the aquatic environment. The assessment of mixture stress remains a challenge considering that we can not predict the toxicity of a mixture on the basis of single compounds. Therefore the analysis of the effects of environmentally relevant waterborne mixtures is needed to improve our understanding of the impact of metal pollution in aquatic ecosystems. Our aim was to assess whether 10 % of the concentration of the 96â¯h LC50 (the concentration that is lethal to 50 % of the population in 96â¯h) of individual metal exposures can be considered as a "safe" concentration when applied in a trinomial mixture. Therefore, common carp were exposed to a sublethal mixture of Cu 0.07⯱â¯0.001 µM (4.3⯱â¯0.6⯵g/L), Zn 2.71⯱â¯0.81 µM (176.9⯱â¯52.8⯵g/L) and Cd 0.03⯱â¯0.0004 µM (3.0⯱â¯0.4⯵g/L) at 20⯰C for a period of one week. Parameters assessed included survival rate, bioaccumulation and physiological biomarkers related to ionoregulation and defensive mechanisms such as MT induction. Our results showed a sharp increase in Cu and Cd concentration in gills within the first day of exposure while Zn levels remained stable. The accumulation of these metals led to a Na drop in gills, liver and muscle as well as a decreased K content in the liver. Biomarkers related to Na uptake were also affected: on the first day gene expression for H+-ATPase was transiently increased while a concomitant decreased gene expression of the Na+/H+ exchanger occurred. A fivefold induction of metallothionein gene expression was reported during the entire duration of the experiment. Despite the adverse effects on ionoregulation all fish survived, indicating that common carp are able to cope with these low metal concentrations, at least during a one week exposure.
Subject(s)
Bioaccumulation , Cadmium/toxicity , Carps/metabolism , Copper/toxicity , Water Pollutants, Chemical/toxicity , Zinc/toxicity , Animals , Bioaccumulation/genetics , Biomarkers/metabolism , Cadmium/metabolism , Carps/genetics , Copper/metabolism , Ecosystem , Electrolytes/metabolism , Gene Expression/drug effects , Homeostasis/drug effects , Lethal Dose 50 , Metallothionein/genetics , Proton-Translocating ATPases/genetics , Water Pollutants, Chemical/metabolism , Zinc/metabolismABSTRACT
The article describes the vibrational characterization of the secondary thioamide formation and especially a spectroscopical interesting study of different types of hydrogen bonding in NN'-dihydroxyalkyldithiooxamides.
Subject(s)
Thioamides/chemistry , Bromides/chemistry , Hydrogen Bonding , Models, Chemical , Potassium Compounds/chemistry , Software , Spectrophotometry, Infrared/methods , Temperature , VibrationABSTRACT
CH3HNCSCSOH(LH) forms AuLCl2, AuLBr2, AuL2Cl and AuL2Br complexes in acid media. The complexes are characterised by their elemental analysis and the vibrational spectra. A thorough analysis of the vibrational spectra is carried out to reveal the structure of these complexes. From this study we could conclude that all complexes exhibit a square-planar geometry around the metal ion and that in all cases the ligand acts as a bidentate, coordinating through the sulphur atoms of the thioamide and monothioacid functional groups, forming chelate ring systems.
