The search for alternative aqueous film forming foams (AFFF) with a low environmental impact: physiological and transcriptomic effects of two Forafac(®) fluorosurfactants in turbot.

Fluorosurfactants are the key components in aqueous film forming foams (AFFF). They provide these fire fighting agents with the required low surface tension and they enable film formation on top of lighter fuels to prevent burn back. Development of effective and environmentally acceptable PFOS alternatives is one of the most important priorities in the fire fighting foam industry. DuPont™ offers the fluorosurfactant mixtures Forafac(®)1157 and Forafac(®)1157N for the formulation of AFFFs which are alternatives to the persistent and toxic perfluorooctane sulphonate (PFOS). Ecotoxicological testing of these inadequately documented mixtures is necessary to include them in AFFF hazard and risk assessment. Juvenile turbot (Scophthalmus maximus) were exposed for 14 days to 0.1; 0.5 and 1.5mg/L of the fluorosurfactant mixtures used in Forafac(®)1157 and Forafac(®)1157N. In an initial transcriptomics experiment, microarray analysis revealed differentially expressed transcripts of genes which were mainly involved in digestion and in the immune system. This discovery-driven screening approach offered the basis for new hypotheses that were tested in two subsequent experiments in which food intake, energy reserves, growth and a set of haematological parameters were examined. Additionally, effects of the two mixtures were compared to those of PFOS. Based on the results of this study, the mode of action of Forafac(®)1157N was the activation of the acute phase reaction resulting in increased leukocyte concentrations and the inhibition of growth due to the high energetic cost of toxicant exposure. For Forafac(®)1157, evidences of immunosuppression were found on the transcriptional level and the altered differential leukocyte profiles indicated that stress was induced in these fish. However, food intake, energy reserves and growth were not compromised, even at high exposure concentrations, which was in contrast to the effects seen after PFOS exposure. Taking into account that Forafac(®)1157 appeared to be less toxic than PFOS, this mixture could be considered as a more environmentally acceptable PFOS alternative for the use in AFFFs.

Toxicity evaluation of perfluorooctane sulfonate (PFOS) in the liver of common carp (Cyprinus carpio).

Perfluorooctane sulfonate (PFOS) has been manufactured for over 50 years in increasing quantities and has been used for several industrial and commercial aims. Due to persistence and bioaccumulation of this pollutant, it can be found worldwide in wildlife and humans. Biochemical effects of PFOS exposure are mainly studied in mammalian model species and information about effects on fish species remain largely scarce. This lack of toxicity data points out that there is an urgent need for the mechanistic molecular understanding of the mode of action of this pollutant. In the present study, common carp (Cyprinus carpio) was exposed through water for 14 days at concentrations of 0.1, 0.5 and 1 mg/l PFOS. Liver was selected as target tissue. Custom microarrays were constructed from cDNA libraries obtained with Suppression Subtractive Hybridization-Polymerase Chain Reaction (SSH-PCR) experiments. Microarray data revealed that the expression of several genes in the liver was influenced by PFOS exposure and real-time PCR was used to confirm these gene expression changes. The affected genes were mainly involved in energy metabolism, reproduction and stress response. Furthermore, the relative condition factor, the hepatosomatic index, and the available glycogen reserves of the exposed fish were significantly lower after 14 days of exposure than in the control fish. At all levels of biological organization, indications of a trade-off between the metabolic cost of toxicant exposure on one hand and processes vital to the survival of the organism on the other hand were seen. Our results support the prediction that increases in energy expenditure negatively affects processes vital to the survival of an organism, such as growth.

Observation of a variant creatine kinase isoenzyme in sera and breast tumor cytosols.

A variant creatine kinase (CK) isoenzyme was identified in the sera of some patients who had advanced adenocarcinoma of the breast, stomach, and large intestine. A similar variant isoenzyme, together with a high concentration of CK-BB isoenzyme, was identified in some breast tumor cytosols. The variant creatine kinase activity in both sera and tumor cytosols was unaffected by antibodies specific for both the CK-M and DK-B subunits. This indicates that DK-MB isoenzyme determinations are currently best performed by electrophoretic rather than immunologic technics.