The use of Atlantic hagfish (Myxine glutinosa) as a bioindicator species for studies on effects of dumped chemical warfare agents in the Skagerrak. 2. Biochemical biomarkers

The sea bottom of the Skagerrak Strait (North Sea) contains munitions loaded with chemical warfare agents (CWA), mostly stored in shipwrecks scuttled intentionally after the end of the World War II. The munition shells inside the wrecks are in different states of deterioration and corrosion and their environmental risk potential is unknown. The Atlantic hagfish (Myxine glutinosa), a sediment-dwelling chordate, was used as a model organism to study the potential impact of dumped CWA on the local ecosystem by using biochemical biomarkers. The hagfish were collected in 2017 and 2018 at three sampling sites: in the immediate vicinity of a wreck with CWA in the Skagerrak, a few kilometres from the wreck, and a reference site 21 km from the wreck, considered to be free of CWA. Significant differences were observed between the wreck site and the reference sites in the activities of glutathione reductase, superoxide dismutase and glutathione S-transferase, while the activity levels of catalase and acetylcholinesterase were identical at all sites. The recorded differences demonstrated negative biological effects in the hagfish sampled close to the dumped chemical munitions. Due to the limited knowledge of hagfish biology and of the extent of CWA contamination in Skagerrak, the results presented here warrant more research to further elucidate the potential environmental risks of the scuttled wrecks. The usefulness of the species as a bioindicator organism is further discussed.

Immunological responses in the mussel Mytilus trossulus transplanted at the coastline of the northern Baltic Sea

The applicability of immune responses in transplanted Baltic blue mussels (Mytilus trossulus) as biomarkers of immunotoxic effects was studied at differently contaminated locations in the Gulf of Bothnia (northern Baltic Sea). Here, we present a detailed report on the immune responses measured as complementary part of transplantation study by Turja et al. (2014).Various immunological endpoints such as total and differential cell count, morphological alterations,phagocytic activity, and caspase 3/7 activity of mussel haemocytes as well as haemolytic activity of the haemolymph were used. Mussels collected at a reference site at a Finnish coastal site (Hanko, H) were transplanted at the Swedish coast near industrial and urban regions of the cities Sundsvall (S1, S2) and Gävle (G1, G2), respectively. Based on the measured immunological responses, multivariate statistical analysis (PCA biplot) showed a clear separation of the most polluted site S1, indicating immunotoxic impacts of the mixture of contaminants present at this location. Based on these observations and results from Turja et al. (2014), we suggest the implementation of immunotoxic biomarkers for the evaluation of ecosystem health. However, these should be accompanied by complementary endpoints of biological effects encompassing i.e., physiological, antioxidant and bioenergetic markers.

A multibiomarker approach to the assessment of pollution impacts in two Baltic Sea coastal areas in Sweden using caged mussels (Mytilus trossulus)

Blue mussels (Mytilus trossulus) were transplanted in cages for three months in two Swedish coastal areas in the Bothnian Sea (northern Baltic Sea) to investigate the interactions between analysed environmental chemicals and biological responses. A wide array of biological parameters (biomarkers) including antioxidant and biotransformation activity, geno-, cyto- and neurotoxic effects, phagocytosis, bioenergetic status and heart rate were measured to detect the possible effects of contaminants. Integrated Biomarker Response index and Principal Component Analysis performed on the individual biological response data were able to discriminate between the two study areas as well as the contaminated sites from their respective local reference sites. The two contaminated sites outside the cities of Sundsvall (station S1) and Gävle (station G1) were characterised by different biomarker response patterns. Mussels at station S1 showed a low condition index, increased heart rate recovery time and phagocytosis activity coinciding with the highest tissue concentrations of some trace metals, polycyclic aromatic hydrocarbons and organotins. At station G1 the highest organochlorine pesticide concentration was recorded as well as elevations in glutathione S-transferase activity, thiamine content and low lysosomal membrane stability. Significant variability in the geno- and cytotoxic responses and bioenergetic status was also observed at the different caging stations. The results obtained suggest that different chemical mixtures present in the study areas cause variable biological response patterns in organisms.

Exposure of Carcinus maenas to waterborne fluoranthene: accumulation and multibiomarker responses

Fluoranthene (FLU) is a priority polycyclic aromatic hydrocarbon (PAH) commonly detected in estuarine sediments, water and biota. Despite this, information on FLU detection, accumulation and effects on marine crustaceans is scarce. This work investigated the accumulation of FLU in Carcinus maenas and the responses of several early-warning biomarkers after a 7-day laboratory exposure to five FLU concentrations (2.56 to 100 μg L(-1)). After exposure to FLU, sub-samples of the crabs' digestive gland and muscle were collected for biomarker determinations. The remaining digestive gland and muscle, together with the rest of the whole-body soft tissues, were analysed for FLU residues by gas chromatography-mass spectrometry (GC-MS). The biomarkers assessed were: i) the quantification of FLU-type compounds by fixed wavelength fluorescence (FF); ii) the activities of glutathione S-transferases (GST) and glutathione reductase (GR), and the levels of total glutathione (GT) and lipid peroxidation (LPO) for oxidative stress; iii) the activity of acetylcholinesterase (AChE) for neurotoxicity; iv) the activities of isocitrate dehydrogenase (IDH) and lactate dehydrogenase (LDH) enzymes, and total protein, glycogen and lipids as indicators of changes in energy metabolism and storage; and v) the lysosomal membrane stability (LMS) as a measure of cell damage. The results showed strong (R(2)>0.95) concentration-dependent accumulation of FLU residues (as measured by GC-MS) in the remaining whole-body soft tissues and of FLU-type compounds (as measured by FF) in the digestive gland and muscle. A strong positive linear relationship (R(2)=0.91) between FLU residues and FLU-type compounds was also found. Comparing to controls, activities of GST and GR were significantly higher in crabs exposed to ≥16 and ≥40 μg L(-1) FLU, respectively. TG levels and IDH activity showed a significant trend to increase with FLU concentrations whereas AChE activity exhibited the opposite trend. FF measurements in the digestive gland and muscle proved to be an expeditious cost-effective method to assess the uptake and availability of FLU and its metabolites in C. maenas. The results suggest that under continuous environmental exposure, FLU may enhance detoxification and anti-oxidant defences, and cause alterations in the aerobic energy pathway, as well as neuromuscular toxic effects that may increase C. maenas risk of predation.