Effect of Radionuclides and Trace Elements on Antioxidant System of Brown Seaweeds.

Ecological effects in marine living can be understood via the determination of antioxidant molecules in aquatic organisms against pollutants. This study aims to evaluate the radionuclides and trace element stress with response molecules. Cystoseira crinita and Halopteris scoparia have been chosen as study materials because of their susceptibility to pollution. The radionuclides 210Po, 238U, 232Th and 40K and trace elements Al, Fe, Mn, Cr, As, Zn and Pb levels were analysed as well as antioxidants and antioxidant enzymes in two brown algae, seasonally. Marine pollutants in terms of radionuclides and trace elements were correlated with antioxidant molecules in these species and may be used as biomarkers for assessing the radioactive stress. The 210Po and Mn concentrations in C. crinita seem to activate catalase (CAT) and superoxide dismutase (SOD) enzyme activities while 210Po concentrations inclined the proline amount in H. scoparia. This study demonstrated the radiation stress-induced the antioxidant defence system in macroalgae, the primary producers of the marine environment.

Activity concentrations of 210Po and 210Pb in fish and mussels in Izmir, Turkey, and the related health risk assessment (dose assessment and pesticide levels) to the consumers.

The activity concentrations of natural radionuclides (210Po and 210Pb) and residual pesticide levels were determined from the fish (red mullet, common sole, anchovy, horse mackerel, gray mullet, and sardine) and mussel samples collected in Izmir Bay seasonally from October 2012 and July 2013. The 210Po and 210Pb concentrations varied between 5.7 ± 4.0 Bq kg-1 dry weight (dw) to 353.7 ± 45.0 Bq kg-1(dw) and 0.7 ± 0.2 Bq kg-1 (dw) to 4.3 ± 0.8 Bq kg-1 (dw), respectively. From a public health point of view, the fish and mussel collected from the Izmir Bay are not harmful to consumers.

Atmospheric depositional characteristics of 210Po, 210Pb and some trace elements in Izmir, Turkey.

The total atmospheric deposition rates of 210Po, 210Pb and some trace elements (Li, Be, B, Na, Mg, Al, Si, P, K, Ca, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, As, Se, Rb, Sr, Mo, Ag, Cd, Sn, Sb, Ba, La, Ce, Tl, Pb and U) have been determined for a year (November 2014-October 2015) collecting samples monthly using bulk collectors at three sites in Izmir, Turkey (Aliaga, Bornova, and Dikili). The annual 210Po flux was found as 34.8 Bq m-2 y-1 in Aliaga, 29.2 Bq m-2 y-1 in Bornova, 21.1 Bq m-2 y-1 in Dikili; the annual 210Pb flux was found as 41.7 Bq m-2 y-1 in Aliaga, 43.6 Bq m-2 y-1 in Bornova, 28.6 Bq m-2 y-1 in Dikili. The annual depositional fluxes of 210Po and 210Pb were generally correlated with the amount of precipitation. For most trace elements the highest fluxes were observed in Aliaga, while the lowest fluxes were observed in Dikili.

An investigation on the seasonal variations of the biomarkers of oxidative stress response and their correlations to Polonium-210 in mussel (Mytilus galloprovincialis) and common sole (Solea solea) from Izmir Bay, Turkey.

It is well known that the marine organisms are used as biological indicators for environmental pollution studies. Among these studies, the research on oxidative stress has been increasing in recent years. In this study, mussels (Mytilus galloprovincialis) and fish (Solea solea) samples were collected seasonally from Inciralti, Izmir, Turkey. This station was in an area where fishing is carried out for human consumption. The relationship between 210Po and oxidative stress markers (lipid peroxidation (LPO), H2O2 and proline) was investigated in the mussel tissue (digestive gland, gills) and fish tissue (liver, gills) samples. The present study indicated that H2O2 accumulated with increasing 210Po concentration in mussel samples. Statistically significant correlation were found between H2O2 and 210Po and LPO and proline in mussel samples. This correlation between LPO and proline can be attributed to common environmental parameters (other than 210Po) affecting expression of both LPO and proline levels. There was not a significant correlation between 210Po and LPO levels. Similarly, a significant correlation was not found between 210Po and proline.

Radionuclides (210Po and 210Pb) and Some Heavy Metals in Fish and Sediments in Lake Bafa, Turkey, and the Contribution of 210Po to the Radiation Dose.

The pollution level of Lake Bafa was investigated by collecting fish samples {Dicentrarchus labrax (sea bass), Liza ramada (mullet) and Anguilla anguilla (eel)}, surface sediment, and core samples. In all these samples, 210Po and 210Pb concentrations were estimated, and total annual dose rates were obtained for each species. Some heavy metal (Cr, Ni, Pb, Cd, Mn, Fe, and Zn) concentration levels were obtained for the fish and a core sample. The sediment mass accumulation rate was found to be 3.27 g·m-2·day-1 (0.119 g·cm-2·y-1) from a core sample. The heavy metal concentrations in the vertical profile of samples from the core were also observed. The measured concentration of Zn, Pb, Cd, and Cr were between the ERL (effects range low) and ERM (effects range median) limits, while Ni concentrations were higher than the ERM limit. The observed concentrations of Cd, Pb, and Zn in fish samples did not exceed the limits in accordance with Turkish Food Regulations. Further, the maximum effective dose equivalent of 210Po in the area was found to be 1.169 µSv·y-1.

Estimation of sediment accumulation rates using naturally occuring ²¹°Pb models in Gülbahçe Bay, Aegean Sea, Turkey.

The sediment chronology was determined using Lead-210 (²¹°Pb) dating method in Gülbahçe Bay. Sediment cores were obtained using gravity core sampler from hydrothermal area and also from reference point and surfical distribution of Polonium-210 (²¹°Pb) was investigated in the study area. The average of surfical concentration of ²¹°Po was found as 175.25 ± 3.80 Bq kg⁻¹ in the hydrothermal area which was higher than the reference point value of 133.20 ± 3.30 Bq kg⁻¹. Sedimentation rates in Core reference point (RN) displayed an increase till the year 1942 and a decrease afterwards, sedimentation rates in any core from hydrothermal area have not exhibited any continuous increase or decrease. The ²¹°Pb fluxes measured from core inventories are close to each other. Average enrichment factors for Cu, Cd, Sr, Zn, Cr vary between 20.35 and 12.18 indicating that the sediments have been contaminated with these metals in the reference point. Maximum enrichment factor values for Cr, Cu, Zn, Ba, Sr, Ni, Co vary between 22.91 and 11.42, implying that the sediments in hydrothermal area have been contaminated with these metals.