Aysun Uğur Görgün

This study investigated the seasonal variations of polonium-210 (²¹⁰Po) activity concentrations in two marine invertebrate species: Mediterranean limpet (P. caerulea) and the sea urchin (P. lividus). Seasonal sample collection was conducted across three Aegean and Sea of Marmara coastal stations from December 2018 to October 2019. The stations included İzmir-Urla, Karaburun, and İstanbul Island-Kınalıada. To assess the size-dependent bioaccumulation of ²¹⁰Po, individuals were categorized into size groups. The activity concentrations in both species exhibited seasonal fluctuations, ranging from 4.9 ± 3.4 Bq kg⁻¹ dry weight to 28.0 ± 8.4 Bq kg⁻¹ dry weight in Mediterranean limpets and 8.7 ± 6.1 Bq kg⁻¹ dry weight to 58.0 ± 18.5 Bq kg⁻¹ dry weight in sea urchins. The highest ²¹⁰Po activity concentrations were consistently observed in spring across all sampling locations.

Environmental risks in wetlands are considered with radionuclides and trace elements to understand pollution accumulation. In this study, we aimed to determine the levels of radiation and heavy metals in water systems and assess pollution configurations. Radionuclides (²²²Rn, ²¹⁰Pb and ²¹⁰Po) and trace elements (Ag, As, Ba, Be, Cd, Co, Cr, Cu, Fe, Li, Mo, Ni, Pb, V and Zn) were measured to evaluate anthropogenic factors. Water pollution in wetlands was indicated by mean concentrations of 66.2 mBq/L for ²²²Rn, 3 mBq/L for ²¹⁰Pb, 42 mBq/L for ²¹⁰Po, 41 ppb for Zn, 37 ppb for Ba, 190 ppb for Fe and 481 ppb for Sr. These pollutants may be related to industrial facilities in Kırklareli city, Türkiye.

The Middle East is a hot spot of dust, and there are reports of as much as 1400 µg m⁻³ of dust in aerosols from Kuwait, which is among some of the highest dust loadings globally. A significant volume of literature has emerged on dust–air-quality–human-health, and the World Health Organization in its recent air quality guidelines has lowered the limit of annual PM_2.5 exposure to 5 μg m⁻³ from the previous limit of 10 μg m⁻³. We present a mini-review based on a screening and search of the published data generated in Kuwait on contaminants associated with dust in different size fractions. We also include an unpublished study on organic contaminants in size-fractionated aerosols. The ΣPAHs concentrations in all the six size fractions range between 570 and 3350 pg m⁻³. The ∑PBDE concentration ranges from ~2 to 1307 pg m⁻³. The average ²¹⁰Po activity in aerosol size classes varies between 2289 and 2581 Bq kg⁻¹. The average ²¹⁰Pb concentration varies between 352 and 412 Bq kg⁻¹. The MP inventory in Kuwait’s outdoor aerosol is between 5 and 35 MP in 815 ± 5 m³ of air. The bacterial load in outdoor aerosols is between 6.05 × 10³ cells m⁻³ and 1.24 × 10⁸ cells m⁻³. The fungal load ranges between 2.11 × 10² cells m⁻³ and 2.66 × 10⁶ cells m⁻³. The data suggest that the inhalable fraction of 210Po, ²¹⁰Pb, microplastics, and microbes. These enriched ultrafine aerosols pose a significant risk to human health. The review also highlights the scarcity of contaminant data in respirable and inhalable size fractions that are critical for a comprehensive inhalation risk assessment.

Phytoplankton and zooplankton are key marine components that play an important role in metal distribution through a food web transfer. An increased phytoplankton concentration as a result of ocean acidification and warming are well-established, along with the fact that phytoplankton biomagnify ²¹⁰Po by 3–4 orders of magnitude compared to the seawater concentration. This experimental study is carried out to better understand the transfer of polonium between primary producers and consumers. The experimental produced data highlight the complex interaction between the polonium concentration in zooplankton food, i.e. phytoplankton, its excretion via defecated fecal pellets, and its bioaccumulation at ambient seawater pH and a lower pH of 7.7, typical of ocean acidification scenarios in the open ocean. The mass of copepods recovered was 11% less: 7.7 pH compared to 8.2. The effects of copepod species (n = 3), microalgae species (n = 3), pH (n = 2), and time (n = 4) on the polonium activity in the fecal pellets (expressed as % of the total activity introduced through feeding) was tested using an ANOVA 4. With the exception of time (model: F_{20, 215} = 176.84, p < 0.001; time: F₃ = 1.76, p = 0.16), all tested parameters had an impact on the polonium activity (copepod species: F₂ = 169.15, p < 0.0001; algae species: F₂ = 10.21, p < 0.0001; pH: F₁ = 9.85, p = 0.002) with complex interactions (copepod x algae: F₂ = 19.48, p < 0.0001; copepod x pH: F₂ = 10.54, p < 0.0001; algae x pH: F₂ = 4.87, p = 0.009). The experimental data underpin the hypothesis that metal bioavailability and bioaccumulation will be enhanced in secondary consumers such as crustacean zooplankton due to ocean acidification.

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.

Bottom sediments reflect in general the relative contamination of a sea area. Therefore, a great deal of monitoring work has been dedicated to the analysis of bottom sediments. Izmir Bay is a very important pollution centre in Turkish Aegean coast region due to a densely populated community, industrial complex and maritime transportation, and there are many streams flowing into the bay that pass through a number of industrial and agricultural areas. It had received the majority of domestic and industrial wastewaters until the wastewater treatment plant was constructed. It is well known that sediments play an important role as reservoirs of a fraction of the pollution in aquatic systems. Therefore, sediment samples were collected monthly from three stations which are located in the inner part of the bay during the period January to December 2003. Temporal variations and seasonal changes on their ²¹⁰Po and ²¹⁰Pb contents were examined, and the activity concentrations of ²¹⁰Po and ²¹⁰Pb were found to vary from 43±6 to 132±12 and 27±5 to 91±9 Bq kg^− 1 dry wt, respectively. The highest values of those natural radionuclides were measured at Karşıyaka Station because of the current systems of the bay. Seasonally, the ²¹⁰Pb levels were found to increase during the winter time for all the stations.