Accumulation of Am by suspended matter, diatoms and aquatic weeds of the Yenisei River

In this work we experimentally estimated the capacities of the key components of the Yenisei River (Russia): particulate suspended matter (seston), diatom microalgae, and submerged macrophytes for accumulating ²⁴¹Am from water. In our experiments large particles of seston (>8 μm), comparable in size with diatoms, took up most of americium from water. The accumulation of americium by isolated diatom algae (Asterionella formosa and Diatoma vulgare) was lower than by total seston. The concentration factors (CFs) of ²⁴¹Am for seston of the Yenisei River in our experiments were (2.8-6.9)·10⁵; for diatoms - (1.5-4.2)·10⁴. The CFs for aquatic plant Elodea canadensis were within the same order of magnitude as those for diatoms. Activity concentration and CFs of ²⁴¹Am were nearly the same in experiments under dark and light conditions. This is indicative of an energy independent mechanism of americium uptake from the water by diatoms and submerged macrophytes.     

Determination of concentration factors for Cs-137 and Ra-226 in the mullet species Chelon labrosus (Mugilidae) from the South Adriatic Sea

Concentration factors for Cs-137 and Ra-226 transfer from seawater, and dried sediment or mud with detritus, have been determined for whole, fresh weight, Chelon labrosus individuals and selected organs. Cesium was detected in 5 of 22 fish individuals, and its activity ranged from 1.0 to 1.6 Bq kg⁻¹. Radium was detected in all fish, and ranged from 0.4 to 2.1 Bq kg⁻¹, with an arithmetic mean of 1.0 Bq kg⁻¹. In regards to fish organs, cesium activity concentration was highest in muscles (maximum - 3.7 Bq kg⁻¹), while radium was highest in skeletons (maximum - 25 Bq kg⁻¹). Among cesium concentration factors, those for muscles were the highest (from seawater - an average of 47, from sediment - an average of 3.3, from mud with detritus - an average of 0.8). Radium concentration factors were the highest for skeleton (from seawater - an average of 130, from sediment - an average of 1.8, from mud with detritus - an average of 1.5). Additionally, annual intake of cesium and radium by human adults consuming muscles of this fish species has been estimated to provide, in aggregate, an effective dose of about 4.1 μSv y⁻¹.     

Contribution of (222)Rn-bearing water to indoor radon and indoor air quality assessment in hot spring hotels of Guangdong, China

This study investigates the contribution of radon (²²²Rn)-bearing water to indoor ²²²Rn in thermal baths. The ²²²Rn concentrations in air were monitored in the bathroom and the bedroom. Particulate matter (PM, both PM₁₀ and PM_2.5) and carbon dioxide (CO₂) were also monitored with portable analyzers. The bathrooms were supplied with hot spring water containing 66-260 kBq m⁻³ of ²²²Rn. The results show that the spray of hot spring water from the bath spouts is the dominant mechanism by which ²²²Rn is released into the air of the bathroom, and then it diffuses into the bedroom. Average ²²²Rn level was 110-410% higher in the bedrooms and 510-1200% higher in the bathrooms compared to the corresponding average levels when there was no use of hot spring water. The indoor ²²²Rn levels were influenced by the ²²²Rn concentrations in the hot spring water and the bathing times. The average ²²²Rn transfer coefficients from water to air were 6.2 × 10⁻⁴-4.1 × 10⁻³. The 24-h average levels of CO₂ and PM₁₀ in the hotel rooms were 89% and 22% higher than the present Indoor Air Quality (IAQ) standard of China. The main particle pollutant in the hotel rooms was PM_2.5. Radon and PM₁₀ levels in some hotel rooms were at much higher concentrations than guideline levels, and thus the potential health risks to tourists and especially to the hotel workers should be of great concern, and measures should be taken to lower inhalation exposure to these air pollutants.