Biotreatment strategies for the removal of microplastics from freshwater systems. A review

Environmental Chemistry Letters - Research on plastic pollution has recently evidenced the ubiquitous presence of tiny plastic particles called microplastics. Microplastics alter organisms because...     

High natural radiation exposure in radon spa areas: a detailed field investigation in Niska Banja (Balkan region)

The measurement campaigns have been done in the rural community of Niska Banja, a spa town located in southern Serbia, to evaluate population exposure to natural radioactivity. After a screening survey in 200 houses, annual radon and thoron concentrations were measured in 34 houses, and in 2004 a detailed investigation was carried out at six houses with elevated indoor radon concentrations. The paper presents the results of these detailed measurements. The complementary techniques were applied to determine radon and thoron concentrations in indoor air, in soil gas, radon exhalation from soil, soil permeability, and indoor and outdoor gamma doses. Soil and water samples were collected and analysed in the laboratory. Indoor radon and thoron concentrations were found to be more than 1kBqm(-3) and 200Bqm(-3), respectively. Extremely high concentrations of soil-gas radon (>2000kBqm(-3)) and radon exhalation rates (1.5mBqm(-2)s(-1)) were observed. These results will be utilised to set up the methodology for a more systematic investigation.     

Remobilization of metals from slag and polluted sediments (case study: the canal of the Deûle River, northern France)

The anthropogenic impact on the environment in the last century has proven to be very negative due to the fast development of industry. A typical example is the De?le River in northern France, one of the most polluted sites in this region. The concentrations of Pb, Cd, Zn and Cu in river sediments are 300, 800, 50 and 15 times higher, respectively, than the background values. The present study was undertaken to evaluate the capacity of already polluted sediments to capture metals released from industrial wastes (slag). As it were, in spite of the high metal pollution level, sediments have still shown the ability to adsorb metals released from slag under the conditions provided. Their efficiency in "cleaning up" some of the metals (e.g. Pb) seems to be additionally enhanced in anoxic conditions. This study provided some additional information on the importance of sediments as a pollutant sink.     

The Pollution Load by Nitrogen and Phosphorus IN the Jadro River

The objective of the investigations of the Jadro River, located in Croatia, was to estimate the nitrogen and phosphorus loads in the Jadro River spring and its streamflow by calculating the load in kg/day or tons/year and to compare this with the load for the maximum allowed concentrations (MAC) for drinking water (Official Bulletin, No 46/94) expressed in kg/day or tons/year.Daily pollution loads at the Jadro River spring for total N ranged from 0 to 304 kg, for NH₃-N from 0 to 38 kg, for NO₃-N from 0–1321 kg and for PO₄-P from 0–92 kg in the period from September 1993 to September 2003. When compared with MAC loads the results prove that the Jadro River spring is not polluted by nitrogen compounds and phosphorus.The average annual load for total N ranged from 10 to 33 t, for NH₃-N from 0.25 to 5.15 t, for NO₃-N from 40 to 190 t, and for PO₄-P from 0.3 to 11.5 t. The nitrogen compounds and phosphorus loads vary from one year to another without any constant decreasing or increasing trends. The annual average loads compared with the average annual MAC loads (especially for NH₃-N and PO₄-P) show that there were no threats of constant pollution of the spring.The loads for total N and PO₄-P along the Jadro River flow from the spring to the fishpond entrance were monitored over a five year period from September 1999 to September 2004. The results show no regularities. The highest annual total nitrogen load of 45 t was recorded at the entrance to the fishpond during the 2002/2003 period. The highest annual PO₄-P load of 10 t was measured at the Vidović Bridge during the 2003/2004 period; however, the concentrations of N and P did not exceed the MAC concentrations which are prescribed for drinking water.According to the investigation results of the daily and average annual loads compared with MAC loads for drinking water, it can be concluded that the Jadro River spring and its streamflow are not polluted by nitrogen and phosphorus.     

Utilization of municipal solid waste bottom ash and recycled aggregate in concrete

In the combustion process of municipal solid waste (MSW), bottom ash (BA) represents the major portion of the solid residue. Since BA is composed of oxides, especially SiO(2) and CaO, the feasibility of its application in concrete as a substitute for cement was tested. It was found that at the age of 28 days, the flexural and compressive strengths of the binder linearly decrease at the rate of 0.03 and 0.02 MPa per wt% of BA in the binder, respectively. According to the results it may be recommended to replace up to 15 wt% of cement by BA and to use such binder where a low strength of concrete elements is required. Furthermore, the aggregate used for low strength concrete need not be of a very good quality. Therefore, gravel aggregate was partially replaced by recycled aggregate (RA). Consistency measured by slump was significantly reduced (>50%) when BA or/and RA were introduced into the mixture. However, concrete density and compressive strength were not affected and were approximately 2300 kg/m(3) and approximately 40 MPa, respectively.     

Mapping of cosmic radiation dose in Croatia

The Earth is continually bombarded by high-energy particles coming from the outer space and the sun. These particles, termed cosmic radiation, interact with nuclei of atmospheric constituents and decrease in intensity with depth in the atmosphere. Measurements of photon and gamma radiation, performed with a Radiameter at 1 m above the ground, indicated dose rates of 50-100 nSv/h.The neutron dose rate was measured with the CR-39 track etch detector calibrated by the CERN-EU high-energy Reference Field (CERF) facility. Correlation between neutron dose rates and altitudes at 36 sites was examined in order to obtain a significant positive correlation coefficient; the resulting linear regression enabled estimation of a neutron dose at particular altitude. The measured neutron dose rate in Osijek (altitude of 89 m, latitude of 45.31° N) was 110 nSv/h.