The effect of olive mill wastewater on seed germination after various pretreatment techniques.

Olive mill wastewater (OMW) management has been a major issue of environmental concern for olive oil producing countries. OMW can be a serious nuisance, when disposed of untreated, due to its significantly high organic load, its phytotoxic properties and its relatively low biodegradability. Field and plant irrigation with raw or pretreated OMW is an easy and relatively inexpensive method to treat and dispose of OMW. Typical pretreatment techniques could be comprised of phase separation through a settling basin, dilution with water, aeration to promote biological degradation and pH neutralization. A full factorial experimental design approach was used here to study the main effects and interactions of the above four pretreatment techniques on the germination of tomato and chicory seeds. Results of the study showed that the most statistically significant technique affecting OMW phytotoxicity is water dilution. The next most significant technique was aeration. In particular, phytotoxicity decreased with increased OMW dilution with water, when OMW was aerated and without pH adjustment. pH neutralization resulted in increased phytotoxicity. Settling did not significantly decrease the phytotoxicity of settled OMW and is therefore not considered necessary in an OMW management system in which plant irrigation is the goal. The interaction of aeration and pH was, marginally, the most significant two-way interaction for tomato seeds, while no interactions were significant when chicory seeds were used.

Radon exposure in the thermal spas of Lesvos Island--Greece.

The aim of this work is to study the exposure due to radon to bathers and personnel in the spas of Lesvos Island under a specific use pattern. 222Rn concentrations in the supplying water were measured during a long time period. Variations in indoor 222Rn, attached and unattached progenies, and influence of the ambient atmosphere were thoroughly analysed during bath treatment for the purpose of investigating a consequent probable short-term health impact. Concentration peaks both for 222Rn and PAEC were found to appear during bathtubs filling. These peaks considered imposing an additional short-term radiation burden for spa users. The additional doses delivered to bathers during bath treatment were found to be very low and for personnel did not exceed the value of 5 mSv per year.

Radon variations during treatment in thermal spas of Lesvos Island (Greece).

The aim of this paper was to study the variations of radon and daughter nuclei during treatment in the thermal spas of Lesvos Island (Greece). For this purpose, in the thermal spas of Lesvos we have measured the radon concentrations of thermal waters, as well as indoor radon, daughter and coarse particle (>500 nm) concentration. Various instruments and procedures were employed for measurements. Radon concentrations of thermal waters were found to lie in the range 10 and 304 Bq l(-1). Concentration peaks both for radon, radon daughter and coarse particle, were found to appear during filling of baths in the treatment process. The doses delivered to the bathers during treatment were in the range of 0.00670 mSv per year to 0.1279 mSv per year, while the doses delivered to personnel were below 20 mSv per year.

Contribution of (222)Rn-bearing water to the occupational exposure in thermal baths.

The present study investigates the short- and long-term effects of radon ((222)Rn) released from water on the progeny exposure in a thermal spa. For the purposes of this work, the Polichnitos spa was used as a case study. The bathroom was supplied with water containing 110-210 kBq m(-3) of (222)Rn. The (222)Rn concentration in air and the short-lived (222)Rn progenies in attached and unattached form were monitored into the bathroom and the surrounding premises. The equilibrium factor (F-factor) and the unattached fraction were estimated. The results of this study show that water flow during bath filling is by far the dominant mechanism by which (222)Rn is released in the air of the bathroom. The progeny exposure was correlated linearly with the (222)Rn concentration in the entering water. The annual effective dose received by a worker was found to be below the lower limit value of 3 mSv recommended by ICRP 65. The dose limit was exceeded only for water containing more than 300 kBq m(-3).