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Factors underlying persistently high radon levels in a house located in a karst limestone region of Ireland : lessons learned about remediation

Long S. C., Fenton D., Scivyer C., Monahan E.

Nukleonika

2016

Vol. 61, No. 3

327--332

The remediation of buildings with elevated radon concentrations is generally straightforward. However, in some cases a number of attempts may be needed to reduce concentrations to below the reference level and, occasionally, it may be impossible to reduce concentrations to below the reference level in a cost effective way. This paper details the work carried out between 2004 and 2012 to reduce radon concentrations in a house with initial radon concentrations of almost 1500 Bq/m3. Over this period, high radon levels were consistently recorded despite the introduction of various radon remedial measures. Remedial work was carried out on ten occasions with 29 radon tests carried out to measure the effect of this work. The paper describes the structure of the house and the karst geology that it is built on and the likely contribution of these factors to the difficulties encountered reducing concentrations. Ultimately, radon concentrations were reduced to about 450 Bq/m3 but no further reductions were considered practicable without substantial and costly renovation to the house. Nonetheless, the remedial work carried out to date has resulted in a significant reduction in the risk to the homeowner of developing lung cancer. This work has also added to the understanding of radon remediation techniques in Ireland, particularly for houses built on karst limestone.

Kinetyka adsorpcji jonów fosforanowych z wód powierzchniowych z użyciem preparatu Phoslock

Jodłowski A, Gutkowska E, Dobrzański M

Inżynieria i Ochrona Środowiska

2012

T. 15, nr 3

295--305

Phoslock jest adsorbentem produkowanym na bazie glinki bentonitowej modyfikowanej lantanem, który zgodnie z informacjami literaturowymi skutecznie obniża stężenie fosforanów w wodach powierzchniowych. Mechanizm reakcji polega na wiązaniu anionów fosforanowych z jonami lantanu w stosunku 1:1. W artykule zaprezentowano wyniki badań nad kinetyką adsorpcji jonów fosforanowych przy użyciu preparatu Phoslock, wykorzystując podczas ich interpretacji równanie szybkości reakcji rzędu pseudodrugiego. Przedstawiono wyniki badań dotyczące skuteczności działania preparatu Phoslock prowadzone z wykorzystaniem roztworów wodnych odpowiednio przygotowanych w laboratorium oraz porównawczo wody naturalnej pochodzącej ze sztucznego zbiornika Rochna położonego w odległości około 30 km od Łodzi. Proces adsorpcji jonów fosforanowych zachodził intensywniej w roztworze modelowym niż w wodzie naturalnej.

Eutrophication and its harmful effects cause the need for finding methods of slowing, halting or even reversing this process and its consequences. Currently, the most important and most frequently used methods of remediation are these that use compounds that bind/remove phosphorus. Phoslock is an adsorbent based on lanthanum-modified bentonite clay that effectively lowers the phosphate concentration in surface waters. The reaction mechanism involves binding of phosphate anions with the lanthanum ions in a molar ratio of 1:1 and thus forming lanthanum phosphate (rhabdophane). A characteristic feature of this reaction is that the rhabdophane may be formed when concentrations of La3+ and −34PO are low. Research on the use of Phoslock in phosphate reduction revealed that the complex of lanthanum and phosphate may occur in the pH range 5÷9. It was also found that the rate of adsorption rate increased at higher temperatures. This article studied the kinetics of adsorption of phosphate ions with Phoslock described by the equation of reaction rateof pseudo-second order. Article presents results of research on the effectiveness/efficiency of Phoslock when using water properly prepared in laboratory, and comparatively, natural water coming from the artificial lake Rochna which is used for recreational purposes. Lake Rochna is situated about 30 km from the city of Lodz. Results indicate that the process of adsorption of phosphate ions occurred more intensively in the pre-made model water than in natural water.