Research Article: Contamination of livestock due to the operation of a small waste incinerator: a case incident in Skutulsfjörður, Iceland, in 2010

Date Published: February 24, 2012

Publisher: BioMed Central

Author(s): Thorhallur I Halldorsson, Guðjón Atli Auðunsson, Rannveig Guicharnaud, Ólafur R Dýrmundsson, Sigurður Örn Hansson, Kjartan Hreinsson.


Partial Text

Polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs), referred to as dioxins, are formed as unintentional by-products in various industrial processes including waste incineration. Dioxins may also be formed by natural processes like natural fires of vegetated areas but these sources are usually of much less importance than the anthropogenic ones. Other compounds possess dioxin-like properties, notably some polychlorinated biphenyls (PCBs), i.e. the dioxin-like PCBs (DL-PCBs). Based on adverse developmental effects observed in laboratory animals, the tolerable weekly intake of dioxins and dioxin-like PCBs for humans has been estimated to be 14 pg WHO1998-TEQ/kg b.w. [1]. Dioxins and dioxin-like PCBs are also classified as human carcinogens [2] and human exposure to these contaminants has been associated with a number of other adverse health effects [3-5]. The toxicity of dioxins and dioxin-like compounds is quantified in terms of toxic equivalents (TEQ) calculated by way of toxic equivalent factors (TEFs), which rank the different congener’s relative toxicity towards the most toxic dioxin, 2,3,7,8-TCDD, which has a TEF equal to one [6]. There are 210 possible congeners of PCDD/Fs and 209 congeners of PCBs of which seventeen and twelve have TEFs, respectively. Dioxins and PCBs are very persistent compounds with elimination half-life in humans ranging from 1 to >20 years [7]. Dioxins and PCBs accumulate in fat and biomagnify in the food web of aquatic and terrestrial animals. As a result, foods of animal origin usually account for more than 90% of human exposure [8].

Overview of the types of samples collected and description of the sample location is given in Table 1. To examine the spread of the contamination, PCDD/Fs, dioxin-like PCBs and 7-marker PCBs in milk from Engidalur were compared with contaminant levels in samples collected in two nearby fjords. For all sample types (milk, beef, sheep (lambs/ewes), and hay), average values from samples collected in 2003-2004 at various locations around Iceland were also used for comparison. The data of 2003-2004 represent background contamination in Iceland.

The current study suggests that the operation of a small municipal waste incinerator, not satisfying modern day emission standards, may result in non-compliant levels of dioxins and dioxin-like PCBs in locally produced foods. The incident was limited to a small area were non-compliant levels in milk and beef were observed. Our results do, however, demonstrate the difficulty of evaluating contaminant levels in lambs and ewes, which could migrate freely in and out of the contaminated area.

Although limited in scope, the current incident clearly demonstrates that operation of a small waste incinerator that is non-compliant with the current EU legislation may result in elevated levels of dioxins in foods in the nearby surroundings. This incident also demonstrates the difficulty of tracing contaminant sources by migratory animals such as sheep that can freely move in and out of the contaminated area. With respect to future monitoring programs conducted by the Icelandic Food and Veterinary Authority, the incident highlights the need of good flow of information between different inspection authorities; and the importance of targeted monitoring of food production close to potential sources of contamination, even though the sources may be relatively small in scale.

The authors declare that they have no competing interests.

KH and SOH designed the experiment and collected the samples. TIH, GAA, OD, and RG provided expert advice during the experiment and with respect to interpretation of the results. TIH and GAA drafted the manuscript with input and critical revisions from KH, SOH, OD and RG.