A debate over potential hazards of arsenic-fed chickens has erupted between scientific experts.
Bruce Bernard, a toxicologist from Cambridge, accused his colleague Ellen K. Silbergeld from the John Hopkins University, for having based her criticism on the use of arsenic compounds in chicken feed-supplements on wrong data.
The debate revolves around a letter by Silbergeld to the editor of Environmental Health Perspectives
last year in which she comments that feed additives containing organoarsenic compounds used to improve growth in chickens are leading to tissue contamination levels higher than previously estimated, which could pose an increased risk of cancer for consumers.
In her comments Ellen Silbergeld referred to an earlier publication of Lasky et al. (2004)
, in which the authors indicated that the use of arsenic compounds as feed additives should be revisited not only because of environmental concerns but also for their role in human dietary exposures to arsenic (see EVISA News from February, 8th, 2005
Ellen Silbergeld emphasized such viewpoint by stating that Lasky et all. had even under-estimated the true risks, because they had based their estimation of arsenic intake on data for chicken liver rather than chicken muscle. She further gave some evidence that the assumption that arsenic concentrations in muscle is lower than in liver could be wrong. Also the risk assessment of Lasky et al. was based on an outdated report (JECFA 1983) that according to NRC (2000, 2001) greatly underestimated the risk of cancer from arsenic exposure.
In her response
to Bernard's accusation
, also published in the current issue of Environmental Health Perspectives, Silbergeld acknowledges that she "used the wrong metric in quoting her conclusions," but asserted that her findings nonetheless are sound. "I do not agree that this mistake invalidates the conclusions of my letter", she writes and further argues that "if the concentrations of arsenic in edible chicken meat are not one-tenth of those in liver, then the exposure of Americans who consume chicken is in fact 3-10 times higher than Lasky et al. estimated, resulting in an intake of 4-50 µg/day. This is still in excess of the current National Research Council (NRC) recommendation (NRC 2001)".
This kind of dispute should result in further studies, to which the analytical chemists could contribute by a representative analysis of the arsenic speciation in chicken tissues as marketed in the US.
JECFA (Joint FAO/WHO Expert Committee on Food Additives). 1983. Evaluation of Certain Food Additives and Contaminants. Twenty-seventh Report of the Joint FAO/WHO Expert Committee on Food Additives. WHO Technical Report Series 696. Geneva:World Health Organization. Available: http://whqlibdoc.who.int/trs/WHO_TRS_696.pdf
T. Lasky, W. Sun, A. Kadry, M.K. Hoffman, Mean total arsenic concentrations in chicken 1989-2000 and estimated exposures for consumers of chicken
, Environ Health Perspect 112 (2004) 18-21.
NRC (National Research Council). 2001. Arsenic in Drinking Water: 2001 Update. Washington, DC:National Academy Press.
Aleksandra Polatajko, Joanna Szpunar
, Speciation of Arsenic in Chicken Meat by Anion-Exchange Liquid Chromatography with Inductively Coupled Plasma-Mass Spectrometry
, J. AOAC International, 87/1 (2004) 233. doi: 10.5555/jaoi.2004.87.1.233
last time modified: August 12, 2008