A recent news article titled, Root of all evil: Vegetables in NYC gardens are 'toxic', published by the New York Post brings attention to heavy metal contamination within urban farms. The article describes how citizens who get there produce from New York City urban gardens are at high risk of exposure to unsafe levels of Lead in carrots and other root vegetables. The article also mentions how no threshold containment level for lead is currently set for vegetables in the United States, comparing observed lead levels to the European Union's threshold. Furthermore, the levels of lead found in various herbs including basil and thyme were noted as being "off the charts"!
(Image credit: NYPost.com)
Generating the "toxic buzz" expressed by this article is a recent study published in Environmental Pollution by researchers at Cornell University's Department of Crop and Soil Sciences. The study analyzed levels of Lead, Barium (Ba), and Cadmium (Cd) in garden soil and vegetables around urban areas of New York State. The objectives of the study were to determine if soil contaminant levels could be linked to vegetable levels, compare metal concentrations in urban garden produce to market-bought produce, and to determine if a significant health hazard exists at the contaminant levels observed. Samples of fruit, leafy vegetables, root vegetables, and herbs were gathered from farms in New York City and Buffalo. Because the U.S. does not have health-based standards for metals in garden food, the study used European food guidance standards. Overall, soil and vegetable levels did not correlate (i.e. high variability between vegetable and soil contaminant levels), and although Pb levels in urban produce was higher than market-basket produce, the researchers concluded that the data are not significant enough to represent a health hazard.
(Pb concentrations in garden-grown vegetables by crop type (mg kg−1 d.w.). Boxes represent 25th, 50th and 75th percentiles. Whiskers extend to 5th and 95th percentiles. Image credit: McBride et. al)
The New York Post article paints a very different image of the results presented by the journal study. Although the levels of Pb were highest in root vegetables and herbs were highest, the news article makes no mention of the high variability, confounding factors and level of error presented by the study. Factors that affected the variability included soil pHs, organic matter, and aerosol lead deposition dependent on each garden's location. The study also mentions that rudimentary analytic tools may have contributed to the high level of error in some of the measurements. The news article further inflates the subject with its use of exaggerated language; quoting a pharmacologist claiming, "your playing Russian roulette with this," and including urgent calls to action by local politicians purporting the "serious health risk" presented by the data displays an irresponsible and inaccurate reporting style by the New York Post.
I enjoyed reading into the issue of heavy metal contamination within urban farming systems. This article brought attention to the issue and gives a decent summary of the the risks and health implications of lead exposure and the presence in community gardens. I think a valuable piece of information expressed by the article was that the exposure levels to contaminants in urban produce must be further addressed and studied. However, the political and reporting biases presented in this NY Post article drastically overinflated the results of the study cited. I therefore would give this article a rating of 6/10.
New York Post article: http://nypost.com/2014/11/16/toxic-veggies-found-in-nycs-community-gardens/
Original research study: http://www.sciencedirect.com/science/article/pii/S0269749114003431
I would have liked to see the NY Post article talk more about the other metals mentioned in the research study, such as Barium, Aluminum and Cadmium. Though there was quite a bit of variance in the amounts of metals taken up by most types of vegetables, the fact that some differences existed interested me. I am particularly impressed by the finding of high concentrations of barium (typically >10 mg/kg) in many vegetables.
ReplyDeleteOn a similar note, I would be curious to see research about why differences in metal concentrations exist for different plants.
I definitely found the research article very interesting, although it would have been nice to see a map showing how the concentrations of the metals varied over the sampling areas. I would also liked to see if having a high level of one kind of metal goes along with higher levels of the other metals.
ReplyDeleteNice review. I struggle with the NY Post article because of the flaky language (Russian Roulette, jolly green giant in the sky, etc.). Phrases like this are distracting and make the author lose credibility. This is a serious topic that people need to understand but this article makes it difficult to take seriously.
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