The authors of a 2013 paper in the journal Foods which sounded alarms about the concentrations of pesticides in vegetables and other commercial crops have pulled the article, citing an insurmountable mistake. To wit: the levels of pesticides they reported were, in fact, not what the data really showed.
The article, titled “Health risk assessment of pesticide residues via dietary intake of market vegetables from Dhaka, Bangladesh,” came from a group from that country and Australia.
Here’s the abstract, which is still available online:
The present study was designed to assess the health risk of pesticide residues via dietary intake of vegetables collected from four top agro-based markets of Dhaka, Bangladesh. High performance liquid chromatography with a photo diode array detector (HPLC-PDA) was used to determine six organophosphorus (chlorpyrifos, fenitrothion, parathion, ethion, acephate, fenthion), two carbamate (carbaryl and carbofuran) and one pyrethroid (cypermethrin) pesticide residues in twelve samples of three common vegetables (tomato, lady’s finger and brinjal). Pesticide residues ranged from below detectable limit (<0.01) to 0.36 mg/kg. Acephate, chlorpyrifos, ethion, carbaryl and cypermethrin were detected in only one sample, while co-occurrence occurred twice for fenitrothion and parathion. Apart from chlorpyrifos in tomato and cypermethrin in brinjal, all pesticide residues exceeded the maximum residue limit (MRL). Hazard risk index (HRI) for ethion (10.12) and carbaryl (1.09) was found in lady’s finger and tomato, respectively. Rest of the pesticide residues were classified as not a health risk. A continuous monitoring and strict regulation should be enforced regarding control of pesticide residues in vegetables and other food commodities.
But here’s what the retraction notice had to say about that:
The following article: doi: 10.3390/foods2010064, available online at: http://www.mdpi.com/2304- 8158/2/1/64 [1], has been retracted by the authors because of some major errors in the broad field of identifying pesticide residue and its concentration. During random cross-check, retention time of pesticides by HPLC did not match with the standard values. As a result, the concentrations of all detected pesticides, maximum residue limits (MRLs), and health risk assessments were altered. These errors render the article [1] incorrect. All authors have confirmed that the reported results were produced using quite inappropriate procedures. As first author, I take full responsibility for the retraction and any other errors in its contents, and would like to offer my apologies on behalf of my co-authors to the readership of Foods for any inconvenience caused by this retraction.
“During random cross-check, retention time of pesticides by HPLC did not match with the standard values”
Short of requesting internal standards on every chromatograph or a m/z mass spectrograph of every peak, a humble LC/GC/TLC chromatograph or CE electrograph is probably as ambiguous as a western. And of course, there’s always a chance that you have a peak that matches retention time, but what’s in the peak?
We use standards on every run. Doing otherwise, as you say, makes LC effectively no better than a western.
I don’t know about the science part, but the retraction notice is honorable and I respect his directness and responsibility – instead of choosing the easy path of obscure excuses and ‘the dog ate my HPLC’
I agree – a perfect and honourable note.