Title:
Analysis of pesticide residues on cut flowers as the basis of an assessment regarding florist exposure.
Authors: Hagmann, Michael; Rade-Schinke, Sigrun; Grothus, Birgit; Schmidt, Klaus-Dieter; Offenbacher, Gustav. Journal: Nachrichtenblatt des Deutschen Pflanzenschutzdienstes (Braunschweig), volumn 51, pages 146-151,(1999).
Abstract:
“Cut flowers were investigated for residues of insecticides, acaricides, and fungicides on the surface of the plants. 3 Active agents/sample were detected. 6.5% Of the samples were free of residues. In total 43 active agents were proven (26 insecticides or acaricides and 17 fungicides). Methiocarb, bitertanol, etridiazol, and methomyl were present in 76, 21, 20, and 13%, resp., of all samples. The highest residue contents showed bitertanol, methiocarb, captan, chlorthalonil, tolylfluanid, and methomyl 3.47, 1.02, 0.59, 0.28, 0.27, and 0.18 mg/cm2. Captan and chlorthalonil belonged to carcinogenic category 3 and phosphamidon to mutagenic category 3. In a worst-case calcn., the exposure to pesticide residues on the hands would be 2.086 (bitertanol), 0.586 (methiocarb), 0.352 (captan), and 0.275 (chlorthalonil) mg per person per day. In the case of chlorthalonil, the dermal exposure for florists is high.”
It’s good to see that there’s no evidence of serious danger posed by exposure to captan, especially in the small amounts we are likely to encounter while using captan to protect seeds and seedlings from fungus.
Peter, the first paper that I presented (and the most recent published in 2001) stated the following: “Among individual compounds, in multivariate analyses, the risk of NHL was statistically significantly increased by exposure to …; and to the fungicides captan and sulfur compounds.”
Note the words “statistically significantly increased”.
I suggest that anyone who is still considering using Captan in their hybridizing obtain (through interlibrary loan or from their local university library) the full article if they still have any questions about its safety.
Note, the proposed maximum exposure is 5 mg/m3 (from Ludwicki et.al. paper). Compare that to the amount found on the cut flowers 0.59 mg/cm2 (which is 5900 mg/m2).
Peter quoted a reference that stated “The International Agency for Research on Cancer has classified captan in Group 3: Not classifiable as a carcinogen (IARC. 1987a)”.
A Google search found the following actual Interational Agency for Research on Cancer (IARC) link (which was last updated: 16 April 1998):
What does it say?
"5.3 Evaluation
Results of the experiments in mice provide limited evidence that captan is carcinogenic to experimental animals. No data on humans were available.
The available data are insufficient to evaluate the carcinogenicity of captan to humans."
Link: www.inchem.org/documents/iarc/iarc/iarc446.htm
Have decided not to use it. Better safe than sorry, and there are safer alternatives. Besides, Orange County Farm Supply only has 5lb bags for $23, and if hydrogen peroxide does the same thing, I can buy two more roses with the money I save! I’ve soaked my seeds in h2o2 and they’re in sand or peat in the crisper. I’ll let you know what happens.
A