Polychlorinated Dibenzo-p-Dioxins and Dibenzofurans (PCDD/Fs) Impurities in Pesticides: A Neglected Source of Contemporary Relevance

Abstract

Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) may be formed during the manufacture of chlorinated pesticides, and can remain in the products as impurities. However, the contemporary release of PCDD/Fs to the environment from pesticide use is poorly understood. For this study, 27 pesticide formulations were analyzed for PCDD/Fs (n = 23 registered for use in Australia). PCDD/F impurities were present in all samples, ranging from 0.020 to 2100 ng SigmaPCDD/F g(-1) active ingredient (AI). Among current use pesticides, pentachloronitrobenzene (PCNB) contained the highest impurity levels (up to 2000 ng SigmaPCDD/F g(-1) AI and 5.6 ng TEQ g(-1) AI). The quantity of pesticide used in Australia and associated release of PCDD/Fs was estimated for PCNB and phenoxy herbicides (2,4-dichlorophenoxyacetic acid (2,4-D) and 2,4-dichlorophenoxybutyric acid (2,4-DB)) using a probabilistic approach. Input parameters to model pesticide use contributed the highest proportions to the variability of the estimated PCDD/F release, and were considered to have the highest uncertainty. Preliminary estimates of PCDD/F release suggest that contaminated pesticides represent an important ongoing PCDD/F source to the Australian environment (10th-90th percentiles for PCNB = 14-42 and 2,4-D/2,4-DB = 0.35-1.6 g TEQ annum(-1)). These results may have global relevance given that many of the pesticides analyzed were imported into Australia, and are used in high volumes in other countries.

Formation and contamination of PCDD/Fs, PCBs, PeCBz, HxCBz and polychlorophenols in the production of 2,4-D products

“…The total concentrations of 2,3,7,8-PCDD/Fs in the 2,4-D acid samples, D1 and D2, were 355 and 8034 ng kg À1 and the corresponding TEQ values were 13.4 and 267.9 ng WHO-TEQ kg À1 , respectively, which were similar to the results reported by Holt et al (2010). The significant difference found in the concentrations of PCDD/Fs in these two 2,4-D acid samples may be a consequence of the different production processes used in their production and the corresponding difference in raw materials.…”

A comparison of the levels and particle size distribution of lower chlorinated dioxin/furans (mono- to tri-chlorinated homologues) with those of tetra- to octa-chlorinated homologues in atmospheric samples

“…Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/ Fs) are persistent organic pollutants that are byproducts of industrial thermal and chemical processes (Liu et al, 2015a(Liu et al, , 2015b, such as metal smelting (Ba et al, 2009;Nie et al, 2011), waste incineration (Ni et al, 2009;Tang et al, 2013), coking facility processes (Liu et al, , 2013a, herbicide and pesticide production (Rappe et al, 1978;Holt et al, 2010), and chlorine bleaching in paper mills (Wang et al, 2012(Wang et al, , 2014.…”

Environmental Risks of Fungicides Used in Horticultural Production Systems

“…Dioxins can be un-intentionally formed during the manufacture of some agricultural chemicals. This may present an environmental concern when the chemicals are used as dioxins are recognised as persistent pollutants of concern (Holt et al, 2010). In recognition of the potential risks, Australian researchers took a somewhat more proactive approach by analysing the concentration of dioxins in 27 different current use agrochemical formulations.…”

“…In recognition of the potential risks, Australian researchers took a somewhat more proactive approach by analysing the concentration of dioxins in 27 different current use agrochemical formulations. This research highlighted that unacceptably high concentrations of dioxins were present in quintozene formulations (Holt et al, 2010). The scientists notified the APVMA of this concern in June 2009 and following results of confirmatory analysis the APVMA initiated regulatory action and suspended the use of quintozene in April 2010.…”