Global Inventory, Long-Range Transport and Environmental Distribution of Dicofol

Abstract

The uncertainties on whether dicofol can be identified as a persistent organic pollutant (POP) in terms of its long-range transport (LRT) potential and global distribution, are always a controversial topic during international regulation deliberations. The lack of monitoring data in remote background regions necessitates a model-based evaluation approach for assessing the global distribution of dicofol. However, few model simulations are available at present, as there is no inventory available for global historical usage of dicofol that has sufficiently high spatial and temporal resolution. To describe the current status of global emission, we first developed an inventory of global dicofol usage for the period of 2000-2012 at 1° × 1° latitude/longitude resolution. We then assessed the LRT potential of dicofol by calculating its Arctic Contamination Potential using the Globo-POP model. In addition, we simulated the global mass distribution and the fate of dicofol in the environment using the BETR-Global model at 15° × 15° latitude/longitude resolution. Our estimated inventory established that over the period of 13 years, a total of 28.2 kilo tonnes (kt) of dicofol was applied and released into the environment. East and Southeast Asia, the Mediterranean Coast, and Northern and Central America were identified as hotspots of usage and release. Dicofol exhibited a higher Arctic Contamination Potential than several confirmed Arctic contaminants, and a larger current volume of consumption than most existing POPs. The results of our BETR-Global simulation suggest that (i) dicofol can indeed be transported northward, most likely driven by both atmospheric and oceanic advections from source regions at midlatitudes, and (ii) dicofol will be enriched in remote background regions. Continuous use of dicofol in source regions will result in exposure both locally and in remote regions, and the examination of the potential for adverse effects is therefore of paramount importance. Proactive restrictions at the international level may be warranted.

Spatial distribution and seasonal variation of four current-use pesticides (CUPs) in air and surface water of the Bohai Sea, China

“…The mean dicofol concentration measured in this study was slightly higher than those observed in the Bohai Sea in 2012 (89.57 ± 72.05 pg L − 1 ) (Zhong et al, 2014) ( Table S3), and was markedly higher than those reported in the North Pacific and the Arctic Oceans (9 ± 23 pg L − 1 ) (Zhong et al, 2012a) ( Table S3), and the India-Pacific sector of the Southern Ocean (bMDLs) (Marie et al, 2016) (Table S3). Although the pesticide registration of dicofol was banned in China, high levels in the Bohai Sea could have been due to the large use of dicofol, with domestic consumption of 19,500 tons from 2000 to 2012, occupying 69% of the global total (Li et al, 2015). Higher concentrations of the four compounds were present in SW6 and SW7 in August, which were sampled close to the interface between the Bohai Bay (BB) and Laizhou Bay (LB) (Fig.…”

“…Riverine inputs could be important sources not only for CUPs with relatively high water solubility, but also for CUPs with low water solubility (Zhong et al, 2014). CUPs can be transported by currents into the offshore and deep ocean regions, and hence threaten coastal and pelagic ecosystems (Carratala et al, 2017;Li et al, 2015;Mai et al, 2013). Airwater exchange is also an important process that transports CUPs.…”

A refined method for analysis of 4,4′-dicofol and 4,4′-dichlorobenzophenone

“…This can be explained by the manufacturing process of 4,4′-dicofol being synthesized from DDT. China was the largest consumer of dicofol globally, from 2000 to 2012, with a cumulative usage of 19,500 MT, occupying 69% of the global total amount (Li et al 2015). …”

“…Dicofol has been listed as a persistent toxic compound in a series of multilateral agreements, e.g., Convention on Long-range Transboundary Air Pollution Protocol on persistent organic pollutants (POPs), and banned in many developed countries (Li et al 2015). Dicofol has been proposed (2013) as a candidate for POPs in the Stockholm Convention (UNEP 2015a).…”

Reaction mechanism of dicofol removal by cellulase

“…It is now believed to exert a negative influence on both animals (Jadaramkunti and Kaliwal, 2002;Kojima et al, 2004;Wiemeyer et al, 2001) and humans (Reynolds et al, 2005;Settimi et al, 2003). The toxicity and environmental persistence of dicofol have drawn attention, and it has been prohibited in most developed countries (Li et al, 2015).…”