Spatial and temporal pattern of pesticides in the global atmosphere

Abstract

As part of the Global Atmospheric Passive Sampling (GAPS) study, XAD-resin based passive samplers are being deployed for consecutive one-year periods at numerous sites on all seven continents to determine annually averaged concentrations of persistent organic pollutants. Concentrations of banned organochlorine pesticides as well as a number of current-use pesticides in samples from the first four years, roughly coinciding with 2005, 2006, 2007 and 2008, show distinct spatial and temporal patterns. Whereas organochlorine pesticides such as alpha- and gamma-hexachlorocyclohexane, endosulfans, DDT and its metabolites, and chlordane-related compounds tend to be more prevalent in developing countries, especially in Asia, concentrations of current use pesticides such as trifluralin and chlorothalonil are often higher in Europe and North America. Based on 15 stations with four years of data, levels of hexachlorobenzene, hexachlorocyclohexanes and chlordanes decline in most world regions, which may reflect decreased usage in response to global restrictions. Levels of organochlorine pesticides in India, however, remain exceptionally high. Concentrations of alpha-endosulfan, chlorothalonil and trifluralin decrease in the European atmosphere during the sampling periods, indicating reduced usage. Consistently high alpha/gamma-HCH ratios in air samples from high Northern latitudes confirm that re-volatilization from the Arctic Ocean is a significant source of alpha-HCH. The highest levels of alpha-HCH, however, occur in conjunction with high gamma-HCH levels, suggesting that lindane use is now the major source of alpha-HCH to the global atmosphere. Although a wide variety of sampling site types aids in characterizing the entire global concentration variability of a pesticide, it also increases greatly the number of sites required for a robust regional differentiation.

Current status of persistent organic pesticides residues in air, water, and soil, and their possible effect on neighboring countries: A comprehensive review of India

“…Further, they theorized that the volatilization process enhances the active transfer of OCPs from seawater into the atmosphere. Today, levels of organochlorine pesticides in India remain exceptionally high (Shunthirasingham et al, 2010). The highest levels of α-HCH, together with high γ-HCH levels, suggests that lindane use is now the major source of α-HCH in the global atmosphere (Shunthirasingham et al, Dua et al (1996) 2010).…”

Distribution and Air–Sea Exchange of Current-Use Pesticides (CUPs) from East Asia to the High Arctic Ocean

“…9 Similar to trifluralin, in the GAPS study during 2005À2008, levels of chlorothalonil in Europe and North America were higher than those in Asia and the southern hemisphere. 29 Extemely low chlorothalonil and dacthal in seawater at lower latitudes may result from low chlorothalonil and dachtal levels in the air, whereas high concentrations in Chukchi Sea are possibly due to long-term deposition from circumpolar countries.…”

“…In the Global Atmospheric Passive Sampling (GAPS) study during 2005À2008, levels of trifluralin in Europe and North America were higher than those in Asia and the southern hemisphere. 29 Although we know of the existence of trifluralin in the environment of these regions, more research is needed to understand the attribution of different regions on the occurrence and distribution of trifluralin in the Arctic. Trifluralin can undergo rapid photochemical conversion, e.g., dealkylation and cyclization with a half-life of approximately 15 min under sunlight condition and reaction with HO radicals and O 3 , 30 which implies atmospheric degradation of trifluralin is mostly controlled by photolysis with HO radicals during transport from source region to remote ocean.…”

Atmospheric organochlorine pesticides and polychlorinated biphenyls in urban areas of Nepal: spatial variation, sources, temporal trends, and long-range transport potential

“…croplands, vegetable produce areas, industrial areas, tourist areas, and residential areas, among others) within the cities is unclear; such information would be useful for identifying the source features and assessing the "hot spots" of personal exposure and health risks from air pollution. There has been notable absence of a systematic monitoring campaign for POPs in the urban areas of Nepal and this country has not been considered for any global or regional regular monitoring plan except for singleyear monitoring of atmospheric OCPs in a background region (Shunthirasingham et al, 2010). Thus, there is a need to obtain atmospheric concentrations of POPs, and understand the spatial variations and seasonal trends of the contaminants in Nepal, to highlight the potential contribution of the region to the POPs burden of the Himalayan mountains and the global environment.…”