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Environmental Impacts

Heidi  N Geisz, Rebecca M Dickhut, Michelea Cochran, William R Fraser and Hugh W Ducklow. Melting Glaciers: A Probable Source of DDT to the Antarctic Marine Ecosystem. Environmental Science and Technology, February 2008
Panna Summary: Following bans of the organochlorine pesticide DDT in many countries, by the 1980s annual use dropped from 36,000 to a mere 1,000 tons (used mostly for mosquito control in the Southern Hemisphere). But despite this drop, Adélie penguins in the Antarctic continue to have the same levels of DDT in their bodies as they did 30 years ago. Persistent organic pollutants like DDT travel to polar regions on wind and water currents and bioaccumulate in the bodies of mammals, fish, birds and humans. Scientists were puzzled by the fact that there has been a dramatic drop in DDT levels in the Arctic's birds, whales, and seals over the past decade while DDT levels in Antarctic Adélie penguins remained steady. Heidi Geisz of the Virginia Institute of Marine Science and her colleagues found that the birds were being exposed to the “remnants of older DDT deposition, not new sources.”
Abstract: Persistent organic pollutants reach polar regions by long-range atmospheric transport and biomagnify through the food web accumulating in higher trophic level predators. We analyzed Adlie penguin (Pygoscelis adeliae) samples collected from 2004 to 2006 to evaluate current levels of ∑DDT (p,p′-DDT + p,p′-DDE) in these birds, which are confined to Antarctica. Ratios of p,p′-DDT to p,p′-DDE in Adlie penguins have declined significantly since 1964 indicating current exposure to old rather than new sources of ΣDDT. However, ∑DDT has not declined in Adlie penguins from the Western Antarctic Peninsula for more than 30 years and the presence of p,p′-DDT in these birds indicates that there is a current source of DDT to the Antarctic marine food web. DDT has been banned or severely restricted since peak use in the 1970s, implicating glacier meltwater as a likely source for DDT contamination in coastal Antarctic seas. Our estimates indicate that 1−4 kg·y−1 ΣDDT are currently being released into coastal waters along the Western Antarctic Ice Sheet due to glacier ablation.
Xiang Liu, Gan Zhang, Jun Li, Li-Li Yu, Yue Xu, Xiang-Dong Li,Kobara Y and Jones KC. Seasonal Patterns and Current Sources of DDTs, Chlordanes, Hexachlorobenzene, and Endosulfan in the Atmosphere of 37 Chinese Cities, Environ. Sci. Technol., 2009, 43 (5), pp 1316–1321

PANNA Summary: The Chinese cities for this study included: Kashi, Kuerle, Kelamayi, Jiayuguan, Urumchi, Ejinaqi, Lanzhou, Xi’ning, Changchun, Shenyang, Beijing, Tianjin, Xi’an, Shijiazhuang, Taiyuan, Hohhot, Xinxiang, Zhengzhou, Guiyang, Chongquing, Kunming, Chengdu, Wuhan, Changsha, Hefei, Zhuzhou, Nanchang, Guangzhou, Nanning, Hangzhou, Nanjing, Dalian, Tsingdao, Fuzhou, Xiamen, Haikou, Beihai, Hok Tsui, Waliguan, and Xianghuangqi.
The key findings from this Study were relatively high levels of DDTs (summation of o,p′-DDT, p,p′-DDT and p,p′-DDE) were observed mostly in the cities of southern, southwestern and central parts of China. In the summer, high chlordane levels are observed in southern, southwestern and eastern China, indicating a fresh chlordane input. In autumn, high levels were found in northern, eastern, and southern China, signifying a fresh use of chlordane in these regions. China is an important global source for HCB. Endosulfan was mainly used for controlling cotton bollworm in China, and geographically, the high concentrations of total endosulfan occurred in the cotton production areas in China.

Abstract: China has a history of large scale production and application of organochlorine pesticides (OCPs) although, data on their nationwide distribution and seasonal variations in the atmosphere is still sparse. Passive air samplers (PAS) were therefore utilized to obtain seasonal data from 37 Chinese cities and three background sites in 2005. Concentrations and spatial and seasonal distribution of dichlorodiphenyltrichloroethanes (DDTs), chlordanes (CHLs), hexachlorobenzene (HCB), and endosulfans (Endo) are presented in this paper, and their potential sources are discussed based on the data-set. It is estimated that ca. 95% of DDTs present in the atmosphere of Chinese cities was still from technical DDT, while only ca. 5% was “dicofol-type of DDT”. DDT application for public health control and DDT activated antifouling paint for fishing ships may be the two most important current sources of technical DDT. The DDT concentrations in several Chinese cities seem to match well with the reported DDT concentrations in human breast milk. A low TC/CC ratio was observed across China in the winter to spring, which may provide a fingerprint of Chinese chlordane emission. It was suggested that “weathered” chlordane emitted from urban construction foundations in winter may give the distinctively low TC/CC ratio. The data showed that China is an important global source for HCB. Higher HCB concentrations were observed in winter and spring, and in colder cities, highlighting an important contribution from combustion sources. Samples with higher endosulfan concentrations occurred in the cotton production areas, indicating its major use in killing cotton pests.

Persistence of organochlorine chemical residues in fish from the Tombigbee River (Alabama, USA): Continuing risk to wildlife from a former DDT manufacturing facility. Environmental Pollution, August 2008

PANNA Summary:

Abstract: Organochlorine pesticide and total polychlorinated biphenyl (PCB) concentrations were measured in largemouth bass from the Tombigbee River near a former DDT manufacturing facility at McIntosh, Alabama. Evaluation of mean p,p′- and o,p′-DDT isomer concentrations and o,p′- versus p,p′-isomer proportions in McIntosh bass indicated that DDT is moving off site from the facility and into the Tombigbee River. Concentrations of p,p′-DDT isomers in McIntosh bass remained unchanged from 1974 to 2004 and were four times greater than contemporary concentrations from a national program. Total DDT in McIntosh bass exceeded dietary effect concentrations developed for bald eagle and osprey. Hexachlorobenzene, PCBs, and toxaphene concentrations in bass from McIntosh also exceeded thresholds to protect fish and piscivorous wildlife. Whereas concentrations of DDT and most other organochlorine chemicals in fish have generally declined in the U.S. since their ban, concentrations of DDT in fish from McIntosh remain elevated and represent a threat to wildlife.  DDT persists in the environment near a former manufacturing facility that ceased production over 40 years ago, and concentrations represent a risk to fish and piscivorous birds in the area.

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