Dieldrin POPs

POPS currently regulated under the Convention include pesticides such as aldrin, chlorodane, DDT, dieldrin, endrin, heptachlor, mirex and toxaphene chemicals with industrial applications such as polychlorinated biphenyls (PCBs)2 and chemical byproducts such as dioxins and furans and hexachlorodbenzene, which fits in all three categories.3... 

A workshop participant reported that China has phased out the production and use of five of the POPs covered by the Stockholm Convention—aldrin, dieldrin, endrin, toxaphene and heptachlor. He explained that chlordane and mirex are still produced in limited quantities for termite protection and hexachlorobenzene (HCB) is still produced for use as a chemical feedstock. Mirex... 

Dieldrin—which belongs to the 12 POPs banned by the Stockholm convention and is in the same class of other pesticides named drins, such as aldrin and endrin—possesses six aliphatic chlorine atoms on a polycyclic skeleton. The multiphasic dechlorination, in the presence of A336, isooctane, aqueous KOH, Pd/C, and hydrogen, proceeded with a different selectivity and degree of dechlorination, depending on the choice of catalyst system, and base concentration. It always required the base and was favored by the presence of A336. It produced a mixture of products derived from the subsequent removal of chlorines, up to a small percentage of monochlorinated derivative. ... 

The POP protocol elaborated on occasion of the Stockholm Convention in 2001 contained 12 compounds, known as the dirty dozen aldrin, chlordane, DDT, dieldrin, endrin, heptachlor, HCB, mirex, PCBs, pol veil I orod i be nzo-/ -d i ox ins. polychlorodibenzofurans and toxaphene. After several years of implementation other compounds, were also included HCHs, PAHs, certain brominated flame retardants, perfluorooctanesulfonic acid (PFOS) and pentachlorobenzene (http // www.chem.unep.ch/pops/). This protocol is aimed to control, reduce and/or eliminate discharges, emissions and spills of POPs into the environment. 

The government has been measuring PCB, HCB, DDT, chlordane, heptachlor epoxide and dieldrin since 1998 to identify their effects on wildlife as part of the Environmental Survey on Endocrine Disruptors. The specimens taken include land animals such as raccoons, bears, monkeys and frog, and marine mammals such as seals and whales, in addition to domestic birds and birds of prey. A relatively high concentration of POPs was seen in birds of prey and Phalacrocorax carbo. Eggs of mountain hawk eagles were also found to have a higher concentration of PCB, DDT, heptachlor epoxide, chlordane and dieldrin than other wildlife specimens... 

China had produced many kinds of POP pesticides, i.e., DDT, HCB, HCH, chlordane, mirex, toxaphene, heptachlor, aldrin, and dieldrin, although some were produced only tentatively and on a very small pilot scale. While endrin has never been produced in China, DDT, HCH, HCB, toxaphene, and chlordane have been produced in relatively large amounts. 

The Stockholm Convention is a global treaty committing the international community to protecting human health and the environment from the potentially harmful effects of POPs (UNEP Chemicals, 2005). The United Nations Environment Programme (UNEP) has identified 12 most toxic POPs (the Dirty Dozen ) for control under the Convention, including 10 intentionally produced POPs pesticides/industrial chemicals (aldrin, chlordane, DDT, dieldrin, endrin, heptachlor, hexachlorobenzene (HCB), mirex, toxaphene and polychlorinated biphenyls (PCBs)) and two unintentionally produced POPs by-products (polychlorinated dibenzo-/ -dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs)). In implementing the Convention, Parties to the Convention will take measures to restrict the trade, production and use of the intentional POPs and to reduce and, where possible, to ultimately eliminate the production and release of the unintentional POPs by-products. 

In Hong Kong, the nine intentional POPs pesticides (aldrin, chlordane, DDT, dieldrin, endrin, heptachlor, HCB, mirex and toxaphene) targeted for global elimination or restricted production and use were not registered, or their registration status had been cancelled for many years due to toxicological or environmental concern. 

Results of the ecological risk assessment of POPs in the marine environment to local cetaceans (the hump-backed dolphins and the Unless porpoises) showed the HQs for eight POPs studied (chlordane, DDT, dieldrin, heptachlor, HCB, toxaphene, PCBs and dioxins/furans) were all less than unity, suggesting that there was no unacceptable risk of toxicological significance associated with exposure of local cetaceans to the current contamination level of these POPs in the marine environment (Table 7.17). 

In 1997, the United Nations Environment Programme (UNEP) Governing Council decided that immediate international action should be taken to protect human health and the environment. International negotiations to reduce and eliminate the emission and discharges of an initial set of 12 POPs were initiated at the Stockholm Convention on POPs in May 2001. The 12 substances that were addressed at the Stockholm Convention were aldrin, endrin, dieldrin, dichlorodiphenyltrichoroethanes (DDTs), polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), chlordane, toxaphene, heptachlor, hex-achlorobenzene (HCB) and mirex. Basic information and status of major organochlorine pesticides in China are summarized in Table 8.1. 

The first official report on the import statistics of these chemicals was made in 1971. After this, the import of POPs chemicals increased year by year. There were increases and decreases year by year until various chemicals were banned in different years. For example DDT was banned for agricultural use in the year 1983 and totally in the year 1994 aldrin in the year 1988 dieldrin in 1986 endrin in 1981 heptachlor in 1988 toxaphene in 1982 HCB in 1980 and PCBs in the year 1975. Only chlordane remained in use until 1996 (www.chem.unep.ch/pops-Inc/). 

Import, export, manufacture, and possession of hazardous substances have been controlled under the Hazardous Substances Act, 1992. However, banning of the import or severely restricted uses of chemicals had been notified in the Ministerial Notifications since 1977. Two insecticides, namely chlordimeform and leptophos were the first two of the banned chemicals in 1977. According to the Act, Ministerial Notifications of the Ministry of Industry were issued to harming of nine specified POPs pesticides usage since 1980 (Table 10.4). Only seven specified POPs pesticides were imported and widely used in Thailand, namely aldrin, chlordane, DDT, dieldrin, endrin, heptachlor, and toxaphene, whereas hexachlorobenzene and mirex have never been imported. Although... 

To meet its obligations under the Stockholm Convention on POPs, the Philippine government, through the Environmental Management Bureau of the Department of Environment and Natural Resources under a GEF-UNDP Grant, conducted an initial National Inventory of POPs (Factora et al., 2004). It was reported that 5 of the 12 POPs—aldrin, dieldrin,... 

The use of pesticides in Malaysia dated back since after the Second World War. These persistent pollutants were primarily used for agriculture and vector control. DDT, dieldrin and endrin found extensive use before they were banned recently. Most of the other persistent organic pollutants (POPs) have been banned in Malaysia. However, residues of these pesticides were found in various compartments of the environment such as water, sediment and biota. Nonpesticide POPs were not monitored as much but recent efforts have included monitoring and management of these POPs among other hazardous chemicals. This chapter presents the current status of POPs in Malaysia and various initiatives to manage these pollutants. 

There is no available information on the amount of pesticides being imported into the country. Some POP chemicals such as DDT, dieldrin,... 

Table 14.2 summarizes available data on selected POP contamination in water in Malaysia. DDTs were found in most rivers in Malaysia but the concentration levels varied from region to region with centrally located rivers being detected to be highly contaminated. Surprisingly, DDTs concentration increased in these rivers as compared to rivers from other parts of the country even after DDT was banned from use in 1999. End-osulfans were not detected in most rivers in the 1989 survey but were found at relatively high concentrations in later studies (Table 14.2). Concentrations of other pesticides in river waters have also been reported in these studies. In the earlier study (Tan et al., 1991), aldrin, dieldrin, end-rin, and heptachlor were also found in some of the rivers. The concentration levels were ND-0.5 ng L-1 for aldrin, ND-0.3 ng L-1 for dieldrin, ND-3.2ng L-1 for endrin, and 0.3-3.4 ng L-1 for heptachlor. Our study...

Ritter, L., (1995). A review of the persistent organic pollutants DDT, aldrin, dieldrin, endrin, chlordane, heptachlor, hexachlorobenzene, mires, toxaphene, polychlorinated biphenyls, dioxins and furans. Geneva International Programme on Chemical Safety. www.chem.unep.ch/pops/indxhtms/assesO.html... 

Some possible toxicological effects such as endocrine disruption continue to be uncertain, particularly for DDT, DDE, dieldrin and dioxin exposures. The history of environmental health shows that safe levels are uncertain and vary as knowledge improves. The long-term trend is often towards lower levels as uncertainties decrease. This should be considered when accounting for the public benefits of further reducing POPs residues and wastes in the Australian environment. 

The global POPs agreement initially covers the dirty dozen, which includes nine pesticides (aldrin, chlordane, DDT, dieldrin, endrin, heptachlor, hexa-chlorobenzene, mirex, and toxaphene), and three industrial chemicals (PCBs) and unintentional by-products (dioxins and furans) of industrial and combustion... 

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