Persistent organic pollutants (POPs) have been of considerable public health and environmental concern for several decades. These are organic substances that persist in the environment, can undergo long distance transportation, are able to bioaccumulate, and pose a risk of causing adverse effects to animals and human health. As a measure to control and mitigate the threats of POPs, an international treaty was signed in 2001 and came into force on May 2004 for its signatories (1). The treaty, called the Stockholm Convention on Persistent Organic Pollutants (SC), initially listed twelve chemicals, the so-called "Dirty Dozen" for final elimination (Annex A), or restricted use (Annex B), and/or reduced releases of unintentional production (Annex C). The SC also included a section stating that additional chemicals can be nominated by its member parties, after which the candidate chemical would undergo several screening and evaluation rounds before it could be voted for inclusion into the Convention (Figure 1). The (possible) inclusion of one of these suspected POPs, perfluorooctane sulfonate (PFOS), is currently a controversial issue and we provide some of our viewpoints below, mainly concerning the current production pattern, adverse health effects, and economical issues. Review documents were mainly cited due to limitations on article length, and interested readers are advised to consult relevant articles cited within these reviews.

a b s t r a c tThree commonly applied extraction techniques for persistent organic chemicals, Soxhlet extraction (SE), accelerated solvent extraction (ASE) and microwave-assisted extraction (MAE), were applied on soil and fish samples in order to evaluate their performances. For both PCBs and PBDEs, the two more recent developed techniques (ASE and MAE) were in general capable of producing comparable extraction results as the classical SE, and even higher extraction recoveries were obtained for some PCB congeners with large octanol-water partitioning coefficients (K ow ). This relatively uniform extraction results from ASE and MAE indicated that elevated temperature and pressure are favorable to the efficient extraction of PCBs from the solid matrices. For PBDEs, difference between the results from MAE and ASE (or SE) suggests that the MAE extraction condition needs to be carefully optimized according to the characteristics of the matrix and analyte to avoid degradation of higher brominated BDE congeners and improve the extraction yields.

Polybrominated diphenyl ethers (PBDEs) have been extensively used as flame retardants in consumer goods. Sufficient evidence shows that PBDEs have been rapidly accumulating in the environment worldwide. In Asia, deca-bromodiphenyl ether has been produced and used in large quantities, while penta-BDE has largely ceased in the mid-1990s. This paper summarizes and critically reviews the status of PBDE pollution in East Asia, with emphases on the comparisons with Europe and North America and the interpretation of the differences. In general, the concentrations of PBDEs in atmosphere, sludge, human and biological samples of East Asia are comparable to or lower than those in Europe and North America. However, in the sediments of waters near densely populated and heavily industrialized areas, PBDE levels are among the highest ever reported in the literature. In Japan and China, concentrations of PBDEs in sediment cores showed an increasing trend for the past 20-30 years. Also, PBDEs levels in human breast milk in Japan increased about 10-fold in the past 20 years. The presence of PBDEs in fur seal has increased about 150-fold in 1994 than that in 1972. Regional and inter-continental transport cannot be confirmed due to insufficient information. However, the detection of a number of PBDE congeners in a pristine lake on the Qinghai-Tibet Plateau may be an evidence of their long-range transport.