Risk assessment PCDDs

Litz [2] PCDDs, PCDFs, AOX, PCBs, PAHs, LAS, nonylphenol, tributyltin oxides, DEHP Risk assessment were conducted in this study, concentrations were not addressed Sewage sludge... 

Kang, Y.-S., Choi, S., Han, J., Choi, S., Lee, M., Park, J., 2003. Residue and risk assessment of PCDD/Fs and PCBs in the Korean population. 2003 Research report of KFDA (in Korean), Korea Food and Drung Administration Ed., Seoul, Korea. 

We are working with the Food Quality Control Department of the Ministry of Health to study the contamination of OCPs and PCBs in local fish and chickens. This project is in line with our current effort to assess the health risk arising from consumption of food contaminated with POP chemicals. The health risk assessment of POPs through dietary intakes project involved analyses of OCPs and PCBs in various foodstuff, initially raw materials which will be extended to cooked food. Unfortunately, we do not currently have the capability to analyze PCDD/PCDF in our laboratory but there are two high resolution mass spectrometers in the country that are capable of analyzing PCDD/PCDF. National and international collaborations will definitely improve the country capacity to monitor POPs not only those listed in the Stockholm Convention but other toxic chemicals found in the environment. 

T. S., Viet, P.H., Prudente, M., Tanabe, S., 2002b. PCDDs, PCDFs, PCBs and organochlorine insecticides in human breast milk collected from Asian developing countries Risk assessment for infants. Organohalogen Compd. 58, 285-288. 

Ahlborg UG, Hanberg A. 1992. Toxicokinetics of PCDDs and PCDFs of importance to the development of human risk assessment. Toxic Substances Journal 12 197-211. 

For risk assessment purposes, an important objective in evaluating the environmental fate of PCDD/Fs is predicting the major pathways of human exposure. It is well established that the food chain, especially meat and dairy products, accounts for more than 90% of human exposure to PCDD/Fs and perhaps as much as 99% of human exposure to 2,3,7,8-TCDD.34 In industrialized countries, the average daily intake via food (the major route of exposure to dioxins and furans) ranges from 1.5 to 2.5 pg TEQ kg-1 body weight. 

This chapter begins at the bottom of the agricultural food chain, looking at the uptake of PCDD/Fs in plants from soil. The second section deals with the uptake in plants from the atmosphere. The attention then switches to the next link in the food chain, and the transfer from plants and soil to livestock and animal food products is examined. This is followed by a discussion of uptake in humans from food and in infants from mothers milk. The chapter concludes with a short summary, an overall perspective on bioaccumulation in the agricultural food chain, and a brief reference to some consequences of this knowledge for risk assessment. 

Schlatter C (1991), in Banbury Report 35 Biological Basis for Risk Assessment of Dioxins and Related Compounds, Data on kinetics of PCDDs and PCDFs as prerequisite for human risk assessment", p. 215-226, Eds. Gallo MA, Scheuplein R, van der Heijden K Cold Spring Harbor Laboratory Press, New York... 

Ahlborg UG (1989), Chemosphere 19 603-608. Nordic risk assessment of PCDDs and PCDFs" Ahlborg UG, Brouwer A, Fingerhut MA, Jacobson JL, Jacobson SW, Kennedy SW, Kettrup AAF, Koeman JH, Poiger H, Rappe C, Safe SH, Seegal RF, Tuomisto J, van den Bergh M (1992), Eur. J. Pharmacol. 228 179-199.. .Impact of polychlorinated dibenzo-p-dioxins, diben-zofurans and biphenyls on human and environmental health, with special emphasis on application of the toxic equivalency factor concept"... 

Investigations of PCDD, and especially 2,3,7,8- tetrachloro-dibenzo-p-dloxin (2,3,7,8- TCDD), has led to major advances In environmental sampling and analysis. In toxicology, risk assessment, risk management, and waste treatment. Techniques used for dealing with dioxin contamination represent the most advanced procedures for hazardous waste cleanup. These advanced techniques were developed because of ... 

The second part of the problem definition phase shows clearly that PCDD should be a potential concern to humans and animals in the environment. The degree of concern that we as a society should have can be estimated by a formalized risk assessment process. 

The presence of PCDD in the environment and the acute and chronic toxicity of 2,3,7,8- TCDD and similarly substituted congeners in animals raise concern. How serious should this concern be and what actions are warranted to relieve this concern These questions are addressed by a risk assessment... 

Nevertheless, PCDD, and especially 2,3,7,8- TCDD, exhibit high acute toxicity and many chronic effects in animals. It is prudent, therefore, to estimate acceptable exposure limits. In considering cleanup, it is imperative to establish acceptable levels of cleanliness. The risk assessment process tries to address this number, which has been the subject of much debate. 

TCDD and PCB 77 were slighter greater than additive in toxicity to rainbow trout, indicating the need for more research on chemical interactions. Daily intakes of PCDDs vary substantially between and within species, and this needs to be incorporated into future models of risk assessment. In humans, for example, daily intake of 2,3,7,8-TCDD - on a ng g BW basis - is 78 times higher in neonates than adults, and 2.3 times higher in children and 5.2 times higher in infants than adults. 

Furst P., Furst L. and Widmers K., Body burden with PCDD and PCDF from food. In Gallo M., Scheuplein R.and Van der Heijden K. (Eds.) Biological basis for risk assessment of dioxin and related compounds. Banbury report No. 35. Cold Springs Harbor Laboratory Press. Plainview, NY (1991). 

In contrast to the use of risk assessment techniques to determine decontamination levels of PCB s, PCDD/PCDF s, some regulatory bodies have either said clean to background levels or taken background levels when setting allowable exposures. Tables (II and III) give some levels of background PCB s and PCDD/PCDF s. 

TCDD in areas of intense sunlight has been demonstrated to be significant (4). However, most risk assessments done to date place a half life from 5-10 years on PCB/PCDD/PCDF s found inside buildings or in areas on nondirect sunlight. 

Table VI lists a series of PCB s PCDD/PCDF decontamination standards that have been established for decontamination of selected sites. Most of the standards established in Table V were established as a result of risk assessments.

Increased reliance is being made of the existing risk assessment documents and the resulting standards that have been developed. Thus, future risk assessment for PCB s, PCDD s, and PCDF s likely be on hold until further toxicological evidence is developed. Advances in such risk assessment methods will likely be done as a result of the critiques of the existing risk assessment. The same principles of risk assessment and exposure assessment are being routinely used to evaluate individuates risk following incidental exposure. 

The dioxin toxic equivalency factor (TEF) approach is currently used worldwide for assessing and managing the risks posed by exposure to mixtures of certain dioxin-like compounds (DLCs). World Health Organization-TEF (WHO-TEE) values have been established for humans and mammals, birds, and (For new, refined values, see Ref. 12g.) It should be mentioned that 16 PCBs, the coplanar isomers with nonortho, monoortho, and diortho substitution by chlorine (overall, there are 209 isomers for this class of compounds) show dioxin-like toxic behavior. I-TE values are smaller, in the range of 0.0001-0.1. The most toxic isomers is 3,3, 4,4, 5-pentachlorodiphenyl with I-TE of 0.1. Polybrominated dibenzodioxins and furans with the 2,3,7,8 pattern also show dioxin-like toxicity, but their I-TE values are lower compared to PCDD/F. 

WHO (1988) Assessment of health risks in infants associated with exposure to PCBs, PCDDs and PCDFs in breast milk. Copenhagen, World Health Organization (Environmental Health Series No. 29). 

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