Systemic toxicants, verification

Verification of Uncertainty Factors. As summarized in several publications, uncertainty factors are currently recommended to estimate acceptable intakes for systemic toxicants (1,13,18). The selection of these factors in general reflects the uncertainty inherent with the use of different human or animal toxicity data (i.e., the weight of evidence plays a major role in the selection of uncertainty factors). For example, an uncertainty factor of less than 10 and perhaps even 1 may be used to estimate an ADI if sufficient data of chronic duration are available on a chemical s critical toxic effect in a known sensitive human population. That is to say that this ideal data base is sufficiently predictive of the population threshold dose therefore, uncertainty factors are not warranted. An overall uncertainty factor of 10 might be used to estimate an acceptable intake based on chronic human toxicity data and would reflect the expected intraspecies variability to the adverse effects of a chemical in the absence of chemical-specific data. An overall uncertainty factor of 100 might be used to estimate ADIs with sufficient chronic animal toxicity data this would reflect the expected intra- and interspecies variability in lieu of chemical-specific data. However, this overall factor of 100 might be used with subchronic human data in this case the 100-fold factor would reflect intraspecies variability and a subchronic exposure extrapolation. 

Given the above mentioned impact of past developments in chemical technology and industry on military CW production programmes, verifying the permitted uses of toxic chemicals and related facilities had to assume an important role in the overall verification system of the CWC. Activities not prohibited under the CWC are dealt with in Article VI of the Convention and in Parts VI to IX of the CWC s Verification Annex. While the first three of these parts are informed by the subdivision of toxic chemicals into Schedules 1 to 3, Part IX of the Verification Annex deals with other, unlisted, chemicals -so-called discrete organic chemicals or DOCs - and other chemical production facilities (OCPF), which might be easily adaptable to CW production. 

Dunworth T (2013) The silent kUler toxic chemicals for law enforcement and the Chemical Weapons Convention. N Z Yearb Int Law 2012(10) 3 Peakes D (2002) Evaluating the CWC verification system. Disarmament forum 2002(4) 11 Grip L, Hart J (2009) The use of chemical weapons in the 1935-36 Italo-Ethiopian War. SIPRI Arms Control and Non-proliferation Programme, www.sipri.org/research/disatmament/ chemical/publications/ethiopiapaper/... 

However, data from in vitro studies could be misleading and will require verification from animal experiments. In vivo systems are extremely complicated and the interactions of QDs with biological components, such as proteins and cells, could lead to unique biodistribution, clearance, immune response, and metabolism. More importantly, it could lead to predictive models for assessing toxicity. The in vivo research involves experiments performed in the context of the entire system consisting of the body of an experimental animal. The overall behaviour of QDs could be summed up as follow (1) QDs can enter the body via six principal routes—subcutaneous, intravenous, dermal, intraperitoneal, inhalation, and oral (2) QDs can interact with biological components (3) subsequently QDs can distribute to various organs (4) QDs can enter the cells of the organ and reside in the cells. ... 

Verification of the degradation of plastics in aqueous systems is a part of the worldwide effort to develop environmentally responsible packaging and delivery material. One of the major issues raised in connection with degradable plastics is the fate and toxicity of degraded products. 

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