Toxicity, interactions among chemical

Toxicity data are available for several organophosphate ester components of hydraulic fluids, in particular tricresyl phosphate (NTP 1994). However, these components are always present in products as mixtures with other chemicals. Since insufficient information exists to assess the effect on toxicity of interactions among these mixtures, MRLs for the components were not derived. 

Among chemical-physics properties, lipophilicity is certainly a key parameter to understand and predict absorption, distribution, metabolism, excretion, and toxicity (ADMET) of NCE furthermore, it contributes to model ligand-target interactions underlying the pharmacodynamic phase [15],... 

Table 9.5. Types of interactions related to toxicity among chemical substances...

Interactions among the mixture components produce new chemical species. For example, the concurrent inhalation of ammonia or amines and chlorine produces the extremely toxic chloramines. 

Severe destruction of liver cells with bridging necrosis was observed in all five patients. None of the individual chemicals in the mixture had known toxicology that matched the clinical characteristics that were observed. The authors of the study suggest that the various chemicals detected in the analysis underwent an interaction among themselves, which synergistically raised their toxicity compared with the original material. I33... 

Losses result from component failures, disturbances external to the system, interactions among system components, and behavior of individual system components that lead to hazardous system states. Examples of hazards include the release of toxic chemicals from an oil refinery, a patient receiving a lethal dose of medicine, two aircraft violating minimum separation requirements, and commuter train doors opening between stations. ... 

The use of chemical cues in predator/prey interaction appears widespread among amphibians (Kats Dill 1998). Chemical alarm pheromones have been examined most extensively in larval frogs and toads (Chivers Smith 1998). However, recent experiments also suggest that caudate amphibians use chemical alarm pheromones. Numerous studies have investigated the use of chemical substances that make amphibians noxious or toxic to predators. Chemical cues from predators often induce antipredator responses in amphibian prey. In some cases, chemical cues may be the primary sensory stimuli used for predator recognition. Chemosen-sory-induced antipredator responses may include behavioral defenses as well as alterations in life-history characteristics. 

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