Contaminants naturally occurring

Contaminant Naturally occurring substances whose concentrations have been increased as a result of human activity. 

The Joint FAO/WHO Expert Committee on Food Addihves (JECFA) is an international expert scientihc committee that is administered jointly by FAO and WHO. It has been meeting regularly since 1956, inihally to evaluate the safety of food addihves. Its work now also includes the evaluation of contaminants, naturally occurring toxicants, and residues of veterinary drugs in food. These evaluations are collected in a report published after each JECFA meeting (Section 3.6.1.3) (JECFA 2006). 

Toxicological evaluations of food additives and of contaminants, naturally occurring toxicants and residues of veterinary drugs in food produced by the Joint FAO/WHO Expert Committee on Food Additives (JECFA), and of pesticide residues in food by the Joint FAO/WHO Meeting on Pesticide Residues (JMPR) are used by the Codex Alimentarius Commission and national governments to set international food standards and safe levels for protection of the consumer. 

Over the years, JECFA s responsibilities have been expanded to include evaluation/assessment of food contaminants, naturally occurring toxins, and residues of veterinary drugs in food. JECFA s advice and evaluations are used by several Codex committees (e.g., CCFAC, CCRVDF). JECFA also provides scientific advice directly to FAO, WHO, and their member states. JECFA cooperates very closely with Codex but is not a component of the CAC. 

JECEA is an independent expert committee established (and jointly administered) by the FAO and the WHO in 1956 to evaluate the safety of food additives. Uie work has since expanded to include the evaluation of the safety of contaminants, naturally occurring toxicants and residues of veterinary drugs in food. JECFA serves as the risk assessor for the Codex Committee on Residues of Veterinary Drugs in Foods (CCRVDF), establishing an acceptable daily intake (ADI) for a veterinary drug when sufficient information is available, recommending maximum residue limits (MRLs) for consideration by... 

For the naturally occurring elements, many new artificial isotopes have been made, and these are radioactive. Although these new isotopes can be measured in a mass spectrometer, this process could lead to unacceptable radioactive contamination of the instrument. This practical consideration needs to be considered carefully before using mass spectrometers for radioactive isotope analysis. 

One measure of lire significance of coniaininants in soil or solid waste samples may be determined by comparing the levels with reported naturally occurring concentrations. Provided levels are within the range that may occur naturally, one might conelude that the sample contaminant levels are of little consequence. 

Corrosion products include iron oxide (Fe203), ferrosoferric oxide (Fe304), nickel oxide (NiO), cobalt oxide (CoO), and complex Fe, Ni, and Co oxides. Cobalt in particular may present a problem (as cobalt59, a naturally occurring isotope), and when present as a contaminant in nickel alloys (such as Inconel 800), may enhance the development of an outer-core radiation field (see Section 7.4.1). 

NOTE There are various types of organic contaminants that can be present in boiler FW, including trace amounts of pesticides and naturally occurring humic, fulvic, and tannic acids, and solvent-extractable oily matter, such as nonvolatile hydrocarbons, vegetable oils, animal fats, waxes, soaps, greases, and the like. 

Non-toxic Opportunity for replacing VOCs Naturally occurring Inexpensive Non-flammable High specific heat capacity -exothermic reactions can be more safely controlled Distillation is energy intensive Contaminated waste streams may be difficult to treat High specific heat capacity - difficult to heat or cool rapidly... 

L-tryptophan is a naturally-produced, natural amino acid used as a dietary supplement. Samples from one manufacturer were found to be contaminated by trace amounts of another naturally occurring compound — l,l -ethylidene bis-[i.-tryptophan]. The latter compound appears to have been responsible for causing a number of deaths and additional cases of chronic eosinophilia-myalgia,111 some of which might have been prevented had there... 

The contained-in policy is a special, more flexible version of the mixture and derived-from rules that applies to environmental media and debris contaminated with hazardous waste. Environmental media is the term U.S. EPA uses to describe soil, sediments, and groundwater. Debris is a term U.S. EPA uses to describe a broad category of larger manufactured and naturally occurring objects that are commonly discarded. Examples of debris include the following ... 

Some populations of freshwater isopods are tolerant to lead. Inasmuch as nontolerant isopods from an unpolluted site can be made tolerant by exposure to low levels, it is suggested that naturally occurring tolerance may be achieved by acclimatization (Fraser 1980). Research is needed on lead transformation mechanisms, on toxic forms of lead and interaction effects with other compounds, and on effects of lead-contaminated sediments on benthos (Wong et al. 1978). 

A similar set of conditions was utilized by Reif et al.76 to analyze folic acid, using leucovorin as an internal standard. Other authors77 have used similar conditions to study extensively the identity of possible leucovorin contaminants. In addition to these partition /ionization surpression methods, anion exchange hplc has been used to separate CF from other naturally occurring folates,78 and some correlation has been made between the number of glutamyl residues and retention time. 

Right now, we have to deal with incubation time and wait for victims to develop symptoms. The incubation time for anthrax is one to six days. In this example, anthrax victims would have one to six days between exposure and the onset of symptoms. Anthrax is not transmissible from person to person. Compare this to the incubation time with that of the virus, smallpox, which is ten to seventeen days. Smallpox is highly transmissible from person to person. After exposure to smallpox, a person could travel by air around the world a number of times and contaminate many people before developing any symptoms. However, naturally occurring smallpox has been eradicated worldwide since 1977. Terrorism could rapidly change that eradication to an attack since samples of the smallpox virus have been stored in both the United States and Russia. 

---