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TOPIC 4
THE RISK OF CHEMICAL SUBSTANCES IN FOOD CONSUMPTION
Today is more and more talking about the risk of chemicals which are transferring from
environment into human body via food. These chemicals having different origins can contaminate
our food and in correlation with their dose, toxicity level and their grade of solving in water, can
become a real bomb with delayed effect.
The main toxic substances which could contaminate food with serious implication in our health
status belong to four groups:
 Bio toxins resulting from the metabolic natural processes: plants toxins, mycotoxins.
 Anthropic activities toxins as resulting from: heavy metals, pesticides industrial born
poison, nitrates and nitrites.
 Food processing toxins: self-born toxins.
 Geotoxins as resulting from earth activities (volcanos, erosions, earth quakes): heavy
metals, gases (SO2), ash.

Natural Plants Toxins
What kind of substances are natural plants toxins?
Green plants produce in their organs (steam, roots, leaves, tubers, bulbs, etc.) not only
substances with nutritive value, but also natural substances with toxic effect on animals and
human body.
There are plant’s species which produce a great quantity of toxins as result of metabolism,
others which produce them in low concentrations. Some of these toxic substances are very
dangerous; some of them are less dangerous.
For example:
- cyanogenic glucosides from beans, peas, apricots and almonds seed which are poisonous in
lower concentration;
- caffeine, theobromine and thein from coffee, cocoa and tea respectively, are excitants of
nervous system and in great quantity can disturb heart rhythm;
- solanine from potatoes sell is very toxic, that way it is necessary to remove their bark.
 Mycotoxine
What are mycotoxins?
Mycotoxins are natural produces resulting from metabolic processes of inferiors’ fungi known
as mildews.
The mildews produce many types of substances, some of them useful, as antibiotics, enzymes,
but also the mycotoxins with different toxic potential.
The toxicity of mycotoxins is manifested by the mutagenic and carcinogenic especially the liver
level.
Example of the most dangerous mycotoxins:
 The ochratoxin can contaminate many raw materials as corn, dry beans, cocoa beans,
soybeans, barley, fruits, peanuts, coffee beans, beer, wine, spices and meat products.
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
The patulin can be find on the bread, sauces, fruits, in apple juice and cider (foto1)[9].
Foto. 1 Fruits and bread affected by mildew
(http://powerpictures.crystalgraphics. old_white_mold_bread_and_food)
These two mycotoxins are produced by different species of Aspergillum and Penicillium.
These mycotoxins are very toxic for human body, that’s why is prohibited by law to give in
consumption the food contaminated with ochratoxin and patulin.
Others dangerous mycotoxines are:
 Mycotoxins which induce ergotism they are produced by Claviceps purpurea and is
manifested by inflammation of the extremities, neurological disordes (as blindness, paralysis).
 Mycotoxins which produce aleucia food poisoning, they are secreted by Fusarium
species. The disease begins with gastric mucosal burning and finished with skin and mucous
membrane bleeding.
Given the toxicity of these substances their presence in food are prohibited by law.
 Heavy Metals
What are heavy metals?
In according with chemistry a heavy metal is a toxic metal. Heavy metals are chemical
elements that have a specific gravity (a measure of density) at least five times that of water, more
than 5 g/cm3 [8].
The designation of 'heavy' is because of their high relative atomic mass which persist in
nature, cannot be destroyed and can cause damage or death in animals, humans, and plants even
at very low concentrations as well as 1 or 2 μg.
But heavy metals can be poisonous in lower or in a large concentration.
So, there are heavy metals as iron, magnesium, copper, manganese which are even
necessary for animal and human body metabolism, but only in very small quantities, because their
function of activating enzymes.
Others heavy metals as cobalt, nickel, cadmium, chromium, lead, mercury, arsenium are
very toxic in lower concentrations. These are the main heavy metals which must be the subject of
monitoring [6].
For examples:
- lead destroys the erythrocytes, affects the central nervous system, ultimately causing
death;
- mercury induce abdominal pain, mucosal ulceration, difficulty breathing;
- cadmium destroys kidney, liver and adrenal, inducing carcinomas;
- copper causing nausea and vomiting;
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- chromium (VI) is the form which is absorbing very easy by the lung and gastrointestinal
tract; Cr (VI) compounds are powerful oxidizing agents and thus tend to be irritating and corrosive;
Cr (VI) penetrate easy cell membrane and could attack DNA [2, 3]., proteins, and membrane lipids,
thereby disrupting cellular integrity and functions [4].
Heavy metals sources: natural and anthropic.
Natural sources for heavy metals are the agricultural soils were are set up the agricultural
ecosystems which are producing the raw materials for food industry. The agricultural activities
which are natural sources of heavy metals are: mining, smelting, agrochemicals and sewage sludge
applications, and livestock manure uses. So, it is very important to have clean soils from
environmental point of view and normally as heavy metals concentration and nutrients quality.
Anthropic sources for heavy metals are mainly the industry, almost all types of industries:
paint, mining wastes, mining industry, and incinerator ash, water from lead pipes and solder,
automobile exhaust, electroplating, plastic industries, as well as sewage plant, herbicides, wood
preservatives, not in the last acid rains.
Ways of transport for heavy metals dusty are:
- the air currents which are spreading them all over; from the atmosphere metal dusty can be
breathed and thus enter into our lungs;
- the plants used as vegetables can up take heavy metals from soils were they are growing and
animal and humans eat them.
In this last case it must be say that every crop plant species has a specific affinity for
absorption and storage one or other of heavy metal species. There plant species as sunflower that
absorbs zinc and iron in great quantities from soil.
Spinach and broccoli assimilate a large quantity of iron and magnesium (foto 2, 3).
Foto 2. Spinach
Foto 3. Broccoli
Example of heavy metal circulation throu trophic chain: mercury.
On can see in foto 4 [7] the main sources for mercury, natural (volcano) and anthropic
(industrial plant and mine), all of them pollute air, soil and water.
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Foto 4. The circulation of mercury along the trophic chain
(https://en.wikipedia.org/wiki/Mercury_in_fish)

Pesticides
What are pesticides?
Under “pesticides” word are including the chemicals which are used to kill unwanted, pest
organisms such as rats, insects, nematodes, and others, which attack the plants and destroy the
agricultural ecosystems (by pharmacology definition).
If they are uptake hazardous by animals and human beings, can cause nerve or liver
damage, DNA defects and cancer.
The phenomena of pesticides magniphication are increasing into the organisms which eat
the plants sprayed in pesticide. In this way the pesticide are moving up into the food chain and
finally enter in human body were cause different damages, in numerous cases produce cancer.
The most used pesticides are: bactericide, fungicide, herbicide and insecticide.
The bactericide and fungicide are used against pathogen agents. The insecticides are used
for pest control. The herbicides are used for destruction the weeds which are growing among crop
plants.
The pesticide sources are only anthropic origin.
All of them are very toxic for animals and humans.
The way for transport in food chain: all these substances are easy solving in water so can be
uptakes by vegetables were will be concentrating and in this way enter in our body. Plants storage
pesticides molecules in different organs, steam, leaves, fruits.
The damage caused by pesticides in human body:
- digestive tract reactions - dizziness, voma, cramps, etc.
- movement disorders – movement disorders, motor disturbances, paralysis, muscle
stiffness, etc.
- cardiac disorders – pulse acceleration, arrhythmias, etc.
Ways of entering pesticides in food composition: directly by via plants used for animal
and human food and indirectly to animal meat and then in human body.
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
Self-born toxins
What are the self –born toxins?
Self-born toxins are some types of substances which appear in food during their processing
by classical thermal treatment [1].
By this technology are forming some substances more or less toxic for humans, as
polycyclic
aromatic hydrocarbons (PAHs),
nitrosamines, acrylamide, produces by the
thermal degradation of fats and oils.
This kind of risk appears also in food industrial obtained as as well in food obtained in
home system.
For example:
Nitrosamines are generating in meat or cheese with content of nitrites and nitrates which
are first keep to salt, and then are subject of roasting process or hot fumes.
Nitrosamines produce cancer to kidney, lungs, liver and others.
Polycyclic aromatic hydrocarbons (PAHs) can be pollutants from air, soil water which
entered in food chain, or can be produced in thermal processing of food by incomplete
combustion in case of barbecue, roasting and exposure to hot fumes. PAHs are also carcinogenic.
Acrylamide is one of the most dangerous compounds which are forming during thermal
preparation of meat, brad, and potatoes by roasting and toasting. The chance to generate
acrylamide in great quantity is higher if the pH of raw material is very low. Acrylamide is very toxic
and produce cancer in human body.
Preparing the fats and oils by grilling, at roasters or roasted, are generating some
alterations compounds with impact on food from the following characters:
- the sensorial qualities – alteration of taste, smell, color;
- the physical-chemical properties – modification viscosity, iodine and peroxide index;
- the nutritional values – by losing the polyunsaturated fatty acids (PUFAs), vitamins;
- toxicologically – are generating monomers, dimers, trimers with toxic potential.

Industrial born poison
What are the industrial born poisons?
In the same time with the development of chemicals industry as plastics industry, all over
the world appeared some organic compound with a high toxic effect on population health.
The great problem is that these industrial born poisons, because of human gross
negligence against the environment, polluted soils, air and waters everywhere [1].
So, in this situation was not so hard to pollute the food by way of trophic chain.
The most widespread and dangerous poisons which caused the serious damages to human
beings are:
- polychlorinated biphenyls (PCB)’
- dioxins.
The symptoms of poisoning with industrial born poisons:
- slowed growth of children,
- skin pigmentation,
- weakness,
- diarrhea,
- a certain carcinogen potential,
- the enlarge of liver, etc.
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
Nitrates and nitrites
What are the nitrates and nitrites?
Nitrates and nitrites are inorganic compounds which contain nitrogen in their molecules
and appear in soils after an irrational fertilization with nitrogenous fertilizers or manure (organic
fertilizers).
The source for nitrates and nitrites: is mainly anthropic by two types of activities.
One activity is agricultural practices: introduces the nitrogenous compounds in crop plants.
The culture plans have the property of accumulation and storage nitrates and nitrites in
their organs in great quantities. In this way, they are entering in trophic chain simultaneous with
the vegetables. From soil under reach rains the nitrates are taken into underground water which is
consumed as drinkable water.
The second activities are the food industry practices: introduces the nitrogenous
compounds in canned meat, cold cuts for extend the period of storage them [1].
But all these produces treated with nitrates and nitrites if are consumed in great quantities
contribute at the amount of them in our body. In the measure of increasing the content of nitrates
and nitrites in human body, they begin to have a toxic effect in according with their quantities [5].
Root vegetables and green leafy vegetables like spinach, lettuce and rucola have the highest
nitrate levels. The nitrate level in this vegetable is large increasing in the period when the weather
is cloudy. It is belter to harvest vegetables after a long sunny period.
The most severe effects of intoxication with nitrates and nitrites:
- methemoglobin formation which is the cause of blue baby disease,
- lymphatic cancer and others.
The nitrates were found in cereals as wheat, barley, oats, rye, corn. Generally the fruits
contains low quantities of nitrates (under <10 mg/kg), by exception the strawberries contains 24140 mg/kg.
Drinkable water can contain maximum 10 mg NaNO3/dm3 and must be free of the nitrites.
The place and role of water in food aria
All these groups of chemical substances with high risk in food consumption are
generally soluble in water. The water is a basic food but also the best solvent. That’s why water is
a very efficient vector for transporting chemical substances with risk for human health.
In this idea the water which is a unique kind of food by its property “sine qua non” for
human being life on one hand, and because of its easy penetrability in the body cells on the other
hand, must has the best quality always.
The sources for water there are natural only. The environment must be protected for
keeping clean the water resources. The quality of natural waters and drinkable water are
regulated by law.
How to prevent the risk of consumption chemicals with high toxicity
We can prevent to introduce in our body in larger quantities the chemical with risk on
our health, by following some basic rules:
- using only enamel pots or Teflon cookware for storage and preparation the food;
- do not use canned and drinks from cans;
- do not use for cooking metal cookware;
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- cooking the raw material only by methods which do not generate toxic compounds, for
example by boiling;
- using only clean drinkable water when preparing the food;
- the diet must be rich in fiber that serve to retain the toxins which enter in our digestive
tract along with food;
- to consume food rich in sulphur as eggs, onion, beans, vegetables, garlic and others;
- avoiding exposure to sources of heavy metals with high toxicity;
- avoid smoking or exposure at the atmosphere with smoke.
- avoid also the consumption of marine products, because it is well-known today that
the toxic chemicals are concentrated inside them [7].
References:
[1]Banu C., and all., 2007, Sovereignity, security and food safty, Editura ASAB, Bucuresti
[2]Cohen, M. D., B. Kargacin, et al. 1993. "Mechanisms of chromium carcinogenicity and
toxicity." Critical Reviews in Toxicology 23(3): 255-81.
[3]Dayan and Paine, 2001, Mechanisms of chromium toxicity, carcinogenicity and
allergenicity: Review of the literature from 1985 to 2000
[4]De Mattia, G., M. C. Bravi, et al., 2004. "Impairment of cell and plasma redox state in
subjects professionally exposed to chromium." American Journal of Industrial Medicine 46(2): 1205.
[5]Meert, K. L., J. Ellis, et al. 1994, "Acute ammonium dichromate poisoning." Annals of
Emergency Medicine 24(4): 748-50.
[6]Rom, W. N. 2007, "Environmental and Occupational Medicine. 4th Ed. 2007 by
Lippincott Williams & Wilkins."
[7]www. https://en.wikipedia.org/wiki/Mercury_in_fish
[8] www.thefreedictionary.com/heavy+metal
[9]www.http://powerpictures.crystalgraphics.com/photos/view/cg9p2734364c/old_white
_mold_bread_spoiled_food_mold_food
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PRACTICAL ACTIVITIES
The risk of chemical substances in food consumption
and their implication in health
General objective of the work: To highlight the presence of nitrates and nitrites in foods,
to highlight them in water and to reinforce the importance of the compliance their effect on
health.


Objectives:
determination of the presence of nitrates and nitrites in drinkable water
understanding the effect of nitrits on human health
Problem questions:
What are nitrits?
The water is a kinde of food? What kind of water should be consumed?
What kind of water can replace drinkable water in the case of some diseases in which it is
not recommended the consumption of tap water?
How much water should be consumed per day?
What it is happen with water in our body?
a. Identification of nitrates and nitrites - qualitative determination
1. Rapid test of water analysis - Qualitative test paper
Equipment and materials:
 Potassium iodide starch paper from MN
Limit of method sensitivity is of 1 mg/l NO2–
Procedure
This test paper allows the quick and easy detection of strong oxidizers such as nitrit.
Nitrite oxidizes potassium iodide to form elemental iodine which reacts with starch to a blue-violet
complex.
Potassium iodide starch paper may be used by dipping it into a water sample or by applying drops
of the sample onto the paper.
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To detect gaseous oxidizers, the paper is moistened with distilled water and then exposed to the
gas in question.
Interpretation of the results
If the test paper becomes violet that means that the water contains nitrits.
2. What other beverages could contain nitrates
b. Identification of nitrates and nitrites - quantitative determination
Quantitative determination of a nitrates and nitrites from water samples can be realised by
spectrophotometric method. Spectrophotometer DR 2800 is one with VIZ in the range of
wavelengts between 34- and 900 nm. It providing the digital readings directly in concentration
units, absorbance or rate of transmission.
Procedure:
 The concentrations will be determinated with Spectrophotometer portable DR 2800. As
well in the laboratory and out.
 Start up the Spectrophotometer – press the main button situated in the back.
 Priparing appliance for determinting: select the language, type OK, waiting 2 minute till
displays main menu and choose chemical evaluation form.
 The start of test: press „Programme the barcode”, introduces ampule blank in chamber 1st
for activating the programme.
 Remove ampule blank.
 On prepare the sample in according with instructions.
 For nitrates adds in the ampule 1 ml samples for analisyng and 0,2 ml of reagent available
from the chit. Shake the ampoule in according to the chit instructions and let rest 15 minutes.
 For nitrites, remove aluminium foil on the cover, adds 0,2 ml samples, fixed the cover
imediatly, shake it well and let it to rest 10 minutes.
 Remove the ampoule in chamber and read on screen the result displayed.
 Start the programmme of data storage – select the „Active storage”.
 Finish the programme – follow the inverse steps.
 Switched off – close by pressing the main buton in the back.
Nitriţi
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Nitraţi
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Let’s make it better!
Raising the awareness of the triad
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Project No: 2014-1-RO01-KA200-002931
This project has been funded with support from the European Commission. This presentation
(communication) reflects the views only of the author(s), and the National Agency and
Commission cannot be held responsible for any use which may be made of the information
contained therein.
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