The Hygienic Characteristics of Biological Pesticides

The biological means of plant protection has been intensively introduced recently in connection with toxicity of chemical pesticides. They are based on prevention of destruction and illnesses of plants due to biological means.

The basic groups of biological means are:

· Bacterial, fungoid, virus preparations causing illnesses of pests;

· Biological preparations for struggle against illnesses of plants (antibiotics);

· Ferromones (sexual hormones) of insects - for attraction in chemical traps or scaring away.

Disadvantages of biological way of plant protection are as follows:

· Low efficiency in comparison with chemical pesticides (30 %);

· High cost;

· Allergenic action on workers.

Toxicology and Hygiene of Work at Application of Fertilizers

Apart from pesticides many other chemicals are used in agriculture, among them fertilizers are of primary importance by frequency of application. Fertilizers are substances used to increase productivity of plants.

Classification of Fertilizers

They are subdivided into:

· Organic (peat, manure);

· Mineral fertilizers - macrofertilizers (nitrogen, phosphorus, potassium – simple and complex fertilizers by form) and microfertilizers (microelements for plants).

By application nitric fertilizers make up 90 % of all fertilizers - they promote fast growth of plant mass, but thus in ground and plants nitrates and nitrites accumulate – in big amounts they can cause methemoglobinemia in man. The control over content of nitrates in products is necessary.

Phosphoric fertilizers frequently contain fluorine as impurity, and fluorosis may occur among population near such working manufactures and at application of these firtilizers, as well as the formation of anthropogenic biogeochemical provinces by fluorine.

Hygiene of Work with Fertilizers

As fertilizers refer to low-toxic substances, they do not require such strict measures as at work with pesticides – here the protection of respiratory organs against dust of fertilizers and protection of skin (individual means of protection) are necessary.

Recommendations for Practical Classes on the Theme

Key Questions

Subject and tasks of industrial and agricultural toxicology.

Parameters of toxicity of substances at acute, subacute and chronic action.

Basic laws of action of toxic substances on organism.

Classification of industrial poisons and pesticides.

Way of entry and elimination of poisons from organism. Ways of neutralization of poisons in organism. Detoxication system and its parameters.

Manifestation of toxic action of these substances on organism of working people.

Toxicologic characteristics of the basic groups of industrial poisons.

Prevention of occupational poisonings.

Classification and purpose of basic groups of agrochemicals.

Toxicologic and hygienic characteristics of the basic groups of pesticides.

Hygiene of work at storage, transportation and application of pesticides and fertilizers.

Self Test

1. If the factor of cumulation is less than 1 it means

*A. overcumulation.

B. slight cumulation.

 

2. Into the atmospheric air of the industrial centre the emissions of metallurgical plants enter, such as oxides of sulfur, nitrogen, metals which negatively affect a health condition of population. The action of these harmful factors is characterized as

*A. combined.

B. complex.

C. integral.

D. isolated.

E. mixed.

 

3. The excess of MPC of toxic substance in atmospheric air makes up 100. What changes in a health condition of population should be expected?

A. fatal poisonings of children and elderly people

*B. acute poisonings

C. changes in a health condition by separate parameters

D. chronic poisonings

 

4. Which of the following does not refer to parameters of acute toxicity of industrial poisons?

A. DL 16

B. DL 50

C. C cum.

D. Lim ac.

*E. Lim ch.

Problem Solving

1. What kind of work does a hygienist do at making periodic medical examinations at industrial enterprises?

2. Introduction of toxic substance into animals was carried out daily in doses equal to 1/20 of DL50. Thus at a 5-time-a week introduction during 4 months each animal received totally 10.5 doses of toxic substance equal to DL 50. Determine the factor of cumulation and give its estimation.

3. At doing electrical welding works the aerosols containing oxides of iron, manganese, carbon, chrome and silicon are emitted into the shop atmosphere. In welders the lesion of the nervous system (chronic intoxication) is diagnosed. What can cause chronic intoxication?

Standard Answers

1. He determines the list of persons for physical examination.

2. Factor of cumulation is a ratio of total LD 50 to a dose at a single introduction (LD50). So,

C cum = 10.5/5 since in the task 1/20 of DL50 is taken; C cum = 2.1, that is expressed cumulation.

3. Manganese oxides.

Hygiene of Children and Teenagers

Theme No 21.

Subject and Tasks of Hygiene of Children and Teenagers (HCT)

 

The Physical Development of Children and Teenagers as a Criterion of Health

Subject and Tasks of Hygiene of Children and Teenagers (HCT)

HCT is a section of hygiene studying the action of environmental factors on a growing organism and developing preventive measures to maintain and strengthen the health of children and teenagers.

The primary goals of HCT are: studying the physical development, elaboration of hygienic requirements to children’s preschool and school institutions, to training, physical training of children, to children's toys, hygiene of work of schoolchildren and teenagers, hygiene of children’s nutrition, medical-professional consulting at school.

Basic Methods of Research in HCT

· Epidemiological method (studying the health state of children's contingents depending on environmental factors);

· Method of sanitary description (sanitary inspection of children's preschool institutions, schools, etc.);

· Method of sanitary examination (examination of children's toys, etc.);

· Methods of laboratory experiments (for example, studying the effect of harmful factors on a growing organism in experiments on laboratory animals).

Laws of Growth and Development of Children

· Irregularity of growth and development of organism depending on age – theyounger the organism is, the more intensive these processes are;

· Irregularity of growth and development of different organs and systems at different age;

· Connection of growth and development with sex - unequal rates of growth and development in boys and girls;

· Influence of genetic factors, environmental factors and social conditions, disease incidence on growth and development;

· Influence of acceleration.

Acceleration as an Actual Problem of HCT

Acceleration is a speeded up physical development of children and teenagers as compared with anthropometric parameters of children many years ago. For the recent 10-15 years rates of acceleration have noticeably decreased and even deceleration is observed, i.e. decreasing of physical development of children and teenagers in comparison with anthropometric parameters of children 10-15 years ago.

Theories (Reasons) of Acceleration

Up to now the universal reason of acceleration is not established in view of great amount of factors influencing physical development.

The basic theories of acceleration are:

· Alimentary theory – improvement of qualitative and quantitative parameters of nutrition of the population;

· Medical theory – decrease of disease incidence, gynecologic pathology due to development of medicine;

· Heliogenic theory - influence of cyclic changes of solar activity and levels of UVR;

· Ecological theory - growth of СО2 content in atmosphere, increase of intensity of electromagnetic fields, elevation of level of natural radioactive background;

· Theory of heteresis – increase of mixed marriages of different races and nationalities.