Sanitary and epidemiological well-being of the population

Depletion of adaptation and environmentally induced diseases

The rapid development of scientific and technological progress and a thousandfold increase in energy consumption over the past century have led to environmental degradation. The pressure of aggressive external factors in modern conditions significantly exceeds human adaptive capabilities.

Constant exposure to exogenous chemical factors keeps the body's compensatory and adaptive mechanisms under strain. Since their reserves are limited, over time the following occurs:

1. Failure of adaptation processes.
2. Development of pre-disease states.
3. Chronification of ongoing pathological processes.

The emerging ecopathology is characteristic of modern urbanized areas. Its clinical picture is nonspecific—toxicants affect various organs and systems, which requires increased attention from physicians. Classic historical examples of such ecopathologies are severe intoxications with lead (saturnismus) and mercury (mercurialismus).

Natural endemic diseases

The success of environmental adaptation largely depends on the body's supply of macro- and microelements. A deficiency or excess of salts in the soil and food forms natural endemics, which are divided into two groups:

• Monomicroelementoses occur with a disbalance of a single element. These include: myxedema (iodine deficiency), Keshan disease (endemic cardiomyopathy due to selenium deficiency), fluorosis and caries (excess or deficiency of fluorine), and endemic molybdenum gout (molybdenum excess).
• Polymicroelementoses are associated with a complex disbalance of several substances at once (e.g., urolithiasis). A striking example is Urov disease (Kashin-Beck disease). It affects the musculoskeletal system: cartilage dissolves, and joints deform and shorten. The pathogenesis lies in a profound calcium deficiency against the background of an excess of iron, silver, manganese, and zinc, as well as combined poisoning with mycotoxins of Fusarium fungi parasitizing cereals.

Artificial biogeochemical provinces

Emissions from industry and motor transport pollute local air, water, and soil, creating artificial technogenic provinces. Toxicants are transmitted unimpeded through the food chain.

For example, lead settles in the soil, from where plants absorb it in concentrations multiple times exceeding maximum permissible limits (up to 0.2–1 mg/kg). Animals eat contaminated feed, and the heavy metal concentrates in milk. Entering children's bodies, lead causes malformations and nervous system pathologies (a specific marker of intoxication is the accumulation of the pollutant in hair).

Other examples of anthropotechnogenic diseases:

• Minamata disease: severe CNS damage due to the accumulation of methylmercury in edible shellfish.
• Itai-Itai disease: destruction of the musculoskeletal system as a result of cadmium poisoning via rice grown on contaminated soils.

Priority pollutants and their specific targets

Health risk assessment has revealed a hierarchy of the most hazardous atmospheric pollutants. In descending order of significance, these are: particulate matter (2.5 and 10 microns), sulfur dioxide, nitrogen oxides, benzo(a)pyrene, and lead. Inhalation of these substances in megacities provokes chronic obstructive bronchitis, asthma, fibrosing alveolitis, sarcoidosis, and lung cancer.

The intensification of the toxic action of chemical pollutants causes other specific pathologies:

• Parkinsonism — occurs with an excess of manganese.
• Alopecia (hair loss) — from exposure to oil shale ash with heavy metal salts.
• Anemia — a consequence of cadmium and lead toxicity.
• Allergies — develop under the influence of protein-vitamin concentrates.
• Congenital malformations — are provoked by zinc deficiency or the influence of formaldehyde, arsenic, and molybdenum on the maternal organism.
• Neonatal jaundice — a consequence of the combined action of T-2 toxin and heavy metals.

Briefly: answers to topical questions

Class and exam questions

What else to study on this topic

• Mechanisms of depletion of human compensatory and adaptive reserves.
• The role of essential biomicroelements in reducing toxin accumulation.
• The biogeochemical nature of endemic diseases (Keshan disease, Urov disease).
• Specific markers of heavy metal poisoning in pediatric practice.
• The impact of formaldehyde and benzo(a)pyrene on the development of neoplasms and fetal malformations.

Other topics in the section "Introduction. Subject, History, Modern Environment"

Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.