An environmental hazard is a substance, state or event which has the potential to threaten the surrounding natural environment / or adversely affect people's health, including pollution and natural disasters such as storms and earthquakes.
Any single or combination of toxic chemical, biological, or physical agents in the environment, resulting from human activities or natural processes, that may impact the health of exposed subjects, including pollutants such as heavy metals, pesticides, biological contaminants, toxic waste, industrial and home chemicals.
Human-made hazards while not immediately health-threatening may turn out detrimental to man's well-being eventually, because deterioration in the environment can produce secondary, unwanted negative effects on the human ecosphere. The effects of water pollution may not be immediately visible because of a sewage system that helps drain off toxic substances. If those substances turn out to be persistent (e.g. persistent organic pollutant), however, they will literally be fed back to their producers via the food chain: plankton -> edible fish -> humans. In that respect, a considerable number of environmental hazards listed below are man-made (anthropogenic) hazards.
Hazards can be categorized in four types:
- Physical (mechanical, etc.)
Chemical hazards are defined in the Globally Harmonized System and in the European Union chemical regulations. They are caused by chemical substances causing significant damage to the environment. The label is particularly applicable towards substances with aquatic toxicity. An example is zinc oxide, a common paint pigment, which is extremely toxic to aquatic life.
Toxicity or other hazards do not imply an environmental hazard, because elimination by sunlight (photolysis), water (hydrolysis) or organisms (biological elimination) neutralizes many reactive or poisonous substances. Persistence towards these elimination mechanisms combined with toxicity gives the substance the ability to do damage in the long term. Also, the lack of immediate human toxicity does not mean the substance is environmentally nonhazardous. For example, tanker truck-sized spills of substances such as milk can cause a lot of damage in the local aquatic ecosystems: the added biological oxygen demand causes rapid eutrophication, leading to anoxic conditions in the water body.
All hazards in this category are mainly anthropogenic although there exist a number of natural carcinogens and chemical elements like radon and lead may turn up in health-critical concentrations in the natural environment:
A physical hazard is a type of occupational hazard that involves environmental hazards that can cause harm with or without contact.
Biological hazards, also known as biohazards, refer to biological substances that pose a threat to the health of living organisms, primarily that of humans. This can include medical waste or samples of a microorganism, virus or toxin (from a biological source) that can affect human health.
See also: Toxicology and List of allergies
Psychosocial hazards include but aren't limited to stress, violence and other workplace stressors. Work is generally beneficial to mental health and personal wellbeing. It provides people with structure and purpose and a sense of identity.
- ^"Environmental hazard". Defined Term - A dictionary of legal, industry-specific, and uncommon terms. Retrieved 23 August 2017. quoted from Code of Maryland, January 1, 2014
Throughout the environment—both natural and human built—there are factors that affect human health. Some are naturally occurring hazards, while others are caused by human activities. For example, allergens and irritants in the air (such as pollen and cigarette smoke) can trigger asthma, and exposure to excess radiation or toxic chemicals can cause cancer. Physical, chemical, and biological hazards may be present in all types of media, including air, water, soil, and food. The branch of public health concerned with how these environmental factors affect human health is referred to as environmental health.
The average life expectancy today is significantly longer than it was a century ago. This change in life span is in large part due to improvements in environmental health (such as cleaner drinking water and better sanitation). But along with the advances that have improved environmental health are developments in technology that pose new health hazards. Industrialization—including changes in transportation systems, the manufacturing of consumer goods, and power systems—has introduced pollutants, chemicals, and hazardous waste into the environment. As many environmental health hazards are relatively new, the long-term effects on human health are yet to be understood. However, it has become increasingly clear that factors in the environment can affect health and that it is important to research and better understand their consequences.
While new technologies may introduce new hazards, research and regulations can also offer improved detection of and protection from such hazards. For example, transportation vehicles are a major source of air pollution in cities around the world. Through fuel combustion and evaporation, motor vehicles produce pollutants such as carbon monoxide, hydrocarbons, nitrogen oxides, and fine particles. Air pollution can irritate the eyes and throat, aggravate existing medical conditions such as asthma, and lead to heart and lung disease. As the harmful effects of air pollution have become more evident, steps have been taken to reduce the amount of pollution that people are exposed to, for example, through better engine designs and cleaner-burning gasoline formulations as well as emission standards and laws.
Another pollutant that has been controlled is lead, a toxic metal that was once commonly used in many products including gasoline, solder, plumbing, paints, ceramic cookware, and cosmetics. However, in the mid-twentieth century, research indicated that there were serious health risks from even low-level lead exposure; elevated levels of lead in the blood causes illness, can seriously affect mental and physical development in children, and can be fatal. Since then, leaded gasoline has been banned, lead-based paints are no longer used in homes, and older water pipes have been replaced. In addition, education and awareness of the problem are part of the solution. For example, in recent years there has been a concerted effort to reduce the frequency of childhood lead poisoning by keeping children away from deteriorating lead paint and lead dust and promoting routine medical testing. As a result, the incidence of elevated childhood blood lead levels has decreased.