Lexikon

high-density polyethylene (HDPE) is plastic that is used predominantly in the manufacture of blow-molded bottles for milk and household cleaners and injection-molded pails, bottle caps, appliance housings, and toys.

Special, environmnetal application of HDPE is in form of geomembrane, used for isolation in environmental technologies, such as lining in reservoirs, waste disposal sites, lakes, etc.

the concentration of the volatile molecules in the vapour space above a sample is proportional to the concentration in the sample. Certain methods sample this vapour (headspace analysis).

a kind of gas chromatography sampling the headspace above a sample. The composition in the headspace gives information on the composition of the sample. Suitable for the analyis of volatile components such as VOC, BTEX.

noise consequences on human health consist in loss of hearing and psychological effects.

a physical agent, a chemical substance or a biological organism has health hazard, for which there is statistically significant evidence that acute or chronic health effects may occur in exposed organisms or humans. This evidence should be based on at least one study conducted in accordance with established scientific principles, standardised test methods or epidemiological studies.

There are numerous health hazards that can affect people in their natural environment or at their workplace. According to these two categories we distinguish environmnetal helath hazard and occupational health hazard.

Examples of environmental health hazards may be:

There are numerous health hazards that can affect people in their natural environment. Examples of environmental health hazards enlisted by Wikipedia and completed by authors, are the following:

• air pollution
• allergens
• anthrax
• antibiotic agents in animals destined for human consumption
• antibiotic resistance
• arbovirus
• arsenic - a contaminant of fresh water sources (water wells)
• asbestos - carcinogenic
• avian influenza
• bovine spongiform encephalopathy (BSE)
• carcinogens
• chemical substances (many different substances with a wide range of effects)
• cholera
• climate change
• cold
• cosmic rays
• dioxins
• drought
• dysentery
• electromagnetic fields and radiation
• environmental pollution
• endocrine disruptors
• epidemics
• e-waste
• explosive material
• extreme weather
• floods
• food poisoning
• fungicides
• furans
• global warming
• haloalkanes
• heat
• heavy metals
• herbicides
• hormones in animals destined for human consumption
• immune-disruptors
• ionisation radiation
• lead in paint
• light pollution
• lighting
• lightning
• malaria
• marine debris
• mercury
• metals
• molds
• mutagens
• noise pollution
• onchocerciasis (river blindness)
• pandemics
• pathogens
• pesticides
• pollen for allergic people
• polychlorinated biphenyls
• quicksand
• rabies
• radon and other natural sources of radioactivity
• sensitisers
• severe acute respiratory syndrome (SARS)
• sick building syndrome
• soil pollution
• tobacco smoking
• toxic waste
• ultraviolet light
• vibration
• water pollution
• waste disposal, illegal
• wildfire
• x-rays

a decrease in strength or any abnormality or partial or complete loss of hearing or of the function of ear, or hearing system, due directly or secondarily to pathology or injury; it may be either temporary or permanent.

the total of measures and devices implemented to preserve persons from harm to the faculty of perceiving sound.

body of surface water which as a result of physical alterations by human activity is substantially changed in character, as designated by the Member State in accordance with the provisions of Annex II. of the Water Framework Directive.

hectare is a unit of area, defined as 10,000 square metres, and primarily used in the measurement of land. In 1795, when the metric system was introduced, the are was defined as being 100 square metres and the hectare ("hecto-" + "are") was thus 100 ares or 1/100 km². Data in the table supports conversion of different area units.

HERA = Human and Environmental Risk Assessments on ingredients of household cleaning products. A voluntary industry programme to carry out Human and Environmental Risk Assessments on ingredients of household cleaning products. A European partnership established in 1999 between the makers of household cleaning products (AISE) and the chemical industry (Cefic) who supplies the raw materials.

form of predation in which plants or other photosynthetic organisms are consumed by other plant, fungal or animal organisms. Paraziting plants and animals (arthropods or molluscs) consume living plants and other photosysnthetic organisms, these are phytopatogenes or parasitic herbivory. Microbes degrading organic matter of plant origin are saprotrophs.

the higher heating value (HHV;also known as the gross calorific value or gross energy) of a fuel is defined as the amount of heat released by a specified quantity (initially at 25 °C) once it is combusted and the products have returned to a temperature of 25 °C.

The higher heating value takes into account the latent heat of vaporization of water in the combustion products, and is useful in calculating heating values for fuels where condensation of the reaction products is practical (e.g., in a gas-fired boiler used for space heat). In other words, HHV assumes all the water component is in liquid state at the end of combustion (in product of combustion).

Source: http://en.wikipedia.org/wiki/Higher_heating_value

highly toxic substances are defined by U.S. OSHA as the following:

1. A chemical substance that has a median lethal dose (LD₅₀) of 50 milligrams or less per kilogram of body weight when administered orally to albino rats weighing between 200 and 300 grams each.
2. A chemical substance that has a median lethal dose (LD₅₀) of 200 milligrams or less per kilogram of body weight when administered by continuous contact for 24 hours (or less if death occurs within 24 hours) with the bare skin of albino rabbits weighing between two and three kilograms each.
3. A chemical substance that has a median lethal concentration (LC₅₀) in air of 200 parts per million by volume or less of gas or vapor, or 2 milligrams per liter or less of mist, fume, or dust, when administered by continuous inhalation for one hour (or less if death occurs within one hour) to albino rats weighing between 200 and 300 grams each.

In case of the use of highly toxic substances, standard operating procedures (SOP's) for working with each highly toxic material is obligatory! This written procedure must include knowing the physical properties of the material as well as symptoms of exposure and first aid procedures. Never work with highly toxic materials while alone!

High Performance Liquid Chromatography

high performance liquid chromatography/electrospray tandem mass spectrometry

High Production Volume Chemicals.
is a term that was used in previous European chemicals legislation for substances manufactured annually in volumes of more than 1,000 tonnes. The term is no longer relevant under REACH regulation, but it is currently still use for the global risk assessment of chemicals e.g. by the Organisation for Economic Co-operation and Development OECD.

Source: REACH Glossary

It is abbreviation for more terms and organisation realted to health and safety:

• Health, Safety and Environment − business term
• Health and Safety Executive, United Kingdom
• Health Service Executive, Ireland

HyperText Markup Language

Home Theatre PC

a study that uses biomedical testing or the measurement of a substance, its metabolite, or another marker of exposure in human body fluids or tissues to confirm human exposure to a hazardous substance.

human toxicology aims to give the dose-response relation between hazardous chemical substances and human responses. As these associations cannot be tested in well designed, statistically relevant human population, human toxicity of chemical substances is mainly based on the results of animal toxicity tests. In these tests the information on the effect of chemical substances comes from animal experimentation, which from an extrapolation is possible to man, supposing that the properly selected animal species’ response is analogous to human body’s response and the test-method, the applied test scenario perfectly models real human exposure. The main methodology for extrapolation for example from rat to man, is the application of a safety factor, based on experience. The default for the interspecies safety factor is EC50 (human)/EC50 (animal) = 0.1, because drugs and toxic chemical substances are ten times more potent in humans based on existing pharmacological and toxicological data.

Animal data are suitable to establish the dose or the concentration of the chemical substance that would cause adverse effect, damage or death, and based on these tests we can determine or calculate the lowest effect and the highest no effect concentrations or doses, which are manageable limit values.

Animal testing has many subclasses, according to the applied animal taxon (fish, bird, mouse, rat, dog, monkey, etc.), the type of exposure (acute, repeated or chronic exposure), exposure routes (inhalation, peroral, cutaneous, mixed routes), aim of the test method (toxicity, mutagenicity, reprotoxicity, neurotoxicity testing) and according to the measured endpoint such as death, immobilization, changes in behavior, irritation, corrosion, organ-toxicity (cardiac-, ophthalmic-, cutaneous-, muscle-, bone-, or hepatotoxicity), cellular toxicity (cell death, mitochondrial, perixosome, cellular tight junctions, reactive oxygen species, glutathione and glutathione-transferase, metabolomics, DNA-changes, chemokines, etc.) toxicity on endocrine system, immuntoxicity, phototoxicity, photoallergy.

Humus is the biochemical substance that makes the upper layers of the soil become dark. It is colored dark brown to black. Humus is difficult to see in isolation because it binds with larger mineral and organic particles. Humus provides soil with a number of very important benefits:

• It enhances a soil's ability to hold and store moisture.
• It reduces the eluviation of soluble nutrients from the soil profile.
• It is the primary source of nutrients required by plants for their nutrition.
• It improves soil structure which is necessary for plant growth.

Humus refers to organic matter that has decomposed to a point where it is resistant to further breakdown or alteration. Humic acids and fulvic acids are important constituents of humus and typically form from plant residues like foliage, stems and roots. After death, the plant residues begin to decay, starting the formation of humus. Humus formation involves changes within the soil and plant residue, there is a reduction of water soluble constituents including cellulose and hemicellulose; as the residues are deposited and break down, humin, lignin and lignin complexes accumulate within the soil; as microorganisms live and feed on the decaying plant matter, an increase in proteins occurs.

Lignin is resistant to breakdown and accumulates within the soil; it also chemically reacts with amino acids which add to its resistance to decomposition, including enzymatic decomposition by microbes. Fats and waxes from plant matter have some resistance to decomposition and persist in soils for a while. Clay soils often have higher organic contents that persist longer than soils without clay. Proteins normally decompose readily, but when bound to clay particles they become more resistant to decomposition. Clay particles also absorb enzymes that would break down proteins. The addition of organic matter to clay soils, can render the organic matter and any added nutrients inaccessible to plants and microbes for many years, since they can bind strongly to the clay. High soil tannin polyphenol content from plants can cause nitrogen to be sequestered by proteins or cause nitrogen immobilization, also making nitrogen unavailable to plants.

Humus formation is a process dependent on the amount of plant material added each year and the type of base soil; both are affected by climate and the type of organisms present. Soils with humus can vary in nitrogen content but have 3 to 6 percent nitrogen typically; humus, as a reserve of nitrogen and phosphorus, is a vital component affecting soil fertility.Humus also absorbs water, acting as a moisture reserve, that plants can utilize; it also expands and shrinks between dry and wet states, providing pore spaces. Humus is less stable than other soil constituents, because it is affected by microbial decomposition, and over time its concentration decreases without the addition of new organic matter. However, some forms of humus are highly stable and may persist over centuries if not millennia: they are issued from the slow oxidation of charcoal, also called black carbon, like in Amazonian Terra preta or Black Earths produced by ancient Indians.

a fluid supplied for use in hydraulic systems. Low viscosity and low pour-point are desirable characteristics. hydraulic fluids may be of petroleum or non-petroleum origin. Earlier polychlorinated biphenyles (PCB) were used as hydraulic fluids.

molecules that consist only of hydrogen and carbon atoms. hydrocarbons can be found in raw oil (petroleum hydrocarbons), gas and coal. hydrocarbons can be aliphatic hydrocatrbons with methane as the simplest and aromatics with benzene as the basic unit. The aliphatic hydrocarbons can be divided into alkanes, alkenes and alkines depending on the carbon-carbon bond.