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household chemicals
household sewage

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:


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human exposure investigation

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 health risk
Human Health Risk Quotient
human toxicology

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.

humus formation
Hungarian Environmnetal Authority
Hungarian National Remediation Project
hydraulic barrier
hydraulic conductivity
hydraulic fluid

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.


water generates electricity when it drops gravitationally, driving a turbine and generator. While most hydroelectricity is produced by water falling from dams, some is produced by water flowing down rivers (run-of-the-river electricity).

Conventionally, hydroelectric power comes from the potential energy of dammed water driving a water turbine and generator. The power extracted from the water depends on the volume and on the difference in height between the source and the water's outflow. This height difference is called the head. The amount of potential energy in water is proportional to the head. A large pipe (the "penstock") delivers water to the turbine.

Pumped-storage hydroelectric power plant produces electricity to supply high peak demands by moving water between reservoirs at different elevations. At times of low electrical demand, excess generation capacity is used to pump water into the higher reservoir. When there is higher demand, water is released back into the lower reservoir through a turbine. Pumped-storage schemes currently provide the most commercially important means of large-scale grid energy storage and improve the daily capacity factor of the generation system.

Run-of-the-river hydroelectric stations are those with small or no reservoir capacity, so that the water coming from upstream must be used for generation at that moment, or must be allowed to bypass the dam.

A tidal power plant makes use of the daily rise and fall of ocean water due to tides; such sources are highly predictable, and if conditions permit construction of reservoirs, can also be dispatchable to generate power during high demand periods. Less common types of hydro schemes use water's kinetic energy or undammed sources such as undershot waterwheels.

An underground power station makes use of a large natural height difference between two waterways, such as a waterfall or mountain lake. An underground tunnel is constructed to take water from the high reservoir to the generating hall built in an underground cavern near the lowest point of the water tunnel and a horizontal tailrace taking water away to the lower outlet waterway.

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

hydrogen fuel cell vehicle (HFCV)

hydrogen fuel cell vehicles (HFCVs) use a fuel cell to convert hydrogen fuel and oxygen from air into electricity which is used to run an electric motor. HFCVs are truly clean only if the hydrogen is produced by passing WWS-derived electricity through water (electrolysis). Several companies have prototype HFCVs, and California has about 200 HFCVs on the road (California Fuel Cell Partnership, 2009). Hydrogen fueling stations, though, are practically non-existent and most hydrogen today is produced by steam-reforming of natural gas, which is not as clean as that produced by WWS-electrolysis.

hydrogeology, EUGRIS

is the area of geology that deals with the distribution and movement of groundwater in the soil and rocks of the Earth's crust, (commonly in aquifers). The term geohydrology is often used interchangeably. Some make the minor distinction between a hydrologist or engineer applying themselves to geology (geohydrology), and a geologist applying themselves to hydrology (hydrogeology). (Source: Wikipedia)

EUGRIS defines hydrogeology as the study of the geological factors relating to the subsurface waters.

hydroxypropyl beta-cyclodextrin
abbreviated as HPBCD, a sugar derivative of good solubilizing capacity. By molecular encapsulation (inclusion complex formation) it can dissolve water-insoluble organic compounds, e.g. hydrocarbons in water. It is of ring shape molecule, a cyclodextrin unit with 3-6 hydroxypropyl substituents. It is utilized for mobilizing the organic pollutants in soil (→"sugar flushing" technology), for improving the bioavailability and biodegradability of these contaminants. HPBCD is fast biodegraded in soils (half life time is < 1 year). It is not harmful for the soil microflora, improves the availability of their nutrients. It is harmless for the humans as well, is used as pharmaceutical excipient and as an additive in various food products.

the pituitary gland, or hypophysis, is an endocrine gland about the size of a pea and weighing 0.5 g. It is considered a master gland. The pituitary gland secretes hormones regulating homeostasis, including tropic hormones that stimulate other endocrine glands. It is functionally connected to the hypothalamus by the median eminence.