Heavy metal is a relatively large atomic weight of metal element, the proportion is greater than 5.0 g/cm3 such as mercury, lead, cadmium, etc. But it is not our traditional sense of the metal (such as steel and other alloys, a number of alloys containing heavy metal elements). Arsenic does not form part of heavy metals, but their sources and hazards are similar with heavy metals, so it is usually included in the category of heavy metals to examine and discuss.
Heavy metal contained in the textile is not in a free state, which not cause harm to human body. Soluble heavy metal are extracted under the conditions which simulate the material remaining in contact with acid sweat solution for a period of time after contacting with skin. The concentrations of the soluble elements which may cause harm to human health, are determined by ICP, AAS, UV-Vis, etc.
Lists of soluble heavy-metals in the Oeko TexStandard 100-2009 are Antimony(Sb), Arsenic (As),Lead (Pb),Cadmium (Cd),Chromium (Cr), Hexavalent Chromium (CrVI),Cobalt (Co), Coppper (Cu),Nickel (Ni),Mercury (Hg).
Harm
Trace concentrations of heavy metals can be toxic (usually 1 ~ 10 mg/ L, mercury, cadmium is 0.01 ~ 0.001 mg/ L),translated into more toxic organic metal compounds by the microorganism effect  (such as the ocean - methylmercury ), and bio-accumulation through the food chain into the human body, causing chronic poisoning.
The sulfophile heavy metal elements (such as mercury, cadmium, lead, copper, arsenic, etc.) have particularly affinity with certain sufhydryl enzymes in human tissues, inhibit the activity of enzymes. The siderophile elements(such as nickel) can be accumulated in the body of the kidney, spleen, liver, inhibit the activity of arginine enzyme. Lead is a highly toxic substance, its greatest hazards that affect children’s intellectual development, there will also harm the nervous system, heart and respiratory system. Hexavalent chromium may be the precipitant of protein and nucleic acid, inhibit cell glutathione reductase, lead to methemoglobin and cancer.
Source    
•Usage of metal complex dyes is an important source of heavy metals in textiles.
•Dye-processing and printing -dyeing processing may also be a source of heavy metals. 
•Absorbing heavy metals from the soil or air during the growth process of natural plant fiber.
PTS Testing Service Service   
In order to reduce the risk of consumer products on human health and environmental, while limiting the content of harmful substances in waste, provide a good environment for the development of human society, a series of directives and requirements are drafted in various countries and regions.
With its excellent technical strength and advanced equipment, PTS Testing Service will provide a range of testing and counseling services.
PTS Testing Service heavy metals testing services
PTS Testing Service can test for common heavy metals and their compounds in products including:
Lead
Cadmium
Mercury
Nickel
Chromium 3 and chromium 6
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PTS Testing Service can also test for other heavy metals including:
Aluminium
Antimony
Arsenic
Barium
Boron
Cobalt
Copper
Manganese
Selenium
Strontium
Tin
Organic Tin
Zinc
PTS Testing Service are specialists in heavy metals testing and analysis and provide heavy testing on various consumer products and samples including:
Paint
Jewellery and watches
Leathergoods
Textiles
Clothing and apparel
Upholstery covers
Footwear
What are heavy metals?
The chemical definition of a heavy metal is a chemical element with a specific gravity that is at least 5 times the specific gravity of water. Examples of heavy metals include cadmium, chromium, lead, mercury, nickel, zinc and many more. Heavy metals are commonly used in industrial applications such as in the manufacture of pesticides, batteries, alloys, electroplated metal parts, textile dyes, steel, and so forth.
Why carry out heavy metals testing and analysis?
Interestingly, small background levels of these elements are common in the environment but large amounts of any of them may cause acute or chronic toxicity (poisoning). This is why regular heavy metals testing and analysis especially within industry is so important.
Heavy metal toxicity can result in damaged or reduced mental and central nervous function, lower energy levels, and damage to blood composition, lungs, kidneys, liver, and other vital organs. Long-term exposure may result in slowly progressing physical, muscular, and neurological degenerative processes that mimic Alzheimer’s disease, Parkinson’s disease, muscular dystrophy, and multiple sclerosis. Allergies are not uncommon and repeated long-term contact with some metals or their compounds may even cause cancer.
Global legislation for heavy metals
Heavy metals are the most commonly legislated chemicals globally.
The combination of the large number of available heavy metals and their toxic affects coupled with the vast array of uses for these metals has amounted to a number of different EU and international legislations which attempt to control and restrict their uses. Among these are REACH regulations, the Toxics in Packaging Clearinghouse (TPCH), California Proposition 65, and metal specific directives such as nickel regulation which now sits under REACH. EN71, a European standard governing the safety of toys where Part 3 of the regulations covers the migration of elements, is fast becoming the standard to be used for heavy metal safety and assurance for consumer products including leather and leather-based products.
In addition to this heavy metals are regulated under CPSIA which sets restrictions for lead in paint and substrate.