About the EU RoHS directive 
Jan 27, 2003, the European Parliament and the European Union, the Council adopted Directive 2002/95/EC, "in Electrical and Electronic Equipment Restrictions on the Use of Certain Hazardous Substances Directive" (The Restriction of the use of Certain Hazardous Substances in Electrical and Electronic Equipment), referred to as the RoHS directive. The basic content is: From July 1, 2006, in the new market of electronic products, electrical equipment, restrictions on the use of lead, mercury, cadmium, hexavalent chromium, polybrominated biphenyls (PBB) and polybrominated diphenyl ethers (PBDE), etc. Six hazardous substances. After the RoHS directive issued from February 13, 2003 became the European Union within the framework of the formal legal; August 13, 2004 before conversion European Union member countries the cost of legal / regulatory; February 13, 2005, the European Commission to re-examine Scope of the directive, and to consider development of new technologies, to develop projects to increase the list of banned substances; July 1, 2006, the EU market will be an official ban on six types of substances over the sale of products. 
ROHS directive clarified the electronic and electrical equipment containing banned substances (the first: Cd Cadmium and its compounds, Pb Lead and its compounds, Hg mercury and its compounds, Cr6 + hexavalent chromium compounds, PBBs PBBs, PBDEs polybrominated diphenyl ethers) is not Quasi-market sales in the European Union, and in July 1, 2006 from enforcement. Directives applicable to the work of no more than 1000V AC voltage 1500V DC, as well as all the products and equipment. As the ROHS directive requirements, not the overall product testing, but the product will be carried out in accordance with material split, with a different material for prohibited substances were detected. Therefore, the lower reaches of the supplier selection is very important. In general, the metal material to be testing the four banned heavy metals (Cd Cd / Pb Pb / Hg Mercury / Cr6 + +), non-metallic materials in addition to the four banned heavy metal detection outside the testing needed to brominated flame retardants ( PBBs PBBs / PBDEs PBDEs), at the same time on different materials of the packaging materials were also needed for detection of heavy metals in packaging materials. 

RoHS for all the production process, as well as raw materials may contain harmful substances above the six middle of Electrical and Electronics 
Commodities, including: white home appliances such as refrigerators, washing machines, microwave ovens, air conditioners, vacuum cleaners, heaters, etc. 
And household appliances, such as audio, video products, DVD, CD, TV, IT products, digital products, communications 
, And other products; power tools, electric toys, electronic medical electrical equipment 

Now manufacturers generally do all the RoHS test report, in accordance with the requirements of the directive for products dismantling homogeneous materials, use of destructive methods for chemical experiments, the final value of the content of the concrete. You and the results of the RoHS directive limits than the conducted right. I think in general we should be talking about RoHS certification is based on the RoHS directive made by the report of the test.