Brad Cochrane Graeme Currie February 12 th, 2012
Problems caused by lead in solder Alternatives Costs and Performances of Alternatives Laws in different locations on use of lead-free solder
The major problem with lead solder is lead poisoning. It is caused from increased levels of heavy metal lead in the body. The lead interferes with many body processes and is also toxic to many organs and tissues of the body. Not only will it directly affect a person, but since it affects the development of the nervous system it may cause learning and behaviour disorders in children. Symptoms of lead poisoning include stomach pain, confusion, headaches, anaemia, seizures, coma and death. The problems of lead solder on a more stewardship targeted relation include lead poisoning water and the environment. This is caused from plumbing and fixtures that are either made of lead or use lead solder as well as the disposal of electronic components.
Along with the water, some places have solder in food cans that contain lead. Before this was seen as a big issue even medical instruments were made with lead solder. Even most alternatives to lead-free solder have had a negative impact on the environment. Lead-free solders require more heat for soldering, which means the use of more fossil fuels. Lead can also enter the environment through landfills and the disposal of electronic equipment. From there, lead can remain in the environment as dust and even be absorbed by plants. Once in the environment there are many ways for humans and animals to ingest it and get many of the symptoms from lead poisoning that were listed above.
PVC for plumbing- PVC does not require lead solder Lead-free solders- Although lead-free solders also have their problems (being brittle, needing more heat) they are overall more beneficial to the environment. Without the use of lead in plumbing and electronic devices landfills will be cleaner and lead poisoning rates will drop. Alternatives to Lead solder include tin, copper, silver, bismuth, indium, zinc, and antimony. For conventional solder most replacements have melting points from 5 to 20 degrees Celsius higher then that of lead solder. A problem with tin solder included “tin whiskers” which caused short circuits and arching in electrical equipment. Sn-Ag-Cu solder is quite popular by Japanese manufactures and for hand soldering. It is popular because of its reduced melting point.
The United States Environmental Protection Agency conducted a study on different solders and graded their performances based off a variety of environmental factors. Bar Solders-the tin/copper alloy had the best score. -tin/lead solder had the worst scores in the toxicity category Paste Solders: -bismuth/tin/silver had the lowest impact scores in every category except for non-renewable resource consumption. -again tin/lead solder had the worst scores in the toxicity category Study results allow for an easy review of environmental impact along with cost and performance.
The costs of lead-free solder are more expensive then using lead solder. For most cases, the melting points of these solders are higher which means more energy and costs. Also the solder seems to be more brittle and could cause performance issues in electronic equipment such as short circuits and misconnections.
On July 1 st, 2006 the European Union Waste Electrical and Electronic Equipment Directive (WEEE) and Restriction of Hazardous Substances Directive (RoHS) prohibited the intentional addition of lead to consumer electronics. In 1990 the National Plumbing Code of Canada no longer allowed the use of lead solder in new drinking water plumbing.
Although lead-free solder may be more costly and also have it’s own problems regarding stewardship on the environment, it is a reasonable alternative to using lead-solder as it dramatically reduces the amount of lead that is being disposed into the environment.
United States Environmental Protection Agency: Solder Performances: Indium Corporation Environment and Animals: Lead Solder-Environment Activism at its Worst