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Lead - Pb

GENERAL DESCRIPTION OF THE ELEMENT :

Lead metal: CAS N°: 7439-92-1
-atomic number: 82 -atomic weight: 207.2
-melting point: 327.5°C -boiling point: 1725°C (769°C)

 

Lead (Pb)IN A FEW LINES :

Lead (Pb) is a very soft, malleable, dense bluish-white metal belonging to the so-called group of heavy metals. Although it is naturally occurring in soil and water due to the weathering of soil minerals, it is often released into the environment from artificial sources. Lead is usually found in ores with copper, zinc and silver.

 

An increasingly important source of lead is recycling of Pb- containing materials.

 

Lead is a widely used metal: in lead-acid car batteries, as lead sheets in the construction industry, in PVC plastic, as ammunition, in crystals and ceramics, in scuba-diving weight belts, as fishing sinkers, as shielding from radiation, ... In the past, lead was used as a pigment in paints and as an anti-knocking agent in gasoline. These applications are banned in the EU since the 1990's.

 

The former use of lead in gasoline and historical emissions by non-ferrous metal producers have led to increased concentrations of Pb in soil, water and air. As Pb is strongly bound to soil properties, root uptake of Pb is very small and most of the Pb in above-ground plant parts is associated with atmospheric Pb deposition.

 

Adults and older children are mainly exposed to lead by its content in food and beverages while ingestion of household dust and soil is a major route of exposure for children, who spend considerable time playing on the floor or in the garden. Lead

 

In the (human) body, lead is distributed to soft tissues (blood, liver and kidneys) and mineralizing systems (bones and teeth). Increased blood lead levels in children are associated with an impact on their intelligence (reduced IQ). In adults, high blood lead levels may lead to, amongst others, subtle effects on semen quality, anemia, loss of memory and loss of coordination.

 

Classification according to Regulation (EC) No 1272/2008 of 16 December 2008 :
Repr. 1A: H 360Df: May damage fertility or the unborn child
STOT RE 2*; H373**: May cause damage to organs through prolonged or repeated exposure
Acute Tox. 4*; H332: harmful if inhaled
Acute Tox. 4*; H302: harmful if swallowed
Aquatic Acute 1; H400: Very toxic to aquatic life
Aquatic Chronic 1; H410: Very toxic to aquatic life with long lasting effects

Reference: Regulation (EC) No 1272/2008 of the European Parliament and of the Council of 16 december 2008 on classification, labeling and packaging of substances and mixtures, amending and repealing Directives 67/548/EEC and 1999/45/EC, and amending Regulation (EC) No 1907/2006. Official Journal of the European Union L353/1. http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2008:353:0001:1355:EN:PDF

 

NORMS AND LEGISLATION :

Maximum levels for lead in foodstuffs
http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2008:353:0001:1355:EN:PDF
COMMISSION REGULATION (EC) No 629/2008 of 2 July 2008 amending Regulation (EC) No 1881/2006 setting maximum levels for certain contaminants in foodstuffs.

 

Maximum lead content in products intended for animal feed
http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2008:353:0001:1355:EN:PDF
DIRECTIVE 2002/32/EC of the European Parliament and of the Council of 7 May 2002 on undesirable substances in animal feed.

 

LeadTolerable human intake levels

The Joint FAO (Food and Agriculture Organization of the United Nations)/WHO (World Health Organization) Expert Committee on Food Additives (JECFA) reevaluated lead for the fifth time in 1999 where it maintained the Provisional Tolerable Weekly Intake (PTWI) of 25 µg/kg body weight. The WHO PTWI was mainly derived from studies with infants and children and is based on all sources of lead intake (i.e. not only food intake).

In June, with new data concerning in particular the toxicology and epidemiology of this heavy metal available, the JECFA reassessed lead. This assessment showed that the PTWI of 25 µg of body weight could be responsible for a drop of 3 points of IQ in children and an increase in systolic blood pressure (maximum pressure) of 3 3mm Hg in adults. These changes were deemed to be significant and the PTWI was cancelled as a result. The Committee concluded that it was not possible to establish a new PTWI which entailed no risk for human health. It confirmed that foetuses, nurslings and children were more sensitive to lead and that a chronic intake of lead through food of 0.6 µg per kg of body weight per day (for a child weighing 20 kg) could correspond to a drop of 1 point of IQ compared to the level of the population.

http://www.inchem.org/documents/jecfa/jeceval/jec_1260.htm


http://www.inchem.org/documents/jecfa/jecmono/v21je16.htm

The EFSA (European Food Safety Authority) issued its opinion in March 2010 and concluded that lead has the most harmful effect on the central nervous system of young children and on the cardiovascular system of adults. BenchMark Dose Low (BMDL) levels were determined for a certain number of points:

  • Effects on the central nervous system of children: 0.50 µg per kg of body weight/day
  • Effects on the systolic blood pressure: 1.50 µg per kg of body weight/day
  • Chronic renal diseases: 0. 63 µg per kg of body weight/day


http://www.efsa.europa.eu/en/efsajournal/pub/1570.htm


ROLE OF CODA-CERVA :

  • RESEARCH

The "Trace Elements" Unit at CODA-CERVA has a long history in trace element analysis. The current research projects concerning lead are emphazised on

(1) the determination of lead concentrations in crops for human consumption (potatoes, carrots, scorzonera, ...), in animal fodder crops (maize, pasture grass, silage grass) and in bovine tissues (meat, kidneys, liver), and

(2) the transfer of lead from different environmental compartments (air, soil, water) through the food chain.

 

Field sampling of crops for human consumption started in 2001 and continued over the years. This project focuses mainly on uncontaminated fields and studies the transfer of lead from air and soil towards the crops.

 

In 2005, kidneys, liver and meat tissue of 150 bovine animals were sampled and analyzed for lead.

The samples were collected on the one hand in three metal contaminated areas and on the other hand in rural areas away from trace element point sources, so-called reference areas.

 

Farms where the animals had resided for more than 18 months, were contacted and the farmers were asked to further participate voluntarily. In total, 53 farmers responded positively and the corresponding farms were visited in spring, summer and autumn in the period 2006-2007.

Lead (Pb)

Fresh pasture grass, silage grass, hay, maize and other locally produced feed were collected at the farms. Well water and surface water were sampled if they served as a source of drinking water in the stable or in the pastures. Lead content was determined in all samples.

 

With this information, food chain transfer models will be derived for lead.

 

In 2006-2007 the lead content in home-produced chicken eggs was determined, together with the Pb content in the soils of the chicken runs and in the kitchen leftovers offered to the chickens.

In total, 59 private chicken owners participated in this study named CONTEGG (Chemical Contamination of home-produced eggs).

Elevated lead concentrations were found in the eggs. However, these Pb levels pose no health risks. The major source of Pb in the eggs was found to be the soil in the chicken run.

 

  • SERVICES
The "Trace Element" Unit at CODA-CERVA is mainly dedicated to scientific research and services in the field of food safety, public and animal health. It provides analytical facilities for third parties by the determination of trace elements in food and animal feed. This activity is accredited according to the European Quality norm ISO 17025.

 

CODA-CERVA is the Belgian National Reference laboratory (NRL) for the determination of trace elements in food and animal feed.


TEAM OF SCIENTISTS :

Nadia Waegeneers
Ann Ruttens

Karlien Cheyns


CODA-CERVA PUBLICATIONS :

2012

- De Temmerman L., Ruttens A., Waegeneers N., 2012. Impact of atmospheric deposition of As, Cd and Pb on their concentration in carrot and celeriac. Environmental Pollution, 166, pp. 187-195

2009

- Waegeneers, N., Pizzolon, J.-C., Hoenig, M. and De Temmerman, L. 2009. Accumulation of trace elements in cattle from rural and industrial areas in Belgium. Food Additives and Contaminants 26: 326-332.

- De Temmerman L., Hoenig M. Transfert d'ETM toxiques des sols arables vers les pommes de terre, le froment et l'épeautre., 2009, 149-161. Chapitre 7 dans Contaminations métalliques des agrosystèmes et écosystèmes péri-industriels. Coordinateurs: Cambier Ph, Schvartz C., Van Oort F.

2008

- Vromman, V., Saegerman, C., Pussemier, L., Huyghebaert, A., De Temmerman, L., Pizzolon, J.-C. and Waegeneers, N. 2008. Cadmium in the food chain near non-ferrous metal production sites. Food Additives and Contaminants 25: 293-301.

2007

- Harcz, P., De Temmerman, L., De Voghel, S., Waegeneers, N., Wilmart, O., Vromman, V., Schmit, J.-F., Moons, E., Van Peteghem, C., De Saeger, S., Schneider, Y.-J., Larondelle, Y. and Pussemier, L. 2007. Contaminants in organically and conventionally produced winter wheat (Triticum aestivum) in Belgium. Food Additives and Contaminants 24: 713-720.

2005

- Pizzolon, J.-C. and Hoenig, M. 2005. Analyse des échantillons alimentaires par ICP-MS. Développement et routine : où sont les différences ? Canadian Journal of Analytical Sciences and Spectroscopy 50: 221-227.

2004

- De Temmerman, L. and Hoenig, M. 2004. Biomonitoring lead and cadmium deposition. Journal of Atmospheric Chemistry 49: 121-135.

2003

- De Temmerman, L., Vanongeval, L., Boon, W., Hoenig, M. and Geypens, M. 2003. Heavy metal content of arable soils in Northern Belgium. Water, Air and Soil Pollution 148: 61-76.