Lead contamination, importance

The Occupational Safety and Health Administration (OSHA) regulates the exposure to chemicals ia the workplace. From the poiat of view of the inorganic pigments iadustry, the limits estabUshed for lead and cadmium exposure are particularly important. A comprehensive lead standard adopted by OSHA ia 1978 has been successful ia reduciag the potential for lead contamination ia the workplace. 

People living near hazardous waste sites may be exposed to lead via ingestion of contaminated water or soils or by inhalation of lead particles in the air. For people not living in the vicinity of hazardous waste sites, the major route of exposure to lead is ingestion, particularly of lead-contaminated water, food, soil, lead-based paint chips, or dusts (the latter two are particularly relevant to children in lower-income urbanized populations). For occupationally exposed individuals, the predominant route of exposure is the inhalation of lead particles with oral ingestion also important in many cases. 

In addition may medication related to the uremic state lead to important trace element accumulation. In the past this has clearly been established for aluminum resulting from the use of aluminum hydroxide as a phosphate binding agent. As aluminum-based phosphate binders may be contaminated with other elements, e.g. strontium the possibility for a simultaneous accumulation of different elements has been suggested [7]. Strontium is mainly eliminated by the kidney and has been associated with bone mineralization defects when present at high concentrations. In view of this the use of strontium ranelate for the treatment and preven-... 

Legislative measures (quality standards of fuels) and regulations will progressively prohibit the use of alkyl-lead additions in fuels, and reduce the risks of lead contamination of the food-chain, but there will still remain an important problem of soil, sediments and water contamination by lead. 

In addition, namral waters have been polluted through atmospheric deposition and industrial effluent, including leaching from mine tailings (3, 407). The speciation of lead in these aqueous systems has important implications, both for lead bioavailability and for the treatment of lead-contaminated systems. 

In the city of Modena, the levels of lead, chromium, nickel, and cadmium in the air (as measured by automatic detectors) were compared with those contained in honey, larvae, and pollen samples taken monthly from beehives situated in the vicinity of the detectors themselves. The findings cannot be considered conclusive, as the average monthly data recorded by the automatic detectors referred to a single point in the atmosphere whereas the beehive data were referable to the area around the hive visited by bees in a given month. Nonetheless, they showed that the fresh honey recently imported into the honey chamber was the matrix that best reflected the trend in lead contamination of the atmosphere, as recorded by the detectors [89]. It was also observed, again with regard to lead in the honey matrix, that the values provided by the detectors were a reliable anticipation of the biological data. In the same study, the authors also tried to estimate the ratio of the mean concentration of the various contaminants in honey (in Jig/kg) and that in the air (in pg/m ), which may be estimated as approximately 1000-2000 for lead and nickel, 2000-4000 for chromium, and 3000-5000 for cadmium [90]. 

Note for landlords If you do any kind of renovation in a unit where there is or may be lead paint, you or your contractor need to take measures to protect both the living space and your tenants property from lead contamination. It is also your responsibility to educate tenants about the dangers of lead, the importance of keeping away from work areas, and the importance of their belongings being removed or covered. 

If you grow your own food, Chapter 14 gives advice on how to protect your produce from lead-contaminated soil. Otherwise, be careful about food coming into contact with any ceramics or leaded crystal. These precautions are especially important for young children and pregnant women, whose exposure to lead affects the extremely vulnerable fetus. 

The focus in this section is principally on terrestrial botanica, particularly those plants that comprise economically important agricultural commodities and are an important part of the human food supply. Attention here is on lead entry and deposition during plant growth rather than lead contamination... 

Low-income subsets are more likely to produce more homegrown diet components in gardens. Groups of the population who rely on subsistence fishing and harvest catches where aquatic lead contamination is likely or of concern will ingest amounts of the element significantly above mean population intakes. Ethnic food preferences can also raise the likelihood of higher Pb content in certain imported canned foods. 

It is important to note that large numbers of water systems in the U.S., having no lead service lines or interior lead piping, required some form of enhanced corrosion control as a result of the Lead and Copper Rule, due to a combination (not differentiable from the monitoring data) of leaded brasses and soldered joints in copper plumbing. Therefore, the significant lead release observed in the AWWARF study represented lead contamination from waters already adjusted for some corrosion control, and would not represent nearly a worst-case scenario as may be present elsewhere in North America or Europe. 

Because of this tendency towards HCl elimination, stabilizers are necessary for PVC. There has been a large amount of research in this area. Lead stabilizers are effective but are no longer used to any extent in the U.S. When some imported toys are found to have lead contamination, if it is not from the paint or pigments, it can be from PVC made with lead stabilizers. For some time in the U.S., tin-based stabilizers have been widely used. Compounds such as dibutyltin bis (isooctylthioglycolate) are effective. 

---