Lead
Nature of the Pollutant
Lead is one of the first metals used by humans. Its metallic form rarely occurs in nature but rather is found in combination with sulfates and carbonates. The main uses for lead are as an anti-knock compound in fuels, an agent in paints and insecticides, and in the manufacture of lead-acid batteries. Lead is emitted to the atmosphere by certain industries such as primary and secondary lead smelting, primary copper smelting, gray iron foundry casting and lead-acid battery manufacturing. Lead emissions enter the body principally through ingestion and inhalation, with consequent absorption into the blood stream and distribution to all body tissues.
In setting the standard, EPA determined that young children are the most critically sensitive population because adverse effects appear at lower thresholds, and children are more likely to ingest lead. Once in the body, most of the lead accumulates in bone while the rest remains mobile in other tissues and the blood. Within the body, three systems appear to be most sensitive to lead: the blood forming system (hematopoietic system), the nervous system and the renal system. In addition, lead has been shown to affect the normal functions of the reproductive, endocrine, hepatic (liver), cardiovascular, immunologic and gastrointestinal systems. Among the first effects of lead intoxification are severe consequences such as colic, palsy and encephalopathy. These maladies are generally associated with heavy exposure. Long-term, low-level exposure can produce increased urinary excretion, anemia, central nervous system deficits and neuropathies.
Recent research by various agencies, including the U.S. Department of Health and Human Services, shows that there has been a significant decline of lead in blood levels in the U.S. population, probably due to reduced use of lead in gasoline. Atmospheric lead levels are substantially lower since USEPA's action in January 1986, which reduced by 90% the lead in gasoline. This resulted in lead levels dropping from 1.1 grams per gallon to 0.1 gpg.
The focus now is on lead in paint in older homes and buildings. In other words, it has shifted from outdoor air to indoor air. You should consider testing the lead content of old paints at home, preventing children from eating old, dry paint, and carefully controlling dust from sanding, or otherwise working with, old paint. Old paint is not a problem if it's in good shape, especially if it is covered over with a lead-free paint. You should also take care to avoid lead in candles.
RAPCA has not recorded a violation of the lead standard since monitoring for the pollutant began in 1979. Our values are so low that we no longer monitor for lead in the RAPCA area. The highest quarterly average for 1997 at our one site was 0.04 ug/m3, far below the standard (quarterly NAAQS = 1.5 ug/m3). This level was even lower in the first and second quarters of 1998, with 0.01 ug/m3 being the average for each quarter.
We have some sources (boilers and asphalt plants) that burn waste oil. These sources are inspected, with waste oil samples taken and analyzed for lead and other contaminants on a periodic basis. The waste oil sampling is unannounced and is performed by a private contractor who is accompanied by a RAPCA inspector.