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This work aimed to evaluate the ability of four regulatory sampling protocols to accurately determine weekly water lead levels (WLLs) of exposure at the kitchen tap in twenty-nine households with or without a lead service line (LSL). Proportional sampling was used as the gold standard to which the other protocols, 5-min flush, 30-min stagnation, 6-h stagnation and random daytime were compared. Random daytime samples provided mean WLLs closest to true exposure in the households monitored overall compared to other sampling protocols. Strikingly, mean WLLs after 5 min of flushing underestimated lead exposure by 47%. Supporting these observations, water usage patterns revealed that full flushing only occurs in 3.4% of usage events within the service line and in 0.26% at the tap. The time between usage events in the service line was approximately 30 min but the 30-min protocol tended to slightly underestimate WLLs. These differences were explained by flushing prior to the 30-min stagnation sampling, which limited the contribution of the LSL to WLLs. Furthermore, the average stagnation at the kitchen time was 106 min and usage events rarely exceeded the water volume within premise plumbing (1.1 L). Mean WLLs after 6 h of stagnation without flushing overestimated exposure by 29% but provided a conservative indicator of WLLs of exposure.
This article was published in the following journal.
Name: Water research
Mounting evidence showed that lead exposure increased the risk of child attention-deficit-hyperactivity disorder (ADHD). Epidemiologic studies have typically used the blood-lead as a biomarker of lead...
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Eliminating the sources of human lead exposure is an ongoing public health goal. Identifying the make-up of household plumbing and service line material type is important for many reasons including un...
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Injury to the nervous system secondary to exposure to lead compounds. Two distinct clinical patterns occur in children (LEAD POISONING, NERVOUS SYSTEM, CHILDHOOD) and adults (LEAD POISONING, NERVOUS SYSTEM, ADULT). In children, lead poisoning typically produces an encephalopathy. In adults, exposure to toxic levels of lead is associated with a peripheral neuropathy.
Neurologic conditions in adults associated with acute or chronic exposure to lead or any of its salts. The most common lead related neurologic syndrome in adults consists of a polyneuropathy involving motor fibers. This tends to affect distal nerves and may present as wrist drop due to RADIAL NEUROPATHY. Additional features of chronic lead exposure include ANEMIA; CONSTIPATION; colicky abdominal pain; a bluish lead line of the gums; interstitial nephritis (NEPHRITIS, INTERSTITIAL); and saturnine gout. An encephalopathy may rarely occur. (From Adams et al., Principles of Neurology, 6th ed, p1212)
Neurologic disorders occurring in children following lead exposure. The most frequent manifestation of childhood lead toxicity is an encephalopathy associated with chronic ingestion of lead that usually presents between the ages of 1 and 3 years. Clinical manifestations include behavioral changes followed by lethargy; CONVULSIONS; HALLUCINATIONS; DELIRIUM; ATAXIA; and vomiting. Elevated intracranial pressure (HYPERTENSION, INTRACRANIAL) and CEREBRAL EDEMA may occur. (From Adams et al., Principles of Neurology, 6th ed, p1210-2)
A sampling methodology using small sample sizes when conducting surveys in small geographical or population-based areas or lots.
Sampling of blood levels of the adrenocorticotropic hormone (ACTH) by withdrawal of blood from the inferior petrosal sinus. The inferior petrosal sinus arises from the cavernous sinus and runs to the internal jugular vein. Sampling of blood at this level is a valuable tool in the differential diagnosis of Cushing disease, Cushing syndrome, and other adrenocortical diseases.