Question

Toxicology problem on Lead poisoning

The following is a toxicokinetic model for lead poisoning. Use this information to answer the following questions. Lead concentrations Lead concentrations (24 hours after ingestion) (10 days after ingestion) Gastrointestinal Tract astrointestinal Tract ood and lymph- Hood and lymph- CNS 10.01) CNS (0.019 Storage ON Storage 10 dney dney BN Cortical Bone (90%) Cortical Bone (SON) Urine pas 10 1. Typical lead exposure testing will measure quantities in the urine. Is this a good indicator to know lead exposure? Why or why not? 2. What would be another indicator for lead exposure? What would the benefits and drawbacks be to test that tissue? 3. Lead was one ingredient to paint that was manufactured prior to 1978. Any house build before that year is almost guaranteed to have lead paint in it since very few homes have been gutted of all the walls and sanded down to the wood. Most of that paint is under many newer layers of paint and is not bioavailable to those living in the house. What processes would make this lead bioavailable to those living in the residence? When should precautions be taken? 4. A one-year old child is living in one of these older homes and has been found to be eating the flaking paint chips off the wall and trim. The next day, urine samples are taken and analyzed. The child was found to have 15ug/L lead in urine. In vitro testing using human neurons demonstrate toxicity at concentrations of 10ng/L. Has this child approached that concentration? How much total lead is in the brain if the brain is 1.2L? How concentration of lead is on the cortical bone?

Answer 1

1. the answer will be NO. The spontaneous excretion of lead (in children and adults) is not a reliable marker of lead exposure, being affected by kidney function, circadian variation, and high interindividual variation at low doses.because At relatively high doses, there is a curvilinear upward relationship between urinary lead and intake measures. Urinary lead is measured mainly in connection with the lead excretion that follow provocative chelation, i.e., the lead-mobilization test or chelation therapy in lead poisoning of children or workers.

Ingested lead that is not absorbed is lost through urinary and fecal excretion. Absorbed lead that is not sequestered in bone or some soft tissues is eventually eliminated through the kidneys or through biliary clearance into the intestine.so this will not be good indicator of lead exposure.

2. Blood lead level test will be another indicator for lead exposure.Various factors—such as blood flow, capillary permeability, transport into an organ or tissue, and number of active binding and receptor sites—determine the path of lead through the body and can influence the biologically effective dose.

A simple blood test can detect lead poisoning. A small blood sample is taken from a finger prick or from a vein. Lead levels in the blood are measured in micrograms per deciliter (mcg/dL). There is no safe blood level of lead.

benefits : Lead testing is done to check for lead poisoning. In the early stages, lead poisoning typically doesn't cause symptoms. That’s why routine testing is necessary in children and adults exposed to lead.The risk of having your blood drawn is low.

drawbacks : multiple puncture wounds due to trouble finding a vein,excessive bleeding,feeling lightheaded or fainting,infection etc.

3. degree of exposure to lead depends very much on the chemical and mineral form in which the lead occurs.Bioavailability is an expression of the fraction of the total mass of a compound present in a compartment that has the potential of being absorbed by the organism.

Environmental chemistry Ecotoxicology Environmental concentrations For example: source, route quantity Toxicokinetics For example: uptake, metabolism elimination Bioavailability Environmental fate For example: transport distribution degradation Toxicodynamics For example: effects across levels of biological organization Exposure Effect

Bioavailability is a concept that incorporates many integrated processes. Bioavailability bridges environmental chemistry and ecotoxicology, integrating contaminant concentration, fate, and behavior, as well as the effect of contaminants within the environment.With the proper ventilation and protection chemical strippers is the method of choice. Scraping does not provide effective removal and sanding by hand or mechanically produces copious amounts of lead-impregnated dust. Avoid blowtorches or heat guns, as they produce toxic fumes.Plastic sheeting (6-mil polyethylene) sealed at its edges with duct tape, for example, is effective in keeping most lead dust within the immediate work area, where it can be picked up with HEPA vacuuming.

precautions : You would be doing a service by reminding people to think about lead, and to learn how to work safely to contain the dust and chips when working on any pre-1978 home.

Isolate and restrict access to the work area.Select the safest methods for paint removal.Wear appropriate clothing.Use required safety equipment.Cleanup Disposal.

4. no the child has not approached that level of concentration, because it is in nanograms.lead exposure in children is associated with region-specific reductions in adult gray matter volume. Affected regions include the portions of the prefrontal cortex and ACC responsible for executive functions, mood regulation, and decision-making.childhood lead exposure is associated with brain volume loss in adults, in specific regions of the brain.

Average tibia-Pb levels were found to correlate strongly with the cumulative Pb dose (r2 = 0.81).concentration is less than 1 microgram.,precisely : 23.4 ± 15.96 ppm