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Educating an Andean Ecuadorian Community on the Hazards of Lead Exposure

An International Perspective

Leo H. Buchanan, Ph.D. University of Massachusetts Medical School Harvard University Health Services

Annual Diversity Workshop "Hazardous Sites in Underprivileged Communities: Challenges of Diagnosis, Clean-up, and Redevelopment" Harvard School of Public Health

Environmental Sources of Childhood Lead Poisoning · Air: primarily from leaded gasoline · Food: lead soldered food cans, leadcontaining kitchenware · Water: primarily from plumbing systems · Lead-Based Paint: houses built before 1950 pose the greatest risk

Continued on next page

Dr. Leo H. Buchanan

Environmental Sources of Lead cont'd · Soil: a significant source of Lead

poisoning in the United States · Occupation of Parents: Leadcontaminated dust may be brought into the home

· Alternative Medicines and Cosmetics: primarily in developing

countries

· Lead Glazing of Ceramics: popular

in Latin America

Dr. Leo H. Buchanan

Overview Lead Effects

Lead has been associated with:

· · · · ·

kidney problems; hypertension neurologic disorders decrements in IQ delinquent behavior neurodevelopmental disabilities, such as learning disabilities, language disorders, autism, attention deficits, hyperactivity, neuroauditory disorders · sensory-neural hearing loss

Dr. Leo H. Buchanan

Map of South America

Dr. Leo H. Buchanan

Map of Ecuador emphasizing the Andes Mountain range. The village of interest for this presentation is La Victoria, which is located about 100 km south of Quito (Ecuador's capital city), near the town of Latacunga.

Dr. Leo H. Buchanan

Demographics of Ecuador

· Population: ~ 13.5 millions · Ethnicity/Race: 65% of the population is Mestizo (Indian & Spanish); 25% Amerindian; 7% Spanish; 3% of African descent

­ Spanish is the official language, but Quechua is the second most frequently spoken language

· · · ·

Population Below Poverty Line: 41%* GDP per capita: $4,300 Infant Mortality Rate: 22.87 deaths/live birth Life Expectancy at Birth: 76.42 years

From The World Factbook (2006) [http://www.cia.gov/cia/publications/factbook/geos/ec.html]

*More recent information from an Ecuador colleague indicates the Population Below the Poverty Line is now greater than 60%. Dr. Leo H. Buchanan

A Quechua AmerIndian Woman Walking Her Livestock through the Village of La Victoria. La Victoria, Ecuador is located in Pujili county in the Province of Cotapaxi in a "valley" in the Andes Mountains at about 2,850 meters (9,348 feet) above sea level. The population of the area consists of approximately 2800 inhabitants who are Mestizos (Spanish and Indian heritage) and indigenous Quechua AmerIndians. The primary occupation of the adult inhabitants of the La Victoria area is ceramic production and lead glazing. But, children also participate in the leadglazing activities. Dr. Leo H. Buchanan

The Making of Lead-Glazed Roof Tiles

Photo Copyright Dr. Leo H. Buchanan

Photo Copyright Dr. Leo H. Buchanan

Roof tiles being made from clay and shaped by two women at La Victoria.

The tiles are laid out in the sun to dry. They will later be glazed with lead and "baked" in a lead kiln.

Dr. Leo H. Buchanan Leo

A Lead-Glazing kiln

This is one of the many lead-glazing kilns in the Village of La Victoria, Ecuador. Note the lead-glazed roof tiles in the lower right corner where the child is standing. Both children and adults participate in lead-glazing activities. The inhabitants of the area, especially the children, have extremely high blood lead levels, in some cases more than 10 times higher than the CDC's risk level of 10 microgram per deciliter.

Photo Copyright Dr. Leo H. Buchanan

Counter, S.A., Ortega, F., Shannon, M.W., and Buchanan, L.H. (2003). Succimer (meso-2,3(2003). (meso- 2,3dimercaptosuccinic acid [DMSA]) treatment of Andean children with environmental lead exposure. with International Journal of Occupational and Environmental Health, 9: 164-168. 164Counter, S.A., Buchanan, L.H., Ortega, F., Amarasiriwardena, C., and Hu, H. (2000). Environmental lead contamination and pediatric lead intoxication in an Andean Ecuadorian village. International Journal of Ecuadorian Occupational and Environmental Health, 6: 169-176. Health, 169-

Dr. Leo H. Buchanan Dr.

Steps in the Education & Prevention Program

1. Determine the Prevalence & Degree of Lead Poisoning 2. Perform Medical/Health, Neurologic, & Neurodevelopmental Evaluations 3. Explain Results to Parents & Guardians 4. Educate the Community about the Hazards of Lead Exposure 5. Perform Environmental Lead Analysis 6. Inform the Ecuadorian Health Officials of the Situation 7. Meet with Members of the University 8. Monitor Blood Lead Levels 9. Introduce Portable Lead Analysis System (LCS) 10. Distribute Nutritional Supplements 11. Teach Proper Food Cleaning Techniques 12. Distribute Protective Masks to Adults 13. Keep Children Away from Kilns 14. Discuss Alternative Glazing Compounds

Dr. Leo H. Buchanan

Photo Copyright Dr. Leo H. Buchanan

Photo Copyright Dr. Leo H. Buchanan

Some Faces of La Victoria

Upper Left: Dr. Ortega (middle, sitting on floor), an Ecuadorian doctor, and member of our medical team, and the nurse (white coat) in charge of the Subcentro de Salud with a La Victoria family waiting to be tested. Top Right: Children of La Victoria. Bottom Left: Children of La Victoria with two of our team members.

Dr. Leo H. Buchanan

Photo Copyright Dr. Leo H. Buchanan

Distribution of Blood Lead Levels for Children in La Victoria, Ecuador

60 50 40 30 20 10 6 10-19 20-44 45-69 > 70 41 57

This figure shows the prevalence of lead poisoning in a cohort of 166 children in the village of La Victoria. Only six children (3.6%) had blood lead levels (BLL) less than 10 micrograms per deciliter (the Center for Disease Control (CDC) and Prevention, and the World Health Organization's (WHO) action or risk level), and about 40% of the children had high to extremely high BLLs ( > 45 micrograms per deciliter). Similar BLL distributions were found in other cohorts of children in the La Victoria area (e.g., in another cohort of 88 children, more than 50% had BLLs > 50 µg/dL).

Counter, S.A., Buchanan, L.H., Ortega, F., et al. (2000). Environmental Environmental lead contamination and pediatric lead intoxication in an Andean Andean Ecuadorian village. International Journal of Occupational and Environmental Health, 6: 169-176. Health, 169Counter, S.A., Buchanan, L. H., Ortega, F, and Rifai, N. (2000). Blood lead and hemoglobin levels in Andean children with chronic lead lead intoxication. Neurotoxicology, 21: 301-308. Neurotoxicology, 301-

Number of Children

38 24

0 < 10

Blood Lead Level (µg/dL)

Dr. Leo H. Buchanan

Average Blood Lead Levels (BLL) in Children in La Victoria, Ecuador and the United States

Blood Lead Level (µg/dL)

Ecuador United States

This figure shows that the average BLL for children in the La Victoria area is about 15 times higher than that of children in the United States.1 In several cohorts of the Ecuadorian children, the BLLs averaged 40-50 microgram per deciliter (µg/dL). average BLL for children younger than 6 years old in the U.S. was 2.7 µg/dL during a 1991-1994 NHANES survey. Since that time, the average BLL for young children in the U.S. has declined to 1.9 µg/dL (NHANES 19992002).

Counter, S.A., Buchanan, L.H., Ortega, F., et al. (2000). Environmental lead contamination and pediatric lead intoxication in an Andean Ecuadorian village. International Journal of Occupational and Environmental Health, 6: 169-176. Health, 1691The

60 50 40 30 20 10 0

40.0

2.7

Dr. Leo H. Buchanan

Sensory & Neurocognitive Testing

Families Waiting to be Tested

Dr. Buchanan with a Quechua Mother and Daughter

Neurophysiologic Testing Hearing Testing Neurocognitive Testing

Photos Copyright Dr. Leo H. Buchanan

Hearing Thresholds in Lead-Exposed Children

0 10

Data collected by the United States National Health & Nutrition Examination Survey (NHANES) during 1976-1984 indicated that lead exposure causes significant hearing loss in children. Because of these NHANES results, we investigated auditory function in the Andean Ecuadorian children to determine if hearing loss was a problem that would need medical or non-medical treatment. The figure on the left shows mean hearing thresholds (with + 1 standard deviation bars) for 136 lead-exposed Ecuadorian children. The gray area at the top of the graph shows the range of normal hearing, i.e., a hearing threshold of 20 decibels (dB) or less is within the normal range. As can be seen from the figure (audiogram), the children have normal hearing for all frequencies.

Hearing Level (dB)

20 30 40 50 60 70 80 90 100 1 2 3 4 6 8

N = 136 Lead-Exposed Andean Ecuadorian Children

Frequency (kHz)

Counter, S.A., Buchanan, L.H., Ortega, and Laurell, G. (1997). Normal auditory brainstem and cochlear function in extreme pediatric plumbism. Journal of Neurological Sciences, 152: 85-92. Sciences, 85Counter, S.A., Vahter, M., Laurell, G., Buchanan, L.H., Ortega, F., and Skerfving, S. (1997). High lead exposure and auditory sensory-neural function in Andean children. Environmental sensoryHealth Perspectives, 105: 522-526. Perspectives, 522-

Dr. Leo H. Buchanan

Hearing Thresholds in Lead-Exposed Adults

0 10 20 Hearing Level (dB) Hearing Level (dB) 30 40 50 60 70 80 90 100 1 2 3 4 Frequency (kHz) 6 8

Right Ear Females Males

A

0 10 20 30 40 50 60 70 80 90 100 1 2 3 4 Frequency (kHz) 6

Left Ear Females Males

B

8

Hearing thresholds for Andean adults are shown in Figure A and B for the right and left ears, respectively. The results show diminished high frequency hearing for the adults, especially the men, who are exposed to noise in addition to lead. These results suggest that for the adult inhabitants of La Victoria, Ecuador, occupational noise exposure is an important variable contributing to their hearing loss, but a combined lead and noise exposure effect cannot be completely ruled out. This makes it important to perform longitudinal hearing tests on the children. [Gray Area at Top of Figure shows the normal hearing range ( < 20 dB)]

Counter, S.A., and Buchanan, L.H. (2002). Neuro-ototoxicity in Andean adults with chronic lead and noise exposure. Journal of Neuroexposure. Occupational and Environmental Medicine, 44:30-38. Dr. Leo H. Buchanan 44:30-

Otoacoustic Emissions in Lead-Exposed Children and Adults

DPOAE Amplitude (dB SPL) DPOAE Amplitude (dB SPL)

30

Mean DPOAEs: Pb-Exposed Children Mean DPOAEs: Reference Group + 1 SD Range: Reference Group DPOAE NF: Reference Group DPOAE NF: Pb-Exposed Children

A

30

20

20

Mean DPOAEs: Pb-Exposed Adults Mean DPOAEs: Reference Group + 1 SD Range: Reference Group DPOAE NF: Reference Group DPOAE NF: Pb-Exposed Adults

B

10

10

0

0

-10

-10

-20 1187 1500 1906 2406 3031 3812 4812 6031

-20 1187 1500 1906 2406 3031 3812 4812 6031

f2 Frequency (Hz)

f2 Frequency (Hz)

Possible sub-clinical effects of lead (Pb) exposure on the inner ear (cochlea) were examined using a noninvasive physiologic procedure known as distortion product otoacoustic emissions (DPOAEs) for Pb-exposed children (A) and adults (B) from the village of La Victoria, Ecuador. Mean DPOAEs for the Pb-exposed children and adults are compared to mean DPOAEs of a reference group of non-Pb-exposed children and young adults. The broken lines in the upper portion of each graph represent the ± 1 standard deviation range for the Reference Group (i.e., normal range). DPOAEs noise floors (NF) are shown as solid and dotted lines at the bottom of each graph for the Pb-exposed groups and the Reference Group, respectively. Overall, the results indicated that the DPOAEs were within the normal range for the children, but the children did differ significantly from the Reference Group at 2406 Hz, 3031 Hz, and 3812 Hz Hz. However, the only frequency that was clearly outside of the normal range was 3031 Hz. The adults showed diminished DPOAEs in in the high frequencies, consistent with their high frequency hearing loss as shown in the previous slide. Buchanan, L.H., Counter, S.A., Ortega, F., and Laurell, G.

(1999). Distortion product oto-acoustic emissions in Andean children and adults with chronic lead intoxication. Acta otolead Otolaryngologica, 119: 652-658. Dr. Leo H. Buchanan 652-

Auditory Brainstem Responses in Lead-Exposed Children

8 7 6

I-III III-V I-V

N = 114

Latency (ms)

5 4 3 2

200 nV

1

A

1 2 3 4 5 6 7

1 ms

8 9 10

0 0

B

20 40 60 80 100 120 140

PbB (µg/dL)

Time (ms)

The auditory brainstem response (ABR), which is a non-invasive measure of the integrity of parts of the auditory brain, has been reported to be sensitive to the neurotoxic effects of lead. Figure A shows normal ABRs from a leadpoisoned individual. The peaks of the waveform can be identified by the Roman numerals. The time between each peak gives data about the functioning of brain.

Figure B shows the mean inter-peak latencies (time in milliseconds between the specified wave peaks) of the ABR as a function of blood lead level (PbB) in 114 lead-exposed Andean children. The inter-peak latencies are within the normal range.

Counter, S.A., Buchanan, L.H., Ortega, and Laurell, G. (1997). Normal auditory brainstem and cochlear function in extreme pediatric plumbism. Journal of Neurological Sciences, 152: 85Sciences, 8592. Counter, S.A. (2002). Brainstem neural conduction biomarkers in lead-exposed children of Andean lead-glaze workers. Journal leadleadof Occupational and Environmental Medicine, 44: 855-864. Medicine, 855-

Dr. Leo H. Buchanan

Summary of Auditory Effects

· Previous hearing threshold data obtained by NHANES showed subtle effects of lead on the inner ear, amounting to less than a 5 dB change in hearing. Since the standard error of measurement in hearing threshold testing is 5 dB, a change in auditory threshold of less than 5 dB may not be of any biological/medical significance. Our results showed the children of La Victoria, who had very high blood lead levels (BLL), to have normal hearing. These disparate results suggest that hearing threshold measurements may not be sensitive to lead exposure in children. However, because the adults showed high frequency hearing loss, the children's hearing should be monitored on a longitudinal basis. Otoacoustic emissions (OAEs) have been investigated in only one human study (Buchanan, et al., 1999), which showed some subtle effects. Further studies should be performed using OAEs. If shown useful, OAEs would be an ideal test procedure to monitor the effects of lead exposure on the cochlea (inner ear). Although the results for auditory brainstem responses are inconsistent from study to study, further investigations are warranted. Auditory processing ability in lead exposed children should be investigated

Dr. Leo H. Buchanan

·

· ·

Neurologic and Neurocognitive Examination of Lead-Exposed Andean Ecuadorian Children

This figure shows that a substantial number of the lead-exposed children in the La Victoria area had neurologic and neurocognitive problems that put them at risk for health and academic learning problems.

100 80

62.7 53.7 46.3 40 33.3 20 5.7 1.9 0 22.7 23.4 32.7

% of Children with Deficits

60 40 20 0

Tendon Reflexes Tandem Walking Standing Balance Finger-to-Nose Finger Tapping Visual Tracking Draw-A-Person Color Discrim.

Size Discrim. Right/Left Discrim. Math Calculation Raven's Matrices

Counter, S.A., Buchanan, L.H., Rosas, H.D., and Ortega, F. (1998). (1998). Neurocognitive effects of chronic lead intoxication in Andean children. Journal of Neurological Sciences, 160: 47-53. Sciences, 47-

Dr. Leo H. Buchanan

Lead Exposure and Cognition

Raven's Coloured Progressive Matrices (RCPM) test was used to assess aspects of cognition in the leadexposed children. The RCPM is a language-free measure of visual-spatial skills and non-verbal reasoning that correlates with standard tests of intelligence, such as the Wechsler Intelligence Scale for Children. In addition, RCPM is reported to have minimal cultural bias, and to be capable of evaluating the intellectual status of children exposed to toxic chemicals. The RCPM test involves the matching of pattern constructions of increasing complexity. The patterns increase in complexity as the test progresses, thus providing a simple and standard means of evaluation. On each test page of the RCPM is a single pattern with a missing piece, and a selection of 6 design pieces, one of which will complete the pattern. The child is required to examine the 6 individual pieces and select the appropriate missing piece in order to complete the pattern. This figure shows that as blood lead level (BLL) increases, there is a significant (p = < 0.0001) decrease in RCPM standard decreases. Converting the RCPM standard score to RCPM IQ score showed a 2-point decline in IQ for each 10µg/dL increase in BLL.

Dr. Leo H. Buchanan

RCPM Standard Score

10 9 8 7 6 5 4 3 2 1 0

r = - 0.331 p = < 0.0001 n = 188

0 10 20 30 40 50 60 70 80 90 100

Blood Lead Level (µg/dL)

Counter, S.A., Buchanan, L.H. and Ortega F (2005). Neurocognitive Neurocognitive impairment in lead-exposed children of Andean lead-glazing workers. leadleadJournal of Occupational and Environmental Medicine, 47:306-312. Medicine, 47:306-

La Victoria Area, Cotapaxi Province, Ecuador

This map of the village of La Victoria, and its neighboring communities of El Tejar and El Calvarlo, shows the location of leadglazing baking kilns (ovens) in the backyards of homes. There are about 70 kilns in the La Victoria area. The red squares represent kilns located at houses with children, and the gray triangles show kilns located at houses without children. As can be seen from the map, most homes have lead-glazing baking kilns, and 87% of those homes have children.

Counter, S.A., Buchanan, L.H., Ortega, F., Amarasiriwardena, C., and Hu, H. (2000). Environmental lead contamination and pediatric lead intoxication in an Andean Ecuadorian intoxication village. International Journal of Occupational and Environmental Health, 6: 169-176. Environmental 169-

Dr. Leo H. Buchanan Buchanan

Concentration of Lead in Soil in La Victoria

This figure shows the lead (Pb) concentration in parts per million (ppm) in the soil at La Victoria as function of the distance from a cluster of Pbglazing kilns. The soil is essentially free of Pb at a distance of 6 km (about 3.73 miles) from the kiln cluster. At a distance of 0.001 km (about 3 feet), the Pb concentration of 29,213 ppm would qualify as a hazardous waste site. Children and pregnant women should stay a distance of at least 0.01 km (about 33 feet) from the kilns.

Counter, S.A., Buchanan, L.H., Ortega, F., Amarasiriwardena, C., and Hu, H. (2000). Environmental lead contamination and pediatric lead intoxication in an Andean Ecuadorian village. International Journal of Occupational and Environmental Health, 6: 169-176. Health, 169-

100000 50000 10000 5000 1000 500 100 50 10 5

29213.2

Soil Lead (ppm)

171.6 80.9 55.1 18.8

1.4

1 0.001 0.005 0.01 1 2 6

Dr. Leo H. Buchanan

Distance (km) from Kiln Cluster

Lead Isotope Ratios of the Soil and Children at La Victoria Compared to a Non-lead Exposed Group

This figure compares the lead (Pb) isotopes ratios of the children's blood and the soil in La Victoria (lower part of figure), and that of a non-Pb exposed group of children (upper part of figure). The lead isotope ratio analysis revealed a common source or "fingerprint" of Pb in the soil and blood of the children in La Victoria. This gives us scientific evidence that the children's Pb poisoning is indeed the result of the Pb-glazing activities.

Counter, S.A., Buchanan, L.H., Ortega, F., Amarasiriwardena, C., and Hu, H. (2000). Environmental lead contamination and pediatric lead intoxication in an Andean Ecuadorian village. International Journal of Occupational and Environmental Health, 6: 169-176. Health, 169-

Dr. Leo H. Buchanan

Declining Blood Lead Levels

Blood Lead Level (µg/dL)

This figure shows the decline in blood lead levels (BLL) for the children of La Victoria since we instituted our lead (Pb) education and prevention program. The boxes contain individual PbB levels between the 25th and 75th percentiles. The horizontal lines inside the boxes represent the 50th percentile. The small horizontal lines above the boxes represent the 90th percentile, and the small horizontal lines below the boxes represent the 10th percentile. The individual data points represent cases above the 90th percentile and below the 10th percentile. The box plots in the figure compare the distributions of BLLs for 166 La Victoria children tested between 1996-2000, and 90 La Victoria children tested in 2003. The mean BLL was significantly lower for the children tested in 2003 (t-test, p = < 0.0001). The results indicate that our Pb education and prevention program has achieved a measure of success.

Dr. Leo H. Buchanan H.

120 100 80 60 40 20 0

Reference Group Current Group (n = 90) (n = 166)

Counter, S.A., Buchanan L.H., and Ortega F (2004). Current pediatric and maternal lead levels in blood and breast milk in Andean inhabitants of a lead-glazing enclave. Journal of leadOccupational and Environmental Medicine, 46: 967-973. 967-

Conclusion

· Judging from the declining blood lead levels, and the fact that more villagers appear to be using non-lead glazing compounds, the education and prevention program seems to be working. · However, the children of La Victoria still need to be monitored by the Ecuadorian Health officials.

Dr. Leo H. Buchanan

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