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ENVIRONMENTAL RISK ASSESSMENT ENVIRONMENTAL RISK ASSESSMENT FOR LEAD EXPOSITION IN VETAGRANDE, FOR LEAD EXPOSITION IN VETAGRANDE,
ZACATECAS, MEXICOZACATECAS, MEXICO
DIRECTORATE OF RESEARCH ON CHEMICAL SUBSTANCES AND ECOTOXICOLOGICAL RISKS
INE-SEMARNATMario Yarto-Ramírez; José Castro-Díaz; Arturo Gavilán-García
AUTONOMOUS UNIVERSITY OF ZACATECASRadiobiology Academic EntityEduardo Manzanares Acuña
229th ACS National MeetingMarch 15th, 2005
CONTENTCONTENT
INTRODUCTION
OBJECTIVES
MATERIALS & METHODS
RESULTS
CONCLUSIONS
RECOMMENDATIONS
I
IIIII
IV
V
VI
INTRODUCTIONINTRODUCTIONI
IINTRODUCTION
IIOBJECTIVE
IIIMATERIALS &
METHODS
IVRESULTS
VCONCLUSIONS
RECOMMENDATIONS
VI
INTRODUCTIONINTRODUCTIONI
•Mining in Zacatecas was developed by Mining in Zacatecas was developed by amalgamation from 1546 to 1800 amalgamation from 1546 to 1800 (Ramírez, 1955)(Ramírez, 1955)..
•Tailings were dispersed by rivers and Tailings were dispersed by rivers and deposited in the Zacatecan Valley.deposited in the Zacatecan Valley.
•Some of the contaminated sites are Some of the contaminated sites are currently used for agriculture & currently used for agriculture & residential uses. residential uses.
•Importance was given to the site because of the CEC-NARAP on Importance was given to the site because of the CEC-NARAP on Mercury & the Substance Selection Group (Lead). Mercury & the Substance Selection Group (Lead).
•Previous research has shown that lead is found in higher Previous research has shown that lead is found in higher concentration than other metals in Zacatecas.concentration than other metals in Zacatecas.
MINEMINE
CRUSHINGCRUSHINGSCREENINGSCREENING
AMALGAMATIONAMALGAMATION
DISTILLATIONDISTILLATION
WASHINGWASHING
MAP OF THE STATE OF ZACATECAS
•Vetagrande is a small community that Vetagrande is a small community that grown in the vein of silver minegrown in the vein of silver mine..
•7228 habitants (2526 form 0 to 14 7228 habitants (2526 form 0 to 14 years old). years old).
•Dust from tailings is carried out by wind Dust from tailings is carried out by wind and small particles are deposited within and small particles are deposited within the town or breathed/ingested by the the town or breathed/ingested by the populationpopulation..
•Houses in Vetagrande have soil floors Houses in Vetagrande have soil floors with high concentration of lead & streets with high concentration of lead & streets are not paved. are not paved.
•Risk groups comprises children & Risk groups comprises children & pregnant women.pregnant women.
Mexican regulation (NOM-199-SSA1-2002) establishes a maximum permissible level of lead in blood of 10 g/dL, for children & pregnant & lactating women.
For the rest of the population a maximum permissible level of lead in blood of 25 g/dL was established.
There are no Mexican regulations for lead concentration in soil.
EPA established a recommended concentration of lead of 400 g/g for residential use.
In 2002, INE & UAZ developed a study titled:
DETERMINATION OF LEAD IN BLOOD OF CHILDREN & PREGNANT WOMEN IN VETAGRANDE, ZACATECAS
Blood sampling: 30 children > 15 years 13 pregnant women
Analysis: Flame Atomic Absorption Spectrometry (FLAAS).
Results: Lead mean concentration in blood of children: 15.7
7.1 mg/dL Lead mean concentration in blood of pregnant
women: 11.2 8.5 mg/dL
OBJECTIVESOBJECTIVESII
To identify the health and environmental risk by sampling the houses indoors and throughout the natural floodlands within the town, as well as a risk characterization to identify bioavailability and exposition routes (using data from blood levels of lead). With this information, strategies are to be proposed to reduce environmental impact in the town.
IINTRODUCTION
IIOBJECTIVE
IIIMATERIALS &
METHODS
IVRESULTS
VCONCLUSIONS
RECOMMENDATIONS
VI
MATERIALS & METHODSMATERIALS & METHODSIII
Soil sampling:
89 sites were sampled within the town at 2.5 cm depth. Analysis was developed by X-Ray Dispersive Energy
Spectrometry and were validated by Atomic Absorption Spectrometry.
Quality control was developed by using certified standards (NIST & NBS).
Number of samples was calculated by assuming that: Infinite number of possible samples. 50% of samples with higher concentration than 400 µg/g. 95% confidence.With this, the number of samples was calculated: 73
samples.
IINTRODUCTION
IIOBJECTIVE
IIIMATERIALS &
METHODS
IVRESULTS
VCONCLUSIONS
RECOMMENDATIONS
VI
RESULTSRESULTSIV
IINTRODUCTION
IIOBJECTIVE
IIIMATERIALS &
METHODS
IVRESULTS
VCONCLUSIONS
RECOMMENDATIONS
VI
CONCENTRATION OF LEAD IN SOIL
CONCENTRATION OF LEAD IN SOIL
Lead concentration ranges from 8 to 7730 µg/g.
Mean concentration is 1397 ± 86 µg/g.
% of total number of samples
Range (µg/g) Mean
(µg/g)
28.1 8-398 136 ± 104
20.2 400-800 607 ± 107
14.6 805-1141 944 ± 109
10.1 1247-1551 1401 ± 98
6.7 1715-1936 1825 ± 82
20.2 2102-7729 4123 ± 1952
11.23% of samples were taken at the kinder garden & a mean concentration of 1901 µg/g was found.
gstat: Win32/MinGW version 2.4.1 (12 March 2003), Copyright (C) 1992, 2003 Edzer J. Pebesma
CONCENTRATION OF LEAD IN BLOOD
Vetagrande, Zacatecas
Category II (10 - 14 μg/dL)
Category III (15 -24 μg/dL)
Category IV (25 - 44 μg/dL)
Kinder
Museo Comunitario
Presi
denci
a
CONCLUSIONSCONCLUSIONSV
IINTRODUCTION
IIOBJECTIVE
IIIMATERIALS &
METHODS
IVRESULTS
VCONCLUSIONS
RECOMMENDATIONS
VI
Lead in soil
1. According to this study, lead concentration in soil ranges from 8.0 to 7730 (µg/g) & a mean concentration of 1397 ± 86 µg/g which is higher than the recommended concentration for residential soil according to EPA (400 µg/g). This rises a potential risk for the population of the town while no speciation has been developed in the site.
2. Soil pollution can be associated to ancient mining activities, and no clear relationship is observed to current mining activities.
3. Several cases for high lead levels in blood were identified but no correlation was identified between lead in soil vs lead in blood. This can be related to different factors such as alimentation, drinking water pollution or bioavailability of contaminants in soil.
RECOMMENDATIONSRECOMMENDATIONSVI
IINTRODUCTION
IIOBJECTIVE
IIIMATERIALS &
METHODS
IVRESULTS
VCONCLUSIONS
RECOMMENDATIONS
VI
HealthHealth
Improve dietetics & nutritional habits within the population such as:
Glazed pottery usage.
Ingestion of dirt by hand-mouth mechanism.
Personal hygiene.
Consumption of food products that reduce assimilation of lead.
Establishment of a monitoring strategy of lead levels in blood for pregnant women & children.
EnvironmentEnvironment Identify other routes of entry to the organism such as
respiratory, ingestion of contaminated water, consumption of contaminated crops &/or meat.
Improve reforestation in the zone with endemic species to avoid generation of dusts.
Covering of the tailings with gravel or other materials to avoid spreading of such materials.
Improve urbanization in the town by paving the streets, paving the houses indoors & schoolyards, avoid contact with tailings deposited in the nearby.
Complete the study by analyzing the chemical species of lead in the contaminated area to identify the bioavailability of this contaminants to quantify the health risks & further remediation activities.
