Environmental mercury pollution in Nicaragua; Xolotlán Lake a case of pollution.

Francisco J. Picado PavónResearch Center for Aquatic Resources of NicaraguaNational Autonomous University of Nicaraguafrancisco.picado@cira.unan.edu.ni

Cosigüina (1859)

Momotombo (2015)El Hoyo

San Cristóbal (2012)Telica (2015)

Cerro Negro (1999)

Apoyeque

Masaya (Continuing)Apoyo

Mombacho (1570)Zapatera

Concepción (2009)

Maderas

Nicaragua main Volcanoes

Worldwide flux of Hg from volcanic eruptions is ̴ 57.0 t/year

Worldwide flux of Hg from degassing activities is 37.6 t/year

1980-2000 (20 year)Total global flux of Hg to the atmosphere is ̴

112 t/year(Nriagu and Becker, 2003)

0 20 40 60 80 100

Africa

Europe and western Asia

Japan +northern Asia

Australia

North America + Hawaii

Southeast Asia

South and Central America

Worldwide

Regional average of Volcanic Hg emissions (t/year) between 1980 and 2000 

(Nriagu and Becker, 2003)

Volcanic Hg emissions (t) between 1980‐2000

Cosigüina

Momotombo (0.010)El Hoyo

San Cristóbal (0.472)Telica (0.144)

Cerro Negro (0.015)

Apoyeque

Masaya (22.7)ApoyoMombacho

Zapatera

Concepción

Maderas

• Hg concentrations in the plumewere above background andranged up to 350 ng/m3

• TGM concentrations range from100 to 225 ng/m3

• RGM accounted for 1% of TGM,and TPM is ̴ 5% of the TGM

• Hg flux from Masaya of 7.2t/year) (Witt et al, 2008;University of Oxford, 2008, June30)

The Hg emissions from Nicaraguans volcanoesaccounts for 25% of worldwide Hg volcanicemissions (Nriagu and Becker, 2003)

0,05%

Anthropogenic Hg emissions to the atmosphere 2010 (AMAP/UNEP, 2013)

Xolotlán Lake a case of pollution

To assess the current Hg concentrations in Xolotlán Lake for continue benefiting from its hydrobiological resources.

Objective

Nicaragua government aims for strengthening capacities for Hg analysis

Economic support of the Japanese government through the Japan International Cooperation Agency (JICA) and the Nicaraguan counterpart

Before laboratoryimprovement

After created the conditions and equipped the laboratory

Strengthening capacities for Hg analysis at NIMD, Japan

Strengthening capacities for Hg analysis at EML, Nicaragua

Sampling (water, sediment and fish)Februray, 2016 June, 2016 September 2016 – February, 2017 (Chlor Alkali production facility)

Laboratory analysesDTHg and PTHg (water)THg (sediments)THg (fish)

Quality Control AssuranceDuplicatesBlanksCotrol SamplesCRMsInter laboratory comparison

GuidelinesCanadian Environmental QualityGuidelines for (water and sediment)International (fish)

Sampled sites at Xolotlán Lake, 2016.

San Fco Libre

La Bocana de Tipitapa

Chlor Alkali production facility

Collected samples at Xolotán LakeFirst

sampling(Feb.2016)

Secondsampling

(Jun.2016)

Sediment samplingat polluted site

(Dic.2016-Feb.2017)

Surface water 35 34 ‐‐‐Depth water 18 18 ‐‐‐Surface sediment 11 14 72

Guapotes (146)Mojarras (215)Guabinas  (194)Tilapias (74)

Quality Control AssuranceFebruary 2016 Water

(ppt)Sediment (ppm) Fish

(ppm)

CertifiedValues→(

BCR579(1,9 ± 0,5)

IAEA‐158(0,132 ± 0,014)

DORM II(4,64 ± 0,26)

LaboratoryResults→(

1,85 ± 0,40  0,132 ± 0,007  4, 78  ± 0,04 

Laboratorio de Mecurio Ambiental, CIRA/UNAN‐Managua. 2016

June 2016 Water(ppt)

Sediment(ppm)

Fish(ppm)

Certified Values→(

BCR579(1,9 ± 0,5)

IAEA‐158(0,132 ± 0,014)

DORM II(4,64 ± 0,26)

LaboratoryResults→(

2,28 ± 0,13  0,131 ± 0,009  4, 72  ± 0,09 

Laboratorio de Mecurio Ambiental, CIRA/UNAN‐Managua. 2016

No statistic difference (p=0.52, α=0.05) of the total dissolved Hg concentrations was observed between sampling campaigns, but significant difference (p = 0.03, α= 0.05) was observed in the values of concentration of particulate Hg.

The few data of Hg concentrations exceeding the Canadian values for aquatic life protection (water=26.0 ng/l, sediment=0.17 μg/g) were observed close to anthropogenic or natural Hg sources.

Recognition Sampling for Sediment at most polluted area of Xolotlán Lake. September 2016. THg (mg/kg)

14.6916.6813.6220.15.370.850.870.781.061.061.230.92

Protection of aquatic lifeCEQGs Sediment (ppm) = 0,17

Total Hg concentrations (mg/kg) in surface sediments from pollutedsite of Xoltlán Lake (Chlor Alkali production facility), December 2016.

Protection of aquatic life

CEQGs Sediment (ppm) = 0,17

THg concentration (mg/kg wet wt.)

All fishFish from two fishing villages

San Francisco Libre La Bocana de Tipitapa

Fish n Min. Max. Prom n Min. Max. Prom n Min. Max. Prom

Guapotes 146 0,109 1,020 0,465 109 0,109 1,020 0,473 37 0,175 0,897 0,442

Mojarras 215 0,008 0,658 0,251 101 0,013 0,620 0,299 114 0,008 0,658 0,209

Guabinas 194 0,080 0,454 0,230 101 0,121 0,454 0,248 93 0,080 0,427 0,209

Tilapias 74 <LD 0,062 0,018 68 <LD 0,062 0,018 6 <LD <LD <LD

Total 629 379 250

Total mercury concentration (ppm) in four especies of edible fishfrom Xolotlán Lake

<LD: Less than Detection limit (0,001 mg/kg); n: number of analyzed fish.

Total Hg concentration (mg/kg wet wt.) in four edible fish fromXolotlán Lake. 2016

19.1% of all four studied species is above 0.40 μg/g, the recommended concentration for fish consumption in Japan.

The average total Hg concentrations in fish was: Parachromismanaguensis, Parachromis dovii(0.46 μg/g) > Amphilophus citrinellus(0.25 μg/g) > Gobiomorus dormitor(0.23 μg/g) > Oreochromis niloticus, Oreochromis mossambicu, Oreochromis aureus (0.02 μg/g)

The low bioavailable mercury aqueous concentrations suggest that fish Hg intake occurs mainly through food chain.

Sediments are an important source of mercury for aquatic food chain in Xolotlán Lake.

Current Hg content in edible fish indicates a bioaccumulation that in the future could increase and consequently turn a threat whether people increase the consumption of these fish.

A multimedia Hg monitoring, including Hg speciation, of Xolotlán Lake is needed.

Conclusions

References

• Jerome Nriagu and Christian Becker, 2003. Volcanic emissions of mercury to the atmosphere: global and regional inventories. The Science of the Total Environment. 2003: 304: 3–12.

• AMAP/UNEP, 2013, Technical Background Report for the Global Mercury Assessment 2013, Arctic Monitoring and Assessment Programme, Oslo, Norway/UNEP Chemicals.

• University of Oxford. (2008, June 30). Volcano 'Pollution' Solves Mercury Mystery. ScienceDaily. Retrieved September 17, 2018 from www.sciencedaily.com/releases/2008/06/080629081932.htm

• Witt, M. L. I., T. A. Mather, D. M. Pyle, A. Aiuppa, E. Bagnato, and V. I. Tsanev (2008), Mercury and halogen emissions from Masaya and Telica volcanoes, Nicaragua, J. Geophys. Res., 113, B06203, doi:10.1029/2007JB005401.

• Reporte técnico: Estado actual de la contaminación por Mercurio del Lago Xolotlán y evaluación de riesgos para la salud de los habitantes por la exposición al Mercurio. Proyecto para el fortalecimiento de capacidades en el estudio y análisis de Mercurio en la república de Nicaragua, Agosto, 2017.