Mongolia Boroo Mercury (Hg) spill site Investigation Results [UNIDO Reduce Exposure of Mercury Project]

Transcription

1 Mongolia Boroo Mercury (Hg) spill site Investigation Results [UNIDO Reduce Exposure of Mercury Project] August 22(FRI), 2014 MIRECO

2 Field Investigation & Sampling Site Abstract Location : Tailing Dam and Streams around Boroo of Mongolia(120km from UB) The government of Mongolia investigated the mercury contamination in Boroo in 2008, and took out the soil of main polluted area and buried on the outside. As the survey area was gold production place in the past, there are 2 gold dressing structures abandoned and tailing & soil are forming two-layered < Processing facility > < Tailing sample>

3 Field Investigation & Sampling Survey Abstract When : 18 th ~ 22 th in April, 2014 Investigator: Korean experts 6, Mongolian Expert 1 etc. total 10 Location : Tailing dam and water system along the downstream by 6km contents Investigation and Confirmation of Tailing zone & surrounding environment Sampling of water, regosol(river deposit soil) and soil from tailing dam (topsoil : 0~30cm, subsoil : 30~60cm) Indirect inquiry investigation to the residents around tailing dam and streams <Identification the boundaries> <Sampling of Soil & Water> < Inquiry investigation >

4 Field Investigation & Sampling Tailing dam and surroundings Difficult to check the tailing field by eye sight, except a little exposure of tailing Tailing layer under about 20~40cm from the surface, Maximum thickness : 20cm Tailing is orange colored, consisted of clay and with high moisture content Plants grow on the topside of tailing dam, livestock eat plants and drink leachate Main kinds of livestock living in the site are investigated as horses, cows and pigs The residents have cultivated potato and wheat using water of Boroo river < Exposure of Tailing > < livestock drinking tailing dam s water > < Farmland & water system near tailing dam >

5 Field Investigation & Sampling Confirmation of tailing field River Boroo divided into several streams passing thorough the tailing dam, it is assumed as one of causes to spread contaminant materials Clear confirmation of tailing field by trench investigation & identification of tailing-exposed area Tailing mainly distributes around the processing facilities in a shape of oval Wide distribution of the tailing is caused by the events of streams flooding that caused tailing around the processing facilities to be washed off < Investigation of present-condition > < Confirmation of tailing layer > < Trench investigation >

6 Field Investigation & Sampling Confirmation of tailing field Confirmation of tailing field by trench investigation and checking the tailing -exposed area : approximately 450m x 460m (total area : 8ha) Based on the water system, divided into 3 districts of Zone A, B, C Processing facilities Zone B Zone A Approx. 460m Zone C Approx. 450m Tailing field

7 Field Investigation & Sampling Sampling points in Tailing Dam upstream Processing Facilities Zone B Zone A < Sampling in tailing dam > upstream : Soil sampling spot (total 92) Zone A : total 40spots Zone B : total 24spots Zone C: total 28spots : Tailing sampling spot (total 3) Zone C downstream downstream < Setting up the grid 40X40 > < Subsoil(60cm) containing tailing >

8 Field Investigation & Sampling Sampling of water & soil Sampling of water & soil in cultivated land and regosol(river deposit soil) in distance of 6Km from the tailing dam at 500m equidistant intervals upstream Tailing dam 1km 2km 3km legend Water sampling (14) Tailing dam leachate sampling (2) Sampling river deposit soil (14/28) Sampling soil of cultivated land (3/6) (Crops of cultivation : Wheat) 4km 5km 6km downstream

9 Field Investigation & Sampling Field measurement (7items) : temperature, ph, ORP, EC, DO, turbidity, alkalinity ph is alkaline(average:8.94) / High EC(Average:1,102uS/cm) / High Alkalinity (Average:over187), AssumptionⅠ : the area has high content of alkaline materials CaCO 3, NaCl in the water * General value in natural river ph : approx. 7.0 / EC : approx. 500uS/cm / Alkalinity : below 50 Name Location Temperature ph EC(uS/cm) ORP(mv) Do(mg/l) turbidity Alkalinity W-1 Inter water , W-2 Leachate W-3 Sampling of water & soil AssumptionⅡ : Most heavy metal ions are deposited on the river bed because of high PH. -It can explain that the concentration of heavy metals of regosol is higher than the value of river tailing dam Leachate , W-4 Confluence , W-5 500m , W-6 1,000m , W-7 1,500m , W-8 2,000m , W-9 2,500m , W-10 3,000m , W-11 3,500m , W-12 4,000m , W-13 4,500m , W-14 5,000m , W-15 5,500m , W-16 6,000m , Average ,

10 Results of Sample Analysis Analysis subject & Instrument Soil and tailing sample Mercury analysis : Analysis using EPA 7473 method - Heavy metal analysis : As, Cd, Cu, Pb, Zn etc. using ICP to calculate total content Mine drainage sample Ultimate analysis(18 elements) : Hg, Al, As, Cr, Cu, Fe, Li, Mn, Ni, P, Pb, Se, Sr, Cd / ICP Cation(4 elements) : Na +, K +, Ca 2+, Мg 2+ / ICP Anion(7 elements) : F -,CI -, NO 2-,Br -, NO 3-, PO 3-4, SO 2-4 / IC Request analysis of samples to Soil and water quality MNS certification authority in Mongolia Mercury analysis equipment ICP equipment

11 Results of Sample Analysis Results of Soil Sample Analysis Reference Value : The maximum value of a substance contaminating soil, water 5 of heavy metals except Arsenic(As), Average is above Trigger value Regarding Arsenic(As), exceeding Trigger value higher than 90 times, the most contaminated Regarding Lead(Pb), total 184 samples from 92 sampling points, No sample exceeding Trigger value / Only 2 samples exceeding Precaution value Regarding (Zn) & Copper(Cu), total 184 samples from 92 sampling points, No sample exceeding Reference value (Scale : mg/kg) Categories Hg As Cd Cu Pb Zn Precaution Value Trigger Value Action Value ,000 1,200 1,000 Average Maximum Value , Minimum Value

12 3. Results of Sample Analysis Mercury(Hg) distribution in tailing field(1) Regarding Topsoil, most of concentration values are below Trigger value, except only one point in zone A exceeding reference value. Regarding Subsoil, the concentration values of some part of zone A exceed Trigger value, whereas the values of the other are below Trigger value Processing facilities Zone A Processing facilities Zone A Zone B Zone B Upstream Upstream Legend Land Zone C Down stream Legend Zone C Down stream < Hg distribution (Topsoil) > < Hg distribution (Subsoil) >

13 Results of Sample Analysis Mercury(Hg) distribution in tailing field(2) Regarding both Top & Sub soil, only values of Zone A exceed Trigger value Mercury distribution in Zone B, C is almost constant, Whereas Zone A shows irregular values from high to low concentrations Regarding Zone A, different from Zone B, C, there must be another contaminant on the outside with high concentration of Hg Target area of restoration is the soil of highly contaminated part & the soil of contaminated surroundings in Zone A : approx. 1.8ha in total Processing facilities Zone A Processing facilities Zone A Total area : 1.8ha Zone B Zone B Upstream Upstream Legend Zone C Legend Zone C Down stream Down stream < Hg distribution at each point > < Sum(Topsoil + Subsoil) Hg distribution >

14 Results of Sample Analysis Arsenic(As) distribution in tailing field(1) Regarding Topsoil, the area of zone A exceeding Trigger value is wider than B, C Regarding Subsoil, the As values of the almost every point(approx. 95%) are high exceeding Trigger value Arsenic highly contaminated area(blue) is distributed from the processing facilities to the downstream Processing facilities Processing facilities Upstream Zone B Zone A Upstream Zone B Zone A Legend Zone C Down stream Legend Zone C Down stream < As distribution (Topsoil) > < As distribution (Subsoil) >

15 Results of Sample Analysis Arsenic(As) distribution in tailing field(2) Since long period operation of Au processing facilities, Arsenic constantly accumulated so that top & subsoil of almost every area has been severely contaminated Tailing in front of processing facilities have been washed off by river flooding so that Arsenic highly contaminated soil is discovered along the downstream (following arrows) Restoration area concerning Arsenic value above Trigger value is approximately 7.1 ha Processing facilities Zone A Processing facilities Zone A Zone B Upstream Zone B Upstream Legend Zone C Legend Zone C Down stream Down stream < As distribution at each point > < Sum(Topsoil + Subsoil) As distribution >

16 Results of Sample Analysis Cadmium(Cd) distribution in tailing field(1) Cadmium(Cd) highly contaminated area is distributed around the processing facilities and continuously contaminated along the downstream Contaminated Subsoil above Trigger value is about 20% wider than Topsoil Cadmium(Cd) Highly contaminated area distribution is similar with the distribution of Arsenic contaminated Subsoil Processing facilities Processing facilities Zone A Zone B Zone A Zone B Upstream Upstream Legend Down stream Legend Zone C Down stream Zone C < Cd distribution (Topsoil) > < Cd distribution (Subsoil) >

17 Results of Sample Analysis Cadmium(Cd) distribution in tailing field(2) Regarding Cadmium(Cd), same as Arsenic(As), highly contaminated area is distributed from the processing facilities to the downstream In the same vein of Arsenic(As), Cadmium(Cd) highly contaminated soil is discovered along the downstream of river because of tailing washed off from processing facilities by water flooding Restoration area concerning Cadmium value above Trigger value is approximately 1.5 ha Upstream Processing facilities Zone B Zone A Upstream Zone B Processing facilities Zone A Legend Legend Zone C Down stream Zone C Down stream < Cd distribution at each point > < Sum(Topsoil + Subsoil) Cd distribution >

18 Results of Sample Analysis Restoration Area & Restoration Volume This area is judged to implement the soil contamination restoration concerning Mercury(Hg), Arsenic(As) and Cadmium(Cd) Regarding each area, Zone A is in need of the restoration concerning Hg and Cd, whereas Zone B, C are in need of the restoration concerning As and Cd The total restoration area is approx. 1.8ha (regarding As : 7.1ha, regarding Cd : 1.5ha) As contaminated area almost includes the area contaminated by Hg and Cd If the object of restoration is restricted to Hg, restoration area is approx. 1.8ha in Zone A Heavy metal element Mercury(Hg) Arsenic(As) Cadmium(Cd) Remark Restoration Area(m 2 ) 18,000 71,000 15,000 Exceeding Trigger value Restoration Bulk Volume(m 3 ) 10,800 42,600 9,000 Subsoil standard : 0.6m Restoration Bulk Volume is calculated by applying the maximum depth of subsoil(=0.6m)

19 Results of Sample Analysis Analysis of Tailing Sample In every sample, As & Cd concentration exceed Trigger value, especially in case of Arsenic, the average concentration is very high 2,950ppm Pb & Hg concentration of few samples exceed Precaution value, yet below Trigger value Hg concentration is more below than the average Hg concentration(a1~a20 : 4.49ppm) the restoration area in Zone A (1.8ha) Possibilities in the presence of other contaminants which have caused the high concentration of mercury(hg) in zone A Additional survey is needed to figure out the source of severe Hg pollution in Zone A Heavy Metal Element Reference value Copper (Cu) Cadmium (Cd) Lead (Pb) Arsenic (As) Zinc (Zn) (Scale : mg/kg) Mercury (Hg) Precaution value Trigger value Tailing (zone A) Tailing (zone B) Tailing (zone C) The average

20 Results of Sample Analysis Analysis of Regosol, Cultivated Land (Hg) Hg & As concentration exceed Trigger value, the other heavy metal elements show below the reference value Regarding Mercury(Hg), 7 points of topsoil, 5 points of subsoil exceed Precaution value, no sample exceed Trigger value If overlap the contaminated area of Topsoil and Subsoil, 9 points of regosol sample are contaminated by Hg, the other samples are not contaminated <Status of Contamination(Topsoil)> <Status of Contamination(Subsoil)> <Status of Contamination(Overlapped>

21 Results of Sample Analysis Analysis of Regosol, Cultivated Land (As) Regarding Arsenic(As), Topsoil of 13 points(10 points above Precaution value, 3 points above Trigger value) and Subsoil of 12 points(9 points above Precaution value, 3 points above Trigger value) exceed reference value If overlap the contaminated area of Topsoil and Subsoil, 15 points(10 points above Precaution value, 5 points above Trigger value) exceed reference value Regarding Arsenic(As), 2 points in cultivated land exceed Precaution value In the case of Cultivated Land 1&3, Arsenic contamination must have been caused not by residential water but by Small-scale gold mining in form of ninja <Status of Contamination(Topsoil)> <Status of Contamination(Subsoil)> <Status of Contamination(overlapped)>

22 3. Results of Sample Analysis Analysis of Water Sample Reference values for judgment of water contamination are applying The maximum allowance of contaminants in natural water and The maximum allowance of contaminants in ground water Reference Value Al As Cu Hg F - NO 2- Br - Ground water Underground water All analysis elements(29 in total) are detected below reference value except 6 elements including Arsenic(As), Copper(Cu), Arsenic(Al), Fluorine(F - ), Nitrous acid(no 2- ), Bromine(Br - ) Mercury(Hg) is not detected in every points, besides As, Cu, Al which exceed the reference value are detected in tailing dam but not in water samples It is a contrast from the fact that Heavy metals are detected in every regosol(river deposit soil) samples, and it is assumed that heavy metal ions are deposited on the river basin, caused by high ph(the average 8.94) Fluorine(F - ) values exceed the reference value in every points, therefore it is assumed that the site is situated near the Fluorspar mineralized zone Affected by geological reason of mineralized zone, Alkaline materials e.g. CaCO 3 and NaCl are high-concentrated in the water, therefore the water is strongly alkaline

23 Results of Sample Analysis Contamination Status at Sampling Points <Status of Contamination(As)> <Status of Contamination (Al)> <Status of Contamination (Cu)> <Status of Contamination (F - )> <Status of Contamination (NO 2- )> <Status of Contamination (Br - )>

24 Indirect Inquiry Investigation & Epidemiological Survey Indirect inquiry investigation Purpose : To secure the basic information around tailing dam in boroo Date : Research area : Around tailing dam and the downstream of river boroo Research subject : total 15 people(men 9, women 6) Result of general research Total residents Average residence period Average age Main job Main drinking water resource Availability of boroo river occurrence of disease recognition of mercury exposure 54 9 years 48 year farming, livestock Underground water 80% 30% 60% Resident indirect inquiry investigation

25 Indirect Inquiry Investigation & Epidemiological Survey Indirect inquiry investigation Result of investigation concerning livestock Most of livestock are fed herbs near river boroo and residents eat them. If the boroo river is polluted by heavy metals, residents can be higher probable to accumulate heavy metals in their bodies Livestock retention ratio Type of breed livestock Average Number Average Scale of pasture Main feed of livestock Purpose of farming Sudden death 73% cow, horse, lamb, goat, pig 309 Within a 7.6Km radius of boroo river Surrounding herbs sell / Self-edible 3 cases Result of investigation concerning the agriculture when cultivating farmland, they are using and drinking a water of boroo river if the water is polluted by heavy metals, residents can be higher probable to concentrate the body of heavy metals Percentage of agriculture Main crops Average farm scale Average location of farmland Purpose of agriculture 33% Wheat, potato 326ha Within 10Km from river boroo sell / self-edible Result of other investigation Batsuh who lives near river boroo, has worked alluvial mining for 10 years. But his wife gave birth disabled child and had a miscarriage one child. (it is judged that it has high probability with concentration in a body heavy metals)

26 Indirect Inquiry Investigation & Epidemiological Survey Abstract of Epidemiological Survey Purpose Through investigation of Hg concentration of the residents and livestock, disease occurrence and heavy metal concentration, we will analyze mercury contamination & Casual relations between residents and livestock Location Around river Boroo, Mandal sum, Selenge aimag, Mongolia Contents of investigation Examine current status of the surrounding environment of the river Boroo Select object for ecotoxicological evaluation & analyze sample - Targets : residents, livestock living near downstream of water system in a distance of 6 km and tailing dam - Sampling : hair, blood of Livestock and Residents Evaluate health risk through the analysis of heavy metal and Hg

27 Indirect Inquiry Investigation & Epidemiological Survey Results of Epidemiological Survey Blood & Urine sampling of 50 residents & Heavy metals concentration analysis(hg, Pb, As) Psychiatrist test people whether they are having the problems in the central nervous system(mental problems, speech disorder etc.) caused by mercurial poisoning In survey, describe personal data(e.g. ages, name, residence) in detail Except the residents who have lived for less than 1 year Germany HBM(Human BioMonitoring) is used as Reference value of Hg & Pb, In case of As, Korean Industrial Safety and Health Act is used (scale : ppm) Type Reference value Mercury(Hg) Lead(Pb) Arsenic(As) Blood Urine Blood Blood Remarks Hg, Pb : HBM in Germany As : Korean Industrial Safety and Health Act * HBM(Human BioMonitoring) : Reference values proposed by Germany, for the ordinary people and children/the elderly exceeding HBM values might cause bad impact on health

28 Indirect Inquiry Investigation & Epidemiological Survey Results of Epidemiological Survey Heavy metal accumulation in the body of most residents shows below reference value There is no one exceeding reference value of all farmers and the people who engage in stockbreeding (41) (51 residents in total) Most heavy metals transferred along the water stream have been deposited, therefore it didn t affect seriously the residents and livestock Contamination of farmland using water in river Boroo is also not so severe Hg accumulation in the bodies of 4 people exceeding reference value of all people who engage in Small-Scale-Mining(10 in total), especially 2 of them have urine test results exceeding reference value In the blood test, Hg concentration(0.0837ppm) is approx. 16.7times higher than reference value, and in urine test, the result(0.2695ppm) shows approx. 10.8times higher In the Small-Scale-Mining, Gold screening process is assumed to cause the Hg accumulation in the bodies No one shows distinctive behaviors or symptoms of nerve disorders and skin diseases affected by Mercury(Hg) or Arsenic(As)

29 Indirect Inquiry Investigation & Epidemiological Survey Results of Epidemiological Survey Blood collection of 50 livestock and Analysis of the concentration of 3 heavy metals(mercury(hg), Lead(Pb), Arsenic(As) etc.) Target livestock are cows(10), goats(18), sheep(21) and horse(1) etc. No reference value to evaluate the accumulation of heavy metals, therefore use the reference value for human Heavy metal accumulation in the body of livestock shows below reference value Most results have the value below 10% of reference value, therefore the heavy metal accumulation in the plants can be judged to be below reference value Therefore Heavy metal accumulation in the body of human by eating livestock assumed to be limited, because heavy metal accumulation in the body of livestock shows below reference value. Besides, the result of blood test for residents prove it

30 Conclusions Conclusions Total contaminated area with tailing in Boroo is approximately 7.5ha(75,000m 2 ) Hg contaminated area is approx. 1.8ha(18,000m 2 ), the bulk volume is approx.10,800m 3 Hg, As and Cd exceed the reference value, and the contaminated area by Arsenic(As) exceeding Trigger value is approximately 95% of total area (7.1ha=71,000m 2 ) In regosol(river deposit soil), Mercury(Hg) and Arsenic(As) are discovered, especially in case of Arsenic, its values exceed Trigger value In water from river, Heavy metal elements are not detected, assumed that it is because of high ph(average 8.94) As a result from epidemiological survey, Heavy metal accumulation in the body of most residents shows below reference value, whereas ninjas are assumed to be directly affected by Mercury(Hg) exceeding Trigger value This result is assumed to be caused by low eating rate of fish in Mongolia