5 methods of environmental monitoring

Bohdan Kříbek, Vladimír Majer, Ilja Knésl, Jan Pašava Czech Geological Survey, Klárov 3, 118 21 Prague 1, Czech Republic

e-mail: [email protected]

Vojtěch Ettler, Martin Mihaljevič Institute of Geochemistry, Mineralogy and Mineral Resources, Faculty of Science, Charles

University, Albertov 6, 128 43 Praha 2, Czech Republic

Ondra Sracek Department of Geology, Faculty of Science, Palacký University, 17. listopadu 12, 771 46

Olomouc, Czech Republic

Methods of environmental monitoring in mining areas: The Zambian Copperbelt Case Story

IGCP/SIDA 594 Training course, University of the Witwatersrand, Johannesburg, July 13-15, 2013

P ala ck y U niv e rs it yO lom o uc

mailto:[email protected]


One of the tools enabling to assess the effect of mining and mineral processing on the environment and human health is

environmental-geochemical monitoring

Regional environmental-geochemical mapping and monitoring involve in particular:

The localization and identification of the sources of contamination

The elucidation of the mode of contaminants spreading

The determination of areal extent and intensity of contamination

The estimation of harmful properties and biotoxicity of contaminants

The proposal for application of the most efficient methods to

improve land remediation and land-use planning


SOURCES OF ANTHROPOGENIC CONTAMINATION IN MINING AREAS

Industrial water discharged into the watercourse

Erosion and washout of fine-grained particles from spoil banks

and tailing impoundments (siltation)

Seepage and owerflow from tailing impoundments

Dust from mining operations, processing plants and slag deposits

Gaseous and solid emissions from smelters

Soils and Plants:

Surface Waters and Stream Sediments

Dust from dry parts of tailing impoundments

Transport of concentrate and products


ROUTES OF POLLUTANTS INTO ENVIRONMENT IN MINING DISTRICTS

Atmosphere

Hydrosphere

Terrestrialsystems

(soil, plants)

Mining operations

Vaste heaps

Vaste heaps

Ore crushing andgrinding

Thickeners Flotation

Tailings

Tailings

Roasting,Smelting

ReprocessedSlag

Chemicalrafination

Mine waterChemical weathering,Suspensionwash-out

Dust

Suspensionoverflow

Dust

Water andsuspensionsoverflow, seepage

Dust,SO2, NOx

Technologicalsolutions

Dust fallout

Winderosion

Runoff, Throughflow

Irrigation

River outflow

?

Legend:

Very important flow

Less important flow

Important flow

Inflow from non-contaminatedcatchements

Rootuptake

Throughflow

Stream flow Deep percolation

Decomposion

Mineralisation

Throughfall

Stem flow

Runoff

Dust fallout

Canopy deposition

Inflow from natural sources(forest fires, volcanoes)

Inflow from anthropogenic sourcesnot related to mining (road traffic)

Inflow from man-made sources(fertilizers, municipal sewage)

Dust


SOURCES OF ANTHROPOGENIC CONTAMINATION IN MINING AREAS - DUST

Sandstorm over a dry beach of the Mindolo impoundment, Copperbelt, Zambia, Zambia

Sandstorm over the Mufulira impoundment

Sandstorm over a dam of the Muntimpa impoundment, Zambia


SOURCES OF ANTHROPOGENIC CONTAMINATION IN MINING AREAS - SEEPAGE

Chambishi tailing pond seepage, Chambishi, Zambia

Muntimpa tailings pond seepage, Zambia

Chalcantite and gypsum precipitates,

the Uchi River, Kitwe, Zambia


SOURCES OF ANTHROPOGENIC CONTAMINATION IN MINING AREAS - SILTATION

Collapse of the Luanshya tailings dam, Copperbelt, Zambia

Siltation of the Chingola River, Chingola, Zambia


SOURCES OF ANTHROPOGENIC CONTAMINATION IN MINING AREAS – TECHNOLOGICAL WATERS FROM CHEMICAL LEACHING PLANTS

Chibuluma- South II Open Pit

Technological water from the Nkana Smelter and Processing Plant

Chambeshi River, whitish precipitates of carbonates and gypsum, efluents from the Chambishi Chemical Plant


BOX 1 Soil sampling

• Each soil sample is a composite of 3-5 sub-samples collected from sampling sites located at the distance of 10-20 m from each other. Soil samples may be collected from soil pits or using soil auger.

• Two different depth-related samples should be collected:

(1) A topsoil sample from the 0 to 25 cm depth (excluding material from the organic-rich

layers where present) and,

(2) lower soil (subsoil) sample from a 25 cm thick section within a depth range of 50-100 cm.

• Comparison of topsoil and subsoil data gives information about enrichment or depletion processes between soil layers.

• Topsoil and subsoil samples (0.5-1 kg) have to be dried on paper or plastic dishes and sieved using plastic sieving set equipped with nylon mesh (2 mm). The < 2mm fraction (50-100 g) is recommended to homogenize in agate ball mill to analytical fineness (< 0.063 mm)

• Recommended soil sampling density for local phase of survey: 1 – 10 samples for km2

• Recommended soil sampling density for detailed phase of survey: 10 – 100 samples for km2


SOIL SAMPLING

Sampling of subsurface soil with soil auger

Silty surface layer

Layer with high content of metals

Silty to clay-rich layerwith remnants of roots

Laterite

Soil profile


SOIL SAMPLING

0

5

10

15

20

25

30

35

40

0 10 20 30 40 50 60 70 80

Co - surface soil (ppm)

Co

- s

ub

su

rfa

ce

so

il (

pp

m)

1 : 1

Distribution of metals in soils

– Surface vs. sub-surface soil concept

Higher concentration of chemical element in sub-surface soil compared to its concentration in surface soil indicates its geogenic origin. This is typical for Cr, Ni and V.

Higher concentration of chemical element in surface soil compared to its concentration in sub-soil indicates an anthropogenic contamination. This is characteristic for As, Co, Pb, Zn, Hg and S.

Sub-surface soil

Surface soil

0

20

40

60

80

100

120

140

0 10 20 30 40 50

Cr - surface soil (ppm)

Cr

- s

ub

-su

rfa

ce

so

il (

pp

m)

Chromium

Surface soil

Sub-surface soil

Cobalt

Straight lines in graphs correspond to the Metal(surface soil) /Metal(sub-surface soil) concentration ratio=1


Geological sketch map of Zambian Copperbelt and the extent of the environmental-geochemical survey

GEOLOGICAL MAP OF ZAMBIA

Surveyed area

- 760 composite samples of surface soil - 264 samples of subsurface soils - 270 samples of stream sediments - 120 samples of surface waters - 60 special samples (slag, tailings, ochres)

Total area: 4700 km2

Mufulira

Chambishi

Kitwe

Kalulushi

Chibuluma

Nkana

Mindola

ChingolaNchanga

Chililabombwe

Konkola

25 km

13°15'

27°30'

12°15'

27°30' 29°

12°15'

13°15'

29°

N

Map Sheet 1228A3 NsatoMapped in 2004

Map Sheet 1228A4 MokamboMapped in 2004

Map Sheet 1228C1 Mufulira Mapped in 2002

Map Sheet 1228C3 KitweMapped in 2004

Map Sheet 1227B4 Chililabombwe Mapped in 2005

Map Sheet 1227D2 Chingola

Mapped in 2005

NDOLA

Map Sheet 1228C2Mufulira-EastMapped in 2006

ZAMBIA

D. R. CO

NG

O

Map Sheet 1228D2Ndola

Mapped in 2009

Map Sheet 1228C4Kitwe-EastMapped in 2006

Map Sheet 1228C41Bwana MkubwaPartly mapped in 2009

Luanshya

Map Sheet 1228C42LuanshyaPartly Mapped in 2010

Concentration of copper in surface soil, the Copperbelt Area, Zambia

Central-northern part of the Zambian

Copperbelt (Kitwe, Mufulira,

Chambishi, Chingola,

Chililabombwe

Mining Districts)

W ind velocity (m /s)

1.9 2.6

W IND ROSE

Zambia: Geochemical-environmental mapping in the Copperbelt Province


1.9 2.6

W IND ROSE

SURFACE SOIL (0-3 cm) SUBSURFACE SOIL (80-90 cm)

TOTAL SULFUR IN SOILS

IGCP/SIDA 594 Training course, Johannesburg, July 13-15, 2013


1.9 2.6

W IND ROSE

ARSENIC IN SURFACE SOIL ARSENIC IN SUBSURFACE SOIL

ARSENIC IN SOILS



1.9 2.6

W IND ROSE

GEOLOGICAL MAP DIFERENCE: SURFACE TO SUBSURFACE SOIL

ARSENIC IN SOILS



1.9 2.6

W IND ROSE

COBALT IN SURFACE SOIL COBALT IN SUBSURFACE SOIL

COBALT IN SOILS



1.9 2.6

W IND ROSE

GEOLOGICAL MAP DIFERENCE: SURFACE TO SUBSURFACE SOIL

COBALT IN SOILS


MERCURY IN SOILS

MERCURY IN SURFACE SOIL MERCURY IN SUBSURFACE SOIL


1.9 2.6

W IND ROSE


GEOLOGICAL MAP

NICKEL IN SOILS

NICKEL IN SURFACE AND SUBSURFACE SOIL


COEFICIENT OF INDUSTRIAL POLLUTION (SURFACE SOIL)

Explanation:

Coeficient of Industrial Pollution

6

ZnPbHgCuCoAs m

Zn

m

Pb

m

Hg

m

Cu

m

Co

m

As

CIP

mX – value of the metal concentration


1.9 2.6

W IND ROSE

Close-up: Mufulira area

RESULTS OF THE ENVIRONMENTAL GEOCHEMICAL MAPPING

Factor analysis – trace elements in surface soils

Factor No. Factor Loading

Interpretation

Factor 1: Explains the

variability of Co, Cu, Ni, Pb, Zn Hg, Se As, and Stot

19.1% Contamination of soils by trace

elements transported by air in form of sulphide or sulfate particles from smelters, tailing ponds and mining operations

Factor 2: Explains the variability of Co, Cr, Ni, V, Zn and Fetot

22.7% This association reflects geochemical characteristics of soils and bedrock in the mapped region

(This factor not related to mining)

Factor 3: Explains the variability of Zn, Hg Stot and Corg

13.0 % This factor reflects geochemical characteristics (content of Corg Corg) in soils

(This factor is not related to mining)


FACTOR 1

FACTOR 2

RESULTS OF THE ENVIRONMENTAL GEOCHEMICAL MAPPING

Factor analysis – Maps of Factor Scores (topsoils)

Factor 1 - CONTAMINATION Factor 2 – SOIL AND BEDROCK CHEMISTRY


Sm all in te rstine

S tom ach

L ive r

O esophagus

O ra l cavitySo il con tam inan t ingestion

B ioaccessib le fraction

re leased from the so il (F )B

Fraction o f FB absorbed by

the sm a ll in te rstine (F )A

Fraction o f FA passing the live r

w ithou t be ing m etabo lized (F )H

O ra l b ioava ilab le fraction

reach ing system atic c ircu la tion (F )

F = F F FB A H* *

Total vs. gastric-available metals is surface soil

Total metal

(Aqua regia extraction) Gastric-available metal (extraction to glycine at pH 2.2, T= 38 oC). Extraction simulate solubility of metals in human stomach


Nkana Smelter Area Chingola Mining Area

Gastric-available lead

Gastic-available lead: 20% of TOTAL lead

Gastric-available lead: 80% of TOTAL lead

Lead in soils is more grastric-available in the smelter contaminated areas compared with mining areas

Total Pb/ Available Pb


Nkana Smelter Area Chingola Mining Area

Gastric-available arsenic

Gastric-available arsenic: 5% of TOTAL arsenic Gastric-available arsenic:

30% of TOTAL arsenic

Total As/ Available As


0,0

10,0

20,0

30,0

40,0

50,0

60,0

70,0

80,0

90,0

As Co Cu Fe Pb Zn

Chemical Element

% o

f to

tal

am

ou

nt

of

me

tal

.

Gastric-available metals

Dust from ore crushers

Dust from electric furnance

Dust from Pierce-Smith convertor

Mining area

Smelter area

30 m

30 m

30 m

BOX 2 Stream sediment sampling

• Stream sediment composite sample has to be prepared from sub-samples taken from 5 points along a 250-500 m length of the stream.

• From each sampling site, 1 kg of material (taken from the 0-25 cm depth) should be collected. Blended (composite) samples may be sieved on spot (wet sieving) or after drying of samples (dry sieving) in the field laboratory. For sieving, plastic sieve set equipped with nylon mesh (0.15 mm) has to be used to avoid contamination. The <0.15 fraction (50-100 g) is recommended to homogenize in agate ball mill to analytical fineness.

Note: Together with stream sediment samples, panned heavy mineral concentrates may be collected on selected sampling sites. The panned heavy mineral concentrates are an excellent resource for identifying drainage catchment mineralization as well as anthropogenic contamination.

Note: It is recommended to collect water samples (for sampling details see above) before collecting stream sediment samples on individual sampling sites.


Stream sediment sampling

CHILILABOMBWE

KAFUE

MUFULIRA

CHAMBISHI

KITWE

KALULUSHI

KAFU

E

Lu

be

ng

ele

Mus

his

ima

Musakashi

Mu

ful ir

a

Mwambashi

Mindolo

Mw

anshimba

Uchi

10 km

M02

M01M04

M05M03

M06

M07

M08M09

M10

M11M12

M13

M14M15

M16

M17

M18

CHINGOLA

SMELTER

TAILINGS DAM(ACTIVE/ABANDONED)

ACTIVE OPEN PIT

ACTIVE SHAFT

D.R. Congo

Zambia


Drying of stream sediment samples

Sieving of stream sediment samples

KAFUE MUFULIRACHAMBISHIKITWEKALULUSHI

KAFUE

Lubengele Musakashi Mufuli raMwambashiMindoloMwanshimba Uchi

M02M01 M04 M05 M06 M07M08M09 M10M11 M12M13 M14M15 M16M17M18

Uncontaminated Kafue Contaminated Kafue, Chigola

Contaminated Kafue

Contaminated Kafueoutflow from the Copperbelt

CHINGOLA

COEFICIENT OF INDUSTRIAL POLLUTION - STREAM SEDIMENTS

Explanation:

Coeficient of Industrial Contamination

6

ZnPbHgCuCoAs m

Zn

m

Pb

m

Hg

m

Cu

m

Co

m

As

CIP

mX – value of the metal concentration

Kafue

Kafue

Kafue

Uchi

Lwanshimba

Lubengele

Mushishima

Changa

Muntimpa

Mufulira

Musakashi

Chambeshi Mindolo

Kitwe

Busakile

Chibuluma

Stream sediments, Busakile River, Kitwe: - As: 1296 ppm - Co 3660 ppm - Cu 65 465 ppm - Hg 6.4 ppm - Mo 48 ppm - Ni 360 ppm - Pb 1370 ppm - Zn 3590 ppm - S tot 2.1 %


KAFUE




Contaminated Kafue


CHINGOLA

KAFUE

MUFULIRA

CHAMBISHI

KITWE

KALULUSHI

KAFU

E

Lub

enge

le

Musakashi

Mufu

li ra

Mwambashi

Mindolo

Mw

anshimba

Uchi

M02

M01M04

M05M06

M07

M08M09

M10

M11M12

M13

M14M15

M16

M17

M18


Contaminated Kafue


CHINGOLA

Results of sequential extractions show that compared with uncontaminated sediments, substanially higher amount of Cu, Co and Mn are bound to the acid-extractable fraction (exchangeable metals and carbonates)

Element

mg.kg-1

Uncontaminated Kafue

Kontaminated Kafue

Co 17-21 131-1174

Cu 115-161 1520-8837

Pb 4-13 21-54

As 0.14-0.57 1.9-7.4

Hg 0.02-0.03 0.03-0.14

Mn 103-133 395-2849

Contents of selected chemical elements in uncontaminated and contaminated

sediments of the Kafue River, Zambia


STREAM SEDIMENTS

SEQUENTIONAL EXTRACTIONS OF STREAM SEDIMENTS


KAFUE




Contaminated Kafue


CHINGOLA


STREAM SEDIMENTS

Comparison with the Canadian Guidelines for Sediments

Element (ppm)

ISQG PEL

As 5.9 (8.2%) 17.0 (2%)

Cd 0.6 (0%) 3.5 (0%)

Cr 37.3 (22.9%) 90 (2%)

Cu 35.7 (98.4%) 197 (55.7%)

Hg 0.17 (8.2%) 0.49 (0%)

Pb 35 (6.6%) 91.3 (2%)

Zn 123 (0%) 315 (0%)

Concentrations between ISQG and PEL represent the range in which adverse biological effects are occasionally observed

Concentrations above the PEL are expected to be frequently associated with adverse biological effects

Percentage of samples exceeding the ISQG and PEL values in the Zambian Copperbelt


KAFUE




Contaminated Kafue


CHINGOLA

Minerals identified in heavy fraction of uncontaminated and contaminated sediments of the Kafue River, Zambia

Uncontaminated

Kafue River

Contaminated

Kafue River

Ilmenite, hematite, hornblende,

clinochlorite, rutile, zircon,

dravite, apatite, quartz, albite, microcline

Hematite, chalcopyrite, pyrite, goethite, bornite, covelline, malachite, brochantite, pseudomalachite, hornmblende, muscovite, chlorite, clinozoisite, rutile, zircon, dravite, quartz, albite

CHILILABOMBWE

KAFUE

MUFULIRA

CHAMBISHI

KITWE

KALULUSHI

KAFUELu

be

ng

ele

Mus

hisi

ma

Musakashi

Mu

f ulir

a

Mwambashi

Mindolo

Mw

anshimba

Uchi

M02

M01M04

M05M03

M06

M07

M08M09

M10

M11M12

M13

M14M15

M16

M17

M18

Explanation


HEAVY MINERALS SURVEY,

KAFUE RIVER, COPPERBELT,

ZAMBIA


KAFUE




Contaminated Kafue


CHINGOLA

Cv

Hfo

Hfo (FeO, Al, Si, P)

A B C

Chcp

Chcp

Bn

Ti

Spi

Microphotographs of heavy minerals in contaminated Kafue River sediments. A: Rutile (Rt), bornite (Bn), covellite (Cv), limonite/goethite (Hfo). Mushishima River, Chingola Area. B: Limonite/goethite (Hfo) with copper metal (Cu). Kafue River, downstream of the Chingola Town. C: Limonite/goethite, (Hfo), limonite/goethite with admixture of Al, Si and P and grain of covellite (Cv), Mushishima River, Chingola Area. D: Limonite/goethite. Mushishima River, Chingola Area. E: Magnetite-rich slag particle (Gmt), rutile (Rt) and intermediate solid solution (ISS) particle with oxidation rims (SM). The Uchi River, Kitwe Area. F: Bornite (Bn), chalcopyrite (Chcp), titanite (Ti) and chacopyrite with a rim of secondary spionkopite (Spi). The Uchi River, Kitwe Area.


HEAVY MINERALS IN CONTAMINATED KAFUE RIVER, COPPERBELT, ZAMBIA

BOX 3 Stream water sampling

•Two sub-samples of stream water have to be collected from each site:

- unfiltered water for major anion analysis,

- filtered water for cation analysis.

• This two sub-samples can be supplemented with:

- unfiltered water sample for mercury analysis,

- filtered water sample for dissolved organic carbon (DOC) analysis.

• Trace elements-free polyethylene bottles have to be used for water sampling. Bottles have to be filled with distilled water acidified with 1.0 ml of concentrated HNO3 for at least one week before the sampling campaign.

• For filtering, 0,45- m disposable filters mounted on disposable syringes are recommended. Filtered water samples have to be acidified on the same day as sampling by the addition of 1.0 ml of super-pure concentrated HNO3 using a droplet bottle.

• A blank water sample has to be collected, filtered, and preserved in the same manner as the actual samples after every 20th sample.

• Electrical conductivity (EC) and pH and water temperature have to be measured in the field

and alkalinity has to be determined by titration in the field laboratory.


The pH values and concentration of chemical elements in uncontaminated and contaminated Kawue River water. The pH values and concentration of metals in surface water during acid spikes in the Lwanshimba and Chambeshi rivers (contaminated tributaries of Kafue) are given for comparison

Uncontamin. Kafue

(2006-2011)

Contaminated

Kafue

(2006-2011)

Acid spike

Lwanshimba

July7.2006

Acid spike

Chambeshi

July 7, 2006

Zambia limit efluent

water

EU limit

efluent water

pH 6.8-7.1 6.9-7.2 3.62 2.04 6-9 6-8

Al (ppb) 4-8 11-21 3.62 2115 2500 1500

As (ppb) < 0.5 < 0.5-2.9 6929 872

Cd (ppb) < 0.05 < 0.05-3.43 6.5 2.0 50 1

Co (ppb) < 0.05 10-30 2.0 29528 1000 10

Cu (ppb) 2.5-4.2 38-107 29528 16442 1500 30

Mn (ppb) 19-25 200-374 16442 466 1000 500

Pb (ppb) < 0.2 0.2-0.7 317 161 500 15


RESULTS: pH VALUES AND CONCENTRATIONS OF CHEMICAL ELEMENTS, the Kafue River

RESULTS OF THE ENVIRONMENTAL-GEOCHEMICAL MAPPING SURFACE WATER CHEMISTRY

Mushishima – Co, Cu, Mn

Musakashi – Mn

Muntimpa – Co, Mn

Chambeshi – Co, Cu, Mn, Pb, Mn, pH

Uchi – Co, Cu

Busakile – As, Co, Cu, Pb, pH

River water exceeding Czech and European Union effluent limits shown in red colour

BOX 4 Groundwater sampling

• In order to collect groundwater samples it is important to remove stagnant water of the well before collecting the sample. Many sampling practitioners collect samples after electrical conductivity (EC) of groundwater is stabilized. For water sampling, grab samplers (bailers) are recommended. They are portable, simple to use and relatively easy to clean.

• It is highly recommended to rinse bailer several times in the well water before taking sample. Groundwater samples have to be processed in the same way as surface water samples (unfiltered water sample and filtered and acidified water samples).

• Together with sampling, parameters such as geographic coordinates of the sampled well, sampling depth (water level), pH, temperature, electrical conductivity, oxidation-reduction (or redox) potential and dissolved oxygen have to be recorded. The alkalinity has to be determined in the field laboratory.

• Before transporting samples to analytical laboratory, samples should be kept at a temperature lower than that at which it was collected (cool box or fridge).



THE BWANA MKUBWA COPPER PROCESSING PLANT, COPPERBELT, ZAMBIA

MONITORING BOREHOLES

ive

VILLAGE

Monitoring of groundwater quality, The Bwana Mkubwa processing plant, Zambia



Jan Feb Mar May Jun Jul

pH units 6.0 6.2 6.3 5.7 5.4 6.0

Electric conductivity 241 940 312 159 242 241.6

Total suspended

solids TSS)

13 15 10 85 15 28.3

Total dissolved solids

(TDS)

169 658 220 112 69 146

Dissolved copper < 0.01 0.31 < 0.01 < 0.01 0.05 < 0.01

Dissolved cobalt 0.3 < 0.01 < 0.01 < 0.01 < 0.01 < 0.01

Dissolved Iron < 0.01 < 0.01 < 0.01 0.29 0.09 0.3

Dissolved manganese 0.06 0.08 < 0.01 < 0.01 0.09 < 0.01

Borehole depth (m) 28.6 28.6 28.6 28.6 28.6 28.6

Water level fom

surface (m)

9.59 7.96 8.75 9.8 10.1 28.6

Well Volume (m3) 0.36 0.39 0.35 0.34 0.33 0.35

Bwana Mkubwa, Groundwater Monitoring Site BH 2A, East Side of the Tailing dam TD5A



Jan Feb Mar May Jun Jul

pH units 6.2 6.2 5.3 4.1 4.4 4.4

Electric conductivity 4080 3308 3632 8205 7895 5383

Total suspended

solids TSS)

51 47 40 40 70 20

Total dissolved solids

(TDS)

2865 2320 2550 5778 5537 5383

Dissolved copper < 0.01 < 0.01 39.66 384.2 317 1.39

Dissolved cobalt 0.36 < 0.01 0.91 9.01 1.67 0.48

Dissolved iron 22.5 8.5 9.9 243.1 140.2 410.5

Dissolved manganese 30.5 26.2 23.3 544.0 171.3 281.9

Borehole depth (m) 9.25 9.25 9.25 9.25 9.25 9.25

Water level fom

surface (m)

4.86 3.98 3.9 4.89 5.43 5.55

Well volume (m3) 0.04 0.04 0.05 0.05 0.04 0.03

Bwana Mkubwa, Groundwater Monitoring Site BH 4 South-east Side of the Tailings Dam TD4


THE BWANA MKUBWA COPPER PROCESSING PLANT, COPPER CONCENTRATIONS

ive

VILLAGE

Explanation

Concentration below limit

Concentration higher than limit

Surface of the Bwana Mkubwa Tailings Pond

Eroded dam of the Bwana Mkubwa Tailings Pond

BOX 5 Sampling of plants

• In order to assess the content of chemical elements in plants it is recommend to sample especially agricultural products, for example: lettuce (leaves), giant rape (leaves), cassava (leaves and tubers), sweet potato (leaves and tubers), maize (grains), rice (grains ) and fodder (grass). Samples should be taken from several plants of the same species and from the same place. • When sampling leaves of bushes and trees samples should be taken around the whole of circumference of the crown. • The amount of collected plant material depends on the type of subsequent chemical analysis. For "wet" digestion, i.e. the decomposition of plant samples in a mixture of acids is required 1-5 g of dry sample, for more precise analyses of vegetation ash 15-30 g of dry plant tissues is needed. • Plant samples should be straight in the field spread on a nylon sieve and washed thoroughly several times with tap water. The used tap water should be sent for chemical analysis. Samples of tubers or bulbs must be peeled prior to washing.

• It is recommended to homogenize plant samples in agate ball mill to analytical fineness (< 0.063 mm) before sending them to analytical laboratories.



Sampling of plants

•Maize - grains

•Cassava – leaves

•Cassava – roots

•Sweet potatoes – leaves

•Sweet potatoes – roots

•Lettuce

•Millet – grains

Together with agricultural product, soil

rhizosphere was sampled from the same point

Cassava field, Kitwe

Region, Zambiua

Cassava leaves sampling in

cooperation with owner

Soil rhizosphere sampling

It is recommend to sample especially agricultural products:


CONCLUSIONS

Environmental-geochemical mapping and monitoring allow geological surveys, the state administration, regional authorities and nonprofit organizations engaged in environmental protection to control effectively the obligations adopted by mining companies in the field of environmental protection

Regional departments for land-use planning may use the results of monitoring in their planning activities in contaminated areas, in urban planning, in meaningful industralization of rural areas

On the other hand, the mining companies may use the environmental-geochemical monitoring and its results to assess the efficiency of commitments made by them to protect the environment and to select priorities in remediation and reclamation works

5 methods of environmental monitoring

Documents