M A L U K U S E A

1
(No Transcript)
2
MAP OF STUDY AREA

LEGEND

4
Artisanal Gold Mine
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
.
City
BUNAKEN
4

Town
,
4
4
Lake
0
15
30
MANADO
.
BITUNG
River
Kilometers
.



Study Area
TONDANO
.
.
TOMOHON
S U L A W E S I S E A
.
AMURANG
M I N A H A S A
4
,
POIGAR
,
4
BELANG
Ô
Ô
Ô
Ô
Ô
Ô
Ô
Ô
M A L U K U S E A
KOTAMOBAGU
.
4
4
B O L A A N G M O N G O N D O W
4
4
4
4
4
4
3
Ratatotok Gold Mining Area
Basaan
NMR
A
B
C
Totok Bay
D
Ratatotok
Buyat
E
4
Ore Crushing
5
Amalgamation
6
Tailing System
7
Amalgam Burning
Retort Used
Open Roosted
8
Stone Water
9
(No Transcript)
10
(No Transcript)
11
WATER AND SEDIMENT SAMPLING
Sediment
Water
Composite

HNO3
Laboratory
12
(No Transcript)
13
45
40
0 - 10 cm
35
10 - 20 cm
30
20 - 30 cm
25
Hg in sediment (mg/kg dry weight)
20
15
10
5
0
A
B
C
D
E
Sampling sites
14
(No Transcript)
15

• ESTIMATED AND MEASURED
• In average 58 g of amalgam was produced in one
  cycle of amalgam process, then the amount of
  amalgam produced by all processing units within
  one day would be 4,640 g (40 x 2 x 58 g).
• Using the amalgam-recaptured mercury regression
  equation, an estimate of 3,222 g or approximately
  3 kg of mercury lost to the atmosphere by burning
  the 4,640 g amalgam every day.
• Take into account that every processing unit
  operate 20 days in a month and be able to work 10
  months in a year, then the amount of mercury
  vapor released to surrounding environment is
  about 600 kg per year.
• If a gold processing unit adopt and implement
  retort technology for amalgam burn practice, then
  its will reduces or save 15 kg per year or 1.25
  kg per month..
• According to Harada et al. (1999), mercury lost
  from amalgam burn process contributes 60 of the
  total mercury lost from artisanal gold mining
  activities. Then the estimate of total mercury
  emission from all processing units would be about
  1,000 kg per year.
• The corresponding estimation of gold bullion
  production is about 235 kg per year.

16

• CONCLUTIONS
• Artisanal gold processing practice in Ratatotok
  area had been discharging a substantial amount of
  metallic mercury into catchment area of Totok
  River. Primarily during high flow, the
  mercury-enriched sediment had been transporting
  through the river system and accumulating at the
  river mouth in Totok Bay. Agitation of sea wave
  and current may has an essential role on the
  accumulation of mercury in deeper layer of
  sediment as well as its spatial distribution in
  the bay.
• Bio-accumulation and bio-magnification of mercury
  through the food chain in Totok Bay may be
  significant. The rate of the process may be small
  at present, however the amount of mercury
  presence in sediment must has an important
  implication, less visible but potentially the
  most damaging impact and severe that will extend
  for many years in the future.

17

• RECOMMENDATIONS
• An organized response to the pollution problem
  must be prepared by Provincial Government of
  North Sulawesi and its representatives in South
  Minahasa Regency and District of Belang.
  Integrated official determination by all
  responsible authorities or stakeholders should be
  sought and obtained immediately.
• The actual gold processing practices should be
  improved or changed to clean technologies in
  order to guarantee the minimal risk of poisoning
  the miners as well as the community. The simple
  measures that involve education, improvement
  tailing system, and used of retort for amalgam
  burn should be implemented immediately.
• The spatial distribution and bio-geo-chemical
  transformation of mercury in sediment within
  Totok Bay are critical to be evaluated. In
  considering that fish is the main protein source
  for the local community, it is vital to have a
  more detail understanding of mercury
  contamination on fish species in order to provide
  fish consumption guide line.