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Prior to this research project,
there was very little independent study of the environmental impacts of
mining at Vatukoula. Thus, a major goal of this study was to collect
information on the extent of environmental impacts at the site, to be
made directly available to the public. We hope that providing this
information to the people living and working near the Vatukoula mine
will contribute to informed decision making and improved risk
management. Additionally, information about environmental impacts will
help us to better interpret our survey findings about how people
perceive the environmental and health risks of mining.
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A total of six samples of surface
water and drinking water were collected and analyzed. Water quality was
chosen as the primary focus because water represents a likely pathway
through which people may be exposed to contaminants from mine wastes.
Many of the households in Vatukoula are supplied with untreated water,
pumped directly from the nearby Nasivi River and families routinely use
river water for washing clothes, washing dishes, fishing, and swimming.
To learn about some of the health effects of cyanide and arsenic, click
HERE. The
six sample locations were chosen because they are places where
Vatukoula residents may commonly come into contact with potentially
contaminated surface waters or drinking water. Detailed information
about each sample is described in the Sample Key, and sample locations
are presented in Figure 2. Click HERE to view Sample Key.
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Figure 2, Sample Locations
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Samples were analyzed locally at
the University of the South Pacific (USP) Institute of Applied Sciences
(IAS) Analytical Laboratory and the Fiji Mineral Resources Department
(MRD). Analytical parameters were determined based on local geology, the chemicals used in the gold mining processes,
and their potential by-products. A priority list of analytical
parameters was then developed based on the degree of toxicity to humans
of the potential contaminants, and the analysis options available at
the local laboratories. Historical analytical data, collected by the
MRD, was also reviewed during the development of the sampling and
analysis plan.
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During the course of the study, the residents of Vatukoula expressed concern
about the potential for contamination of drinking water and surface water
due to inadequate management of human and animal wastes. Sanitation
facilities at Vatukoula primarily consist of flush toilets with septic tanks
and pit latrines, which do not provide adequate removal of pathogens.
Additionally, many settlements are located in very close proximity to the
Nasivi River and its tributaries, increasing the risk of contamination.
Animals such as pigs and cows are also commonly located in the settlements,
close to unprotected water supplies.
Faecal coliforms (and other bacteria in the coliform group) exist naturally
within the intestinal tract of humans and other warm-blooded animals. Thus,
if water is contaminated with faecal coliforms, this may indicate that the
water is contaminated with faecal matter and is not safe for human
consumption. Therefore, an important indicator of water quality is the
absence of faecal coliform bacteria, which may indicate that pathogens, such
as typhoid or cholera, are present (Mosley & Sharp, 2004). Since most tests
for pathogenic organisms are costly and difficult to perform, indicator
organisms, such as total and faecal coliforms, are commonly used to assess
the risk that pathogenic organisms may also be present (Mosley & Sharp,
2004). However, coliforms may occur naturally in soil and water in tropical
climates, making them a poor indicator organism in such areas. As such,
another test has been developed which uses a more appropriate indicator,
hydrogen-sulfide reducing bacteria, to assess the risk that pathogenic
organisms may exist. The Hydrogen Sulfide (H2S) Paper-Strip Test also has
many other advantages because it is very inexpensive and easy for
non-technical people to learn to use. This makes the test ideal for use in
rural Pacific island communities. Each test tube contains a medium in which
certain bacteria in the Enterobacteriacae group, such as Salmonella,
Citrobacter, Clostridia, Klebsiella, and Proteus can produce hydrogen
sulfide (Mosley & Sharp, 2004). The production of hydrogen sulfide is
indicated in the test tube when thiosulphate is reduced and subsequently
reacts with ferric salt to form an insoluble black ferrous precipitate.
This black precipitate may then be interpreted to indicate a certain level
of risk that pathogenic organisms may be present. The H2S test has been
recommended for testing drinking water sourced from surface water,
boreholes, or rain water, for faecal contamination (Mosley & Sharp, 2004).
For our study, several H2S strip tests were obtained free-of-charge from the
World Health Organization (WHO) in the capital city of Suva. A total of
ten tests were performed, including one control sample. Chlorinated bottled
water was used as the control sample. Each sample was collected in
accordance with suggested methods outlined in the H2S Paper-Strip Test
Instruction Guide provided by WHO in Fiji. For samples collected from taps,
the tap were first cleaned with a clean cloth then allowed to run for 20
seconds. The sample bottle was then filled up to the marked level and
immediately closed. For samples collected from surface waters, a clean
plastic container was used to transfer water into the test tube. This
container was rinsed several times prior to collection of the sample. The
samples were then stored in a dark place to prevent sunlight from killing
bacteria, which may invalidate results. Samples were monitored over a three
day period, and observations of color change were recorded at the same time
each day. Color change was assessed using the color code provided in the
WHO Instruction Guide.
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Paper Strip Testing - Color Variation of Black Ferrous Precipitate
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Analytical results indicated that all six samples contained acceptable
levels of Mercury (Hg), Zinc (Zn), Nickel (Ni), Cobalt (Co), Chromium (Cr),
and Total Cyanide (CN), as recommended by the drinking water guidelines of
the World Health Organization. There were no detections of Copper (Cu),
Lead (Pb), or Cadmium (Cd), in all six samples, however, minimum detection
limit achievable by the MRD Analytical Unit was higher for these three
metals that the WHO drinking water guidelines. Therefore, although no gross
contamination of Cu, Pb, or Cd was detected, it cannot be concluded for
these three contaminants that levels were necessarily within the WHO
drinking water guidelines. Samples 003, 005, and 006 exceeded the maximum
allowable WHO drinking water guideline of 10 ppb for Arsenic (As), however,
each of these three samples was collected from surface water in locations
unlikely to be sources of drinking water. Sample 003 was collected from
Lololevu Creek, which is not a source of drinking water; Sample 005 was
collected downstream of both the PWD and EML water intake points; and Sample
006 was collected from the old tailings dam at Slime Dam, which is also not
a drinking water source. Click HERE to view Analytical Results.
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When compared with historical water quality data collected during mining
operations, the results of this study show an improvement in water quality.
However, it is important to recognize that samples were collected after the
mine had been closed for eight months. Additionally, samples were collected
during the dry season (May to November). Waterways probably experienced
heavy sediment and water movement during the wet season, which lasted for
several months following the mine closure (December- April). This movement
probably caused a large degree of natural remediation of metals, while
cyanide was likely largely evaporated as HCN gas. For example, many common
arsenic compounds can dissolve in water, but over time the majority of As
will be present in sediment rather than in water (Agency for Toxic
Substances and Disease Registry, 2007). Given the large volumes of mine
wastes discharged into the river during operation, a significant degree of
natural remediation appears to have occurred in surface waterways, however,
conclusions cannot be drawn from this study regarding the potential
contamination of sediment.
Results also indicate that natural processes of remediation have led to an
improvement in water quality in the old tailings dam near Nademo (Slime
Dam). This is a positive indicator of the potential of all of the former
tailings dams for successful rehabilitation through a program of
re-vegetation and monitoring. However, residents are currently using the
old tailings dam at Nademo for fishing, and this study did not test the
safety of fish for human consumption. Although some fish accumulate arsenic
in their tissues, most of this arsenic is in an organic form called
arsenobetaine (commonly called "fish arsenic"), which is less harmful
(Agency for Toxic Substances and Disease Registry, 2007). A recent study by
the University of the South Pacific found that arsenic consumption in Fiji
is already close to the provisional tolerable weekly intake (PTWI)1, however,
this study only tested for total arsenic, while the toxic form is inorganic
arsenic (Aalbersberg, 2007). The report recommended that further study of
the inorganic and organic arsenic levels in fish in Fiji be undertaken as a
priority matter (Aalbersberg, 2007). Additionally, the risk of mercury and
other heavy metal contamination in fish from the tailings dam has not been
assessed. It is thus recommended that a study of the safety of fish for
human consumption be undertaken at the tailings dam at Nademo and in all of
the waterways in the Vatukoula region as a priority matter. This is an
important issue because variations in pH could potential mobilize additional
metals into waterways in the future. pH levels were not tested as part of
this study, but given the lack of metal detections, it is unlikely that pH
levels in surface and drinking water were acidic at the time samples were
collected. However, when mining operations resume, excessive sulfur dioxide
emissions from the roaster stack could potentially create acidic surface
water conditions. pH measurements should thus be an integral part of future
monitoring programs.
It is important to note that this study was limited to only six samples, and
a select list of potential chemical contaminants. Additionally, this study
only focused on drinking water and surface water quality, despite the
potential risks of soil contamination, air pollution, land degradation,
contamination or fish, seafood, or crops, impacts on marine life where the
Nasivi River enters the sea, or the potential for disasters such as the
collapse of a tailings dam. Although the samples of drinking water tested as
part of this study did not exceed WHO drinking water guidelines, the study
cannot be considered a substitute for a comprehensive Environmental Impact
Assessment (EIA). Despite the fact that untreated water is drawn from
upstream of the contaminated Nasivi River sample site (003), it cannot be
concluded from this study that all untreated water drawn from upstream is
necessarily safe from contamination of metals and/or cyanide. During past
mine operations, when wastes were routinely discharged into surface
waterways, the risk of heavy metal and cyanide contamination was much higher
than the current post-closure risk. The 1994 environmental audit conducted
by Sinclair Knight & Merz found that "maintaining human drinking water
quality at the point of discharge is an unrealistic expectation (Sinclair
Knight Merz Pty Ltd, 1994)." It is thus recommended that signs be clearly
posted if future discharge occurs, advising people not to drink from streams
and rivers in the Vatukoula area. Now that Westech has resumed mining
operations, a consistent environmental monitoring program and a full EIA
must also be undertaken. Additionally, disaster management plans should be
developed in both Vatukoula and Tavua, including plans for tailings dam
failure in the case of an extreme rainfall event or earthquake
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Nine samples and one control sample (a total of ten) were tested for
the risk of bacterial contamination. Using the H2S Color Code provided by
the WHO, eight out of nine samples were coded as noticeably black (+++) by
the end of the three day observation period, indicating a high level of risk
of bacterial contamination Click HERE to view Hydrogen-Sulfide Water Quality Testing Results.
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These samples were collected from both surface water and tap
sources. One of the samples was taken from a tap inside a residence in the
Nasomo settlement. This was a source which residents insisted was safe,
because it came from the mountains. Two other samples were actually boiled
water that residents were drinking from tea cups at the time of testing.
The only remaining sample that was not coded a (+++) was coded as (+), a
slight change to grey color, indicating a slight possibility of bacterial
contamination.
H2S test results indicate that the majority of drinking water
sources available to Vatukoula residents are not safe for human consumption
due to the high risk of bacterial contamination. Residents must take care
to boil water, including water originating from taps. Residents must also
take care to avoid cross-contamination, which may originate from
contamination on hands, taps, or dishes. Because the H2S test kits area
readily available from WHO, it is recommended that a longer term monitoring
program be undertaken. This program could potentially be administered
initially with the help of the U.S. Peace Corps volunteer based in Tavua
town. The program could then be continued by local residents under the
direction of the Vatukoula Community Consultative Committee. WHO also
provides an easy to use Sanitary Survey Sheet, which may be used in
conjunction with the H2S testing, to assist in identifying the potential
source of contamination for a particular water source.
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1 A Maximum Allowable Daily Body Load (MADL) of
total arsenic of 50 ug/kg bw/day was set in 1967 by WHO, however, more
recently the Joint FAO/WHO Expert Committee on Food Additives (JECFA)
set a PTWI of 15 ug/kg bw/week for inorganic arsenic, the more toxic
form (Aalbersberg, 2007).
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Aalbersberg, W. (2007). Better Food for Fiji. Suva: University of the South
Pacific.
Agency for Toxic Substances and Disease Registry. (2006). ToxFAQs for
Cyanide. Retrieved January 15, 2008, from
lwww.atsdr.cdc.gov/tfacts8.html
Agency for Toxic Substances and Disease Registry. (2007). Public Health
Statement for Arsenic. Retrieved February 4, 2008, from
www.atsdr.cdc.gov/toxprofiles/phs2.html#bookmark02
Akcil, A. (2006). Managing cyanide: health, safety and risk management
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Production, 14(8), 727-735.
International Cyanide Management Institute. (2006). Environmental and Health
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www.cyanidecode.org/cyanide_environmental.php
Keeler, R. F., & Tu, A. T. (1983). Plant and Fungal Toxins:Handbook of
Natural Toxins (Vol. 1): Marcel Dekker.
Mineral Resources Department: Government of Fiji. (2008). Geology of Fiji.
Retrieved January 8, 2008, from
www.mrd.gov.fj/gfiji/geology/educate/geo_fiji.html
Mosley, L. M., & Sharp, D. S. (2004). The Hydrogen Sulfide (H2S) Paper-Strip
Test: A Simple Test for Monitoring Drinking Water Quality in the Pacific
Islands (No. 373). Suva, Fiji: South Pacific Applied Geoscience Commission
(SOPAC).
Muezzinoglu, A. (2003). A Review of environmental considerations on gold
mining and production. Critical Reviews in Environmental Science & Technology, 33(1), 45-71.
Sinclair Knight Merz Pty Ltd. (1994). Environmental Audit of Emperor Gold
Mines.
University of Otago Department of Geology. (2008). Metals in the New Zealand
Environment. Retrieved January 8, 2008, from
www.otago.ac.nz/geology/features/metals/acidrockdrainage.html
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