Environmental Data

Introduction

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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Methods

Methods: Testing for Metals and Cyanide

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.


Figure 2, Sample Locations

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.

Methods: Hydrogen-Sulfide Tests for Bacterial Contamination

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.


Paper Strip Testing - Color Variation of Black Ferrous Precipitate

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Results

Results: Metals and Cyanide

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.

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

Sampling Results: Bacterial Contamination

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.

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.

Endnotes

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).

References

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 practices at Turkey's Ovacik gold-silver mine. Journal of Cleaner Production, 14(8), 727-735.

International Cyanide Management Institute. (2006). Environmental and Health Effects of Cyanide. Retrieved January 15, 2008, from
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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