A June 2015 study done for the World Wide Fund for Nature (WWF) Guianas has voiced concern about mercury pollution from Small-Scale Gold Mining (SSGM) in Guyana, Suriname and French Guiana and has called for a commitment to ban the gold purifying metal and to stringently monitor its trade.
Entitled ` Small-Scale Gold Mining Related Mercury Contamination in the Guianas: A Review’, the study by Legg ED, Ouboter PE and Wright MAP focused on mercury trade; the presence of mercury in the air, freshwater, soil and marine environments; entry into the food chain and exposure of the human population. It collated data from a range of studies on these areas. Mercury builds up in the food chain and can lead to acute poisoning and death.
What was evident from the review was that studies done in Guyana were outdated, in some cases going back to the 1990s. However the report cited more recent data for French Guiana in particular and Suriname which it said should lead to concerns in Guyana about mercury pollution.
One of the key recommendations made in the report was the banning of mercury in the mining sector, possibly through the Minamata Convention. Guyana signed the Convention in Japan in October 2013 but the previous government had stated that the phasing out of mercury would take at least a decade.
Questions were raised in the study about the volume of mercury employed in the industry here and what that might mean for pollution. It said that over the period 2008 to 2013 mercury was sourced from 10 countries. The previous major suppliers including Spain and the US were surpassed by China which provided around 60 tonnes in 2013 or 75% of the total brought in. The study said that there were significant discrepancies on the recording of imports at the relevant government agencies, the GGMC and the GRA.
Despite its small size, the report said that Guyana ranked 22nd in the world for the import of mercury between 2002 and 2006 though the authors acknowledged that the figures have shortcomings. It however said that official importation of mercury has outstripped mining demand here by at least a factor of two every year between 2008 and 2013 and peaking at 5.4 times the requirement in 2011. Over the period, it said, mercury imports totalled 504 tonnes, an excess of approximately 355 tonnes. It also said that the ratio of mercury used in gold output rose from 1.5:1 to 3:1. It said that the likely explanation for the excess in mercury imports and the hike in the mercury to gold ratio would be clandestine production of gold which might be smuggled out of the country and the smuggling of mercury to Suriname and French Guiana.
Freshwater
In relation to freshwater contamination by mercury in Guyana, a study done between 2005 and 2009 was cited. Samples taken from active and historically mined areas had a concentration of mercury of 0.229 ± 0.223 μg/g which is above the Canadian Council of Ministers of the Environment (CCME) quality guidelines. An earlier study on the Potaro River had yielded mercury concentrations ranging from 0.068 to 0.321 μg/g within the tributaries affected by mining.
Similar results were obtained from a study that extensively sampled sediments from the Mazaruni River as well as a stretch of the Essequibo River. Sediment mercury concentrations were found to be in the range of 0.005–0.707 μg/g and 0.004–0.225 μg/g for the Mazaruni and Essequibo, respectively (Miller et al., 2003).
In the conservation areas of Iwokrama and Konashen in Region Nine, the study found that mean mercury concentrations were 0.187 ± 0.077 μg/g and the range was 0.053 to 0.301 μg/g (Howard, 2010). The author noted that a number of the samples taken from the Iwokrama Reserve may have been affected by illegal mining in the past (as suggested by a mean mercury concentration for Iwokrama of 0.174 μg/g) (Howard, 2010).
Overall, the study said that these figures, while dated, indicate that mercury contamination is widespread in Guyana with mean concentrations consistently above safe guidelines for aquatic life.
The study acknowledged that data on the contamination of fish in Guyana is very limited. It cited small studies in the Potaro River and Isseneru which showed the mean mercury concentration to be above World Health Organization guidelines but said that caution had to be shown in interpreting this data because of the small samples.
Large-scale
“In Guyana, as with data on mercury contamination in general, there is a need for large-scale studies to improve on the completeness of the current data. However, given that there is no evidence of reduced mercury use, the sparse and out-dated information currently available suggest that high levels of contamination are likely present. Indeed data from Suriname and French Guiana, where mercury use has been similarly pervasive, reveals widespread and high levels of mercury contamination in fish. Furthermore, contamination is not restricted to areas affected by SSGM and levels of contamination in fish are sometimes greater than suggested by levels of contamination in river sediments at certain sites in both countries”, the study asserted.
On the issue of indirect mercury exposure in Guyana, the study said that there is a lack of current or geographically extensive data on mercury contamination in non-mining areas. It referred to studies of women in the communities of Isseneru, Micobie and Masekenari which showed elevated levels of mercury in the hair of pregnant and nursing women. However it said that extensive studies are needed and factors like diet have to be taken into account when considering mercury levels.
“Despite the small amount of data available, particularly in Guyana and Suriname, it is clear that certain communities in all three Guianas are exposed to dangerous levels of mercury. Exposure is principally through diet, although both miners and the extended communities around them are also at risk. Examples of neurological dysfunction have been demonstrated in both French Guiana and Suriname. As is the case with contamination of fish and sediments there is a disconnect between areas of gold mining and cases of high mercury exposure in some communities. In the case of human health the main driver of toxicity appears to be a reliance on predatory fish as a major food source”, the study said.
Among its policy recommendations were that the Guianas should:
- Commit to the banning of mercury in the mining sector.
- Strengthen and properly implement import and export laws to ensure mercury trade can only be conducted under licence and that the compulsory recording of all imports and exports of mercury is carried out.
- Increase monitoring of mining activity and movement of mercury, especially in the border areas of the Guianas with explicit coordination and intelligence sharing between authorities on each side of the national boundary.
- Remove mining from Protected Areas and other areas of high conservation value or environmental sensitivity and illegal miners from indigenous lands.
- Implement an awareness campaign targeting the most vulnerable groups to mercury exposure indicating precautionary measures, including fish consumption thresholds, to minimise their risk of contamination.
- Establish mechanisms to demonstrate best practice and mercury free techniques to small scale miners including the engagement of the private sector gold mining companies to share their technical expertise.
It also recommended systematic reviews of the mercury status of representative mining and non-mining communities, including urban areas, throughout the Guianas beginning with those perceived to be at highest risk. This , it said, would create a comprehensive baseline and allow change to be monitored.
A systematic and regular programme to determine the mercury status of fish caught for sale and consumption within the Guianas was also urged.
