Investigation reveals high mercury levels in Kaituma River

…aquatic species affected
Five months after water supply was sourced from alternative means for affected residents, an investigation into mercury contamination of the Kaituma River, North West District has confirmed the preliminary test that the mercury levels were too high for consumption.
In the final report submitted by Environmental Officer, Tamara Gilhuys, it was recommended that complaint officers ensure sample points at and near pump station are included in their routine water quality monitoring. The report further outlined that the environmental division should “lead investigations to ascertain the status of rivers or creeks within mining districts” where Guyana Water Inc pump stations are located and where contamination from mining operations poses an imminent threat to the community.
Eleven river water samples were submitted but only 10 were analysed due to leakage of Sample ID ‘10’ during shipment by Kaizen Environmental Services Inc. In the analysis, it was found that at all sample points, the concentrations were within the World Health Organisation (WHO) guidelines.
Despite the generally low readings, it was however found that in Sample 4 at 125m upstream Pump Creek, there was 0.000219 mg/L of mercury. Meanwhile, the lowest concentration of 0.000016 mg/L was found in Sample 2 which was located on the Kaituma Canal downstream section of Pump Creek. The WHO guideline is 0.006 mg/L. It was explained that mercury is easily transported to bed sediments from the water column due to its high affinity for organic ligands.
The investigation revealed a variety of organisms live in or come into contact with bed sediments and therefore the sediments act as an important route of exposure to aquatic organisms which in turn has implications for human health. “Sediment mercury, therefore, is an indicator of the recreational safety and ecological health of a water source as it relates to wildlife and human health,” the reported observed.
The report stated that the drinking water standard for arsenic is 0.010 mg/L as outlined by WHO and the United States Environmental Protection Agency (USEPA) Maximum Contaminant Levels (MCLs).
“The USEPA MCLs reflect the level at which no adverse health effects are likely to occur within a margin of safety and are set as close as possible to health goals considering cost, benefits and the ability of public water systems to detect and remove contaminants using suitable treatment technologies,” the section of the document noted.
With respect to cadmium, the report found that all samples were found to be below the limits. The Port Kaituma survey also showed that the samples were within the WHO guidelines for lead which is 0.01 mg/L. The results of five samples sent for further analysis at ActLabs are expected to be available on September 30.
It was in July that GWI’s Managing Director, Dr Richard Van West-Charles told reporters that mercury levels of 0.016mg/L was shown which was higher that WHO standard of 0.006mg/L . It was on July 26, 2018, that the Guyana Geology and Mines Commission dispatched a joint team that included the Environmental Protection Agency to investigate the matter.