Knowing the State of Naboc River
First of 4 parts
Hg, Cn content threatens Naboc River
By Jean Duron-Abangan
Davao City (20 October) -- High mercury and cyanide contents threaten the bounty of Naboc River which catches the downstream waters coming from the mountains and slopes of Mt. Diwata, until the river eventually flows down to Agusan River.
The first semester 2009 Naboc River water assessment report of the Mines and Geo-sciences Bureau (MGB) XI has revealed that Naboc River is heavily burdened by poisonous deposits from mining tailings.
Aside from mercury and cyanide, Naboc River is ailing with other heavy metals such as copper (Cu) and lead (Pb) and suspended solids of clay and soils, turning its once clear waters into murky.
"The presence of suspended solids is an indication of how silted Naboc River is," said Engineer Fedelis Echavez, one of the MGB XI team members who conducted the Naboc River water quality assessment from May 12 to May 15, 2009.
The MBG XI assessment of Naboc River was part of its commitment to the Program Monitoring and Coordinating Center of the National Task Force Diwalwal (PMCC-NTFD), spearheaded at the regional by the Department of Environment and Natural Resources (DENR) XI.
MGB XI heads the Mining and Environment Task Group which works under the PMCC-NTFD. The task group also includes the Environmental Management Bureau (EMB), Environmental Research and Development Service (ERDS), Community Environment and Natural Resources Office (CENRO) of Monkayo and the Provincial Environment and Natural Resources (PENRO) of Compostela Valley.
In conducting water quality assessment, the MGB team collected water samples from nine sampling stations, representing the whole stretch of Naboc River and its tributaries from Diwalwal gold-rush area to Agusan River.
The same sampling stations were made as bases of Naboc River water quality assessment that MGB XI also conducted in September of 2008.
The sampling stations were located at the: mixing zone of Buenas-Tinago & Busay 1 Creeks, Brgy. Mt. Diwata (Station 1) ; mixing zone of Busay 2 and Balite Creeks, Brgy. Mt. Diwata (Station 2) ; Mixing zone of stations 1 & 2 Sitio Depot, Brgy. Upper Ulip (Station 3); Tabaka Creek, Sitio Depot, Brgy. Upper Ulip (Station 4); mixing zone of stations 3 & 4, Sitio Depot, Brgy. Upper Ulip (Station 5); NIA Dam, Brgy. Naboc (Station 6); at the foot of Naboc Bridge, Brgy. Naboc (Station 7); Brgy. Naboc Proper (Station 8); and at the foot of Kalaw Bridge, Agusan River (Station 9).
The team collected two water samples each from the nine water sampling stations to find out the levels of total suspended solids (TSS) and heavy metals. It then submitted the samples to Davao Analytical Laboratories, Inc. for laboratory analysis.
Laboratory analysis results revealed that mercury content levels in seven out of nine sampling stations went beyond the standard of 0.002 milligram per liter (mg/L).
MGB XI report said that the May 2009 levels of mercury content of Naboc River "slightly increased" compared with what was found out in the water quality assessment made in September 2008,
MGB XI concluded that the "continuous high content of mercury" of Naboc River "is due to continuous usage of mercury (amalgamation technique) in extracting gold (done by) ball/rod mill establishments at (the) Diwalwal Gold Rush Area."
The May, 2009 total suspended solids (TSS) of samples taken from eight out of nine sampling stations remained high but relatively lower than those taken from the same locations in September 2008.
Meanwhile, the MGB team could not definitely establish the exact levels of cyanide content of Naboc River in its May, 2009 monitoring because it only used a Cyanide testing kit on-site.
In September 2008, the team used cyanide testing equipment which "gives a relatively more accurate result of analyzing cyanide content in water," Echavez explained.
Using the Cyanide testing kit in May, 2009, MGB XI found out that samples from four sampling stations read greater than 2.0 milligram per liter (mg/L), exceeding the standard of 0.05 milligram per liter (mg/L).
The team failed to use the new Cyanide testing equipment "because the available buffer solutions used to read cyanide contents in the water samples already expired," Echavez said.
In its report, MGB XI attributed the continuous high content of cyanide
particularly from samples taken in stations 1, 2, 3, and 5, "to all batch-type mini CIP (carbon in pulp)-plant operators (who) are using excessive cyanide in processing and extracting gold."
MGB said that "all batch-type mini CIP plants" in Mt. Diwalwal gold-rush, "have no tailings or waste dam or ponds", and are directly discharging wastes to nearby creeks and waterways which are tributaries to Naboc River. (PIA XI/PMCC-NTFD/MGB XI) [top]