Mercury (Hg) contamination was assessed in environment near an amalgamation gold recovery operation located at a small scale mining operation (Phanom Pha) in Phichit Province, Thailand. Total mercury (THg) concentrations was determined in water, sediment, bivalves in the aquatic environment and as dry deposition or atmospheric fallout on surface soil and leaves of Neem tree (Azadirachta indica Juss. var. siamensis Valeton) near the mining operation. THg in surface soil, Neem flowers (edible part) and rice grain in surrounding terrestrial habitat and with distance from the mining area were also evaluated for possible contamination. Potential environmental risks were evaluated using the hazard quotient equation. Hg analyses conducted in the aquatic habitat showed that THg in water, sediment and bivalves (Scabies cripata Gould) ranged from 0.4 to 4 microg L(-1), 96 to 402 microg kg(-1)dry weight (dw) and 15 to 584 microg kg(-1) wet weight (ww), respectively. High concentrations of THg in water, sediment and bivalves were observed in the receiving stream near the mining operation which was located near the Khao Chet Luk Reservoir. Whereas the THg concentration in water, sediment and bivalves from monitoring stations outside the gold mining operation (upstream and downstream), were considerably lower with the values of 0.4-0.8 microg L(-1), 96-140 microg kg(-1) dw and 88-658 microg kg(-1) dw, respectively. The elevated concentration of Hg found in the sediment near the mining operation was consistent with Hg accumulation measured in bivalves. The elevated Hg levels found in living bivalves collected from highly contaminated sites suggested that the sediment bound Hg was bioavailable. THg in surface soils, brown rice grain (Jasmine rice #105) and Neem flowers of terrestrial habitats were in the range of 16 to 180 microg kg(-1) dw, 190 to 300 microg kg(-1) dw, and 622 to 2150 microg kg(-1) dw, respectively. Elevated concentrations of mercury were found in Neem flowers with the concentration greater than 600 microg kg(-1) ww, which exceeds the maximum permissible concentration reported for biota tissue (500 microg kg(-1) ww). An evaluation of air and soil pollution near the mining operations showed high concentrations of THg in dry deposit from atmospheric fallout (139 microg m(-2) d(-1)), and in surface soil (10,564 microg kg(-1) dw) at station near where open burning of gold ore extracts using the amalgamation process occurred. High or elevated concentration of THg (1172-1301 microg kg(-1) dw) in leaves of Neem tree was also measured near the mining operations. A survey of Hg in surface soil showed elevated Hg concentrations near the site which corresponded to the elevated THg concentration in dry deposition. These results suggested that atmospheric fallout is a major source of Hg to the area surrounding the mining or gold ore extraction. Results also suggest that Hg emitted into the air (estimated to be 60-150 g d(-1)) from the gold mining activities (over the past 10 years) contaminated air, the aquatic environment, ...
Available forms of mercury (Hg) released from artisanal gold mine activities could be taken up increasingly by plants via root and leaf stomata. Total mercury (THg) concentrations in dry deposit, surface soil and rice grains were investigated as well as the potential risks in september 2011 from three rice fields of concern. The results revealed that the concentrations of THg in dry deposition, top soil (0 to 5 cm depth), sub soil (6 to 10 cm depth) and rice grains (Oriza sativa L.) both brown (once milled) and white (twice milled) grains were ranged from 166 to 322 m-2 day-1, 484 to 4244 μg kg-1dw, 122 to 1812 μg kg-1ww, and 113 to 1084 μg kg-1ww, respectively. Hazard quotient (HQ) values for dry deposition, top soil and sub soil were ranged from 3 to 7, 5 to 42 and 5 to 36, respectively. Target hazard quotient (THQ) for brown and white rice grains consumptions were found in the range of 0.1 to 1.6 and 0.1 to 1.0, respectively. THQ values through brown rice consumption exceeded the guideline (>1) presented that the brown rice in these areas should not be safe for consumption and are at risks for the whole lifespan. However, the THQ values of both brown and white rice grains in some areas were still low and should be safe for the whole life span consumption.
Recently, usage of the metal-based pesticide especially manganese (Mn) and copper (Cu) have been widely used in the agricultural area around the Lam Takhong Reservoir; the major water resource of Nakhon Ratchasima Province and the Southern I-Sarn. The exposures of these metals can causes neurological and Parkinson diseases. Therefore the objectives of this study were to investigate Mn, Cu, and Fe contaminations in the reservoir as well as the environmental risks by using hazard quotient (HQ). The results showed that the average concentrations of Mn, Cu, and Fe in water column were 0.05 mg/l, 0.01 mg/l, 0.39 mg/l in dry season and 0.08 mg/l, 0.01 mg/l, 0.53 mg/l in wet season, respectively. Mn and Cu concentrations were in normal range except those of Fe that were extremely high. Also, Mn and Cu in sediment were found in the normal range. Interestingly, high concentrations of Fe in sediment were found at many stations with respect of the parent materials in this area. Fortunately, there were no risks of Mn and Cu in both water column and sediment. However, Fe in sediment exceeded the recommended guideline. These results suggested that using Mn/Cu-based synthetic pesticides in this area might be limited with respect of Fe abundance that could enhanced the toxicity of Mn/Cu and might increased the incidents of neurological and Parkinson diseases.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.