To estimate the impact of mercury discharged from artisanal and small-scale gold mining (ASGM) activity, variations in the concentrations of elemental mercury (Hg0), mercury ion (Hg2+), particulate ...mercury (P-Hg), and total mercury in filtered river water (FT-Hg) were investigated from sampling locations extending from 10 km upstream to 30 km downstream of ASGM operations in West Java, Indonesia. The average of the annual concentrations at the ASGM site from 2013 to 2017 were 0.14–0.85 μg L
−1
, 0.27–12.9 μg L
−1
, 4.3–49.5 μg L
−1
, and 1.2–12.5 μg L
−1
for Hg0, Hg
2+
, P-Hg, and FT-Hg, respectively. The concentration of mercury species decreased as the distance from the ASGM site increased, while the ratio of P-Hg increased towards the lower reaches of the river system, with the percentage of P-Hg estimated at 90% of Hg at the sample location furthest downstream. A high mercury concentration of 600 mg kg
−1
was observed for suspended particulate matter (SPM) at the ASGM site. The SPM maintained a high concentration of mercury, even in the downstream area. In the annual variations of the mercury species from 2013 to 2017, FT-Hg and P-Hg concentrations tended to decrease from 2016, which suggested a decline of ASGM activity in this area. However, SPM and river sediment showed no apparent changes in their mercury concentrations over this period, indicating that the contamination in the river system is persistent and does not recover quickly.
To evaluate the impact of mercury released into a river system by artisanal and small-scale gold mining (ASGM) activity in West Java, Indonesia, the temporal variations in elemental mercury, mercury ...ions, dissolved total mercury and particulate mercury concentrations in river water were observed in March 2015 (rainy season) and August 2015 (dry season) at a fixed observation point, and the migrated amount of mercury was estimated. Variations for other metals, total organic carbon (TOC), and total nitrogen (TN) contents were also measured. There have been few reports in which the amount of mercury transferred from ASGM activities is quantitatively estimated, and this study provides important data for evaluating the environmental impact of mercury released by ASGM activities. The concentration of filtered total mercury and the particulate mercury concentration observed in the dry season were 161 ± 167 μg L
−1
and 142 ± 93 μg L
−1
, respectively, and these values were significantly higher than the values of 24.5 ± 23.9 μg L
−1
and 53.7 ± 44 μg L
−1
for filtered total mercury and particulate mercury, respectively, observed in the rainy season. On the other hand, the river flow in the rainy and dry seasons was 2.6 × 10
4
± 5×10
3
m
3
h
−1
and 8.2 × 10
3
± 8×10
2
m
3
h
−1
, respectively, and an apparent increase in the amount of water in the rainy season was observed. The transfer amounts in the rainy and dry seasons obtained from these results were 6.2 × 10
2
± 6.7 × 10
2
g h
−1
and 1.6 × 10
3
± 1.6 × 10
3
g h
−1
, respectively, for filtered total mercury and 1.3 × 10
3
± 1.3 × 10
3
g h
−1
and 1.1 × 10
3
± 7×10
2
g h
−1
, respectively, for particulate mercury. The temporal variations in these values exhibited a wide range, indicating the effects of weather conditions and of the mining process.
Many patients who have lower-extremity amputations secondary to peripheral vascular disease or diabetes require reamputation eventually. This study was designed to identify the incidence of and risk ...factors for ipsilateral reamputation after forefoot amputation, to evaluate whether postoperative infection increases the risk of reamputation, and to evaluate whether the risk of reamputation was reduced by the duration of antimicrobial therapy after amputation.
A retrospective analysis of patients who underwent foot amputation for nontraumatic reason from January 2002 to December 2004 at the Veterans Affairs Pittsburgh Healthcare System was performed.
Among 116 patients, 57 (49.1%) had ipsilateral reamputation within 3 years after their first surgeries; 78.9% received reamputation in the first 6 months; 53 (45.7%) died within 3 years; and 16 (13.8%) developed postoperative infections. Upper level of amputation, long duration of hospitalization, insulin-dependent diabetes, and gangrene on physical examination on admission were risk factors for reamputation in univariate analysis. Gangrene (odds ratio: 3.81, 95% confidence interval: 1.60-9.12, P = 0.003) and insulin-dependent diabetes (odds ratio: 2.93, 95% confidence interval: 1.26-6.78, P = 0.012) were risk factors in multivariate analysis. Postoperative infection did not increase the risk of reamputation. Longer than 2-week course of antibiotic use after amputation did not prevent reamputation.
Approximately one-half of patients required ipsilateral reamputation and died in 3 years. Gangrene on admission and history of insulin-dependent diabetes were significant risk factors (P = 0.003, P = 0.028). Long duration of antibiotic use after amputation and postoperative infection did not change the risk of reamputation.
This study investigates the distribution of total mercury (T-Hg) and methylmercury (MeHg) in the soil and water around the artisanal and small-scale gold mining (ASGM) area along the Cikaniki River, ...West Java, Indonesia. The concentration of T-Hg and MeHg in the forest soil ranged from 0.07 to 16.7 mg kg
−1
and from <0.07 to 2.0 μg kg
−1
, respectively, whereas it ranged from 0.40 to 24.9 mg kg
−1
and from <0.07 to 56.3 μg kg
−1
, respectively, in the paddy field soil. In the vertical variation of the T-Hg of forest soil, the highest values were observed at the soil surface, and these values were found to decrease with increasing depth. A similar variation was observed for MeHg and total organic carbon content (TOC), and a linear relationship was observed between them. Mercury deposited on the soil surface can be trapped and retained by organic matter and subjected to methylation. The slope of the line obtained for the T-Hg vs. TOC plot became larger near the ASGM villages, implying a higher rate of mercury deposition in these areas. In contrast, the plots of MeHg vs. TOC fell along the same trend line regardless of the distance from the ASGM village. Organic carbon content may be a predominant factor in controlling MeHg formation in forest soils. The T-Hg concentration in the river water ranged from 0.40 to 9.6 μg L
−1
. River water used for irrigation can prove to be a source of mercury for the paddy fields. The concentrations of Hg
0
and Hg
2+
in river water showed similar variations as that observed for the T-Hg concentration. The highest Hg
0
concentration of 3.2 μg L
−1
can be attributed to the waste inflow from work sites. The presence of Hg
0
in river water can become a source of mercury present in the atmosphere along the river. MeHg concentration in the river water was found to be 0.004–0.14% of T-Hg concentration, which was considerably lower than the concentrations of other Hg species. However, MeHg comprised approximately 0.2% of the T-Hg in paddy field soil. Mercury deposited from the atmosphere and the river water can be subjected to methylation. Paddy fields are very important ecosystems; therefore, the effect of MeHg on these ecosystems and human beings should be further investigated.
The distribution of mercury in the soil, sediment and river water around the artisanal small-scale gold mining (ASGM) area along the Cikaniki River, West Java, Indonesia, was investigated. The total ...mercury concentration (T-Hg) in the forest soil ranged from 0.11 to 7.0mgkg−1, and the highest value was observed at the ASGM village. In the vertical T-Hg profile around the villages, the highest value was observed at the soil surface, and the concentration decreased with depth. This result suggested that the mercury released by mining activity was dispersed through the atmosphere and deposited on the surface. The total organic carbon content (TOC) showed a similar vertical profile as the T-Hg, and a linear relationship was found between T-Hg and TOC. Mercury deposited on the surface can be absorbed by organic matter. The slope of the line was larger near the ASGM village, implying a higher rate of deposition of mercury. The T-Hg in the sediment ranged from 10 to 70mgkg−1, decreasing gradually toward the lower reaches of the river. Mining waste can be transported with the river flow and deposited along the river. The distribution of the mining waste can be determined using the mineralogical composition measured by X-ray fluorescence spectrometry.
•The distribution of T-Hg concentration around the ASGM site was investigated.•The Hg from the ASGM dispersed through the air and causes an increase in T-Hg at the soil surface.•The soil surface showed the highest T-Hg and the value decreased with depth.•A similar vertical distribution was observed between T-Hg and TOC.•The slope of T-Hg vs. TOC plots may reflect a depositional rate of mercury.
Endonasal endoscopic skull base surgery (ESBS) is perceived as having a high risk of infection because it is performed through the sinuses, which are not sterile.
To identify the bacteriological ...characteristics, incidence, mortality, and risk factors for intracranial infection after ESBS.
A retrospective analysis of the first 1,000 ESBS procedures performed at the University of Pittsburgh Medical Center from 1998 to 2008.
In 18 cases (1.8%), the patient developed meningitis. In 2 cases, the patient died within 2 months after surgery, of noninfectious causes. In 11 cases, cerebrospinal fluid (CSF) cultures had positive results. There were no predominant pathogens. Male sex (odds ratio OR, 3.97 95% confidence interval {CI}, 1.21-13.03; P = .02), history of a craniotomy or endonasal surgery (OR, 4.77 95% CI, 1.68-13.56; P = .02), surgery with higher levels of complexity (OR, 6.60 95% CI, 1.77-24.70; P = .003), the presence of an external ventricular drain or ventriculoperitoneal shunt at the time of surgery (OR, 6.38 95% CI, 1.07-38.09; P = .005), and postoperative CSF leak (OR, 12.99 95% CI, 4.24-39.82; P < .001) were risk factors for infection.
The incidence of infection of 1.8% in ESBS is comparable to that in open craniotomy. The most important risk factor was a postoperative CSF leak. All patients recovered from their infection.
A sensitive determination method for mercury speciation analysis was developed. Four mercury species, mercury ion, methylmercury, ethylmercury, and phenylmercury, were complexed with ...emetine-dithiocarbamate (emetine-CS2), and then injected onto a HPLC instrument coupled with a tris(2,2′-bipyridine)ruthenium(III) chemiluminescence detection system. The emetine-CS2 complexing agent was effectively used to measure the concentration in addition to serving as a separation and detection reagent. The calibration curves for these mercury complexes were linear in the range of 0.050 – 10 μg L−1 (as Hg). The limit of detection for (emetine-CS2)2Hg, emetine-CS2-methylmercury, emetine-CS2-ethylmercury, and emetine-CS2-phenylmercury were 30, 17, 21, and 22 ng L−1, respectively. The sensitivity of this method enables the determination of mercury species in water samples at sub-ppb levels. Furthermore, the method was applied to biological samples in combination with acid leaching and liquid–liquid extraction using emetine-CS2 as an extraction reagent. The determination results were in good agreement with the values of the certified reference materials.
Objective
To estimate the impact of mercury released from an artisanal small-scale gold mining (ASGM) activities on the ecosystem.
Methods
Total and organic mercury concentrations in paddy field soil ...and freshwater snails around an artisanal small-scale gold mining area were investigated. Paddy field soil samples and freshwater snails were collected from ten sites along the Cikaniki River. A site located in a national park, which was approximately 12 km upstream from the ASGM site, was considered the reference site for this study.
Results
The organic mercury concentration in soil samples collected at the ASGM site was n.d.–0.018 mg kg
−1
and that at the reference site was 0.005–0.008 mg kg
−1
. The organic mercury concentrations in the freshwater snails collected at the ASGM and reference sites were 0.38 ± 0.21 mg kg
−1
(31.0 ± 26.6% of total mercury,
n
= 38) and 0.056 ± 0.032 mg kg
−1
(40.5 ± 11.5% of total mercury,
n
= 16), respectively.
Conclusion
Although the original form of mercury in the mining waste was elemental mercury and/or Hg
2+
, the mercury form changed to organic mercury in environment and the organic mercury was concentrated two orders of magnitude, even in low-order organisms.
► Hg concentration in native epiphytic fern (Asplenium nidus) is corresponded with Hg in ambient air around ASGM in Indonesia. ► Hg level in air can be estimated from the Hg in A. nidus using a ...regression equation. ► Biomonitoring with A. nidus is a suitable means for estimating atmospheric Hg levels in tropical Asia.
Mercury pollution is caused by artisanal and small-scale gold mining (ASGM) operations along the Cikaniki River (West Java, Indonesia). The atmosphere is one of the primary media through which mercury can disperse. In this study, atmospheric mercury levels are estimated using the native epiphytic fern Asplenium nidus complex (A. nidus) as a biomonitor; these estimates shed light on the atmospheric dispersion of mercury released during mining.
Samples were collected from 8 sites along the Cikaniki Basin during September–November, 2008 and September–November, 2009.
The A. nidus fronds that were attached to tree trunks 1–3m above the ground were collected and measured for total mercury concentration using cold vapor atomic absorption spectrometry (CVAAS) after acid-digestion. The atmospheric mercury was collected using porous gold collectors, and the concentrations were determined using double-amalgam CVAAS.
The highest atmospheric mercury concentration, 1.8×103±1.6×103ngm−3, was observed at the mining hot spot, and the lowest concentration of mercury, 5.6±2.0ngm−3, was observed at the remote site from the Cikaniki River in 2009. The mercury concentrations in A. nidus were higher at the mining village (5.4×103±1.6×103ngg−1) than at the remote site (70±30ngg−1). The distribution of mercury in A. nidus was similar to that in the atmosphere; a significant correlation was observed between the mercury concentrations in the air and in A. nidus (r=0.895, P<0.001, n=14). The mercury levels in the atmosphere can be estimated from the mercury concentration in A. nidus using a regression equation: log (HgA.nidu/ngg−1)=0.740 log (HgAir/ngm−3) − 1.324.
To estimate the current contamination levels in Minamata Bay, the vertical and horizontal distributions of mercury in the sediment were investigated. Sediment core samples were collected in 2002, ...2006, 2008, and 2010 at 12 locations by gravity core sampling in Minamata Bay and Fukuro Bay, which is located in the southern part of Minamata Bay. The average total mercury concentrations during each year in the surface sediment were 2.47-3.34 and 3.50-4.66mgkg-1 for Minamata Bay and Fukuro Bay, respectively; significant variation in the values was not observed during the study period. The total mercury concentration in Fukuro Bay increased with increasing depth and reached a maximum at 8-14cm from the surface and decreased with increasing depth in the deeper layer. In Minamata Bay, the total mercury concentration did not change significantly from the surface to a depth of 10cm and the values were considerably higher than the background level. In the lower layers of the long cores taken from both areas, the total mercury concentration decreased with depth, and the deepest layers exhibited relatively uniform low values. These values can be considered to represent the background concentration in the absence of anthropogenic influence. The depth of the sediment affected by the effluent was estimated to be 20 plus or minus 7cm and 33 plus or minus 4cm for Minamata Bay and Fukuro Bay, respectively. Furthermore, it was estimated from the average concentration and volume of the contaminated layer that approximately 1ton of discharged mercury remained in the sediment of the two bays.
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