TABLE 2.

Mercury analyses of NGF hot springs

Location (reference)	Water temp (°C)b	pHb	MeHgc (ng liter−1)	HgTd (ng liter−1)	% MeHgT of HgTe	THg(s)f (μg g−1)	Hg(0)g (ng liter−1)
NGFa (this study)
Tiger Bath, TS1	35.3–40.5	2.9–3.0	1.56	1,031	0.15	3,467	25
Cub Bath, TS2	24.5–33.4	3.6–3.2	13.9	1,042	1.33	1,274	4.3
Hole to right of Tiger Bath, TS3	35.9–40.3	2.9–3.8	4.33	16,711	0.03	7,000	7.5
Hole 3 m from Tiger Bath, TS4	21.6	3.96	0.53	2,160	0.02
Cinnabar Bath, GN1	40.4	6.72	5.36	1,461	0.37
Jubilee Bath, GN2	38	6.45	1.28	244	0.52
Twin Bath, GN3	34.1	6.44	1.61	722	0.22
Kotanitanga, NS1B	32.4	6.54	4.28	487	0.88
Adjacent to Favourite Bath, NS3B	26.5	7.14	3.57	253	1.41
Waikato Bath, NS4B	45.5	6.7	0.90	326	0.28
Regional valuesh
NGF soils and waters (32)				17,000–710,000		0.017–0.35	2,000–78,500
Tiger Bath (32)	32–57	5–8		710,000
NGF nonthermal waters (32)				300–500
Puhipuhi mine waters (68)			0.61–1.02	69.6–240	0.3–1.6	35–1,748	0.06–0.50
Wairua River, Northland (84)				100–1,000		<100
YNPi
Nymph Lake spring no. 1 (5)			0.026	170	0.02
Nymph Lake spring no. 2 (5)			0.43	520	0.08
Roadside West Spring (5)	65	6.4	0.08	200	0.04
Thermal waters and microbial mats (5)	36.4–80	2.2–8.6	<0.013–0.43	15–520		0.0049–120
Acidic thermal springs (6)			<0.025	38–94
Acidophilic microbial mats (6)			0.03–1.62	2–71		0.16–18
Filtered thermal waters and microbial mats (7)	21.9–74.4	1.8–9.3		7.3–144		0.38–20.52
Reference standards and valuesh
North American lakes (31, 85)			0.003–6	0.04–74	8.11
North American rivers and streams (31, 85)			0.078–0.55	1–7	7.86
NZ drinking water standard				7,000
US EPA, acute aquatic life water standard				2,400
US EPA, chronic aquatic life water standard				770

^aNGF, Ngawha Geothermal Field.

^bMeasurements taken during each sampling campaign are provided as a range.

^cMeHg, methylmercury.

^dHg_T, total mercury.

^eThe fraction of total Hg as MeHg (as %) in filtered water samples.

^fTHg_(s), solid total mercury in hot spring sediments.

^gHg(0), gaseous elemental mercury above the springs.

^hPublished reference and regional background values are included for comparison.

ⁱYNP, Yellowstone National Park.