The soil displacement measurement of mercury emission flux of the sewage irrigation farmlands in Northern China

Figures & data

Table 1. Basic information of soils for this displacement measurement

Test plot		Background of THg	THg	TOM		Water resources	History of
(Province, basin)	Location	(ng g^−1)	(ng g^−1)	(%)	pH	for irrigation	sewage irrigation
Taiyuan	E 112.4867°,	23	61.37 ± 0.51	6.68 ± 0.45	7.93 ± 0.06	Agricultural sewage	10 ~ 30
(Shanxi, Fen river)	N 37.6925°
Luancheng	E 114.6833°,	36	81.64 ± 0.44	6.58 ± 0.38	7.86 ± 0.04	Groundwater	–
(This locality)	N 37.8833°
Tianjin	E 117.0111°,	44	104.64 ± 0.75	6.39 ± 0.32	7.80 ± 0.10	Industrial and	30
(Tianjin, North canal)	N 39.4797°					sanitary sewage
Shijiazhuang	E 114.7761°,	36	1042.73 ± 11.39	8.64 ± 0.89	7.56 ± 0.07	Industrial and	20 ~ 40
(Hebei, Xiao river)	N 37.7117°					sanitary sewage
Xi’an	E 108.8881°,	60	1543.89 ± 35.14	6.54 ± 0.15	7.58 ± 0.05	Industrial sewage	20 ~ 50
(Shaanxi, Wei river)	N 34.3375°

TOM represents for total organic matter content in soil. The background values of THg were obtained from references (China National Environmental Monitoring Centre, 1994).

Figure 1. Boxplots of the soil-air TGM exchange fluxes (ng m⁻² d⁻¹) during different growth stages of maize-wheat in each plot (a–e); Accumulative soil-air TGM exchange fluxes (ug m⁻²) during the whole observation in the five plots (f)

Figure 2. Effects of soil total mercury concentration (a), soil temperature (b), and soil moisture (c) on soil-air TGM exchange fluxes and the ratios of soil-air TGM exchange flux between daytime and nighttime (d) in different sewage irrigation plots (mean ± SD)

Figure 3. (a) Effect of ambient-air total gaseous mercury on soil-air TGM exchange flux in different sewage irrigation plots; (b) Correlation between total soil mercury concentration and compensation points of soil-air TGM exchange

China National Environmental Monitoring Centre. 1994. The Atlas of Soil Environmental Background Value in the People’s Republic of China (in Chinese). Beijing: China Environmental Science Press.

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