Isotopic Fractionation and Source Appointment of Methylmercury and Inorganic Mercury in a Paddy Ecosystem

Bioaccumulation of methylmercury (MeHg) in rice grains has been an emerging issue of human health, but the mechanism of bioaccumulation is still poorly understood. Mercury (Hg) isotope measurements are powerful tools for tracing the sources and biogeochemical cycles of Hg in the environment. In this study, MeHg compound-specific stable isotope analysis (CSIA) was developed in paddy soil and rice plants to trace the biogeochemical cycle of Hg in a paddy ecosystem during the whole rice-growing season. Isotopic fractionation was analyzed separately for MeHg and inorganic Hg (IHg). Results showed distinct isotopic signals between MeHg and IHg in rice plants, indicating different sources. δ202Hg values of MeHg showed no significant differences between roots, stalks, leaves, and grains at each growth stage. The similar Δ199Hg values of MeHg between rice tissues (0.14 ± 0.08‰, 2SD, n = 12), soil (0.13 ± 0.03‰, 2SD, n = 4), and irrigation water (0.17 ± 0.09‰, 2SD, n = 5) suggested that the soil-water system was the original source of MeHg in rice plants. Δ199Hg values of IHg in the paddy ecosystem indicated that water, soil, and atmosphere contributed to IHg in grains, leaves, stalks, and roots with varying degree. This study demonstrates that successful application of MeHg CSIA can improve our understanding of the sources and bioaccumulation mechanisms of MeHg and IHg in the paddy ecosystems.

Medienart:

E-Artikel

Erscheinungsjahr:

2020

Erschienen:

2020

Enthalten in:

Zur Gesamtaufnahme - volume:54

Enthalten in:

Environmental science & technology - 54(2020), 22 vom: 17. Nov., Seite 14334-14342

Sprache:

Englisch

Beteiligte Personen:

Qin, Chongyang [VerfasserIn]
Du, Buyun [VerfasserIn]
Yin, Runsheng [VerfasserIn]
Meng, Bo [VerfasserIn]
Fu, Xuewu [VerfasserIn]
Li, Ping [VerfasserIn]
Zhang, Leiming [VerfasserIn]
Feng, Xinbin [VerfasserIn]

Links:

Volltext

Themen:

Accumulation
FXS1BY2PGL
Journal Article
Mercury
Mercury isotope
Methylmercury
Methylmercury Compounds
Paddy ecosystem
Research Support, Non-U.S. Gov't
Soil
Soil Pollutants

Anmerkungen:

Date Completed 04.02.2021

Date Revised 04.02.2021

published: Print-Electronic

Citation Status MEDLINE

doi:

10.1021/acs.est.0c03341

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM316812323