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Mercury (Hg) isotopic signatures were characterized in polished rice samples from China, U.S., and Indonesia (n = 45). Hg isotopes were also analyzed in paired hair samples for participants from China (n = 21). For the latter, we also quantified the proportion of methylmercury intake through rice (range: 31-100%), and the weekly servings of fish meals (range: 0-5.6 servings/weekly). For these participants, 29% (n = 6) never ingested fish, 52% (n = 11) ingested fish < twice/weekly, and 19% (n = 4) ingested fish ≥ twice/weekly. In rice and hair, both mass-dependent fractionation (MDF, reported as δ 202 Hg) and mass-independent fractionation (MIF, reported as Δ 199 Hg) of Hg isotopes were observed. Compared to rice, hair δ 202 Hg values were enriched on average (±1 standard deviation) by 1.9 ± 0.61‰, although the range was wide (range: 0.45‰, 3.0‰). Hair Δ 199 Hg was significantly inversely associated with %methylmercury intake from rice (Spearman's rho = -0.61, p < 0.01, n = 21), i.e., as the proportion of methylmercury intake from rice increased, MIF decreased. Additionally, hair Δ 199 Hg was significantly higher for participants ingesting fish ≥ twice/weekly compared to those who did not ingest fish or ingested fish < twice/weekly (ANOVA, p < 0.05, n = 21); Overall, results suggest that Hg isotopes (especially MIF) in human hair can be used to distinguish methylmercury intake from rice versus fish.

Mercury accumulation in montane forested areas plays an important role in global Hg cycling. In this study, we measured stable Hg isotopes in soil and litter samples to understand Hg accumulation on the forest floor along the eastern fringe of the Tibetan Plateau (TP). The low atmospheric Hg inputs lead to the small Hg pool size (23 ± 9 mg m -2 in 0-60 cm soil horizon), up to 1 order of magnitude lower than those found at sites in Southwest China, North America, and Europe. The slightly negative Δ 199 Hg (-0.12 to -0.05‰) in the litter at low elevations (3100 to 3600 m) suggests an influence of local anthropogenic emissions, whereas the more significant negative Δ 199 Hg (-0.38 to -0.15‰) at high elevations (3700 to 4300 m) indicates impact from long-range transport. Hg input from litter is more important than wet deposition to Hg accumulation on the forest floor, as evidenced by the negative Δ 199 Hg found in the surface soil samples. Correlation analyses of Δ 199 Hg versus total carbon and leaf area index suggest that litter biomass production is a predominant factor in atmospheric Hg inputs to the forest floor. Precipitation and temperature show indirect effects on Hg accumulation by influencing litter biomass production in the eastern TP.

Calcination of Hg ores has resulted in serious contamination of mercury (Hg) in the environment. To understand the mobilization of Hg in the calcine pile, the speciation of Hg in a profile of a large calcine pile in the Wanshan Mercury Mine, SW China was investigated using the X-ray absorption spectroscopy (XANES), to understand the mobilization of Hg in the calcine pile. Higher concentrations of Hg were observed at the 30-50 cm depth of the profile, corresponding to a cemented layer. This layer is observed in the entire pile, and was formed due to cementation of calcines. Hg species in calcines include cinnabar (α-HgS), metacinnabar (β-HgS), elemental Hg(0), and minor mercuric chloride (HgCl 2 ), but these Hg species show dramatic changes in the profile. Variations in Hg speciation suggest that extensive mobilization of Hg can occur during weathering processes. We show that the cemented layer can prevent the leaching of Hg and the emission of Hg(0) from the pile. High MeHg concentrations were found near the cemented layer, indicating Hg methylation occurs. This study provides important insights into the environmental risk of Hg in mining areas., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Methylmercury (MeHg) exposure can cause adverse reproductive and neurodevelopmental health effects. Estuarine fish may be exposed to MeHg produced in rivers and their watersheds, benthic sediment, and the marine water column, but the relative importance of each source is poorly understood. We measured stable isotopes of mercury (δ 202 Hg, Δ 199 Hg, and Δ 201 Hg), carbon (δ 13 C), and nitrogen (δ 15 N) in fish with contrasting habitats from a large subarctic coastal ecosystem to better understand MeHg exposure sources. We identify two distinct food chains exposed to predominantly freshwater and marine MeHg sources but do not find evidence for a benthic marine MeHg signature. This is consistent with our previous research showing benthic sediment is a net sink for MeHg in the estuary. Marine fish display lower and less variable Δ 199 Hg values (0.78‰ to 1.77‰) than freshwater fish (0.72‰ to 3.14‰) and higher δ 202 Hg values (marine: 0.1‰ to 0.57‰; freshwater: -0.76‰ to 0.15‰). We observe a shift in the Hg isotopic composition of juvenile and adult rainbow smelt (Osmerus mordax) when they transition between the freshwater and marine environment as their dominant foraging territory. The Hg isotopic composition of Atlantic salmon (Salmo salar) indicates they receive most of their MeHg from the marine environment despite a similar or longer duration spent in freshwater regions. We conclude that stable Hg isotopes effectively track fish MeHg exposure sources across different ontogenic stages.

The isotopic composition of atmospheric total gaseous mercury (TGM) and particle-bound mercury (PBM) and mercury (Hg) in litterfall samples have been determined at urban/industrialized and rural sites distributed over mainland China for identifying Hg sources and transformation processes. TGM and PBM near anthropogenic emission sources display negative δ(202)Hg and near-zero Δ(199)Hg in contrast to relatively positive δ(202)Hg and negative Δ(199)Hg observed in remote regions, suggesting that different sources and atmospheric processes force the mass-dependent fractionation (MDF) and mass-independent fractionation (MIF) in the air samples. Both MDF and MIF occur during the uptake of atmospheric Hg by plants, resulting in negative δ(202)Hg and Δ(199)Hg observed in litter-bound Hg. The linear regression resulting from the scatter plot relating the δ(202)Hg to Δ(199)Hg data in the TGM samples indicates distinct anthropogenic or natural influences at the three study sites. A similar trend was also observed for Hg accumulated in broadleaved deciduous forest foliage grown in areas influenced by anthropogenic emissions. The relatively negative MIF in litter-bound Hg compared to TGM is likely a result of the photochemical reactions of Hg(2+) in foliage. This study demonstrates the diagnostic stable Hg isotopic composition characteristics for separating atmospheric Hg of different source origins in China and provides the isotopic fractionation clues for the study of Hg bioaccumulation.

This study presents the first measurement of Hg stable isotope fractionation during gas-phase oxidation of Hg(0) vapor by halogen atoms (Cl(•), Br(•)) in the laboratory at 750 ± 1 Torr and 298 ± 3 K. Using a relative rate technique, the rate coefficients for Hg(0)+Cl(•) and Hg(0)+Br(•) reactions are determined to be (1.8 ± 0.5) × 10(-11) and (1.6 ± 0.8) × 10(-12) cm(3) molecule(-1) s(-1), respectively. Results show that heavier isotopes are preferentially enriched in the remaining Hg(0) during Cl(•) initiated oxidation, whereas being enriched in the product during oxidation by Br(•). The fractionation factors for (202)Hg/(198)Hg during the Cl(•) and Br(•) initiated oxidations are α(202/198) = 0.99941 ± 0.00006 (2σ) and 1.00074 ± 0.00014 (2σ), respectively. A Δ(199)Hg/Δ(201)Hg ratio of 1.64 ± 0.30 (2σ) during oxidation of Hg(0) by Br atoms suggests that Hg-MIF is introduced by the nuclear volume effect (NVE). In contrast, the Hg(0) + Cl(•) reaction produces a Δ(199)Hg/Δ(201)Hg-slope of 1.89 ± 0.18 (2σ), which in addition to a high degree of odd-mass-number isotope MIF suggests impacts from MIF effects other than NVE. This reaction also exhibits significant MIF of (200)Hg (Δ(200)Hg, up to -0.17‰ in the reactant) and is the first physicochemical process identified to trigger (200)Hg anomalies that are frequently detected in atmospheric samples.

The Tibetan Plateau (TP), known as the "Third Pole", is a critical zone for atmospheric mercury (Hg) deposition. Increasing anthropogenic activities in the globe leads to environmental changes, which may affect the loading, transport and deposition of Hg in the environment. However, the deposition history and geochemical cycling of Hg in the TP is still uncertain. Our records of Hg and Hg isotopes in sediment profiles of the two largest lakes in the TP, Lake Qinghai and Nam Co, show increased Hg influx since last century, with the maximum Hg influx enrichment ratios of 5.4 and 3.5 in Lake Qinghai and Nam Co, respectively. Shifts in negative δ (202)Hg in Lake Qinghai (-4.55 to -3.15‰) and Nam Co (-5.04 to -2.16‰) indicate increased atmospheric Hg deposition through rainfall, vegetation and runoff of soils. Mass independent fractionation of both even-Hg (∆ (200)Hg: +0.05 to +0.10‰) and odd-Hg (∆ (199)Hg: +0.12 to +0.31‰) isotopes were observed. Positive Δ (200)Hg suggest high proportion of precipitation-derived Hg in the TP, whereas the positive Δ (199)Hg results from Hg(II) photo-reduction. Both lakes show increasing Δ (199)Hg since the 1900 s, and we conclude that with the decrease of ice duration, Hg(II) photo-reduction may have been accelerated in these TP lakes.

Coastal and estuarine regions are important areas of mercury pollution. Therefore, it is important to properly characterize the sources and bioaccumulation processes of mercury in these regions. Here, we present mercury stable isotopic compositions in 18 species of wild marine fish collected from the Pearl River Estuary (PRE), south China. Our results showed variations in mass-independent fractionation (Δ(199)Hg: +0.05 ± 0.10‰ to +0.59 ± 0.30‰) with a Δ(199)Hg/Δ(201)Hg of ∼1.26, suggesting that aqueous MeHg underwent photo-degradation prior to incorporation into the food chain. For the results, we discovered small but significant differences of Δ(199)Hg values among herbivorous, demersal, and carnivorous fish, indicating that different feeding guilds of fish may have incorporated MeHg with various degrees of photo-demethylation. The consistent mercury isotope compositions between fish feeding habitat and mercury sources in the estuary provide potentially important findings on the transformation and bioaccumulation of this toxic metal in subtropical coastal environments., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

During the past few years, evidence of mass independent fractionation (MIF) for mercury (Hg) isotopes have been reported in the Earth's surface reservoirs, mainly assumed to be formed during photochemical processes. However, the magnitude of Hg-MIF in interior pools of the crust is largely unknown. Here, we reported significant variation in Hg-MIF signature (Δ(199)Hg: -0.24 ~ + 0.18‰) in sphalerites collected from 102 zinc (Zn) deposits in China, indicating that Hg-MIF can be recorded into the Earth's crust during geological recycling of crustal material. Changing magnitudes of Hg-MIF signals were observed in Zn deposits with different formations, evidence that Hg isotopes (especially Hg-MIF) can be a useful tracer to identify sources (syngenetic and epigenetic) of Hg in mineral deposits. The average isotopic composition in studied sphalerites (δ(202)Hg average: -0.58‰; Δ(199)Hg average: +0.03‰) may be used to fingerprint Zn smelting activities, one of the largest global Hg emission sources.

The concentrations and isotopic compositions of mercury (Hg) in surface sediments of the Pearl River Estuary (PRE) and the South China Sea (SCS) were analyzed. The data revealed significant differences between the total Hg (THg) in fine-grained sediments collected from the PRE (8-251 μg kg(-1)) and those collected from the SCS (12-83 μg kg(-1)). Large spatial variations in Hg isotopic compositions were observed in the SCS (δ(202)Hg, from -2.82 to -2.10‰; Δ(199)Hg, from +0.21 to +0.45‰) and PRE (δ(202)Hg, from -2.80 to -0.68‰; Δ(199)Hg, from -0.15 to +0.16‰). The large positive Δ(199)Hg in the SCS indicated that a fraction of Hg has undergone Hg(2+) photoreduction processes prior to incorporation into the sediments. The relatively negative Δ(199)Hg values in the PRE indicated that photoreduction of Hg is not the primary route for the removal of Hg from the water column. The riverine input of fine particles played an important role in transporting Hg to the PRE sediments. In the deep ocean bed of the SCS, source-related signatures of Hg isotopes may have been altered by natural geochemical processes (e.g., Hg(2+) photoreduction and preferential adsorption processes). Using Hg isotope compositions, we estimate that river deliveries of Hg from industrial and urban sources and natural soils could be the main inputs of Hg to the PRE. However, the use of Hg isotopes as tracers in source attribution could be limited because of the isotope fractionation by natural processes in the SCS.

Total mercury (Hg) concentrations (THg) and stable mercury isotopic compositions were measured in coal samples (n = 61) from major coal producing fields in China. The THg concentrations in coals ranged from 0.05 to 0.78 μg g(-1), with a geometric mean of 0.22 μg g(-1). Hg isotopic compositions in coals showed large variations both in mass-dependent fractionation (MDF, δ(202)Hg: -2.36 to -0.14‰) and mass-independent fractionation (MIF, Δ(199)Hg: -0.44 to +0.38‰). The MIF signatures in coals may reveal important information on the coal-forming conditions (e.g., humic and sapropelic). The Δ(199)Hg/Δ(201)Hg of ∼1 determined in coals indicated that a portion of Hg has been subjected to photoreduction process prior to being incorporated to coals. On the basis of THg, Hg isotopic signatures, and other geological factors (e.g., total ash content and total sulfur content), the potential sources of Hg in coals from different coal producing regions were estimated. The main source of Hg in coals from southwestern China and eastern part of northern China is likely geogenic Hg, whereas the source of Hg in coals from other parts of northern China is mainly biogenic Hg. Finally, we estimated that Hg emission from coal combustion in China is characterized by diagnostic Hg isotopic signatures (δ(202)Hg: ∼-0.70‰ and Δ(199)Hg: ∼-0.05‰). The present study demonstrates that Hg isotopes can serve as a tool in understanding the sources and transformation of Hg in coals and may also be used as a tracer to quantify Hg emissions from coal combustion.

Diurnal variations of water total Hg, reactive Hg, and dissolved gaseous Hg concentrations and mercury flux were monitored at 2 sites in warm and cold seasons in an alkaline reservoir in southwestern China. Concentrations of total Hg and reactive Hg, as well as Hg fluxes, usually exhibited a consistent diurnal trend, with elevated values observed during the day. The increasing reactive Hg concentrations and Hg fluxes were highly related to the incident intensity of solar radiation, suggesting that sunlight-induced processes played an important role in the transformation of Hg in the study area. Dissolved gaseous Hg concentrations experienced different diurnal variations among the sampling sites, with peak dissolved gaseous Hg at midday under sunny weather conditions and in the early morning under cloudy and/or partially cloudy weather conditions. The peak values of dissolved gaseous Hg observed at midday agree well with previous results and highlight the sunlight-induced production of dissolved gaseous Hg in freshwaters, whereas dissolved gaseous Hg peaks at night suggest that microbial activity might be an additional mechanism for dissolved gaseous Hg production in surface waters. Total Hg, reactive Hg, and dissolved gaseous Hg concentrations and Hg fluxes in the warm season were consistently higher than those in the cold season; this is probably attributable to the combined effect of seasonal variations of environmental parameters, transformation of Hg species, and microbial activities., (© 2013 SETAC.)

To study the sources and transformations of Hg in the rice plant ( Oryza sativa L.), stable Hg isotope variations in different tissues (foliage, root, stem, and seed) of rice which were collected from the Wanshan mercury mine (WSMM, Guizhou province, SW China) were investigated by multicollector inductively coupled plasma mass spectrometry (MC-ICP-MS). In comparison, Hg isotope compositions of paddy soil, lichen, and direct ambient air samples in WSMM were also analyzed. We observed that mass dependent fractionation (MDF) of Hg differed by up to ∼ 3.0‰ in δ(202)Hg values and that mass independent fractionation (MIF) of Hg isotopes affected the odd Hg isotopes to produce a ∼ 0.40‰ range in Δ(199)Hg (and Δ(201)Hg) values in tissues of rice plant. The 1:1 Δ(199)Hg/Δ(201)Hg ratio in tissues of rice supported the hypothesis that a fraction of Hg in tissues of rice plants has undergone a photoreduction process prior to being accumulated by rice plants. We suggest that the variation of MIF represents a mixing between soil Hg and atmospheric Hg in rice plants. The estimated fraction of atmospheric Hg (f) in tissues of rice followed the trend of f leaf > f stem > f seed > f root. Finally, we demonstrated a significant MDF of >1.0‰ in δ(202)Hg during the processes of absorption of atmospheric Hg by leaf tissues and of absorption of soil Hg by roots. Our study demonstrated that Hg isotopes may represent an important contribution both to the study of Hg transportation in plants and to the understanding of sources of Hg contamination to critical food crops.

Purpose: The distribution and speciation of mercury in surface water of East River, Guangdong province, China were investigated., Methods: All told 63 water samples were collected during a bi-weekly sampling campaign from July 15th to 26th, 2009., Results: Total mercury (THg) concentrations in water samples ranged from 11 to 49 ng/L. Maximum levels of THg were measured in the lower reaches of East River, where it passes through a major industrial area adjacent to Dongguang city. Higher ratios of dissolved mercury (THg (aq)) in proportion to THg were restricted to the downstream section of East River. Concentrations of the minor constituent methyl mercury varied in the range from 0.08 to 0.21 ng/L. On average, methyl mercury made up 0.8% and 0.56% of THg (aq) and THg, respectively. Dissolved species dominated the speciation of methyl mercury in proportions up to 81%, which may imply that methyl mercury is largely produced in situ within the river water. Environmental factors (such as water temperature, dissolved oxygen, etc.) are regarded to play an important role in Hg methylation processes were monitored and assessed., Conclusions: In an international perspective, East River must be classified as a polluted river with considerably sources within its industrial areas. The THg (aq) and particle mercury fluxes to the Pearl River Estuary by East River run-off were estimated to be 0.31 ± 0.11 and 0.17 ± 0.13 t/year, respectively. Hence, in total nearly 0.5 t Hg is annually released to the sea from the East River tributary.

The level of mercury bioaccumulation in wild plants; the distribution of bioavailable Hg, elemental Hg, and total Hg in soil; and the concentration of total gaseous Hg (TGM) in ambient air was studied at three different mining sites (SiKeng [SK], WuKeng [WK], and GouXi [GX]) in the Wanshan mercury mining district of China. Results of the present study showed that the distribution of soil total Hg, elemental Hg, bioavailable Hg, and TGM varies across the three mining sites. Higher soil total Hg (29.4-1,972.3 mg/kg) and elemental Hg (19.03-443.8 mg/kg) concentrations were recorded for plots SK and WK than for plot GX. Bioavailable Hg was lower at plot SK and GX (SK, 3-12 ng/g; GX, 9-14 ng/g) than at plot WK (11-1,063 ng/g), although the TGM concentration in the ambient air was significantly higher for plot GX (52,723 ng/m(3) ) relative to WK (106 ng/m(3) ) and SK (43 ng/m(3)). Mercury in sampled herbage was elevated and ranged from 0.8 to 4.75 mg/kg (SK), from 2.17 to 34.38 mg/kg (WK), and from 47.45 to 136.5 mg/kg (GX). Many of the sampled plants are used as fodder or for medicinal purposes. High shoot Hg concentrations may therefore pose an unacceptable human health risk. Statistical analysis of the recorded data showed that the Hg concentration in plant shoots was positively correlated with TGM and that the Hg concentration in roots was positively correlated with the bioavailable Hg concentration in the soil. The bioaccumulation factor (BAF) in the present study was defined with reference to the concentration of bioavailable Hg in the soil (Hg([root]) /Hg([bioavail])). Three plant species, Macleaya cordata L., Achillea millefolium L., and Pteris vittata L., showed enhanced accumulation of Hg and therefore may have potential for use in the phytoremediation of soils of the Wanshan mining area., (Copyright © 2011 SETAC.)

In China, total Hg (HgT) and methylmercury (MeHg) were quantified in rice grain grown in three sites using water-saving rice cultivation methods, and in one Hg-contaminated site, where rice was grown under flooded conditions. Polished white rice concentrations of HgT (water-saving: 3.3±1.6 ng/g; flooded: 110±9.2 ng/g) and MeHg (water-saving 1.3±0.56 ng/g; flooded: 12±2.4 ng/g) were positively correlated with root-soil HgT and MeHg contents (HgT: r2=0.97, MeHg: r2=0.87, p<0.05 for both), which suggested a portion of Hg species in rice grain was derived from the soil, and translocation of Hg species from soil to rice grain was independent of irrigation practices and Hg levels, although other factors may be important. Concentrations of HgT and other trace elements were significantly higher in unmilled brown rice (p<0.05), while MeHg content was similar (p>0.20), indicating MeHg infiltrated the endosperm (i.e., white rice) more efficiently than inorganic Hg(II)., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

China has undertaken several major programs of terrestrial ecosystem restoration (ERPs) in recent years, including the Natural Forest Protection Program (NFPP) and the Sloping Land Conversion Program (SLCP). There have been reports on the implementation of these programs, their preliminary impacts, and the problems encountered in carrying them out; a great deal has been learned from these studies. Nonetheless, China's ERPs are not limited to the NFPP and the SLCP. Because a complete documentation and a timely update of these major efforts are still missing from the literature, it is difficult to gauge the scope of these programs and the scale of their impacts. In addition, a more thorough and critical analysis of both the general ERP policy and the specific technical measures used in implementing the ERPs remains urgently needed. The purpose of this article is to tackle these tasks. Overall, with the huge government investments in the ERPs, tremendous progress has been made in implementing them. To complete them successfully and to fundamentally improve the targeted ecosystems, however, it is essential for China to have a more balanced and comprehensive approach to ecological restoration. This approach must include: adopting better planning and management practices; strengthening the governance of program implementation; emphasizing the active engagement of local people; establishing an independent, competent monitoring network; and conducting adequate assessments of program effectiveness and impact.

In the late 1990s, the Chinese government initiated some new programs and consolidated other existing ones of ecological restoration and resource development in its forest sector, and renamed them as "Priority Forestry Programs," or PFPs. They include the Natural Forest Protection Program (NFPP), the Sloping Land Conversion Program (SLCP), the Desertification Combating Program around Beijing and Tianjin (DCBT), the Shelterbelt Development Program (SBDP), and the Wildlife Conservation and Nature Reserve Development Program (WCNR). In addition to improving the environmental and resource conditions, a frequently reiterated goal of these PFPs is to increase rural households' income, therefore discussing why looking at rural household income impacts might be an important part of forest program evaluation. Thus, an interesting and important question is: How has implementing the PFPs affected the farmers' income and poverty status? This article addresses this question using a fixed-effects model and a panel dataset that covers 1968 households in four provinces for ten consecutive years (1995-2004). The empirical evidence indicates that their effects are mixed. The SLCP, the SBDP, and the NFPP have made positive impact and, by far, the SLCP has the largest effect. But the WCNR and the DCBT still have not had a pronounced overall effect due to their short time span of execution, even though they may have exerted certain influence at the margin. Notably, the impact of the WCNR, if any, is negative.

Quantifying the spatial and temporal dynamics of carbon stocks in terrestrial ecosystems and carbon fluxes between the terrestrial biosphere and the atmosphere is critical to our understanding of regional patterns of carbon budgets. Here we use the General Ensemble biogeochemical Modeling System to simulate the terrestrial ecosystem carbon dynamics in the Jinsha watershed of China's upper Yangtze basin from 1975 to 2000, based on unique combinations of spatial and temporal dynamics of major driving forces, such as climate, soil properties, nitrogen deposition, and land use and land cover changes. Our analysis demonstrates that the Jinsha watershed ecosystems acted as a carbon sink during the period of 1975-2000, with an average rate of 0.36 Mg/ha/yr, primarily resulting from regional climate variation and local land use and land cover change. Vegetation biomass accumulation accounted for 90.6% of the sink, while soil organic carbon loss before 1992 led to a lower net gain of carbon in the watershed, and after that soils became a small sink. Ecosystem carbon sink/source patterns showed a high degree of spatial heterogeneity. Carbon sinks were associated with forest areas without disturbances, whereas carbon sources were primarily caused by stand-replacing disturbances. It is critical to adequately represent the detailed fast-changing dynamics of land use activities in regional biogeochemical models to determine the spatial and temporal evolution of regional carbon sink/source patterns.

This article surveys the recent literature that has assessed China's ecological restoration programs, including the Sloping Land Conversion Program (SLCP) and the Natural Forest Protection Program (NFPP). Our presumption is that the performance of these programs should be determined by their effectiveness of implementation and significance of impact. Implementation effectiveness can be measured with such indicators as land area converted or conserved, and survival and stocking rates of restored vegetation, while impact significance can be gauged by the induced changes in ecosystem functionality and stability (erosion control, biodiversity protection, etc.) and socioeconomic conditions. Coupling this matrix with an exhaustive search of the publications, we find that: (1) the implementation effectiveness has not been examined as extensively as the impact significance; (2) efforts to assess the impact significance have concentrated on the SLCP, particularly its socioeconomic effects: growth of income, alternative industry, and employment, and likelihood of re-conversion; and (3) most of the socioeconomic studies are based on rural household surveys and discrete choice and difference in differences models. While much has been learned from previous studies, a lot more needs to be done in improving our understanding of the program execution and impacts. Future work should pay more attention to the NFPP and other programs, and the environmental impacts and the implementation effectiveness of all of them. To these ends, analysts must gather more field data regarding the evolving ecosystem conditions and socioeconomic information of higher aggregation, and conduct their research across scales and disciplines, with better application of geospatial technology and more effective modeling.

Land degradation due to erosion is one of the most serious environmental problems in China. To reduce land degradation, the government has taken a number of conservation and restoration measures, including the Sloping Land Conversion Program (SLCP), which was launched in 1999. A logical question is whether these measures have reduced soil erosion at the regional level. The objective of this article is to answer this question by assessing soil erosion dynamics in the Zuli River basin in the Loess Plateau of China from 1999 to 2006. The MMF (Morgan, Morgan and Finney) model was used to simulate changes in runoff and soil erosion over the period of time during which ecological restoration projects were implemented. Some model variables were derived from remotely sensed images to provide improved land surface representation. With an overall accuracy rate of 0.67, our simulations show that increased ground vegetation cover, especially in forestlands and grasslands, has reduced soil erosion by 38.8% on average from 1999 to 2006. During the same time period, however, the change in rainfall pattern has caused a 13.1% +/- 4.3% increase in soil erosion, resulting in a net 25.7% +/- 8.5% reduction in soil erosion. This suggests that China's various ecological restoration efforts have been effective in reducing soil loss.