China is the largest atmospheric mercury (Hg) emitter in the world. Its Hg emissions and environmental impacts need to be evaluated. In this study, China's Hg emission inventory is updated to 2007 and applied in the GEOS-Chem model to simulate the Hg concentrations and depositions in China. Results indicate that simulations agree well with observed background Hg concentrations. The anthropogenic sources contributed 35–50% of THg concentration and 50–70% of total deposition in polluted regions. Sensitivity analysis was performed to assess the impacts of mercury emissions from power plants, non-ferrous metal smelters and cement plants. It is found that power plants are the most important emission sources in the North China, the Yangtze River Delta (YRD) and the Pearl River Delta (PRD) while the contribution of non-ferrous metal smelters is most significant in the Southwest China. The impacts of cement plants are significant in the YRD, PRD and Central China.

The Gulf of Aqaba (GoA) is of significant ecological value with unique ecosystems that host one of the most diverse coral communities in the world. However, these marine environments and biodiversity have been threatened by growing human activities. We investigated the levels and distributions of trace metals in surface seawater across the eastern coast of the Saudi GoA. Zn, Cu, Fe, B and Se in addition to total dissolved solids and seawater temperature exhibited decreasing trends northwards. While Mn, Cd, As and Pb showed higher average levels in the northern GoA. Metal input in waters is dependent on the adjacent geologic materials. The spatial variability of metals in water is also related to wave action, prevailing wind direction, and atmospheric dry deposition from adjacent arid lands. Also, water discharged from thermal desalination plants, mineral dust from fertilizer and cement factories are potential contributors of metals to seawater water, particularly, in the northern GoA.

Urban fugitive dust samples were collected to determine the chemical profiles of fugitive dust over Xi'an. Seventy eight samples were collected and divided into categories of paved road dust, construction dust, cement dust, and soil dust. Eighteen elements, including Na, Mg, Al, Si, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Ba, and Pb, and eight water–soluble inorganic ions, including Na+, Mg2−, Ca2−, NH4−, F−, Cl−, NO3− and SO42−, were measured. The most abundant elements in these urban dust samples were Al, Si, Ca, and Fe. Al, Si, K, and Ti and showed strong positive correlations with each other, indicating they are typical dust trace elements. In contrast, elements of Ca, Zn, As, and Pb had negative correlations to crustal elements. Si/Al, K/Al, Ti/Al, Mn/Al, and Fe/Al ratios varied insignificantly among these four samples types; these ratios are similar to the properties of loess, desert, and Gobi soil dust reported in previous studies. A significantly higher Ca/Al ratio was dominant in the chemical profile of the cement samples. In addition, high Pb/Al and Zn/Al ratios were detected in comparison with those in the Gobi soil, desert soil, and loess soil samples, which indicated that Pb/Al and Zn/Al ratios can be considered as markers of urban dust. To t a l water–soluble ions occupied only a small fraction (<5%) in the urban fugitive soil samples indicating that most of the materials in the fugitive dust were insoluble. Ca2+ and SO42− were the most abundant ions in all samples. Most of the Ca and K in the fugitive soil samples were in insoluble phases, which differ significantly in comparison with combustion sources. A strong correlation was observed between Ca2+ and estimated CO32− levels indicating that most of Ca2+ was in the form of CaCO3 rather than other calcium minerals in Xi’an fugitive dust.

Biomonitoring studies, based on pollutant accumulation analyses in tree leaves, allow evaluating the impact caused by air–dispersed pollutants on ecosystems, providing useful data, complementary to those obtained by instrumental monitoring. In particular, leaves of sclerophylls present morphological characteristics, such as the presence of hairs and of a tick cuticle, making them particularly useful in bioaccumulation studies. The first aim of this research was to compare heavy metal (HM) and polycyclic aromatic hydrocarbon (PAH) leaf accumulation capabilities of two Mediterranean tree species. The second aim was to evaluate the impact of a cement plant and/or of other anthropogenic activities occurring in industrial and urban areas on HM and PAH depositions. For these purposes, holm oak (Quercus ilex L.) and olive (Olea europaea L.) leaves collected along a transect industrial–urban–remote sites in southern Italy were employed. A different accumulation degree was observed for the two species. For HMs, Q. ilex leaves had the highest concentrations. The results showed that the influence of the cement plant emissions on pollutant concentrations was substantial in the area closer to clinker production and storage with the highest Pb, Ni, V, Cr, Fe, indeno(1,2,3–c,d)pyrene, benzo(g,h,i)perylene and benzo(a)anthracene leaf concentrations. However, Q. ilex leaves showed high HM and PAH concentrations also in the urban site, in relation to vehicular traffic emissions and depositions. The comparison of the results of the present study with those from the literature indicates that the overall air quality of the studied sites is not particularly compromised, also in proximity of the cement production. The use of holm oak should be preferred in biomonitoring due to its wider distribution compared to O. europaea.

This study assessed the level of contamination of the topsoil by Pb, Cu, Cr, Cd and Zn and the spatial distribution of these heavy metals around a cement factory. Thirty–eight composite soil samples were collected around the cement factory and subjected to nitric–perchloric acid digestion. Total metal contents of the soil were determined by flame atomic absorption spectrophotometry (FAAS) and the data generated were analyzed statistically. Spatial mapping of the distribution of heavy metals was done through the use of Inverse Distance Weighted technique (IDW) of ArcGIS 10. The results showed that the contamination domain of Cd was in the extreme domain while Pb and Cu levels in the soil were in the severe and moderate contamination domains. Zn and Cr posed no potential environmental hazard because of their low level in the soil. The spatial mapping of the heavy metals indicated Pb and Cu enrichment of the soil not only to come from cement production activities but also from vehicular activities while Cd enrichment of the soil was mainly from the cement production. Mapping of Zn and Cr distribution showed that their enrichments in the soil were from cement production activities. From these findings, it is highly recommended that environmental auditing of the cement production line be carried out to reduce the release of pollutants. It is also important that remediation activities be carried out on the soil to reduce the levels of Cd, Pb and Cu to avert potential ecological disasters.

Cemented paste backfill has been proposed in the mining industry for managing metal mill tailings. Low sulfide tailing (0.49 wt%) samples were prepared into different cemented pastes that were mixed with flocculants (polymerized aluminum chloride). The best mixing proportions of tailings, binder, flocculant, and filling structure (containing 0.5 wt% of ordinary Portland cement in one paste layer, 100 g/L polymerization aluminum chloride) were determined through leaching experiment. The addition of polymerization aluminum chloride improved the mechanical property of the paste. The strength of the cemented pastes by adding 100 g/L flocculant met the requirement of mine backfill. The cemented paste could also fix heavy metals, as shown in the paste leachate analysis of copper (Cu, about 0.01–0.08 mg/L of concentration) and chromium (Cr, about 0.03 mg/L of concentration). In summary, results from this study demonstrate that tailings can be managed by cemented paste backfill technique, preventing its contamination of the environment.

Alkalisation of soil by dust pollution from a cement plant was assumed to be the principal cause of changes in heavy metal uptake and allocation between hybrid aspen (Populus tremula × Populus tremuloides Michx.) compartments. Emission of over 40 years of alkaline dust (pH 12.3–12.6) into the atmosphere had resulted in an increase of pH and an elevated concentration of total heavy metals in the upper layer of the soil (0–30 cm), which is considerable even 14 years after dust pollution has stopped. The accumulation and allocation of heavy metals in stem, shoot and leaves varied between themselves and between the trees from polluted and unpolluted plantations depending more on the mobility of elements and pH than element concentrations in the alkaline soil. High levels of heavy metals in the soil do not mean similar concentrations and ratios in plants growing in contaminated soil.

In this study, improvement of acidic soil with respect to soil pH and exchangeable cations was attempted for sample with an initial pH of approximately 5. Acidic soil was amended with various waste resources in the range of 1 to 5 wt.% including waste oyster shells (WOS), calcined oyster shells (COS), Class C fly ash (FA), and cement kiln dust (CKD) to improve soil pH and exchangeable cations. Upon treatment, the soil pH was monitored for periods up to 3 months. The exchangeable cations were measured after 1 month of curing. After a curing period of 1 month, a maize growth experiment was conducted with selected-treated samples to evaluate the effectiveness of treatment. The treatment results indicate that in order to increase the soil pH to a value of 7, 1 wt.% of WOS, 3 wt.% of FA, and 1 wt.% of CKD are required. In the case of COS, 1 wt.% was more than enough to increase the soil pH value to 7 because of COS's strong alkalinity. Moreover, the soil pH increases after a curing period of 7 days and remains virtually unchanged thereafter up to 1 month of curing. Upon treatment, the summation of cations (Ca, Mg, K, and Na) significantly increased. The growth of maize is superior in the treated samples rather than the untreated one, indicating that the amelioration of acidic soil is beneficial to plant growth, since soil pH was improved and nutrients were replenished.

Deposition of cement dust on soils and plant surfaces is known to affect plant growth and the species composition of plant communities, but little is known about its effects (and those of its pH and constituents) on germination. Therefore, the aim of this study was to assess the toxicity of an aqueous cement extract, constituents of the extract and pH on the germination of seeds of a selected species, Medicago sativa. First, the effects of the extract were tested in assays with concentrations and exposure durations ranging from 0 to 1.0 g/mL and 4 to 96 h, respectively. At 0.8 g/mL, the extract strongly inhibited germination; a 4-h exposure reduced the germination rate, from 77 ± 1.8 to 50 ± 2.6 % (mean ± SE), while 8-h exposure completely inhibited it. Further, treatment at this concentration killed the non-germinating seeds, thus the inhibition was due to toxic effects. Neither the pH of the extract nor the concentration of its main soluble elements separately (K, Ca, S, Na, or Cr) caused the toxicity since germination rates were not significantly reduced when these variables were tested individually. However, a mixture of the elements in solution reduced germination rates, suggesting that they have adverse synergistic effects.

The production of cement in China is accompanied by various emissions, such as fine particulate matter, heavy metals, nitrogen oxides, sulfur oxides, carbon dioxide…. Moreover, cement kiln presents a potential health risk to its surroundings, linking to emissions of persistent organic pollutants (POPs), such as polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), in brief dioxins. Flue gas samples were collected from five typical cement kilns during twelve runs and were used to evaluate the levels and distribution of PCDD/Fs in the emissions from cement kilns. The PCDD/Fs concentrations (136 congeners) and I-TEQ values ranged from 2.3 to >40 ng/m³and 9.3 ∼ 90.8 × 10⁻³ ng I-TEQ/m³, respectively, which were lower than the emission standard in China (0.1 ng I-TEQ/m³). In weight units, the dominant congeners were OCDD, 1,2,3,4,6,7,8-HpCDF, and OCDF; 2,3,4,7,8-PeCDF is the largest contributor (36–66 %) to the total I-TEQ value of twelve runs. HxCDF and TCDF were the first two most abundant homologue groups (12–85 and 4–52 %), and the homologue concentration decreased with rising chlorine number for PCDDs. In addition, there was no marked difference in homologue profiles when solid wastes (refuse-derived fuel and municipal solid waste) and hazardous wastes (DDT and POPs) were combusted as supplemental fuels. The use of various supplemental fuels had no obvious effect on the fingerprint of PCDD/F homologues. Moreover, there was no significant difference in levels of PCDD/Fs emission due to the diversity of production capacity, which were consistent with reported previously. Air pollution control device had effect on the homologue profiles, and cement system with electrostatic precipitators (ESP) had more fractions of octachloro congeners to the total.