Impacts of atmospheric copper and cadmium deposition on the metal accumulation of camphor leaves and rings around a large smelter.

The atmospheric deposition of copper (Cu) and cadmium (Cd) was monitored in eight sites around a Cu smelter with similar distance to verify whether tree leaf and ring can be used as bio-indicators to track spatial pollution record. Results showed that total atmospheric deposition of Cu (103-1215 mg/m2/year) and Cd (3.57-11.2 mg/m2/year) were 4.73-66.6 and 3.15-12.2 times higher than those in background site (164 mg/m2/year and 0.93 mg/m2/year). The frequencies of wind directions significantly influenced the atmospheric deposition of Cu and Cd, and the highest atmospheric deposition of Cu and Cd were at the prevalent northeastern wind (JN), and low frequency south (WJ) and north (SW) winds for the lowest deposition fluxes. Since the bioavailability of Cd was higher than that of Cu, the atmospheric deposition of Cd was more easily adsorbed by tree leaf and ring, resulting in only significant relation between atmospheric Cd deposition and Cinnamomum camphora leaves and tree ring Cd. Although tree rings cannot correctly record the atmospheric Cu and Cd deposition, higher concentrations in the indigenous tree rings than the transplanted tree rings suggested that tree rings can reflect to some extent the variations of atmospheric deposition. Generally, spatial pollution of atmospheric deposition of heavy metals cannot reflect the distribution of soil total and available metals around the smelter, and only camphor leaf and tree ring can bio-indicate Cd deposition. A major implication of these findings is that leaf and tree ring can serve for biomonitoring purposes to assess the spatial distribution of atmospheric deposition metal with high bioavailability around a pollution source with similar distance.

Pollution resistance assessment of plants around chromite mine based on anticipated performance index, dust capturing capacity and metal accumulation index.

Plant species sustaining under a polluted environment for a long time are considered as potentially resistant species. Those plant species can be considered as an eco-sustainable tool used to bio-monitor and mitigate pollution. This study was carried out on a total of ten commonly available plant species to assess their anticipated performance index (API), dust capturing capacity (DCC), and metal accumulation index (MAI) in chromite mine and control areas. According to the anticipated performance index (API), Macaranga peltata (Roxb.) Müll.Arg., Holarrhena pubescens Wall. ex G.Don and Ficus hispida Roxb. ex Wall. are highly tolerant species while Terminalia arjuna (Roxb. ex DC.) Wight & Arn. and Trema orientalis (L.) Blume are intermediate tolerant species. F. hispida was also shown to have the highest dust capturing capacity (5.94 ± 0.43 mg/cm2) whereas that of Woodfordia fruticosa Kurz (1.03 ± 0.11 mg/cm2) was found to be lowest. The metal accumulation index ranged from 17.29 to 4.5 and 6.38 to 1.94 at the mine and control areas, respectively. Two-way ANOVA analysis revealed area-wise significant differences between biochemical and physiological parameters. Also, results showed that the pollution level and heavy metal affected different biochemical and physiological parameters of plant species at the mining area. The plant species with the highest API, DCC, and MAI value could be recommended for greenbelt development in different polluted areas.

Air pollution tolerance, metal accumulation and dust capturing capacity of common tropical trees in commercial and industrial sites.

Total nine tree species of common tropical trees were assessed for their air pollution tolerance, dust capturing capacity and possibility to act as metal bio-monitors in commercial, industrial and control sites. Two seasons sampling was done respectively in monsoon and post-monsoon, to study their seasonal variations. According to Air Pollution Tolerance Index (APTI) values Mangifera indica, Azadirachta indica and Ficus religiosa were the most tolerant species while Ficus bengalensis and Alstonia scholaris were intermediately tolerant towards air pollution. Single factor ANOVA of biochemical parameters between the sampling sites, revealed that APTI of plants did not vary significantly in both the seasons. Site-wise variation was significant both at commercial and industrial sites. The same trend of result was also found in Anticipated Performance Index (API) which also includes other social benefits. So, these species can be recommended for the green belt development in urban commercial and industrial areas. Ficus bengalensis, Ficus religiosa and Mangifera indica were also having the best dust capturing capacity as Scanning Electron Microscope image revealed that they have rough and large surface area of leaf with short petiole and large canopy structure. According to the Geoaccumulation index (Igeo) and Enrichment Factor (EF) of soil in the sampling sites were found to be contaminated with copper and cadmium. Psidium guajava, Mangifera indica, Alstonia scholaris and Ficus religiosa were found to be good phytoextractors of copper. They did not accumulate cadmium. So, these plants can be recommended as copper bioindicators. However, the metals accumulation efficiencies were high for Mangifera indica and Ficus religiosa.

Screening of seaweeds in the East China Sea as potential bio-monitors of heavy metals.

Seaweeds are good bio-monitors of heavy metal pollution and have been included in European coastal monitoring programs. However, data for seaweed species in China are scarce or missing. In this study, we explored the potential of seaweeds as bio-monitor by screening the natural occurring seaweeds in the "Kingdom of seaweed and shellfish" at Dongtou Islands, the East China Sea. Totally, 12 seaweed species were collected from six sites, with richness following the sequence of Rhodophyta > Phaeophyta > Chlorophyta. The concentration of heavy metals (Cu, Cr, Ni, Zn, Pb, Cd, As) in the seaweeds was determined, and the bioaccumulation coefficient was calculated. A combination of four seaweeds, Pachydictyon coriaceum, Gelidium divaricatum, Sargassum thunbergii, and Pterocladiella capillacea, were proposed as bio-monitors due to their high bioaccumulation capabilities of specific heavy metals in the East China Sea and hence hinted the importance of using seaweed community for monitoring of pollution rather than single species. Our results provide first-hand data for the selection of bio-monitor species for heavy metals in the East China Sea and contribute to selection of cosmopolitan bio-monitor communities over geographical large area, which will benefit the establishment of monitoring programs for coastal heavy metal contamination.