The relative importance of sediment and water column supplies of nutrients to the growth and tissue nutrient content of the green macroalga Enteromorpha intestinalis along an estuarine resource gradient

Large blooms of opportunistic green macroalgae such as Enteromorpha intestinalis are of ecological concern in estuaries worldwide. Macroalgae derive their nutrients from the water column but estuarine sediments may also be an important nutrient source. We hypothesized that the importance of these nutrient sources to E. intestinalis varies along a nutrient-resource gradient within an estuary. We tested this in experimental units constructed with water and sediments collected from 3 sites in Upper Newport Bay estuary, California, US, that varied greatly in water column nutrient concentrations. For each site there were three treatments: sediments + water; sediments + water + Enteromorpha intestinalis (algae); inert sand + water + algae. Water in units was exchanged weekly simulating low turnover characteristic of poorly flushed estuaries. The importance of the water column versus sediments as a source of nutrients to E. intestinalis varied with the magnitude of the different sources. When initial water column levels of dissolved inorganic nitrogen (DIN) and soluble reactive phosphorus (SRP) were low, estuarine sediments increased E. intestinalis growth and tissue nutrient content. In experimental units from sites where initial water column DIN was high, there was no effect of estuarine sediments on E. intestinalis growth or tissue N content. Salinity, however, was low in these units and may have inhibited growth. E. intestinalis growth and tissue P content were highest in units from the site with highest initial sediment nutrient content. Water column DIN was depleted each week of the experiment. Thus, the water column was a primary source of nutrients to the algae when water column nutrient supply was high, and the sediments supplemented nutrient supply to the algae when water column nutrient sources were low. Depletion of water column DIN in sediment + water units indicated that the sediments may have acted as a nutrient sink in the absence of macroalgae. Our data provide direct experimental evidence that macroalgae utilize and ecologically benefit from nutrients stored in estuarine sediments.     

Integrated assessment of heavy metal contamination in sediments from a coastal industrial basin, NE China

The purpose of this study is to investigate the current status of metal pollution of the sediments from urban-stream, estuary and Jinzhou Bay of the coastal industrial city, NE China. Forty surface sediment samples from river, estuary and bay and one sediment core from Jinzhou bay were collected and analyzed for heavy metal concentrations of Cu, Zn, Pb, Cd, Ni and Mn. The data reveals that there was a remarkable change in the contents of heavy metals among the sampling sediments, and all the mean values of heavy metal concentration were higher than the national guideline values of marine sediment quality of China (GB 18668-2002). This is one of the most polluted of the world's impacted coastal systems. Both the correlation analyses and geostatistical analyses showed that Cu, Zn, Pb and Cd have a very similar spatial pattern and come from the industrial activities, and the concentration of Mn mainly caused by natural factors. The estuary is the most polluted area with extremely high potential ecological risk; however the contamination decreased with distance seaward of the river estuary. This study clearly highlights the urgent need to make great efforts to control the industrial emission and the exceptionally severe heavy metal pollution in the coastal area, and the immediate measures should be carried out to minimize the rate of contamination, and extent of future pollution problems.     

Trace metal interactions in the macroalga Enteromorpha prolifera (O. F. Müller) J.Ag., grown in water of the Scheldt estuary (Belgium & SW Netherlands), in response to cadmium exposure

The littoral macroalga Enteromorpha prolifera was sampled along the Scheldt estuary at Lillo (Belgium), Bath and Ellewoutsdijk (SW Netherlands). The algae were incubated in water from the same locations with salinities of 7, 14 and 23%, at about 50 molquanta m^–2 s^–1 irradiance and 15 °C. One series of cultures was exposed to 400 nm Cd, a second series served as a control. Temporal changes in cadmium, copper, iron, lead and zinc contents of E. prolifera were monitored with atomic absorption spectroscopy in a 21 day experiment. Both synergistic and antagonistic metal interactions became evident in response to cadmium uptake. During the first 8 days of incubation iron contents increased in both cadmium-exposed and control algae. However, iron contents were relatively higher in cadmium-exposed algae. Similar, but weaker synergisms were also found between lead/cadmium and coper/cadmium. Zinc contents decreased in controls and cadmium-exposed algae, but were significantly lower in cadmium-exposed algae. A distinct antagonism between cadmium and zinc was observed in cadmium-exposed algae.     

Bioavailability and Concentration of Heavy Metals in the Sediments and Leaves of Grey Mangrove, <Emphasis Type="BoldItalic">Avicennia marina</Emphasis> (Forsk.) Vierh,in Sirik Azini Creek,Iran

The concentration and bioavailability of Ni, Cu, Cd, Zn, and Pb in the sediments and leaves of grey mangrove, Avicennia marina, were studied throughout Sirik Azini creek (Iran) with a view to determine heavy metals bioavailability, and two methods were used. Results show that Zn and Ni had the highest concentrations in the sediments, while Cd and Cu were found to have the lowest concentrations in the sediments. Compared to the mean concentrations of heavy metals in sedimentary rock (shales), Zn and Cu showed lower concentration, possibly indicating that the origin of these heavy metals is natural. A geo-accumulation index (I _geo) was used to determine the degree of contamination in the sediments. I _geo values for Zn, Cu, Pb, and Ni showed that there is no pollution from these metals in the study area. As heavy metal concentrations in leaves were higher than the bioavailable fraction of metals in sediments, it follows that bioconcentration factors (leaf/bioavailable sediment) for some metals were higher than 1.     

Impact of bimetallic combinations of Cu,Ni and Fe on growth rate,uptake of nitrate and ammonium,14C02 fixation,nitrate reductase and urease activity ofChlorella vulgaris

Summary The toxicity of Cu, Ni and Fe individually, as well as in combination (Cu + Ni, Cu + Fe, Ni + Fe), on growth-rate depression, uptake of NO₃ ^– and NH₄ ⁺, photosynthesis, nitrate reductase and urease activity ofChlorella vulgaris has been studied. All the test metals when used individually showed pronounced toxicity on all the parameters studied. However, their interactive effect was mostly antagonistic except for Cu + Ni (synergism). Pre-addition of Fe offered more protection to the cells against copper and nickel toxicity. The data of statistical analysis reconfirmed that¹⁴C0₂ uptake is the most sensitive parameter (significant atP<0.005, both for time and treatment) than others in metal toxicity assessment. However, these results suggest further that exposure time and sequence of metal addition are very important in biomonitoring of heavy metal toxicity.     

金毛狗对重金属的富集特性的研究

为探讨金毛狗[Cibotium barometz(L.) J. Sm.]对重金属的富集能力,在广东省选取6个样点(南岭、南昆山、白云山、大岭山、梧桐山、西樵山)采集金毛狗的叶片、根状茎和根际土壤,采用ICP-MS测定9种重金属元素(Cr、Mn、Ni、Cu、Zn、As、Cd、Hg、Pb)的含量。结果表明,样地土壤已受到不同程度的重金属污染,土壤中Cd和Hg含量均高于广东省土壤背景值,分别为背景值的1.61~4.82倍和4.74~11.79倍。西樵山土壤中Cd含量最大,南岭土壤中Hg含量最大。在9种元素中,金毛狗对Hg的转运系数最高,达4.8,对Cd的富集系数最高,达2.2,Cu和Cd元素的转运系数和富集系数均大于1。这说明金毛狗对重金属元素的富集能力较弱而转运能力较强。     

Thiol pools and glutathione redox ratios as possible indicators of copper toxicity in the green macroalgae Enteromorpha spp. from the Scheldt Estuary (SW Netherlands,Belgium) and Thermaikos Gulf (Greece,N Aegean Sea)

Defence mechanisms against Cu toxicity were examined in two dominant Enteromorpha species from two coastal water types. The macroalgae were collected at three locations in the eulittoral of the Scheldt Estuary (Netherlands, Belgium) and the Thermaikos Gulf (Greece). For 10 days E. prolifera (Scheldt) and E. linza (Thermaikos) were incubated in seawater media of different salinities: 6, 9, 23 psu and 25, 30, 35 psu, respectively. In one series, media were enriched with 100 μg Cu l-1; responses were compared with those in controls with no extra Cu added. Enteromorpha, which is frequently used as a monitor species for heavy metal contamination, had relatively high Cu tissue levels (0.5–3.8 μmol Cu gdwt-1). Cu levels in E. prolifera controls (Scheldt) decreased with salinity; this was not the case with Cu levels in E. linza controls (Thermaikos). During the 10-d incubation algal protein contents and tissue Cu were rather stable. In E. linza (Thermaikos) algal protein contents were significantly lower than those of E. prolifera (Scheldt), although there was no indication for nitrogen limitation in E. linza. E. linza also had much lower glutathione pools than E. prolifera. Only under acute Cu stress (metal addition) did E. prolifera synthesise metal-binding thiols (phytochelatins). Phytochelatin pools are not suitable as an indicator of the Cu levels in these algae. The glutathione redox ratio GSH:(GSH + 0.5GSSG) was used as an indicator of (Cu-induced) oxidative stress. In E. prolifera (Scheldt) this ratio decreased with algal Cu content (P <0.05), from ~0.5 to ~0.2. The average glutathione ratios in Enteromorpha from the Scheldt and Thermaikos showed some oxidative stress induction with increasing algal Cu contents, however more clearly if Cu was added. As this redox ratio can also be influenced by environmental factors such as irradiance and desiccation, it may not be useful as an indicator for Cu-induced oxidative stress in situ. This revised version was published online in September 2006 with corrections to the Cover Date.     

Response of ectomycorrhizalPinus banksiana andPicea glauca to heavy metals in soil

Pinus banksiana andPicea glauca inoculated or not with the ectomycorrhizal fungusSuillus luteus were grown in a sandy loam soil containing a range of Cd, Cu, Ni, Pb and Zn concentrations. Ectomycorrhizal colonization rates were significantly reduced on Pinus and Picea seedlings by the heavy metals, particularly Cd and Ni. Needle tissue metal concentrations were lower in ectomycorrhizal seedlings at low soil metal concentrations. However, at higher soil concentrations, heavy metal concentrations of needle tissue were similar in ectomycorrhizal and nonmycorrhizal plants. The growth of nonmycorrhizal seedlings exposed to heavy metals was reduced compared to those inoculated withSuillus luteus. Apparently ectomycorrhizal colonization can protect Pinus and Picea seedlings from heavy metal toxicity at low or intermediate soil concentrations of Cd, Cu, Ni, Pb and Zn.     

Biomonitoring of trace metal contamination in mangrove-lined Brazilian coastal systems using the oyster Crassostrea rhizophorae: comparative study of regions affected by oil, salt pond and shrimp farming activities

The oyster Crassostrea rhizophorae has been used as a biomonitor of trace metal contamination in two Brazilian coastal systems. C. rhizophorae were collected in January 1998 from 15 stations (from 4 coastal inlets (including 1 estuary) and 1 coastal beach) near Macau, Rio Grande do Norte (RN), Brazil, a region affected by the activities of the oil industry and salt manufacture in coastal salt ponds; oysters were also collected in September 1999 from 8 stations in the Curimatau estuary (RN), an estuary becoming increasingly affected by shrimp farming activities. C. rhizophorae is a net accumulator of trace metals and can be used as a biomonitor, the accumulated soft tissue concentrations representing integrated records of bioavailable metal over the life of the oyster. At Macau, significant differences in oyster accumulated concentrations (and hence bioavailabilities to the oyster) of Fe, Zn, Cu, and Mn were found between stations; raised zinc availabilities at the coastal site are in close proximity to oil industry activities but the very high availabilities of Fe, Cu and Mn in the Rio dos Cavalos estuary originate from an unknown source. In the Curimatau estuary, bioavailabilities of Mn, Pb and Cd, but particularly of Cu and Zn, to the oysters are raised at the two most downstream sites, the only sites below the effluent of a large shrimp farming enterprise. The oysters also act as a local food source, and concentrations of Zn, Cu and Pb of some of the oysters are above typical public health recommended limits.     

Identification by SDS PAGE of green seaweeds ( Ulva and Enteromorpha) used in the food industry

SDS PAGE was tested as an analytical tool for the identification of fourgreen algae (Ulva rigida, U. rotundata, Enteromorphaintestinalis, E. compressa) used as food ingredients. A referencepattern composed of the bands present all year long was performed foreach species. The pattern for Ulva rotundata consists of 7 bandslocated between 69.9 and 15.5 kDa with the presence of triplicate bandsat 29.5, 26.3 and 22.9 kDa. The pattern for Ulva rigida is consistsof three bands with apparent molecular weights of 68.5, 56.4 and 44.7kDa. The Enteromorpha compressa pattern is characterised by sixbands located between 65.8 and 19.8 kDa. A double band withmolecular weights of 23.1 and 23.9 distinguished this pattern from theothers. Six bands situated between 66.4 and 19.4 kDa with a specifictriplicate band of 25.9, 23.9 and 22.5 kDa constituted the specific patternof Enteromorpha intestinalis. SDS PAGE appears to be suitable forthe identification of green seaweed foods.     

The Lusitanian toadfish as bioindicator of estuarine sediment metal burden: The influence of gender and reproductive metabolism

Early diagenetic processes and anthropogenic activities are responsible for metal enrichment in estuarine sediments. The Tagus estuary (Portugal) is no exception, and as a result of past and present pressures, surface sediment contamination is still an issue in some areas. Since such metal loads may be incorporated by benthic organisms, this study analyzed the accumulation of trace metals in the Lusitanian toadfish (Halobatrachus didactylus) in the Tagus estuary. In order to determine the role played by the seasonal reproductive cycle of the Lusitanian toadfish in the bioaccumulation process of trace metals in its tissues, the concentrations of Cd, Co, Cr, Cu, Ni, Pb and Zn were determined in the liver of male and female specimens captured during reproductive and non-reproductive periods. The results showed that metal accumulation in the liver was related simultaneously with gender and season, with females having higher levels of Cd, Cu and Zn during the reproductive period. The metabolic roles of Cu and Zn in embryonic development may explain such results, as both metals accumulated in the female liver to be transported to the gonads later on. Cd, on the other hand, does not have a metabolic role, and the higher concentrations of this metal found in spawning females could be related to the high affinity of Cd to vitellogenin, which is produced in the liver. To assess the species’ potential as an indicator of metal contamination, the concentrations of the seven elements were compared in the muscle tissue of adult, type I males (age ≥5), from two areas with distinct sediment metal loads. Non-essential metals in the muscle reflected the same differences between areas that were found in the sediment samples, evidencing H. didactylus as a potential indicator of those elements bioavailability from the sediment. The results showed that the muscle tissue of adult specimens of a relatively sedentary species such as H. didactylus is a useful indicator of long term accumulation of trace metals. On the contrary, liver concentrations of trace metals showed variation according to the reproductive status, which could lead to overestimate of the environmental status concerning trace metals bioavailability. Spawning season and liver tissue should thus be avoided in biomonitoring studies targeting this benthic fish.     

Effectivity of host-Rhizobium leguminosarum symbiosis in soils receiving sewage water containing heavy metals

Disposal of sewage water in cultivated soils often containing considerable amount of potentially toxic metals such as Cu, Zn, Ni, Cd, Pb and Cr can be beneficial or harmful to plant growth, rhizobial survival, nodulation and nitrogen fixation. Soil samples from 14 such locations were collected. Symbiotic effectivity of host-Rhizobium leguminosarum symbiosis in these soils was assessed. The total metal contents of Cd, Cu, Zn and Ni in all the 14 samples collected from farmer's fields receiving sewage water ranged between 1.3 and 6.7, 55.8-353.2, 356.0-1028.0 and 90.0-199.7 mg kg(-1) of soil, respectively. In Rohtak 1 soil, levels of Cd, Cu and Zn were highest while Ni was highest in Sonipat 2 soil. The content of available Cd, Cu, Zn and Ni in these soils ranged from 1.0-29.3; 6.2-47.0; 2.4-13.5, respectively, and was 2-9 percent of their total metal contents. All the N2 fixing parameters in pea and Egyptian clover were adversely affected by the presence of heavy metals. Available Cd and Cu contents significantly affected the N contents of pea and Egyptian clover plants, whereas Ni contents were negatively correlated with the plant biomass of pea and Egyptian clover.     

调水调沙工程黄河口近岸沉积物重金属和砷含量的空间分布及其生态风险评估

为了明确调水调沙工程长期影响下黄河口近岸沉积物中重金属含量的分布特征及其生态风险,基于2012年黄河口近岸27个站位的表层沉积物样品,通过ICP-MS测定重金属(Zn、Cr、Ni、Pb、Cu、Cd)和砷(As)含量,并运用潜在生态风险指数法(RI)对其进行生态风险评估。结果表明:近岸沉积物中重金属和As的平均含量表现为AsZnCrNiPbCuCd。Cr、Ni、Cu和Pb四种元素的分布规律较为一致,整体呈现出近岸和近黄河口高而远离河口和岸线低的空间分异特征。Ni、Cu、Pb、Zn与粘土均呈极显著或显著正相关(P0.01或P0.05),而Cd、Cr和As与其相关性均未达到显著水平(P0.05)。近岸沉积物中6种重金属和As的平均单项潜在生态风险指数大小顺序整体表现为CdAsNiPbCuCrZn。就潜在生态风险(RI)而言,研究区域18.52%的站位属轻微生态危害,70.07%的站位属中等生态危害,7.41%的站位属强生态危害,Cd和As是造成危害的两种主要元素。近岸沉积物中重金属和As的来源复杂且多样,主要是由于农业化肥使用、海上石油开采和泄漏、化石燃料燃烧以及河口污染物输入所致。对比研究发现,随着调水调沙工程的长期实施,除Cd和As外沉积物中其他重金属含量均呈下降趋势,说明二者的生态风险将会随调水调沙的长期实施呈增加趋势,而其他重金属的生态风险将呈降低趋势,故未来应重点关注近岸沉积物中Cd和As的生态毒理风险。     

Mitigation of Heavy Metal Contamination in Soil via Successive Pig Slurry Application

This study evaluates heavy metal removal associated with phytomass management in a Typic Hapludox after three applications of pig slurry. Like humic acids in pig slurry were characterized through physics and chemical spectroscopy technics. Heavy metal levels were determined in ration that was offered to pigs, anaerobically digested pig slurry, and plant tissues from pig slurry-fertilized black oat (Avena strigosa Schreb.) and ryegrass (Lolium multiflorum Lam.) intercrop. Soil contamination was evaluated by the pseudo-total heavy metal levels in six soil layers and the bioavailable levels in the top soil layer. Results indicate that the ration is the origin of heavy metals in the pig slurry. The approximate levels in the ration were as follows (mg kg^?1): Cu 23.9, Zn 92.02, 153.15, Mn 30.98, Ni 0.23, Pb 10.75, Cr 0.34, Co 0.08, and Cd 0.05. The approximate levels of these metals in the pig slurry were as follows (mg kg^?1): Cu 71.08, Zn 345.67, Fe 83.02, Mn 81.71, Ni 1.13, Pb 4.35, Co 0.28, and Cd 0.16. Like humic acids contained 55% aliphatic chains, 14% oxygenated aliphatic chains, and 15% carboxyls, demonstrating their high capacity for interaction with heavy metals by forming soluble complexes. Soil contamination was indicated by the accumulation of heavy metals in the six soil layers in relation to the applied pig slurry dose (ranged as follows (mg kg^?1): Cu 110 to 150, Zn 50 to 120, Ni 20 to 40, and Pb 12 to 16) and as bioavailable forms (levels ranged as follows (mg kg^?1): Cu < 1, Zn 1.0–1.5, Ni 0.1–1.5, and Pb 1.9–6.3). The positive correlation between heavy metal accumulation in the plants and soil bioavailable heavy metal levels and the lowest heavy metal levels under higher intensity of phytomass removal demonstrate the ability of phytomass management to reduce soil contamination.     

Ulva lactuca as bioindicator of metal contamination in intertidal waters in Hong Kong

The use of Ulva lactuca L. as an indicator of metal contamination was assessed by analysing the levels of Mn, Fe, Ni, Cu, Zn, Cd and Pb in the alga collected from 24 intertidal sites around the Island of Hong Kong. Twelve of the sites are in the rural southern parts of the Island where the coastal waters are relatively clean. The remaining 12 sites are located in the north and within Victoria Harbour which receives, apart from industrial effluents, untreated domestic sewage from a population of some 3.5 million. The mean levels of Mn, Fe, Ni, Cu, Zn and Pb in Ulva from the urban sites were respectively 4.0, 4.6, 1.8, 2.3, 2.4 and 4.6 folds those from the rural sites. However, similar levels of Cd were found in the alga amongst all the sites. Locations of high levels of metal contamination, particularly to the eastern end of the Harbour, have been identified. Preliminary results indicate that Ulva is a good indicator of Mn, Fe, Cu, Zn and Pb contaminations.     

The spatial distribution,contamination, and ecological risk assessment of heavy metals of farmland soils in Karashahar–Baghrash oasis,northwest China

The issue of heavy metal pollution is of high concern due to its potential health risks and detrimental effects on human beings, animals, and plants. In this study, farmland soil samples from 79 sampling sites were collected in Karashahar–Baghrash oasis, northwest China, and the contents of eight heavy metal elements (As, Cd, Cr, Cu, Mn, Ni, Pb, and Zn) were determined by standard methods. The spatial distribution, pollution, and ecological risks of heavy metals were analyzed based on Geographical Information System (GIS) technology, contamination factor (CF), pollution load index (PLI), and potential ecological risk index (RI). Results indicated that: (1) The average contents of Cd, Cr, Ni, Pb, and Zn exceeded the background values of irrigation soils of Xinjiang by 54.0, 1.34, 1.39, 3.44, and 5.01 times, respectively. The average contents of Cd exceeded the national standard of China by 10.80 times; (2) The pollution order of CF was ranked as Cd > Zn > Pb > Ni > Cr > Cu > As > Mn, and the ecological risk order of E_rⁱ was ranked as Cd > Ni > As > Cu > Ni > Pb > Cr > Zn. The average PLI of the study area showed heavy pollution level, and the average RI of the study area fell into considerable risk; (3) The moderately polluted areas with moderate potential ecological risks distributed in the northern parts, whereas heavily polluted areas with considerable potential ecological risks distributed in the southern parts of the study area; (4) Cr, Cu, and Mn of farmland soils were mainly originated from natural factors. Cd, Ni, and Pb were mainly originated from anthropogenic factors. As and Zn may be associated with both natural and anthropogenic factors. Cd contributed most to the PLI and RI of the farmland soils in the study area.     

沙地不同发育阶段的人工生物结皮对重金属的富集作用

生物结皮广泛存在于沙地生态系统,具有重要的生态功能.通过对位于库布齐沙漠腹地达拉特旗火力发电厂附近沙地中不同年代人工生物结皮及物理结皮中重金属含量的测定,旨在分析不同类型生物结皮及物理结皮在不同的发育阶段对重金属富集的影响和重金属污染的指示程度.通过分析和比较,得出以下结论:不同年代生物结皮和物理结皮各种重金属含量均表现为随着发育时间的增加而增加的趋势,生物结皮重金属含量多数类型表现为:Zn＞Cr＞Ni＞Pb＞Cu＞As＞Co＞Cd＞Hg的顺序关系,少数类型表现为:Cr＞Zn＞Ni＞Pb＞Cu＞As＞Co＞Cd＞Hg的顺序关系.通过单因素方差分析(ANOVA),不同年代藓结皮中各种元素差异显著性(P＜0.05)明显低于藻结皮和物理结皮.相同年代生物结皮和物理结皮重金属含量都表现为同样地规律:藓结皮＞藻结皮＞物理结皮,表明相同背景条件下,藓结皮对各种重金属的富集能力明显比藻结皮和物理结皮的富集能力强.通过单因素方差分析(ANOVA),Hg和Ni元素含量在所有相同年代样地的生物结皮和物理结皮均无差异,Cr、Zn、Cu、Co元素含量均存在差异(P＜0.05),但差异有的表现在藓结皮和藻结皮之间,而有的表现为藻结皮和物理结皮之间,而Pb、As、Cd元素含量则表现为有的年代有差异,有的年代无差异.通过污染因子CF值分析,藓结皮对污染的指示作用要明显比藻结皮和物理结皮敏感.同时生物结皮对于重金属的富集具有一定的选择性,像Hg、Ni、Zn、Cu、Pb、Co等元素生物结皮相对富集较少,而像Cr、Cd、As等元素相对富集较多.     

Spatial Distribution of Heavy Metals in Soil and Flora Associated with the Glass Industry in North Central India: Implications for Phytoremediation

The effect of the glass industry on soil metal characterization was assessed at five test sites at five successive distances in a semi-arid area. A comprehensive profile of Zn, Cd, Pb, Ni, Cu, and As levels in soils was obtained. The spatial distribution patterns of integrated contamination indices for these metals show a similar decreasing trend in distribution as we move further from the industrial cluster. There was significant correlation among individual heavy metal concentrations in the soil samples. Integrated contamination indices indicate that 64% of the sites were in the high contamination range and 28% were in the moderate contamination range. A statistically significant difference (P ≤ 0.001) was obtained for each metal on comparing mean metal content among soil samples. Phytoremedial potential of 12 native plant species was also evaluated. Individual elements displayed remarkably different patterns of accumulation in soils as well as plants. Plants established limited capabilities in mobilizing Zn, Pb, Ni, and Cu in the root zone. While Cd, Cu, As, Zn and Pb were predominantly partitioned in shoots, Ni was equally partitioned between shoots and roots. Interestingly, some plants showed a different partitioning trend at higher concentrations of different metals compared to lower concentrations. Potential species for phytoremediation include Calotropis procera (Milk weed), Chenopodium murale (Goosefoot),Poa annua (Annual bluegrass) and Datura stramonium (Thorn apple). None of the species showed phytoremedial potential for Ni and Cu.     

Metal concentrations in Sargassum algae from coastal waters of Nha Trang Bay (South China Sea)

The concentrations of metals, viz., Fe, Mn, Cu, Zn, Cd, Pb, and Ni, were investigated in brown algae of the genus Sargassum collected in the coastal waters of Nha Trang Bay (South China Sea). Metal concentrations in algae growing in the zone of influence of the city of Nha Trang were higher than those in macrophytes collected to the south and north of the city. Similar levels of Cu and Fe concentrations were observed in macrophytes from the urbanized coastal areas of Nha Trang Bay and in algae from the Peter the Great Bay (Sea of Japan). This is suggestive of comparable metal inputs from the anthropogenic sources of the cities of Nha Trang and Vladivostok (Peter the Great Bay). However, the concentrations of Pb, Ni, and Cd in algae from the coastal waters of Nha Trang Bay were lower than in macrophytes from the inshore zone of Vladivostok. The high level of pollution of sea water with Zn compounds near Nha Trang was local. The metal levels in macrophytes from background areas reflect the geochemical features of the environment. Sargassum algae from Nha Trang Bay had lower concentrations of Zn, Cd, and Ni and higher concentrations of Mn than algae from Peter the Great Bay. The background concentrations of Cu, Pb, and Fe in macrophytes from both bays were virtually the same.     

Using wild plant species as indicators for the accumulation of emissions from a thermal power plant, Candiota, South Brazil

The impact of Candiota coal-fired thermal power plant on air quality was evaluated during two years by means of passive biomonitoring. The monitoring consisted of the quarterly collection of leaf samples of Baccharis dracunculifolia, Elephantopus mollis, Eryngium horridum, Paspalum notatum and Piptochaetium montevidense or the shoot of Baccharis trimera at five sites located in the area around the power plant. The element load of these plants was used as indicator for atmospheric pollution. In the samples collected, sulphur and heavy metal cadmium contents were measured. Among the species evaluated, E. mollis presented the highest potential to accumulate metal, followed by B. trimera. The Aeroporto and AFUCAN sampling sites, located in the prevailing wind directions, presented the highest level of metal contamination.