Bioccumulation and toxicity of Cu and Cd in Vallisneria spiralis (L.)

Accumulation of Cu and Cd by Vallisneria spiralis was studied under laboratory conditions. Plants showed ability to reduce 5 µg ml^–1 Cu background concentration to below 0.05 µg ml^–1 (m.p.l., WHO 1985) within 48 h. The Cd concentration of 1.0 µg ml^–1 was reduced to below m.p.l. (0.005 µg ml^–1) in 168 h. Cysteine synthesis was more under Cd stress condition. Both the metals were toxic to the plants at higher concentrations; more in the case of Cd.NBRI Rsearch Publication No. 417 (N.S.).     

Bioconcentration and Phytotoxicity of Cd in Eichhornia crassipes

Plants of Eichhornia crassipes grown at various levels of cadmium ranging from 0.1 to 100 μg ml⁻¹ accumulated Cd in a concentration and duration dependent manner. At all levels, Cd accumulation by various plant tissues followed the order roots shoot leaves. Approximately 80% of total Cd was accumulated by plant at highest concentration (100 μg ml⁻¹) used in the experiment. Cadmium induced phytotoxicity appears at 25.0 μg ml⁻¹ resulting into reduced levels of chlorophyll, protein and in vivo nitrate reductase activity of the plant. However, a slight induction of these physiological variables was obtained at lowest Cd (0.1 μg ml⁻¹) concentration. In contrast, carotenoid content increased at highest Cd concentration i.e., 100 μg ml⁻¹. Similar effects at low and high levels of Cd was obtained with respect to mitotic index and micronuclei in root meristem of the plant. It could be inferred that Cd toxicity in plant is differential depending upon the low and high concentration of Cd in the medium.     

Distribution of heavy metals in Penaeus Semisulcatus from Persian Gulf and possible role of metallothionein in their redistribution during storage

The study was conducted between January and December 2002. The main objective of this study was evaluation of effects of refrigerated storage duration on redistribution of three trace elements (Cd, Cu and Zn) in tissues (exoskeleton, abdominal muscle and hepatopancreas) of a shrimp species (Penaeus semisulcatus). Moreover, the possible roles of metallothionein (a kind of metalloprotein) in redistribution of the elements in tissues of the selected species were assessed. The specimens were sampled from northwestern part of the Persian Gulf. The concentrations of metals in the tissues were measured using Inductively Coupled Plasma-Optical Emission Spectrophotometer (ICP-OES). Metallothionein levels were determined by Differential Pulse Polarography (DPP) method. pH of the muscle samples was also measured in different stages. Different statistical methods were used for interpretation of the results. There were no size-dependent differences in metal contents of the species. The results were compared with specimens from other areas of the world and existing guidelines and limits. Concentrations of the metals in the muscle (0.103, 3.418 and 8.977 µg g^–1 wet weight in the case of Cd, Cu and Zn, respectively) samples were below the most guidelines for human consumption. The results were in general agreement with those obtained by some other researchers. There were highly significant differences between sexes in Zn and Cu contents. Levels of Zn in females were significantly higher than males. The reverse case observed for Cu. The highest mean Cu and Zn concentrations (15.939 and 43.394 µg g^–1 wet weight, respectively) were found in hepatopancreas samples, but the highest level of Cd (0.790 µg g^–1 wet weight) was observed in exoskeleton. There were significant differences between the fresh and refrigerated samples from accumulation of Cd and Zn in tissues point of view, which can be attributed to the metal binding properties of metallothioneins as well as their degradation during the storage.     

A modified toxicity testing method using tropical marine microalgae

Toxicity testing of four heavy metals(Cd, Cu, Mn and As) using four species of tropicalmarine phytoplankton, Chaetoceros calcitrans, Isochrysis galbana, Tetraselmis tetrahele and Tetraselmis sp., was carried out in multiwellplates with test volumes of 2 mL and the resultscompared to those of standard, large volume,shake-flasks. IC₅₀ values (concentrations of metalsestimated to inhibit 50% growth relative to thecontrol) were determined after 96 hours based onautomated O.D. readings measured in Elisa microplatesby a Multiskan spectrophotometer. Good agreement wasachieved between O.D. readings and cell countsindicating that this new method is a simple,economical, practical and rapid technique for toxicitytesting, and provides good reproducibility of IC₅₀ values. Results of the toxicity testsindicate that Cu was the most toxic metal (averageIC₅₀ values ranging from 0.04 to 0.37 mg L^-1), followed by Cd (0.06–5.7 mg L^-1), Mn (7.2–21.4 mg L^-1) and As (33.9–319.3 mg L^-1).Test species had different degrees of sensitivity tothe metals tested, with I.galbana and C. calcitrans the mostsensitive to Cu, Cd and Mn. Based on these findingsit is recommended that the existing Malaysian InterimStandards for Marine Water Quality for Cd and Cu be reviewed.     

Comparative rice seed toxicity tests using filter paper,growth pouch-tm,and seed tray methods

Paper substrate, especially circular filter paper placed inside a Petri dish, has long been used for the plant seed toxicity test (PSTT). Although this method is simple and inexpensive, recent evidence indicates that it gives results that are significantly different from those obtained using a method that does not involve paper, especially when testing metal cations. The study compared PSTT using three methods: filter paper, Growth Pouch-TM, and seed tray. The Growth Pouch-TM is a commercially available device. The seed tray is a newly designed plastic receptacle placed inside a Petri dish. The results of the Growth Pouch-TM method showed no toxic effects on rice for Ag up to 40 mg L^–1 and Cd up to 20 mg L^–1. Using the seed tray method, IC₅₀ (50% inhibitory effect concentration) values were 0.55 and 1.4 mg L^–1 for Ag and Cd, respectively. Although results of filter paper and seed tray methods were nearly identical for NaF, Cr(VI), and phenol, the toxicities of cations Ag and Cd were reduced by using the filter paper method; IC₅₀ values were 22 and 18 mg L^–1, respectively. The results clearly indicate that paper substrate is not advisable for PSTT.     

Regional monitoring of lead and cadmium contamination in a tropical grazing land site,Thailand

An investigation was carried out to monitor Pb and Cd contamination in grazing land located near a highway. Environmental media at different distances fromhighway (soil, grass, water, cow's forage, fertilizer,manure and milk samples) were collected from three samplinglocations. Soil and grass were characterized by high metalmobility (soil with Pb: 5.25±0.71–14.59±1.17 mgkg^-1, dry mass and Cd: 0.038–0.33±0.04 mg kg^-1, dry mass and grass with Pb: 0.76±0.05–6.62±0.18 mg kg^-1, dry mass and Cd: 0.17±0.01–0.73±0.09 mg kg^-1, dry mass). One-way analysis of variane (ANOVA) was applied to find out the correlation between metal (total and bioavailable) concentrationsin the soil and the distance from roadside. In most cases, the finding showed that plants growing nearer to the highway are usually exposed to more heavy metal accumulations than those awayfrom the highway. In addition, a correlation was established between plant available metal concentrations and plant metaluptake concentrations.Analysis of fertilizer and manure showed considerable amountof metals (fertilizer with Pb: 1.53±0.06 mg kg^-1 andCd: 0.038 mg kg^-1 and manure with Pb: 2.55–3.34 mgkg^-1 and Cd: 0.14–0.31 mg kg^-1). Long termsimultaneous application of fertilizer and manure on thecommercial farm showed higher metal accumulation in the soiland plants than those of co-operative farm Considerableconcentrations of metals (Pb: 1.60–2.94 mg kg^-1 andCd: 0.025–0.19 mg kg^-1) were observed in fodder. The finding clearly demonstrated that there are seasonalvariation in total daily metal intake by individual cow (Pb:109.37 mg day^-1 (dry), 273.47 mg day^-1 (rainy) andCd: 2.02 mg day^-1 (dry), 19.62 mg day^-1 (rainy)).The provisional tolerable weekly intake of heavy metals incows is 390 g Pb and 28 g Cd per kg bodyweight in the rainy season and 156 g Pb and 2 gCd per kg body weight in the dry season. The levels of metals (Pb: 0.014 mg L^-1 and Cd: not detectable) and bio-transferfactor (10^-5–10^-4) in raw milk were found to be well below the Codex Alimentarius Commissions Draft (1997). Ouranalysis revealed that improvements on farm management give significant reduction in elevated levels of Pb and Cdin soil and plants, and however leads to minimize the amountof Pb and Cd in consumed milk.     

Long term monitoring of pollutants in eggs of Yellow-legged Herring Gull from Capraia island (Tuscan Archipelago)

Chlorinated hydrocarbons (hexachlorobenzene, lindane, ppDDE, polychlorinated biphenyls) and trace elements (Hg, Se, Cd, Pb) were determined in eggs of Yellow-legged Herring Gull (Larus cachinnans) collected in an island of the Tyrrhenian Sea during the period 1981–1986. PCBs levels vary on the average between 30.4g g^–1 d.w. in 1981 to 56.1 g g^–1 d.w. in 1983. The capillary chromatograms revealed the presence of about 30 somers of PCBs without significant variations in the eggs of the same year; more than 50% of the residues is made up only three isomers: the 22'44'55', the 22'344'5' and the 22'344'55'. Average DDE residues were 7–8 times lower than those of PCBs and declined during the period (from 9.2 g g^–1 d.w. in 1981 to 4.5 g g^–1 d.w. in 1986). Cadmium and lead are present in low concentrations. The average levels of mercury and selenium are around 2–2.5 g g^–1 d.w., and a cumulative correlation, on a molar basis, exists between these two elements.     

CADMIUM ACCUMULATION AND TOXICITY IN SUBMERGED PLANT HYDRILLA VERTICILLATA (l.f.) ROYLE

Cadmium accumulation and its toxicity in relation tochlorophyll, protein, cysteine contents and in vivo nitrate reductaseactivity were studied under controlled conditions in Hydrillaverticillata, a submerged commonly occurring macrophyte. Plants weresubjected to six different concentrations of Cd ranging from 1.0 to 25.0 µM for 24, 48, 72 and 168 h. Tissue Cd concentration was maximum (13.71 µmoles/g dw) at 25 µM background concentration. At this concentration, a decrease of approximately 79 and 72% was found in chlorophyll and protein content. In vivo nitrate reductase activity was stimulated at 1.0 µM; however, the activity gradually declined beyond this concentration. Exposure to various cadmium concentrations resulted in an increase in cysteine content of the plant.     

Distribution of heavy metals in plants and fish of the Yamuna river (India)

The distribution of cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), iron (Fe), manganese (Mn), nickel (Ni), lead (Pb) and zinc (Zn) in the plants and fish of Yamuna river from Delhi to Allahabad, a distance of about 840 km, at five sampling stations was determined in the year 1981. The results have shown wide variations in the heavy metal levels from one sampling station to the other. The concentrations of Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn in the plants (Eicchornia crassipes) were found to be 0.02–0.12, 2.7–21.3, 4.6–64.8, 9.8–114.0, 193.0–1835.0, 380.0–1443.0, 4.4–83.0, 4.8–30.2, and 22.1–356.5 g g^-1 respectively whereas in the fish (Heteropnuestes fossilis) were found to be ND-0.40, 2.3–13.7, 3.7–26.9, 8.33–58.1, 278.3–1108.0, 81.3–213.8, 2.8–32.7, 1.4–12.8 and 101.8–364.8 gg^-1 respectively on dry weight basis.     

Use of forest inventories and geographic information systems to estimate biomass density of tropical forests: Application to tropical Africa

One of the most important databases needed for estimating emissions of carbon dioxide resulting from changes in the cover, use, and management of tropical forests is the total quantity of biomass per unit area, referred to as biomass density. Forest inventories have been shown to be valuable sources of data for estimating biomass density, but inventories for the tropics are few in number and their quality is poor. This lack of reliable data has been overcome by use of a promising approach that produces geographically referenced estimates by modeling in a geographic information system (GIS). This approach has been used to produce geographically referenced, spatial distributions of potential and actual (circa 1980) aboveground biomass density of all forests types in tropical Africa. Potential and actual biomass density estimates ranged from 33 to 412 Mg ha^–1 (10⁶g ha^–1) and 20 to 299 Mg ha^–1, respectively, for very dry lowland to moist lowland forests and from 78 to 197 Mg ha^–1 and 37 to 105 Mg ha^–1, respectively, for montane-seasonal to montane-moist forests. Of the 37 countries included in this study, more than half (51%) contained forests that had less than 60% of their potential biomass. Actual biomass density for forest vegetation was lowest in Botswana, Niger, Somalia, and Zimbabwe (about 10 to 15 Mg ha^–1). Highest estimates for actual biomass density were found in Congo, Equatorial Guinea, Gabon, and Liberia (305 to 344 Mg ha^–1). Results from this research effort can contribute to reducing uncertainty in the inventory of country-level emission by providing consistent estimates of biomass density at subnational scales that can be used with other similarly scaled databases on change in land cover and use.     

A Survey of Trace Metals in Vegetation, Soil and Lower Animal Along Some Selected Major Roads in Metropolitan City of Lagos

The concentration of trace metals (Cd, Cu, Pb and Zn) in a total of 144 samples of grass, soil and lower animal (earthworm, Lybrodrilus violaceous) were collected and analysed for their metallic content. Levels of cadmium ranged from 0.01–0.07 g g^–1; 0.01–0.12 g g^–1 and from trace–0.05 g g^–1 dry weight for plant, soil and animal samples respectively. Mean concentration of copper ranged 0.10–1.48 g g^–1; 0.10–2.90 g g^–1 and 0.01–0.08 g g^–1 for samples in similar order as above. The levels of Pb varied from 0.01–0.14 g g^–1; 0.02–0.23 g g^–1 and from trace–0.07 g g^–1 while that of Zn ranged from 0.19–1.80 g g^–1; 0.51–3.35 g g^–1and 0.01–0.08 g g^–1 also in the same order of samples as mentioned above. Levels of metals in soil samples were higher than the background levels with the exception of Zn but lower than European Union (EU) limits. The results generally revealed the presence of metals in plant and animal samples and metal dynamics up the food chain is highly possible. Acceptable recoveries of the spiking experiment validate the experimental protocol.     

The influence of two culturing techniques on toxicity of four chemicals in Arabidopsis

Plots of Arabidopsis thaliana L. (Heynh.) plants were grown in two hydroponic systems, one using a solid rooting support media (vermiculite) and the other a flowing solution culture. Both were tested with various concentrations of bromacil (5-bromo-3-sec-butyl-6-methyluracil), dichlobenil (2,6-dichlorobenzonitrile), copper sulfate (CuSO₄·5H₂O) and 3-aminotriazole. The effects on biomass production were compared. Plants treated with bromacil at concentrations up to 0.05 mg l^–1 were similarly reduced in growth in both culture methods. However, the toxic effects of dichlobenil, copper sulfate and 3-aminotriazole were different for both culture methods. Dichlobenil decreased plant growth in the solution culture at lower concentrations than in the vermiculite system. All aspects of growth were suppressed in the solution culture while the vegetative weight was unaffected in the vermiculite culture. Plants treated with 20 mg l^–1 copper sulfate in solution culture yielded mean seed weight of 1.2 g/plot compared to 3.1 g/plot when treated with the same concentration in the double-plot system. Plants treated with 0.5 mg l^–1 3-aminotriazole in solution culture produced no seed, while plants with the same nominal concentration in the double-pot method produced a mean seed weight of 6.5 g/plot. Solution culture testing was generally more sensitive and since roots were bathed directly in a solution of known pH, nutrient level and chemical concentration, the test conditions were more accurately defined.     

Cadmium,zinc, copper and metallothionein levels in the kidney and liver of humans from central Poland

Cd, Zn, Cu, and metallothionein (MT) levels have been determined in the renal cortex and liver of 70 persons who died in Lodz and its surroundings in the years 1985–1989. The mean concentrations were: 44.9±28.6 µg Cd/g, 52.0±16.7 µg Zn/g, 2.4±1.0 µg Cu/g, 0.79±0.40 µmol Hg/g, and 3.5±1.8 µg Cd/g, 66.7±30.5 µg Zn/g, 4.9±2.1 µg Cu/g, 0.50±0.38 µmol Hg/g wet tissue in renal cortex and liver, respectively, with mean age 54.0±13.8. Smokers showed 2.4 times higher levels of Cd in the renal cortex than non-smokers. The mean body burden of Cd was 33.4±17.3 mg. Smoking increases it twofold from 22.0 mg in non-smokers to 41.8 mg in smokers.This work was supported by the grant CPBR 11.12(C-56/86) from the Institute of Rural Medicine, Lublin, Poland.Deceased.     

Electrostatic precipitation in atmospheric aerosols

The use of electrostatic force mechanisms can make a substantial contribution to control the pollution from air solids arising naturally, or from human development. In the present investigation we discuss the efficiency of a technique to precipitate the atmospheric aerosol of a size <5 µm, by energizing metal mesh (Por=0.7) collectors (+, N, and –) using low D.C. voltage (0–30 V or –1.224×10² Vm^–1).     

Aliphatic and polycyclic aromatic hydrocarbons in sediments of Kaohsiung Harbour and adjacent coast, Taiwan

Surficial sediment samples collected from Kaohsiung Harbour and its nearby coast were analyzed for aliphatic hydrocarbons and parent polycyclic aromatic hydrocarbons (PAHs). According to our results, the average total concentrations of n-alkanes (n-C₁₂ to C₃₅) and aromatics (15 PAHs) were 4.33 µg g^–1 dry weight (ranged 0.46–22.60) and 0.59 µg g^–1 dry weight (ranged 0.09–1.75), respectively. The highest concentrations of aliphatic and aromatic hydrocarbons were recorded in stations near the estuaries of Qianzhen River and Love River, respectively. Aliphatic hydrocarbons in the samples indicate that there has been significant non-petrogenic, possibly terrestrial, contribution in the sediment of the open coast of Kaohsiung Harbour and that there has been dominant contribution from petrogenic sources in the sediment of the inner harbour. PAHs, detected in the samples, however, indicated a higher pyrolytic contribution in open-coast samples and a higher petrogenic contribution in the inner harbour. Overall, sediment concentrations of total alkanes in this study were comparable to those found in Victoria Harbour, Hong Kong and are higher than those found in Xiamen Harbour, China. Concentrations of total PAHs in inner Kaohsiung Harbour sediments were relatively lower than those found in Victoria Harbour, Hong Kong and Xiamen Harbour, China, but comparable to those found in Hsin-ta Harbour, Taiwan and Incheon Harbour, Korea. In comparison with several effect-based sediment quality guidelines, most PAH concentrations found in samples taken from inner harbour stations exceeded the Threshold Effect Level of Florida indicating a slight possibility of adverse effects.     

The accumulation of metals and toxic effects in Nereis virens exposed to pulverised fuel ash

The marine polychaete worm Nereis virens was used to study the bioaccumulation patterns of metal exposures with pulverised fuel ash (PFA). Juvenile N. virens were exposed for 12 weeks to sediments comprised of 100% PFA, 50% PFA-50% clean sand, a reference sediment (contaminated harbour-dredged material) and a clean sand control. Mortality after the first 4 weeks was high at 32–45% in the four sediments. However, this declined to a few percent during the following 8 weeks. Growth expressed as biomass (wet weight) was reduced in bout PFA treatments and the reference sediment. Heavy metal accumulation in the tissues of N. virens was characterised as follows: a group of elements showed negligible to low accumulation (Cd, Cr, Ni, and Zn), As and Cu wich showed a definite, but moderate accumulation: and finally Se, which showed a low accumulation rate, where an uptake equilibrium was not reached after 9 weeks. It is concluded that acute toxic effects did not occur but a population of N. virens inhabiting a PFA dumping site could be affected by high Se concentrations.     

Bioindicator organisms: Heavy metal pollution evaluation in the Ionian Sea (Mediterranean Sea—Italy)

Trace metal concentrations of mercury, cadmium, lead and chromium in Patella caerulea, and Mullus barbatus were investigated to provide information on pollution of Ionian Sea, since these metals have the highest toxic potential. High chromium levels (0.47–0.97 g g^–1 ww) were registered in limpet samples collected from two station near the Gulf of Taranto, while elevated concentration of mercury (0.31–1.50 g g^–1 ww) were found in mullet specimens from Sicily. The metal concentrations recorded at the clean stations may be considered as useful background levels to which to refer for comparison within the Mediterranean area. On the contrary, the high levels of chromium and mercury found respectively in the areas near the Gulf of Taranto and at Capo Passero being of concern in terms of environmental health need frequent monitoring.     

Quality of drinking water in the Aligarh Muslim University Campus,Aligarh, U.P. (India) with respect to heavy metals

The physico-chemical characteristics of the drinking water in nine residential halls of the Aligarh Muslim University, Aligarh, U.P. (India), were studied. Nine samples each of running and standing water were taken four times over a period of one month at weekly intervals from all of the residential halls and were analysed for physico-chemical characteristics and heavy metal contents. The temperature, pH and electrical conductivity of water samples ranged between 20.0–26.0°C; 7.00–8.00 and 116.00–199.04 micromhos cm^–1 respectively whereas the values of total alkalinity, total hardness, Cl^–, SO ₄ ^– , F^–, NH₃–N, NO₂–N; NO₃–N were found between 261.00–396.00; 128.00–200.00; 8.00–69.00; 12.00–46.00; 0.90–1.35; 0.20–0.44; ND; 1.60–6.50 mg l^–1 respectively. The ranges of heavy metal concentrations in the running water samples were as follows: Cd (0.70–3.75); Cr (ND-5.00); Co (9.50–18.75); Cu (0.75–15.00); Fe (ND-13.50); Mn (3.50–51.00); Ni (7.00–17.50); Pb (0.50–2.50) and Zn (10.00–176.50) g l^–1. The heavy metal concentrations in standing water samples were found to be: Cd (1.20–4.90); Cr (ND-10.00); Co (10.25–19.00); Cu (1.75–20.00); Fe (ND-18.00); Mn (5.00–66.50); Ni (8.75–19.75); Pb (0.75–5.50) and Zn (28.60–364.00) g l^–1. The concentrations of heavy metals in drinking water supplies of the Aligarh Muslim University campus were well below the guidelines for drinking water quality as prescribed by World Health Organisation (1984). It is evident from the results that the drinking water may not cause any significant health hazard to water consumers due to heavy metals but these may be hazardous if they get accumulated in the body due to continuous consumption of water.     

Development of a Dynamic Pharmacokinetic Model to Estimate Bioconcentration of Xenobiotics in Earthworms

A simple and dynamic pharmacokinetic model was developed to predict bioconcentration of organic contaminants in earthworms. The model was parameterized experimentally by placing Lumbricus terrestris in soil contaminated with 200 μg/cm² of malathion. The toxicokinetics of malathion uptake, depuration, and degradation in soil is measured. After parameterization, the model was able to accurately predict the bioconcentration factor of malathion at steady state. Sensitivity analyses were performed and the rate of absorption was determined to be the most sensitive parameter. Varying the rate of malathion elimination from earthworm tissues, malathion degradation, and the amount of malathion applied to the soil by 25-fold did not result in the bioconcentration of malathion. An increase in the rate of malathion absorption into earthworm tissues by 25-fold did result in bioconcentration. Previously published pharmacokinetic studies on xenobiotics with log K _ow values ranging up to 8.05 were used to test the predictive capacity of the model. The model was able to predict from 83% to 105% of the experimentally derived bioconcentration factors.     

Organochlorines and selenium in California night-heron and egret eggs

Exceptionally high concentrations of DDE were found in black-crowned night-heron (Nycticorax nycticorax) (geometric mean 8.62 g g^–1 wet wt.) and great egret (Casmerodius albus) (24.0 g g^–1) eggs collected from the Imperial Valley (Salton Sea), California in 1985. DDE concentrations in 14 of the 87 (16%) randomly selected night-heron eggs from six colonies (two in San Francisco Bay, three in the San Joaquin Valley, and one at Salton Sea) were higher than those associated with reduced reproductive success of night-herons (8 g g^–1). In addition, mean shell thickness of night-heron eggs collected from the San Joaquin Valley and from San Francisco Bay during 1982–1984 was significantly less than pre-DDT thickness and was negatively correlated (r=–0.50, n=75, P<0.0001) with DDE concentration. Mean selenium concentration in night-heron eggs from Salton Sea (1.10 g g^–1) was significantly higher than in eggs from three locations in the San Joaquin Valley, and in egret eggs from Salton Sea.