Indicators Of Metal Pollution Research Articles

The use of feathers of birds of prey as indicators of metal pollution

Published results concerning metal levels in feathers of birds of prey were listed and evaluated. Mercury concentrations have been studied most and the background values normally vary between 0.1 and 5 mg/kg dry weight the highest concentrations being in birds from aquatic food chains. Pollution causes elevated levels of mercury in feathers. The concentrations of cadmium, copper, lead and zinc show reasonable variation between species, areas and time periods. Feathers of birds of prey have proved to be good indicators of the status of environmental heavy metal pollution. Special attention should be paid to clean sampling and preparation of samples. Interpretation of the results requires knowledge on food habit, molting and migration patterns of the species. Several species representing different food chains should be included in comprehensive monitoring surveys. Chick feathers reflect most reliably local conditions.

Plankton as an Indicator of Heavy Metal Pollution in a Freshwater Reservoir of Madhya Pradesh, India

Halali Reservoir is an important freshwater body of Madhya Pradesh. The water of the reservoir is used for drinking, irrigation and aquaculture practices. It receives untreated sewage, wastes from small scale industries and agricultural runoff from the catchment area. Various heavy metal (Cd, Cr, Cu, Ni, Pb and Zn) levels were measured in plankton of Halali Reservoir during 2006-2007 by inductively coupled plasma-optical emission spectrometry. Mean concentration ranges for Cd, Cr, Cu, Ni, Pb and Zn were 0.0018-0.0037, 0.0038-0.2257, 0.0013-0.0228, 0.0011-0.0086, 0.0133-0.0494 and 0.0130-0.1168 μg g⁻¹, respectively. Overall, mean Cr concentrations in the plankton were generally the highest of the six metals at four of the five study sites. Metal concentrations at these four sites generally followed the order: Cr > Zn > Pb > Cu > Ni > Cd. Mean concentrations of all metals at a fifth site were consistently lower than at the other sites. The high levels of Cr in the plankton are in agreement with high Cr levels that have been reported in fish from this reservoir, indicating that plankton may serve as a useful indicator of metal pollution in fish.

Monitoring of Metal Contamination in the Eggs of Two Bird Species in India

Monitoring of Metal Contamination in the Eggs of Two Bird Species in India The eggs of birds are extensively used as biological indicator of metal pollution because they come from a specific fragment of the population, formed in a specific period, have consistent composition, easily sampled and the removal of one egg from a nest has a minor effect on population parameter. Many workers [2-7] have advocated the use of eggs to monitor metal contamination in birds as the birds get rid of their body burden of metals through feathers and eggs.

Zinc effect on the sea urchin Paracentrotus lividus immunological competence

Pollution by heavy metals has become one of the most important problems in marine coastal areas as a consequence of anthropogenic inputs. Among metal contaminants, zinc, being considered not very toxic, is sometimes released into the sea in appreciable quantities and its concentration is loosely regulated.In this work we analyzed the effects of a high zinc concentration on the sea urchin Paracentrotus lividus immune system. In particular, after 24h of zinc treatment, we evaluated coelomocytes morphology and composition as well as the zinc influence on some humoral parameters such as hemolysis, lysozyme-like activity and antibacterial activity on Vibrio alginolyticus. Our results evidenced that the presence of zinc affected both cellular and acellular components of the sea urchin immune system. The P. lividus coelomocytes changed in morphology and number; moreover, the amebocytes changed from a petaloid to a filipodial-like shape and the red spherula cells increased in number. Among the considered humoral effectors lysozyme-like activity and antibacterial activity on V. alginolyticus decreased in short-term to zinc treatment. The modifications in the sea urchin immunological competence might give an early indication of disease susceptibility thus suggesting to consider the examined defence mechanisms as potential biological indicators of metal pollution.

Seasonal study on <i>Bothriocephalus</i> as indicator of metal pollution in yellowfish, South Africa

Eighty largemouth yellowfish, Labeobarbus kimberleyensis, were collected between April 2005 and February 2006 with gill nets close to the island (26‹ 52, 249Œ S, 28‹ 10, 249Œ E) in the Vaal Dam. The fish were killed, weighed and their length determined. Muscle, liver and spinal cord tissues were collected from each fish and the intestines removed and opened to expose Bothriocephalus acheilognathi. The tapeworms were collected in glass bottles and frozen. Water and sediment, as well as liver, muscle and tapeworm samples were digested and thereafter metal concentrations of 23 elements (lithium, beryllium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, arsenic, selenium, molybdenum, cadmium, tin, antimony, tellurium, barium, mercury, thallium, lead and uranium) were determined with an ICP-MS. Bioconcentration of metals (selenium, mercury, and lead during autumn; copper, zinc, selenium, cadmium, antimony, thallium and mercury during winter; lithium, zinc, selenium, cadmium and antimony during spring; and zinc during summer) occurred in tapeworms. The highest mean value was recorded in sediment, followed by water, tapeworms and host tissue. A seasonal trend showed that a higher concentration of the metals had accumulated in tapeworms during winter when water levels were at their lowest.

Environmental Indicators of Metal Pollution and Emission: An Experiment for the Instrumental Analysis Laboratory

This experiment enlightens students on the use of environmental indicators and inductively coupled plasma–atomic emission spectroscopy (ICP–AES) and demonstrates the ability of these monitoring tools to measure metal deposition in environmental samples (both as a result of lab-simulated and real events). In this two-part study, the initial experiment is designed to simulate the metal pollutants that originate from sparklers (small-scale fireworks). Two environmental indicators, surface water and Spanish moss (Tillandsia usneoides), are exposed to a lit sparkler in a closed container. The Spanish moss is subsequently microwave digested, and both samples are analyzed for 16 elements by ICP–AES. In part two, the metal content is analyzed in real samples taken from the environment (topsoil and surface water) surrounding the Kennedy Space Center (KSC) launch pads before and after a shuttle launch. Students learn several fundamental concepts including atomic spectroscopy, biomonitoring, microwave digestion, mat...

Toxicological effects of arsenic exposure in a freshwater teleost fish, Channa punctatus

High concentration of arsenic in groundwater in the north-eastern states of India has become a major cause of concern. Inorganic arsenic of geological origin is found in groundwater used as drinking-water in several parts of the world. Arsenic is used in various industries and agriculture and excessive arsenic finds its way into lakes and rivers. Since arsenic is a known human carcinogen, the epidemiological studies are extremely important for this metal. Fish are ideal organisms to work with in toxicogenomics studies due to the strong power of fish models to establish biomarkers of exposure. Since, fishes respond to toxicants in a similar way as higher vertebrates, they can be used to screen for chemicals that are potentially teratogenic and carcinogenic to humans. Also fish absorbs dissolved or available metals and therefore can serve as indicator of metal pollution. The objectives of this work were to examine the toxicological effect and molecular changes caused by a heavy metal sodium arsenite (NaAsO 2 ), in Channa punctatus. When fishes were exposed to NaAsO 2 , it induced death of the fishes in a concentration-dependent manner. 100 ppm, the highest concentration tested in this study, was found to be the deadliest and it induced death of the fishes within 18 to 20 h. As the concentration lowered the survival time increased dose dependently. Liver is the target organ of arsenic toxicity. Fish liver plays an important role in uptake, accumulation, bio-transformation and excretion of arsenic. We investigated the effect of NaAsO 2 on fish liver. NaAsO 2 was found to cause liver chromosomal DNA fragmentation and expression of certain proteins. Key words: DNA Fragmentation, sodium arsenite, Channa punctatus.

The Bacterial Community Associated with the Marine Polychaete Ophelina sp.1 (Annelida: Opheliidae) Is Altered by Copper and Zinc Contamination in Sediments

Tolerant species of polychaete worms can survive in polluted environments using various resistance mechanisms. One aspect of resistance not often studied in polychaetes is their association with symbiotic bacteria, some of which have resistance to metals and may help the organism to survive. We used "next generation" 454 sequencing of bacterial 16S rRNA sequences associated with polychaetes from a copper- and zinc-polluted harbor and from a reference site to determine bacterial community structure. We found changes in the bacteria at the polluted site, including increases in the abundance of bacteria from the order Alteromonadales. These changes in the bacteria associated with polychaetes may be relatively easy to detect and could be a useful indicator of metal pollution.

Chemical, biological and physiological indicators of metal pollution in wetlands

Chemical, biological and physiological responses in terrestrial and aquatic plants may be used as biomarkers to monitor contamination in ecosystems. Some plant parameters such as chlorophyll content, photosynthesis, transpiration, metal uptake and metabolism may be used to determine the level of toxic stress in plants. Similarly, the concentrations of metals in soil may be used to establish the levels of pollution. In this review, we present challenge to researchers involved in environmental assessment to use these simple techniques as a basis for establishing guidelines on environmental pollution.

Efficiencies of different microbial parameters as indicator to assess slight metal pollutions in a farm field near a gold mining area

In order to monitor changes in the concentrations of metals in the soil, different microbial indices such as BIOLOG, microbial carbon (C(mic)), basal respiration, and culturable microbe's most probable number were used. We compared these methods and wanted to discover which method was the best at measuring slight changes in the amounts of heavy metals. Factor analyses were applied to the BIOLOG data and metal concentrations so the combined effects of heavy metals on microbes could be analyzed via statistical data reduction and the distribution patterns of metal concentration could also be revealed. The results showed that the BIOLOG method could barely detect subtle characteristic changes in the soil samples, while the C(mic) method was more sensitive. Furthermore, different heavy metals did not have the same origin/source, and their effects on microbial indices should be analyzed separately. Significant positive correlations between C(mic) and metals were observed and suggested the limitation of using traditional microbial parameters as metal pollution indicators. Among all the soil characteristics in our study, pH seemed to be the most active abiotic factor that affected microorganisms.

Metal accumulation and biomarker responses in Daphnia magna following cadmium and zinc exposure

Metal accumulation (quantified as body burden) and the responses of two biomarkers (metallothionein [MT] induction and superoxide dismutase [SOD] activity) in a freshwater cladoceran Daphnia magna were quantified after being exposed to different concentrations of Cd and Zn for 3 d. The Cd and Zn body burdens increased with increasing exposure concentrations. The responses of biomarkers were metal-specific and concentration-dependent. As a detoxification mechanism, MT was induced by exposure to Cd or Zn or Cd + Zn and was dependent on the exposure concentrations. Low concentrations of Cd or Zn exposure increased the SOD activity, which was, however, inhibited at higher metal exposure concentrations. Metallothionein concentrations in daphnids were significantly related to the metal body burden. The SOD activity was inversely related to Cd body burden, while it was independent of the Zn body burden. Survivorship of D. magna was high at lower Cd/MT ratios in the animals but then decreased linearly when the ratio exceeded six. In contrast, the relationship between survivorship and Zn/MT ratio was different due to the essentiality of Zn. Overall, MT induction was a useful indicator of metal pollution in cladocerans.

Responses of aquatic organisms to metal pollution in a lowland river in Flanders: A comparison of diatoms and macroinvertebrates

The role of macroinvertebrates and diatoms as indicator for metal pollution was investigated by assessing both biota along a metal gradient in the Belgian river the Dommel. Macroinvertebrates and diatoms were sampled in summer and winter and physical–chemical characteristics of the water were measured at four different sample periods and related to sediment characteristics. Although metal concentrations, except cadmium, in the water nowhere exceeded water quality standards, high metal concentrations were measured in the sediment, indicating historical contamination of the Dommel. At the sites that were situated downstream of the pollution source, high levels of conductivity and chloride were measured in the water. Redundancy Analysis (RDA) indicated pH, phosphate and zinc as the significant environmental variables explaining each respectively 7.7%, 11.6% and 22.6% of the macroinvertebrate community composition. Two clusters could be separated, with Gammarus pulex, Leptocerus interruptus, Baetis rhodani and Cloeon dipterum associated with low zinc concentrations and Tubificidae, Asellus aquaticus, Erpobdella sp. and Chironomus thummi-plumosus associated with higher zinc concentrations. Ammonium (10.6%), conductivity (16.5%), chloride (11.4%) and zinc (5.9%) turned out to be significant variables explaining the diatom community structure. Based on physical–chemical differences and species composition, three different groups could be separated. With this Tabellaria flocculosa and Fragilaria capucina var. rumpens were associated with low metal concentrations, Gomphonema parvulum and Nitzschia palea with elevated concentrations and Eolimna minima and Sellaphora seminulum with high zinc concentrations. In conclusion, the diatom community best reflected the metal gradient. With regard to water quality indices, those based on macroinvertebrates best followed the metal pollution gradient and were most strongly correlated with physical–chemical variables of water and sediment. This study indicated that to assess the effect of metal pollution in lowland rivers, the combined use of macroinvertebrates and diatoms is more appropriate than the use of both biota separately.

Linking pollution induced community tolerance (PICT) and microbial community structure in chronically metal polluted estuarine sediments

We tested the ability of pollution induced community tolerance (PICT) to detect the effects of chronic metal pollution on estuarine sediment microbial communities, along a gradient spanning two orders of magnitude in metal concentrations. In tandem, we investigated the associated microbial community structure using terminal restriction fragment length polymorphism (T-RFLP). Tolerance of microbes to Cu, measured as IC50 (inhibitory concentration 50%), was strongly correlated with pore water Cu concentration (r(2)=0.842). No strong correlation existed for other metals tested, highlighting the ability of PICT to identify the pollutant causing a toxic effect. There was no correlation between microbial community structure and community tolerance to metals tested, but analysis of community structure did provide some information on reasons for observed PICT response. PICT methodology used here provided a greater strength and consistency of association with pollutant concentration compared to microbial community structure and can be recommended as a sensitive indicator of metal pollution on estuarine sediment microbial communities.

Sedimentary diatoms along a temporal and spatial gradient of metal contamination

We examined changes at the community and population level of sedimentary diatoms over a wide temporal and spatial gradient of metal pollution encountered in cores from three lakes in the Abitibi mining region (Quebec, Canada). Diatom communities on the whole appeared to be very tolerant of metal contamination, as shown by diatom cell accumulation rates decreasing only under the most severe conditions of contamination, which were found from the 1930s to the 1980s in Lac Dufault (cadmium, up to 94 μg/g dry sediment; Cu, up to 8600 μg/g; Zn, up to 9000 μg/g). Under the moderate conditions of contamination observed in the other two lakes and in the most recent sediment of Lac Dufault, diatom cell accumulation rates tended to increase over values typical of the pre-mining period. However, there were increasing rearrangements of the community composition along the contamination gradient. Under moderate metal enrichment, the diatom community of Lac Vaudray experienced only subtle changes, with Cyclotella stelligera, albeit decreasing, remaining the dominant taxon. In the intermediately contaminated Lac Caron, several benthic taxa, noticeably Cymbella silesiaca and several Fragilaria species, rose in taxonomic importance. The most extreme contamination observed in Lac Dufault led to a severely impoverished community almost entirely represented by Achnanthes minutissima and Brachysira vitrea. With increasing levels of contamination, there was a shift from planktonic to benthic taxa and morphotypes and a consistent decrease in the siliceous stomatocysts/diatom frustules ratio. These trends suggest that littoral zones may represent an important refugium under conditions of high contamination. Responses to metal stress were in general more evident at the population than at the community level. Cyclotella stelligera and B. vitrea had a consistent negative and positive response, respectively, along the gradient and are the most promising indicators of metal pollution for this region.

Determination of Heavy Metal Distributions in the Green-Lipped Mussel Perna viridis as Bioindicators of Heavy Metal Contamination in the Johore Straits and Senggarang, Peninsular Malaysia

In this study, the patterns of the distributions and redistributions of heavy metals in the different soft tissues of Perna viridis were determined. Crystalline style and muscle were found to be sensitive organs to pollution as evidenced by total disturbances in the patterns of metal occurrences. The present findings confirmed the use of different soft tissues as an effective way of monitoring the status of metal pollution in tropical coastal waters. Therefore, the distribution of metals in different parts of P. viridis is proposed as a good indicator of metal pollution in tropical coastal waters.

Bioaccumulation of Heavy Metals in Soil Invertebrtes: Part 1: Uptake and Accumulation of Lead and Chromium by <i>Achatina marginata</i> (Linnaeus) and <i>Lymnaea stagnalis</i> (Linnaeus)

Achatina marginata and Lymnaea stagnalis were each exposed to 4.15µg/g and 8.26µg/g diet of lead and chromium respectively over a period of 28 days. Comparative accumulation studies were carried out on the edible (soft) and gut tissues of both snails. The rates of accumulation of Cr by L. stagnalis were 0.025µg/g/week and 0.084µg/g/wee in the soft tissues for the lower and higher exposure concentrations respectively. The corresponding rates in the gut were 0.290µg/g/week and 0.537µg/g/week respectively. However, lower rates of accumulation of Pb were calculated for the tissues of the same species at the two exposure levels. Higher concentrations of Cr and Pb were measured in the gut tissues than the soft tissues. The rates of accumulation of Cr by A. marginata were 0.341µg/g/week and 0.518µg/g/week for the soft tissues at the lower and higher exposure concentrations respectively while the corresponding rates for the gut were 1.347µg/g/week (lower) and 1.477µg/g/week (higher). These values are 13.6 times and 6.2 times greater than those of L. stagnalis at the lower and higher concentrations of exposure respectively. A similar trend in the bioaccumulation of Pb by A. marginata rative to L. stagnalis was also observed. Bioaccumulation rates of Pb and Cr were greater in the gut than the soft tissues for both species. The moderate accumulation factors calculated for L. stagnalis and high values for A. marginata suggest that these species can be used as indicators of metal pollution in field experiments. KEY WORDS: L. stagnalis; A. marginata; Lead; Chromium; Bio-accumulation. Global Journal of Environmental Sciences Vol.3(1&2) 2004: 7-12

Diatom taxonomic and morphological changes as indicators of metal pollution and recovery in Lac Dufault (Québec, Canada)

We studied diatom taxonomic composition and the presence of morphological alterations (size and deformations) along a sediment core collected in Lac Dufault, Abitibi, whose watershed has a long history of mining pollution presently undergoing mitigation. According to sediment dating with 210Pb and metal profiles along the core, we could identify four periods in the contamination history of the lake, which were characterized by different diatoms. Tabellaria flocculosa was dominant in the pre-mining period but was drastically reduced at the onset of pollution when Fragilaria cf. tenera became important. This diatom, together with other Fragilaria species and cysts of Chaetoceros muelleri, typified the transition period in which Cu reached its maximum value and other metals started to increase. During the period of maximum contamination with Zn, Cd, and Fe accompanied by acid mine drainage, Achnanthes minutissima and Brachysira vitrea were dominant. These taxa started to wane in the most recent sediments representing a partial chemical recovery. Asterionella formosa, which almost vanished at mining onset, reappeared with high abundance in these superficial sections. Beside these taxonomical shifts, we observed during the contamination period significant reduction in valve length together with increased percentages of valve deformations. Because available data on water chemistry and a diatom-based pH reconstruction suggest that Lac Dufault escaped severe acidification, diatom patterns observed in the core can be mostly ascribed to metal contamination. Individual diatom abundance and valve length had strong statistical relationships with the different metals identified in the core. Diatom changes both taxonomic and morphological can be excellent specific indicator of metal contamination and early recovery.

Accumulation of heavy metals by intestinal helminths in fish: an overview and perspective.

Intestinal helminths of fish are of increasing interest as potential bioindicators for heavy metal contamination in aquatic habitats. Among these parasites cestodes and acanthocephalans in particular have an enormous heavy metal accumulation capacity exceeding that of established free living sentinels. Metal concentrations several thousand times higher in acanthocephalans than in host tissues were described from field and laboratory studies. Whereas larval stages inside their intermediate hosts are not able to take up high quantities of metals, young worms begin to take up metals immediately after infection of the final host. After four to five weeks of exposure, the parasites reach a steady-state concentration orders of magnitude higher than the ambient water level. Thus, acanthocephalans are not only very effective in taking up metals, but they can also respond very rapidly to changes in environmental exposure. The mechanism which enable acanthocephalans to take up metals from the intestinal lumen of the host appears to be based on the presence of bile acids, which form organo-metallic complexes that are easily absorbed by the worms due to their lipophilicity. Investigations of the environmental conditions affecting metal uptake have shown that the parasites are more consistent and reliable indicators for metal pollution than the host tissues as metal levels of the latter are much more dependent on the water chemistry. Thus, after some years of research on the uptake of metals by acanthocephalans and on the factors affecting metal accumulation in intestinal parasites it should be asked if acanthocephalans meet the criteria commonly accepted for sentinels. If parasites can be considered as promising sentinels, we need reasons for the establishment of 'new' indicators. Therefore, this review summarises the present knowledge about parasites as bioindicators and compares the accumulation properties of parasites and established free living indicators. Finally, this review presents possible answers to the question why it could be advantageous to have new and even more sensitive indicators for environmental monitoring purposes.

Effects of cadmium stress on periphytic diatom communities in indoor artificial streams

SUMMARY 1. Two experiments were performed with periphytic diatoms originating from the River Lot (France) and allowed to grow on clean substrata within indoor artificial streams. Three cadmium (Cd) levels (control, low Cd=10 μg L−1 and high Cd=100 μg L−1) were used to test the effects of Cd on (i) the settlement and development of diatom communities (Experiment 1, 4 weeks Cd exposure) and (ii) predeveloped communities grown over a 2‐week period without contamination (Experiment 2, 2 weeks Cd exposure).2. Experiment 1 revealed that growth and taxonomic composition of diatom communities clearly differed with Cd exposure. Biofilms were more adpressed to substrata under low Cd concentration, and were thinner and patchy under high Cd concentration.3. Exposure of developed diatom communities (Experiment 2) to Cd revealed only minor variations in taxonomic composition, possibly linked to the protective role of the developed organic matrix against metal stress.4. These results support the validity of periphytic diatom communities as indicators of metal pollution, although significant structural changes would take longer within developed communities.

Pomphorhynchuslaevis (Palaeacanthocephala) in the intestine of chub ( Leuciscuscephalus) as an indicator of metal pollution

Chub experimentally infected with the acanthocephalan parasite Pomphorhynchus laevis were exposed to 0.01 mg l −1 Pb 2+ over 5 weeks. Lead was rapidly accumulated in the intestinal worms reaching a steady-state concentration after 4 weeks. This concentration was significantly greater than in the host muscle, liver and intestine and more than 9,000 times higher than the exposure concentration. Lead accumulation in P. laevis increased at a higher exposure concentration but was not correlated with either parasite intensity or with pooled or individual worm weight. The highest lead concentrations were recorded in those specimen of P. laevis that were attached in the posterior intestine. Interestingly, parasitised chub accumulated less lead in their own tissues than uninfected conspecifics. A mechanism of lead uptake by P. laevis and the application of acanthocephalans as accumulation indicators of metal pollution is discussed.