Bioindicators Of Heavy Metal Contamination Research Articles

Fucoxanthin and heavy metals in brown algae of genus Cystoseira C. Agardh from water areas with different anthropogenic influences (Black Sea)

Brown algae are recognized as bioindicators of heavy metal contamination in coastal waters. Comparison of morphological and functional characteristics of algae living in different environmental conditions is essential for understanding mechanisms of marine organism adaptation to anthropogenic environmental impact. The aim of this study is to determinate concentration of fucoxanthin and heavy metals in branches of brown seaweeds Cystoseira barbata (Stackhouse) C. Agardh and Cystoseira crinita Duby in water areas with different anthropogenic pressures. The content of fucoxanthin in the samples is determined by means of thin layer chromatography, and heavy metals are quantified using atomic absorption spectrophotometry. The maximum concentrations of fucoxanthin (3 mg·g-1 of dry weight), lead (48.5 μg·g-1), zinc (62.6 μg·g-1), and cadmium (3.2 μg·g-1) are found in branches of 2- to 3-month-old seaweeds. The content of fucoxanthin in the branches of C. barbata is 1.5 times higher than that in C. crinita. The Cystoseira seaweeds living in a eutrophic bay have higher concentrations of the pigment and zinc than the macrophytes from open waters. The elevated levels of fucoxanthin in brown algae of this genus found in eutrophic and heavy-metal-polluted water areas demonstrate the important role of this carotenoid in the adaptation of the algal photosynthetic apparatus to anthropogenic environmental changes.

Norway rat, Rattus norvegicus in metropolitans, a bio-indicator for heavy metal pollution (Case study: Tehran, Iran)

The present research aims to assess the potential use of the Norway rat, Rattusnorvegicus as a bio-indicator for lead and cadmium accumulation in 10 urban zones in Tehran, the metropolitan city, Iran. During April to May 2014 we collected twenty adult Norway rats from the different predefined zones. By referring to the air pollution data collected over 15 years, the sampling areas were detected to collect rats. ANOVA test showed that the mean concentrations of cadmium and lead were significantly different for the areas studied as the highest value for both metals recorded in the central areas, exhibiting decreased trends towards the north. In the central parts of Tehran, the mean levels of lead and cadmium concentrations were found to be 73.06 and 5.20 μg.g-1 in the rats’ hepatic tissues, respectively. Meanwhile, the lead and cadmium concentrations were 1.85 and 0.07 μg.g-1, respectively in the northern parts of Tehran. In addition, we examined the concentration of lead and cadmium in the sludge obtained from the sampling points. The results also corresponded to the metal concentration in the rats liver samples. Therefore, the present study verified that the Norway rat could be used potentially as a bio-indicator for heavy metal contamination in polluted metropolitans, such as Tehran.

Transcriptome Profiling Analysis of Wolf Spider Pardosa pseudoannulata (Araneae: Lycosidae) after Cadmium Exposure.

Pardosa pseudoannulata is one of the most common wandering spiders in agricultural fields and a potentially good bioindicator for heavy metal contamination. However, little is known about the mechanisms by which spiders respond to heavy metals at the molecular level. In the present study, high-throughput transcriptome sequencing was employed to characterize the de novo transcriptome of the spiders and to identify differentially expressed genes (DEGs) after cadmium exposure. We obtained 60,489 assembled unigenes, 18,773 of which were annotated in the public databases. A total of 2939 and 2491 DEGs were detected between the libraries of two Cd-treated groups and the control. Functional enrichment analysis revealed that metabolism processes and digestive system function were predominately enriched in response to Cd stress. At the cellular and molecular levels, significantly enriched pathways in lysosomes and phagosomes as well as replication, recombination and repair demonstrated that oxidative damage resulted from Cd exposure. Based on the selected DEGs, certain critical genes involved in defence and detoxification were analysed. These results may elucidate the molecular mechanisms underlying spiders’ responses to heavy metal stress.

Earthworms Eudrilus eugeniae as Bio-indicators of Heavy Metal Contamination in Port Harcourt Dumpsites

Earthworms Eudrilus eugeniae as Bio-indicators of Heavy Metal Contamination in Port Harcourt Dumpsites

Evaluating Insects as Bioindicators of Heavy Metal Contamination and Accumulation near Industrial Area of Gujrat, Pakistan.

To study the accumulation and contamination of heavy metals (i.e., Cd, Cr, Cu, Ni, and Zn) in soil, air, and water, few insect species were assayed as ecological indicators. Study area comes under industrial zone of district Gujrat of Punjab, Pakistan. Insects used as bioindicators included a libellulid dragonfly (Crocothemis servilia), an acridid grasshopper (Oxya hyla hyla), and a nymphalid butterfly (Danaus chrysippus) near industrial zone of Gujrat. Accumulation of Cd was highest in insect species followed by Cu, Cr, Zn, and Ni at p < 0.05. Hierarchical cluster analysis (HACA) was carried out to study metal accumulation level in all insects. Correlation and regression analysis confirmed HACA observations and declared concentration of heavy metals above permissible limits. Metal concentrations in insects were significantly higher near industries and nallahs in Gujrat and relatively higher concentrations of metals were found in Orthoptera than Odonata and Lepidoptera. The total metal concentrations in insects were pointed significantly higher at sites S3 (Mid of HalsiNala), S9 (End of HalsiNala), and S1 (Start of HalsiNala), whereas lowest value was detected at site S6 (Kalra Khasa) located far from industrial area. HACA indicates that these insect groups are potential indicators of metal contamination and can be used in biomonitoring.

The intestinal cestode Hymenolepis diminuta as a lead sink for its rat host in the industrial areas of Riyadh, Saudi Arabia

The present study sought to assess the potential of the cestode Hymenolepis diminuta as a bioindicator for lead accumulation in two industrial areas of the city of Riyadh, Saudi Arabia. Rats (Meriones libycus) were collected from two sites (industrial area II and Salbukh) in Riyadh. In the industrial area II, the mean levels of lead concentrations were found to be 1.96, 1.92, 1.4 and 30.72μg/g in the rats’ liver, kidney and intestine, and in H. diminuta, respectively. In Salbukh, meanwhile, the lead concentrations were 1.63, 1.52, 1.20 and 21.31μg/g in the rats’ liver, kidney, and intestine, and in H. diminuta, respectively. In addition, in industrial area II, compared with the liver, kidney and intestine of their host, the bioconcentration factors of lead were found to be, respectively, 15.6, 16 and 21.9 times higher in H. diminuta, and were 7.5, 8, and 10.2 times higher in the same organs compared to H. diminuta in Salbukh. The present study, therefore, proved that H. diminuta could be used as a bioindicator for heavy metal contamination in the industrial areas of the city of Riyadh.

Mercury speciation and effects on soil microbial activities

To study Hg toxicity on soil microbes and their activities, it is necessary to understand its various forms in soils. The objectives of this study were to investigate Hg speciation in four soil types spiked with Hg (300 mg kg−1 soil) and its effects on soil microbial respiration and enzymes (amidohydrolases and phosphatase) activities. An assessment of the chemical forms, amounts, reactions, and mobility of Hg in soils and sediments is of significant importance to improve and maintain soil and environmental health and sustainability. Mercury speciation analysis was investigated under acidic and alkaline conditions using a modified sequential procedure, which differentiates Hg into the four distinct fractions. Soil microbial respiration and enzymes activities were determined under laboratory settings, by incubating the soils at 25°C for 30 days, and then determining the amount of CO2 evolved. Speciation results revealed that the water soluble form was the least, with < 1% of the total Hg in the soil types investigated irrespective of the pH condition, while the residual fraction was the most abundant (> 80%) in Canisteo, Houston, and Ketona soils under acidic conditions and < 35% in Decatur soil. Under alkaline conditions, the residual fraction was ≤ 70% in Canisteo, Houston, and ketona and ≤ 29% in Decatur soil. The exchangeable fraction was the second most abundant fraction in the soils used ranging from 3.7–50.0% under acid conditions and 16.9–52.1% under alkaline conditions indicating that Hg desorption was found to be more favorable under alkaline than acidic conditions. Soil respiration was suppressed by Hg especially at the 100 mg kg−1 concentration level. Amidohydrolases and phosphatases' response in the presence of Hg was variable. Amidohydrolases were more sensitive to Hg (18–90%) than phosphatase (0–35%) in all soils. This study demonstrated that the forms in which Hg exist in soils may determine its bioavailability and toxicity. Also microbial respiration and enzyme activities are potential bioindicators of heavy metal contamination of the environment.

Macroinvertebrates and fishes as biomonitors of heavy metal concentration in the Seixal Bay (Tagus estuary): Which species perform better?

The present study aims to evaluate the utilization of several benthic macroinvertebrate and fish species as bioindicators of heavy metal contamination in a relatively enclosed estuarine area, the Seixal Bay (Tagus estuary, Portugal). 266 specimens of 16 taxa were captured during four sampling campaigns and the concentration of lead, chromium, nickel, copper, zinc, cobalt and cadmium were quantified in fish muscle and whole soft body of the invertebrates, as well as in suspended particulate matter in the water column and sediments. Larger predator fishes with higher mobility presented low levels of contamination, probably due to their feedings sites being located outside the bay in less contaminated areas. The species of the Gobiidae family, Pomatoschistus microps, Pomatoschistus minutus and Gobius niger presented higher values of non-metabolic elements (Pb, Ni and Cd) while Scrobicularia plana, Nereis diversicolor, Carcinus maenas and Palaemon serratus were more associated to the accumulation of Cu, Cr and Zn. Nephtys hombergii and Crangon crangon, showed intermediate concentrations of all metals. These results points out to a future possible utilization of S. plana, N. diversicolor, P. serratus and C. maenas and of Pomatoschistus species as bioindicators of heavy metal contamination in ecological quality monitoring programs.

Accumulation of toxic metals (Pb and Cd) in the sea urchin Diadema aff. antillarum Philippi, 1845, in an oceanic island (Tenerife, Canary Islands)

This document shows the results obtained from a study on the concentration of toxic heavy metals in the internal tissue and exoskeleton of sea urchins, collected from their natural habitat. The levels of lead and cadmium were measured by Graphite Furnace Atomic Absorption Spectrometry. The mean concentrations of lead and cadmium in the internal tissue were 304.04 and 260.54 microg/kg respectively, whereas in the shell they were 185.02 and 142.48 microg/kg. We also performed a statistical analysis of the differences in the distribution of metals between their exoskeleton and their internal content, a correlation study of the metal content in internal tissue and shell and sampling areas, and a correlation study between the metal content and sample size. Since the sea urchin Diadema antillarum presents a wide range of variation in metal content, this study suggests that this species is an excellent bioindicator of heavy metal contamination.

Marine Organisms As Biomonitors

Biomonitors are organisms mostly used for the quantitative determination of contaminants in the environment (see Chapter 1). The present chapter discusses mainly the employment of seaweeds, sea phanerogams and molluscs as bioindicators of heavy metal contamination, since they are the organisms of choice in most of the programmes of biological monitoring of coastal marine waters (see Water Framework Directive 2000/60 EC (WFD) [1]). Bioindicators provide an integrated view of the presence of micropollutants, and in the aquatic environment they respond only to the fraction presenting a clear ecotoxicological relevance (see Chapter 1). Among the different methodological approaches of biological monitoring of a marine ecosystem, the approach based on the bioaccumulation capacity of some chemical species, as for instance trace metals, is among the most important. This capacity is particularly present among macroalgae, sea phanerogams, molluscs, oysters, etc. These organisms can be proposed as possible bioindicators when the presence of a direct correlation between internal and environmental levels of the various metals has been verified [2]. Therefore, the chemical analysis of the tissues of such organisms represents a method for measuring the integrated bioavailability of trace metals in the marine environment over time, given their remarkable bioconcentration capacity [3–5]. Comparing the levels of metals in the organisms collected at different sites is a very useful way to gather information on the biologically available levels of inorganic contaminants in the areas under study. In general, micro and macroalgae, marine phanerogams, mussels, oysters, tellinid bivalves, polychaets and crustaceans are some of the organisms used as bioindicators of marine ecosystems [4]. Marine organisms can accumulate contaminants present in solution and in the particulate material, thus determining a variation in the level of bioaccumulation depending on the trophic level occupied. Some marine invertebrates can take contaminants from the particulate material of the sediment, especially when their physico-chemical conditions are being altered. Algae and phanerogams take contaminants in solutions and many herbivorous crustaceans reflect their concentrations. Therefore, in order to have a full picture of the bioavailability of the various pollutants of water ecosystems, it is necessary to use several kinds of WITPress_BMTA_ch004.qxd 11/26/2007 17:00 Page 81

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.

Heavy metals in bullfrog (Rana catesbeiana) tadpoles: Effects of depuration before analysis

AbstractAlthough tadpoles may well be excellent organisms to use as bioindicators of heavy metal contamination, the relationship of deposition in the body compared to the tail, and the effect of sediments or other debris in the digestive tract on heavy metal concentrations is unknown. We examined the effect of experimental depuration of bullfrog (Rana catesbeiana) tadpoles on heavy metal and selenium concentrations in intact tadpoles, as well as their bodies and tails. We defined depuration in this experiment as allowing defecation as an elimination process for intestinal contents (=clearing). We maintained wild‐caught tadpoles in clean water for 0, 24, 48, and 72 h to determine the effects of clearing on heavy metal concentrations. We also examined the concentrations of heavy metals in the whole body and digestive tract separately. We test the null hypotheses that no differences occur in metals as a function of time in uncontaminated water, and that no differences occur in metal concentrations in the body compared to the tail and to the digestive tract. We rejected these hypotheses based on regression models. Variance in concentrations of chromium (77%) and lead (70%) were explained by part (body, tail, whole body) and clearing time; for manganese (80%), mercury (64%), selenium (28%), and cadmium (25%) the variation was explained only by body part; for arsenic (53%), the variation was explained by part, clearing time, and weight of the various parts. For those metals in which clearing time explained part of the variation, metal concentrations in both the body and tail decreased after 24 and 48 h, but increased slightly thereafter. Clearing, however, did not greatly decrease metal concentrations in either the body or tail. These data suggest that for some metals (mercury, manganese, cadmium, selenium), clearing has no effect, and for others the effect is slight. For fresh tadpoles, however, the digestive tract contained significantly higher concentrations of all metals than either the body or head, probably reflecting metals absorbed to sediment particles in the gut.

Effects of metal contamination from mine tailings on allozyme distributions of populations of great plains fishes

This study was conducted to assess the effects of zinc and lead on genetic variability of minnow populations (Gambusia affinis, Pimephales notatus, and Fundulus notatus) sampled from two creeks, one receiving mine drainage (Willow Creek) and one reference (Brush Creek), in the Tri-State Mining district in Kansas. Zinc and lead concentrations were greater in water samples taken from sites in Willow Creek compared to sites sampled in Brush Creek. While total numbers of fish captured from Willow Creek were smaller than numbers taken from Brush Creek, there were no differences in these fish communities for estimates of species diversity, richness and evenness. Genetic differentiation within creeks was rare. However, there was significant differentiation between creeks for allozymes of the enzymes glucose phosphate isomerase (GPI) in F. notatus and P. notatus, malate dehydrogenase (MDH) in G. affinis, and phosphogluconate dehydrogenase (PGDH) in F. notatus. Proportions of heterozygous genotypes of P. notatus and G. affinis were higher in Willow Creek compared to Brush Creek. In vitro experiments were conducted to assess the effects of zinc and lead on sensitivity of enzyme staining during electrophoresis. Results indicated allozyme sensitivity to zinc for GPI and PGDH loci. Other studies suggest that zinc competitively competesmore » with magnesium as a cofactor for these enzymes. Allozymes did not exhibit differential sensitivity to lead. The significant differentiation between creek populations and the results of the in vitro tests indicate a selective effect of zinc on allozymic distributions of these fishes. These results demonstrate the potential use of genetic variability as a bioindicator of heavy metal contamination.« less