Trace metal accumulation by algae in Sepetiba Bay, Brazil

Trace metal concentrations (Zn, Cd, Pb, Cr and Cu) were determined in some benthic algae from Sepetiba Bay, Brazil. This region has been modified by the increase of industrial activities during the last 30 years. Among species sampled the brown algae Padina gymnospora contained the greatest amount of Zn. The Bioconcentration Factor for Zn in P. gymnospora was found to be 10(4) under laboratory conditions. The absorption of (65)Zn depended on exposure time and increased with Zn concentrations in the medium. An insignificant amount of Zn desorbed from algae suggested a very high affinity with cellular binding sites. Zinc uptake by P. gymnospora is discussed by considering field and laboratory conditions.     

Degradation of azo dyes by algae

The degradation of azo dyes by algae was evaluated and it was found that certain algae can degrade a number of azo dyes to some extent. The reduction rate appears to be related to the molecular structure of the dyes and the species of algae used. The azo reductase of algae is responsible for degrading azo dyes into aromatic amine by breaking the azo linkage. The aromatic amine is then subjected to further metabolism by algae. It is proposed in this paper that in stabilization ponds, algae can play a direct role in the degradation of azo dyes, rather than only providing oxygen for bacterial growth.     

Heavy metal monitoring of marine algae from the Turkish Coast of the Black Sea, 1998-2000

Concentrations of Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn were determined in macroalgae samples collected from the Turkish Coast of the Black Sea. Certain algae species were chosen among the green, brown and red algae species at Sile and Sinop sampling stations from 1998 to 2000. In general, as regards the influence of the collection sites on the whole metal accumulation, Sinop is considered to be more polluted than Sile. The concentrations of the heavy metals in Cystoseira barbata algae are compared with previous studies in the same stations. The results showed that all metal levels have gradually decreased during past years. At the same time, Cd, Co, Cr, Cu, Fe, Ni and Pb levels in the present study are lower than in Bosphorus and Marmara Sea algae. However, Mn and Zn concentrations are higher than Bosphorus but lower than at Marmara. According to these findings the heavy metal pollution decreased in Turkish Coast of the Black Sea during the years investigated.     

Zooplankton community responses to chemical stressors: a comparison of results from acidification and pesticide contamination research

The response of freshwater zooplankton communities to two chemical stressors, acidification and pesticide contamination, were investigated in a review of published research results. The objective was to test Odum's predictions (Odum, 1985) that in response to stress, both the average body size of organisms and their efficiency in utilizing resources are reduced. Acidification and pesticide contamination were both found to favor dominance by small cladorecans and rotifers, the smallest zooplankton taxa. This finding was consistent with Odum's predictions, however, there were exceptions to the trend. The dominance of small taxa may be due to rapid reproductive rates, physiological tolerance, development with few transitions through sensitive stages (eg. post-molting), or to the great richness of small species. Regardless of the mechanism, there is evidence that when acidification and pesticide contamination result in small zooplankton dominance, the efficiency of carbon and energy transfer from algae to zooplankton is reduced. This finding is also consistent with Odum's predictions.     

Fish status survey of Nordic lakes: effects of acidification,eutrophication and stocking activity on present fish species composition

The status of fish populations in 3821 lakes in Norway, Sweden and Finland was assessed in 1995-1997. The survey lakes were chosen by stratified random sampling from all (126 482) Fennoscandian lakes > or = 0.04 km2. The water chemistry of the lakes was analyzed and information on fish status was obtained by a postal inquiry. Fish population losses were most frequent in the most highly acidified region of southern Norway and least common in eastern Fennoscandia. According to the inquiry results, the number of lost stocks of brown trout (Salmo trutta), roach (Rutilus rutilus), Arctic char (Salvelinus alpinus) and perch (Perca fluviatilis) was estimated to exceed 10000. The number of stocks of these species potentially affected by the low alkalinity of lake water was estimated to exceed 11000. About 3300 lakes showed high total phosphorus (> 25 microg L(-1)) and cyprinid dominance in eastern Fennoscandia, notably southwestern Finland. This survey did not reveal any extinction of fish species due to eutrophication. One-third of the lakes had been artificially stocked with at least one new species, most often brown trout, whitefish (Coregonus lavaretus s.l.), Arctic char, rainbow trout (Oncorhynchus mykiss), pike-perch (Stizostedion lucioperca), grayling (Thymallus thymallus), pike (Esox lucius), bream (Abramis brama), tench (Tinca tinca) and European minnow (Phoxinus phoxinus). The number of artificially manipulated stocks of these species in Fennoscandian lakes was estimated to exceed 52000. Hence, the number of fish species occurring in Nordic lakes has recently been changed more by stockings than by losses of fish species through environmental changes such as acidification.     

Effects of pulp mill chlorate on Baltic Sea algae

The long-term effects of pulp mill chlorate on different algal species of the Baltic Sea were studied in land-based model ecosystems simulating the littoral zone. Brown algae (Phaeophyta) exhibited an extraordinarily high sensitivity to chlorate and pulp mill effluents containing chlorate. All brown algal species ceased growth or showed major signs of toxicity at all concentrations tested, down to microgram per litre levels. EC50 levels for growth of Fucus vesiculosus were about 80-100 microg ClO3- litre(-1). Blue-green algae (Cyanophyta) were not deleteriously affected nor were green algae (Chlorophyta). The perennial and annual species of red algae (Rhodophyta) were also unaffected by the effluents. Diatoms did not show any sensitivity and phytoplankton (fresh- and brackish water) were particularly insensitive. A phanerogam, Zostera marina was also unaffected by the treatments.     

Seasonal changes in an intertidal community affected by sewage pollution

Seasonal changes in structure of a rocky intertidal community affected by sewage pollution at Quequén (Argentina) were studied over a period of 2 years. Most species showed a decrease in cover values in the polluted area. On the other hand, a small proportion of organisms favoured by organic enrichment predominated around the outfall during the period of study. Community structure was not significantly altered by frosts or windstorms. Desiccation is identified as the main physical stress. A combination of late spring high temperatures with extreme midday low-tides caused by northerly winds was responsible for heavy losses in dominant algae. Major seasonal changes in community structure were primarily due to variations in area covered by the chlorophyte Ulva lactuca, and crusts of blue-green algae and diatoms in the vicinity of the outfall. Highest diversity values were attained during either late winter or spring, due to increased abundances of several seasonal algae. Abundance of the dominant organism, the bivalve Brachidontes rodriguezi, remained stable, showing only slight, non-seasonal, changes. Since the absence of B. rodriguezi is an indication of heavy pollution, temporal stability of this species suggests that the intensity of sewage discharges did not vary over the period of study.     

The influence of untreated wastewater to aquatic communities in the Balatuin River,The Philippines

A risk assessment of chemical constituents in rivers that receive untreated wastewater should take into account the adverse effects of increased biological oxygen demand (BOD), ammonia and reduced dissolved oxygen (DO). This concept was tested via a field study in the Balatuin River, The Philippines, where the influence of physical and chemical factors, including the consumer product chemical linear alkylbenezene sulfonate (LAS), to aquatic communities (algae, invertebrates, fish) was determined. Periphytic algae were found to be insensitive to high BOD (>10 mg/l) and ammonia (>0.01 mg unionized NH(3)/l), concentrations from organically enriched untreated wastewater discharges. However, taxa richness and abundance of macroinvertebrates were influenced greatly by the discharges. Where BOD and ammonia concentrations were elevated, the dominant taxa were oligochaete worms and chironominds. Fish and crustaceans (freshwater crabs and prawns) were found only in sites with the least BOD concentrations (furthest upstream and downstream). The maximum concentration of LAS (0.122 mg/l) was less than that expected to affect 5% of taxa (0.245 mg/l), whereas exceedences of DO and ammonia criteria were observed in several sites. The lack of recovery observed was attributed to influences of low DO, high ammonia and poor colonization from upstream and downstream reaches due to organically-enriched discharges     

Marine macrophytes as effective lead biosorbents

Several species of seagrass and marine macrophytes were investigated for their biosorption performance in the removal of lead from aqueous solution. The effect of pH on the equilibrium of the seagrass Cymodocea nodosa as a biosorbent also was studied. It was found that increasing pH increased lead biosorption, with a maximum uptake of approximately 140 mg/g in the range pH 3.3 to 5. Equilibrium data at different pH levels were successfully fitted to competitive equilibrium models. In addition, the seaweeds belonging to different phyla (i.e., Chlorophyta, Heterokontophyta, and Rhodophyta) were studied for the effect of their structure on equilibrium at a constant pH 5. The brown algae (Heterokontophyta) showed the highest potential for lead sorption, with a maximum uptake of 220 mg/g for C. compressa and 140 mg/g for S. lomentaria. The green algae (Chlorophyta) showed lead uptake in the range 40 to 90 mg/g, and the red algae (Rhodophyta) was least effective, with uptake in the range 10 to 40 mg/g.     

纤维直接过滤去除原水藻类

以丙纶丝为滤料 ,以自制转鼓装置对高藻原水进行直接过滤除藻试验。结果表明 ,对Chl a及藻总数的去除率分别为 64 %— 95 % (平均 91% )和 82 %— 96% (平均 92 % ) ,对主要藻种的平均去除率均在 85 %以上 ,除藻效果明显。原水中藻类特征、试验运行工况条件直接影响对藻类的去除效果。筛分截留与吸附 -絮凝是试验装置过滤除藻的主要机理     

Is bark pH more important than tree species in determining the composition of nitrophytic or acidophytic lichen floras?

To study the pH preference of epiphytic lichens, the bark pH of Fraxinus, Tilia, Quercus and Ulmus trees in an urban environment was measured using a flat surface electrode. The total number of trees was 253. A survey was made of the lichens in a 40 × 40 cm quadrat surrounding the pH measurement point. Our data analysis using multivariate and univariate statistical techniques indicates that the tree species is the most important factor influencing lichen colonisation, and that bark pH alone is of less importance. We hypothesize that the changed pollution climate, with strong decreases in both sulphur dioxide and ammonia concentrations over the past two decades and a concomitant general increase in bark pH, has made epiphytes less sensitive to pH.     

Littoral microcrustacean (Cladocera and Copepoda) indicators of acidification in Canadian Shield lakes

We identify littoral microcrustacean indicators of acidification in 2 surveys of Canadian Shield lakes conducted 10 years apart. We found a total of 90 cladoceran and copepod species with richness increasing severalfold from acidic to nonacidic lakes. The fauna of the nonacidic lakes differed between the surveys. The 1987 survey employed activity traps, and caught more littoral taxa than the more recent, net-haul-based survey. Similar faunas were identified in the acidified lakes in both surveys, and several good indicator species were identified. For example, Acanthocycops vernalis was restricted to lakes with pH < 6. Sinobosmina sp. was very common but only in lakes with pH > 4.8. Tropocyclops extensus, Mesocyclops edax, and Sida crystallina were commonly found but only at pH > 5, and Chydorus faviformis only at pH > 5.9. These indicators showed promise in gauging the early stages of recovery from acidification in 3 lakes that were included in both surveys.     

农药对藻类的生态毒理学研究Ⅱ:毒性机理及其富集和降解

随着对农药污染认识的深入,农药对生态系统的初级生产者———藻类毒性以及毒性机制的研究不断增多。农药对藻类的毒性在于破坏藻类生物膜的结构和功能、影响藻类的光合作用、改变呼吸作用以及固氮作用,影响藻类的生理进程并改变其生化组分。开展农药对藻类毒性机理的研究,揭示农药结构—活性关系,对农药的研制和应用,评价农药的生态风险,减少农药对藻类的毒害是重要的。在自然环境中还发现藻能富集和降解农药。因此,对于这些藻来说,农药对藻类的毒害作用和藻类对农药的富集和降解作用可能同时存在。本文综述了农药对藻类的毒性机理以及藻类对农药的富集和降解作用。     

Effects of long-term contamination of DDT on soil microflora with special reference to soil algae and algal transformation of DDT

DDT (1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane) and its principle metabolites, DDE (1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene) and DDD (1,1-dichloro-2,2-bis(p-chlorophenyl)ethane) are widespread environmental contaminants but little information is available concerning their effects on non-target microflora (especially microalgae and cyanobacteria) and their activities in long-term contaminated soils. For this reason a long-term DDT-contaminated soil was screened for DDT residues and toxicity to microorganisms (bacteria, fungi, algae), microbial biomass and dehydrogenase activity. Also, five pure cultures isolated from various sites (two unicellular green algae and three dinitrogen-fixing cyanobacteria) were tested for their ability to metabolise DDT. Viable counts of bacteria and algae declined with increasing DDT contamination while fungal counts, microbial biomass and dehydrogenase activity increased in medium-level contaminated soil (27 mg DDT residues kg(-1) soil). All the tested parameters were greatly inhibited in high-level contaminated soil (34 mg DDT residues kg(-1) soil). Species composition of algae and cyanobacteria was altered in contaminated soils and sensitive species were eliminated in the medium and high contaminated soils suggesting that these organisms could be useful as bioindicators of pollution. Microbial biomass and dehydrogenase activity may not serve as good bioindicators of pollution since these parameters were potentially influenced by the increase in fungal (probably DDT resistant) counts. All the tested algal species metabolised DDT to DDE and DDD; however, transformation to DDD was more significant in the case of dinitrogen-fixing cyanobacteria.     

Susceptibility to acidic precipitation contributes to the decline of the terricolous lichens Cetraria aculeata and Cetraria islandica in central Europe

The effective quantum yield of photochemical energy conversion in photosystem II (Phi2) was shown to be reduced in the terricolous lichens Cetraria aculeata and Cetraria islandica by short-term exposure to aqueous SO2 at pH values occurring in the precipitation of areas with high SO2 pollution. Significant reduction of Phi2 was found at pH相似文献   

Leaf pack breakdown and macroinvertebrate colonization: bioassessment tools for a high-altitude regulated system?

Leaf pack processing and invertebrate colonization for bioassessment of metals pollution in a stream also impacted by a dam were examined. Differences in leaf breakdown rates at sites upstream and downstream of a metals point source were not detected. However, multivariate and logistic regression techniques indicated there were differences in aquatic macroinvertebrate assemblages that colonized leaf packs above and below the metal inflow. Development of a logistic regression model allowed for prediction of leaf pack location from indicator taxa in the leaf pack invertebrate community. Collector-gatherers, rather than shredders, were the most important predictors of whether leaf packs were located above or below the metal inflow, and were perhaps related to algae growing on leaf packs and/or fine particulate organic matter quality. Biotic structure, in this study, provided more information for evaluating pollution impacts than did measurement of leaf breakdown rates.     

Arsenosugars and other arsenic compounds in littoral zone algae from the Adriatic Sea

In 10 different marine algae from the littoral zone (found between the highest and lowest tide marks on the seashore) arsenic compounds were determined by means of a high-performance liquid chromatography (anion and cation exchange)-UV photochemical digestion-hydride generation-atomic fluorescence spectrometry (HPLC-UV-HGAFS) system. Samples (Ceramium sp., Cystoseira barbata, Enteromorpha sp., Fucus virsoides, two different species of Gelidium, Padina pavonica, Polisyphonia sp. and Ulva rigida) were collected along the Adriatic Sea coast of Slovenia. The total arsenic content of the algal samples, as determined by ICP-MS, ranged from 1.35 to 28.1 microg g(-1) (fresh weight). In all algae but two, the most abundant arsenic species found were arsenosugars with minor amounts of other arsenic compounds. Cystoseira barbata and Ceramium sp. contained high amounts of mainly inorganic arsenic. A small quantity of arsenobetaine was detected in most of the investigated Adriatic algae, which probably originates from mesofauna attached to the algae in their natural habitat.     

Estimation of the impact of prevailing weather conditions on the occurrence of oil-contaminated dead birds on the German North Sea coast

Chronic oil pollution by illegal oil dumping in the North Sea is difficult to quantify. Beached, oil-contaminated sea birds, however, may be used as an indirect indicator. Reconstructing the drift of oil slicks and sea bird corpses in the southern North Sea for the period 1992-2003 by means of a two-dimensional numerical transport model driven by re-analysed weather data, we show with an example of two common sea bird species that the variability observed within the number of corpses registered during beached bird surveys for the German coast primarily reflects the inter-annual variability of prevailing weather conditions. This should be taken into account when interpreting the data. We propose normalisation of beached bird survey data based on numerical drift simulations to improve the recognition of trends in the level of chronic oil pollution.     

Chemical,biological, and ecotoxicological assessment of pesticides and persistent organic pollutants in the Bahlui River,Romania

Background, aim, and scope

Current knowledge on environmental impacts of industrial activities in Romania, particularly persistent organic pollutants (POPs), indicates that environmental standards of the European Union are not systematically met. In our study area, additional sources of POPs are agriculture and domestic wastes. Very scarce information is available upon environmental contaminations and effects. In the present study, we investigated the chemical pollution and their eventual impact on the ecosystem by measuring POPs and by using biological indicators of pollution.

Materials and methods

The survey was carried out at six main sample sites along the Bahlui River. Sediments were chemically analysed for their content in polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides (OCPs)—hexachlorocyclohexanes (HCHs) isomers and the dichlorodiphenyl trichloroethane (DDT) family. River water was biologically monitored at the level of phytoplankton and benthic invertebrates’ communities. Water samples from six locations have been analyzed for algal species composition and correspondence to various water quality indices. Biological samples have been taken from the same locations so as to calculate the macroinvertebrate indices. In the most polluted areas, as revealed by previous methods, toxicity was tested by exposing the green alga Pseudokirchneriella subcapitata and the cladoceran Daphnia magna to various dilutions of water sample.

Results

Important concentrations of POPs were identified only in sediments at river mouths (sites S5 and S6). Along the year, the sum of PCB concentrations ranged between 3 and 10 ng/g dw (S5), and between 4 and 26 ng/g dw (S6). Concentration of HCHs ranged between 0.4 and 3 ng/g dw (both S5 and S6) with a higher contribution of the gamma-HCH (30–70%), followed by beta-HCH (20–50%). The beta-HCH isomer was found at lower concentrations or even not detected in outer city sites. DDTs were found at higher concentrations than HCHs and ranged between 0.18 and 4 ng/g dw (S5) and between 0.56 and 18 ng/g dw (S6). The parent compound, p,p′-DDT, could be detected only in low concentrations (up to 5 ng/g dw) and contributed with less than 30% to the sum of DDTs in sediment. The principal contributors of the ΣDDTs in sediment were p,p′-DDE, and p,p′-DDD. The o,p′-DDD and DDT isomers were minor contributors to the sum of DDT. PAHs were found at higher concentrations than DDTs and ranged between 6 and 36 ng/g dw (S5) and between 36 and 155 ng/g dw (S6). Fluoranthene was predominant (up to 40%), followed by phenantrene (up to 30%), naphthalene (up to 35%), and benzo-(g,h,i)-perylene (up to 23%). The saprobity index and the diatom index increased from springs to river mouth, indicating a decrease in the water quality, but within the limits of moderate pollution. The saprobity index varied between 1.99 at spring to 2.70 at mouth. The diatom index varied from 3.48 to 3.14. The species’ richness in phytoplankton has a less clear pattern along the river, but in general, it appears to be negatively influenced by pollution. At the level of biological consumer species, the analyses of the macroinvertebrates confirm the situation and the tendency shown with algae. In addition, the Shannon–Wiener index, the Pielou evenness index, and the McNaughton dominance index indicate a peculiar pattern: invertebrate communities appear to a have a more stable structure along the river, with visible shifts at springs and at river mouths. Water toxicity testing indicates low toxicity of river waters around the city of Iasi, with two notable exceptions: the point pollution at the domestic wastewater treatment discharge and at the old open-air deposit of domestic solid wastes. Another important result was that tested algae appeared to be more readily affected than tested cladoceran: EC₅₀ (percent effluent) was 16 in algae and 28 in cladocerans. The slope of toxic effect was also much steeper in cladocerans (6) than in algae (1.8), which means that the toxic effect is more sudden on the tested invertebrates than on the tested algae.

Discussion

Pollutant concentrations reported herein are lower or similar than those reported for the sediments by earlier studies (RIZA 2000; Dragan et al., Int J Environ Anal Chem 86:833–842, 2006). Ratios of individual PAH compounds indicate important pyrolytic inputs and suggest that PAHs in the area are derived from the combustion of fossil fuels. Biologically, the waters appear to be beta-mesosaprobic towards alpha-mesosaprobic according to the saprobic index classification and undergo moderate pollution according to the diatom index classification. Water quality decreases from springs to river mouths. Algal species richness index has a less clear pattern along the river. Water toxicity is low, but certain sources of point pollution require increased attention.

Conclusions

The water quality is better than expected, probably because of the drop in pollution intensity following the collapse of local agricultural and industrial activity following the fall of communism in 1989. Nevertheless, further studies will be needed to confirm and refine our results. While this study draws no strident alarm, it appeals for high attention, particularly because the economic activity in the area is expected to increase.

Recommendations and perspectives

Future close monitoring will be necessary for insuring compliance with the Water Framework Directive, and for refining standards and understanding of the local situation, but with relevance for the wider international community. On the basis of the situation described in the present study, we recommend that future studies dedicate specific efforts to point pollution and effluent toxicity, particularly around the city of Iasi. For a better understanding of pollution and its effects, we recommend pursuing the type of multidisciplinary investigations proposed by the present study: chemical, ecotoxicological, and ecological. We also recommend that new methods should be developed and/or refined, like the empirical determination of partitioning coefficients in water and soils, process-based toxicity methods in ecotoxicological assessments, searching for interactions between pollution, producers, and consumers in aquatic ecosystems. We also recommend preference for cheaper survey methods, as these will be more applicable locally.