Metal accumulation in a biological indicator (Ulva rigida) from the lagoon of Venice (Italy)

Ulva rigida (C. Agardht) was collected from the Palude della Rosa (lagoon of Venice), a particular area characterized by a salinity gradient, from December 1991 to June 1993. Metal contents (Al, Mn, Fe, Cu, Zn, Cr, Co, Ni, Cd, and Pb) were determined by atomic absorption spectrophotometry and statistically analysed for differences between months and sampling sites. The mean seasonal variability is very significant (p<0.001) for all studied metals. Seasonal trends are comparable for groups of metals according to possible functional similarities. A significant positive correlation was calculated for the pairs Fe-Al and Fe-Pb. Mechanisms regulating metal uptake are discussed, particularly the role of Fe and its linear relationship with Al. Metal concentrations in relation to salinity also were studied. Larger amounts of Fe, Zn, and Cd accumulated in correspondence of lower salinity, may be owing to both higher metal activity and burden of bioavailable metals in freshwater flowing into the Palude. Calculation of concentration factor (CF) indicates that U. rigida specifically accumulates Fe. CF linearly correlates with dissolved metal concentrations, suggesting that U. rigida is a good bioindicator of metal bioavailability, although seasonal active accumulation occurs in some cases (Mn). Metal concentrations determined in this macroalga support the conclusion that the studied area is rich in bioavailable Fe and poor in toxic metals. In any case, a great affinity for Al in U. rigida may be proposed.     

Efficacy of two temephos formulations against Chironomus salinarius (Diptera: Chironomidae) in the saltwater lagoon of Venice, Italy.

Two formulations of the organophosphorus insecticide, temephos (Abathion Granulare, 1% AI granular and Tambro Compresse, 2% AI tablet) were evaluated against Chironomus salinarius midge larvae in 50 x 50 m experimental plots in the saltwater lagoon of Venice, Italy. Each formulation was applied at 0.2 and 0.4 kg AI/ha. Abathion Granulare produced 56 to 73% larval reduction at 0.2 kg AI/ha and 69 to 83% reduction at 0.4 kg AI/ha during 3 wk after treatment. Abathion Granulare lost effectiveness at 4 wk after application at both rates. Posttreatment larval reductions resulting from Tambro Compresse applications ranged from 77 to 86% for 3 wk, and 82 to 92% for 4 wk at rates of 0.2 and 0.4 kg AI/ha, respectively. The tablet formulation (Tambro Compresse) gave better control of C. salinarius (magnitude and duration) than the granular formulation (Abathion Granulare) in these evaluations.     

A chironomid (Diptera: Chironomidae) midge population study and laboratory evaluation of larvicides against midges inhabiting the lagoon of Venice, Italy

Chironomid larval densities in the saltwater lagoon of Venice, Italy, were assessed in the spring of 1984. Four organophosphates; chlorpyrifos, temephos, fenthion and fenitrothion, and three pyrethroids; cypermethrin, permethrin and deltamethrin, were tested in the laboratory against field-collected larvae. Three industrial formulations of Bacillus thuringiensis var. israelensis (B.t.i.) were also tested as midge larvicides. Only Chironomus salinarius occurred in the benthic samples taken from different sections of the lagoon. The densities of this species ranged from 0 to 38,976 larvae/m2. The highest mean larval density of 15,673/m2 was encountered in a section of the lagoon adjacent to Venice airport and receiving large quantities of raw sewage. The lowest mean density (less than 1 larva/m2) existed in another area of the lagoon receiving discharge from chemical industry. Cypermethrin and permethrin were 21-233X more active against the larvae than the four organophosphates. Chlorpyrifos was the most active organophosphate. Formulations of B.t.i. were economically ineffective against the larvae.     

Organochlorine compounds (polychlorinated biphenyls and pesticides) and polycyclic aromatic hydrocarbons in populations of Hexaplex trunculus affected by imposex in the lagoon of Venice, Italy

Concentrations of polychlorinated biphenyls (PCBs), organochlorine pesticides, and polycyclic aromatic hydrocarbons (PAHs) were measured in gastropods from the Lagoon of Venice, Italy. The visceral coil and the rest of the soft body of organisms (Hexaplex trunculus) sampled at two stations inside the lagoon and three stations on the seaward side were analyzed to evaluate their contamination levels. Preferential accumulation of PCBs and pesticides in the visceral coil (>80%) compared with the rest of the soft body was observed, whereas on average, PAHs showed no preferential partitioning. Differences between levels of organochlorine contaminants in the gastropods highlighted a gradient of pollution from the stations inside the lagoon (PCBs, 45-363 ng/g; pesticides, 4-51 ng/g) to the sea (PCBs, 13-131 ng/g; pesticides, 2-29 ng/g). The possible role of the three classes of contaminants, in addition to that of organotin compounds (OTCs), previously analyzed in the same samples, in causing one of the anatomic modifications because of imposex in this gastropod also was studied. A modeling approach by partial least squares (PLS) in latent variables was applied to explain the penis length of imposex-affected females with concentrations of organic pollutants. The synergistic role of PCBs, pesticides, and OTCs was evidenced, whereas the contribution of PAHs appeared to be very low.     

Biogeochemical factors affecting mercury methylation in sediments of the Venice Lagoon, Italy

Mercury methylation and sulfate reduction rates, total Hg, and monomethyl Hg in the sediments of the Venice Lagoon (Italy) were measured in June 2005 in order to identify the factors affecting the methylation of inorganic Hg. While the rates of Hg methylation and sulfate reduction were generally higher in the surface layers (0-2.5 cm), the correlation between Hg methylation and sulfate reduction rates was not significant when considering all depths and sites. This discrepancy is discussed considering two factors: the activity of sulfate-reducing bacteria and Hg solubility. The former factor is important in determining the Hg methylation rate in comparable geochemical conditions as evidenced by similar vertical profiles of Hg methylation and sulfate reduction rates in each sediment core. The latter factor was assessed by comparing the Hg methylation rate with the particle-water partition coefficient of Hg. The Hg methylation rates normalized to sulfate reduction rates showed a negative linear correlation with the logarithm of the particle-water partition coefficient of Hg, suggesting that the availability of dissolved Hg is a critical factor affecting Hg methylation. Solid FeS seems to play an important role in controlling the solubility of Hg in Venice Lagoon sediments, where sulfate and iron reductions are the dominant electron-accepting processes. Overall, the production of monomethyl Hg in the Venice Lagoon is controlled by a fine balance between microbial and geochemical processes with key factors being the microbial sulfate reduction rate and the availability of dissolved Hg.     

Toxicity and Estrogenic Activity of a Wastewater Treatment Plant in Northern Italy

Many xenobiotics, widely diffused in the environment, have the potential to disrupt the delicate endocrine system balance of wildlife and humans. Substances showing hormone-like actions in living organisms are defined endocrine-disruptor chemicals and they may mimic, block, or interfere with the synthesis, release, transport, elimination, and binding of natural hormones. Different ecotoxicologic studies were applied to screen for the discharge of estrogenic and toxic substances into the aquatic environment from a small industrial wastewater treatment plant based in Northern Italy. Samples of wastewater (3 L) were taken at three different periods during the year from different points of the plants process: three phases of treatment, and effluent. Untreated samples (1 L) were assayed with two toxicity tests: Microtox and Daphnia magna. A simplified proliferation test using human estrogen receptor–positive MCF-7 breast cancer cells (E-screen assay) was performed on 2-L samples after solid-phase extraction for the determination of total estrogenic activity; the presence of estrogenic substances was evaluated by measuring the proliferation rate in cells exposed to samples. The results of the Microtox assay employing the marine bacterium Vibrio fischeri were compared with data obtained from whole-effluent toxicity testing methods employing D. magna. Toxicity was found only for the influent point. The proliferative effect of the five points, relative to the positive control 17-estradiol (relative proliferation effect), was between 2.4% and 39%, and the 17-estradiol equivalent concentrations were between 0.06 and 3.94 ng/L. A first comparison between results from toxicity load and estrogenic activity was performed. At all process points, the effluent samples were considered acceptable (taking only toxicity into account), but we demonstrated that they had estrogenic activity in the river water indicating an input of estrogenic substances by way of the treatment plant.     

Ecological risk assessment of persistent toxic substances for the clam Tapes philipinarum in the Lagoon of Venice, Italy

Because of contamination of sediments of the Lagoon of Venice, Italy, by inorganic pollutants (e.g., arsenic, cadmium, chromium, copper, lead, mercury, nickel, and zinc) and organic pollutants (e.g., polychlorobiphenyls), as well as the ecological and economical relevance of the edible clam Tapes philipinarum, an ecological risk assessment was undertaken to ascertain the extent of bioaccumulation that would pose a significant risk. Risk was estimated by means of toxic units and hazard quotient approaches, by comparing the exposure concentration with the effect concentration. Clam exposure was estimated by applying previous results based on bioaccumulation spatial regression models. In addition, a comparison was made between sum of dioxin-like polychlorinated biphenyl (PCB) congeners and total PCB bioaccumulation provided by spatial regression models and by a partitioning model. The effect concentrations were calculated as tissue screening concentrations, as the product of pollutant sediment quality criteria and the bioaccumulation factor. Finally, the cumulative risk posed by selected inorganic pollutants and total PCBs was estimated and a map of risk was drawn. The resulting chemicals of potential ecological concern were mercury, cadmium, arsenic, and nickel, as well as, to a lesser extent, total PCBs.     

Estrogenic potential of halogenated derivatives of nonylphenol ethoxylates and carboxylates

Halogenated derivatives of nonylphenol and of its alkylates are generated during drinking water disinfection and treatment procedures. In this paper we analyze the potential of these compounds to interact with the estrogen receptor and to activate hormone-regulated gene promoters. We used the recombinant yeast assay (RYA) and the human breast cancer cell MCF7 proliferation assay for both estrogenic and antiestrogenic activities and the enzyme-linked receptor assay to examine in vitro binding to the receptor. Many nonylphenol derivatives were very weak estrogens in our functional tests when compared to nonylphenol while retaining a substantial affinity for the estrogen receptor in vitro. Antiestrogenicity tests demonstrated that brominated nonylphenol and most of the carboxylated compounds studied here behaved as estrogenic antagonists in the RYA. We also detected an increased cytotoxicity for the carboxylated derivatives in both yeast and mammalian cells. We conclude that derivatization may mask the apparent estrogenicity of nonylphenol, but the resulting compounds still represent a potential hazard since they are still able to bind the estrogen receptor and to influence the physiological response to estrogens. Our results also illustrate the advantage of combining different methods to assay estrogenicity of unknown substances.     

Persistent and toxic substances in the Venice lagoon biota: an approach for quantitative data analysis for risk management

An approach based on hypothesis testing for the management of persistent inorganic and organic toxic chemicals (PTS/POPs) detected in clams and mussels from the Venice lagoon is presented. The chemicals of interest for this evaluation were the polychlorinated biphenyls (PCBs), dibenzodioxins (PCDDs), and dibenzofurans (PCDFs), hexachlorobenzene (HCB), and the heavy metals cadmium (Cd), mercury (Hg), and lead (Pb). Two statistically different populations of data for PCDDs+PCDFs (TEQs), HCB, Cd, and Pb, associated with biota samples collected respectively in the lagoon central district and in the southern and northern districts were identified. The central district is under the impact of the Porto Marghera industrial settlement and the city of Venice, whereas the southern and northern districts are subject to a general impact. Of the aforementioned chemicals, those with more discriminating power were found to be HCB and PCDDs+PCDFs.     

Estrogenic potential of certain pyrethroid compounds in the MCF-7 human breast carcinoma cell line

Estrogens, whether natural or synthetic, clearly influence reproductive development, senescence, and carcinogenesis. Pyrethroid insecticides are now the most widely used agents for indoor pest control, providing potential for human exposure. Using the MCF-7 human breast carcinoma cell line, we studied the estrogenic potential of several synthetic pyrethroid compounds in vitro using pS2 mRNA levels as the end point. We tested sumithrin, fenvalerate, d-trans allethrin, and permethrin. Nanomolar concentrations of either sumithrin or fenvalerate were sufficient to increase pS2 expression slightly above basal levels. At micromolar concentrations, these two pyrethroid compounds induced pS2 expression to levels comparable to those elicited by 10 nM 17ss-estradiol (fivefold). The estrogenic activity of sumithrin was abolished with co-treatment with an antiestrogen (ICI 164,384), whereas estrogenic activity of fenvalerate was not significantly diminished with antiestrogen co-treatment. In addition, both sumithrin and fenvalerate were able to induce cell proliferation of MCF-7 cells in a dose-response fashion. Neither permethrin nor d-trans allethrin affected pS2 expression. Permethrin had a noticeable effect on cell proliferation at 100 microM, whereas d-trans allethrin slightly induced MCF-7 cell proliferation at 10 microM, but was toxic at higher concentrations. Overall, our studies imply that each pyrethroid compound is unique in its ability to influence several cellular pathways. These findings suggest that pyrethroids should be considered to be hormone disruptors, and their potential to affect endocrine function in humans and wildlife should be investigated.     

Mutagenicity, Genotoxicity, and Estrogenic Activity of River Porewaters

We investigated mutagenicity, genotoxicity, and estrogenic activity in the porewaters of two river basins in southern Italy that had different features. Three samples from each site were collected in different seasons from 7 sites for a total of 21 samples. Mutagenicity was measured with the Ames test with and without metabolic activation (S9) using Salmonella typhimurium TA98 and TA100 strains. Genotoxicity was measured with two tests: one involved a chromophore that detected DNA damage in Escherichia coli PQ37 (SOS chromotest), and the other measured micronuclei formation in the root cells of Vicia faba. Estrogenic activity was measured with a yeast-based estrogen receptor assay and an MCF-7 cell-based, estrogen-sensitive proliferation assay. We also applied chemical analyses to detect alkylphenols, pesticides, natural and synthetic hormones, and heavy metals. The porewaters of both river sediments showed mutagenic/genotoxic activity on V. faba test and Ames test, the latter both with and without S9 liver fraction. The SOS chromotest without metabolic activation was not sufficiently sensitive to detect genotoxicity of the porewaters, but the SOS DNA repair system in E. coli PQ37 was activated in the presence of S9 mix. Good correlations were found between mutagenicity/genotoxicity and the concentration of cadmium and between estrogenic activity and the presence of copper. This study assessed the chemical concentrations of some bioavailable pollutants in porewater and detected the overall effects of multiple pollutants that contributed to mutagenicity, genotoxicity, and estrogenic activity of these two basin porewaters, thus increasing our understanding of the environmental consequences of polluted aquatic ecosystems.     

Estrogenic action of DDT analogs

The estrogenic action of DDT analogs, among these methoxychlor, is discussed. Emphasis is placed on investigations of estrogenic properties of DDT derivatives, their long-term effects on reproductive processes, and their mechanism of action. Kepone is discussed briefly as an example of another structural class of insecticides with estrogenic activity.     

Sulfide sensitivity in fishes of the Indian River lagoon, Florida.

Lagoon fishes, in netted holding cages, were placed in an impounded salt marsh and submitted to a gradient of sulfide-rich artesian well water. Near the well head, all specimens of 13 species died within 5-45 min, while all individuals of 5 species survived. More distant from the well, survival time increased sufficiently to rank species in approximate order of sensitivity to sulfide.