Arsenic in Argentina: Technologies for arsenic removal from groundwater sources, investment costs and waste management practices.

An overview about the presence of arsenic (As) in groundwaters of Argentina, made by a transdisciplinary group of experts is presented. In this second part, the conventional and emerging technologies for As removal, management of wastes, and the initial investment costs of the proposed technologies, with emphasis on developments of local groups are described. Successful examples of real application of conventional and emerging technologies for As removal in waters for human consumption, for medium, small and rural and periurban communities are reported.

Arsenic in Argentina: Occurrence, human health, legislation and determination.

An overview about the presence of arsenic (As) in groundwaters of Argentina, made by a transdisciplinary group of experts is presented. Aspects on As occurrence, effects of As on human health, regulations regarding the maximum allowable amount of As in drinking water as well as bottled water, and analytical techniques for As determination are presented. The most affected region in Argentina is the Chaco-Pampean plain, covering around 10 million km, where approximately 88% of 86 groundwater samples collected in 2007 exceeded the World Health Organization (WHO) guideline value.

Living organisms influence on environmental conditions: pH modulation by amphibian embryos versus aluminum toxicity.

The LC10, 50 and 90/24h of aluminum for Rhinella arenarum embryos at complete operculum stage were 0.55, 0.75 and 1mgAl(3+)/L respectively.

Sublethal effects of atrazine on embryo-larval development of Rhinella arenarum (Anura: Bufonidae).

Atrazine (ATR), one of the most widely used herbicides in the world, affects not only target organisms but also the biota in general. Here, the teratogenic and neurotoxic effects of ATR on Rhinella arenarum (South American toad) embryos, and larvae were evaluated by means of standardized bioassays during acute and chronic exposures. The herbicide had a significant incidence of malformations, with a Teratogenic Index (TI) of 3.

Stage-dependent toxicity of bisphenol a on Rhinella arenarum (anura, bufonidae) embryos and larvae.

The acute and chronic toxicity of bisphenol A (BPA) was evaluated on the common South American toad Rhinella arenarum embryos and larvae by means of continuous and pulse exposure treatments. Embryos were treated continuously from early blastula (S.4) up to complete operculum (S.

Stage-dependent susceptibility to copper in Rhinella arenarum embryos and larvae.

Copper toxicity in different embryonic and larval stages of the common South American toad Rhinella arenarum was evaluated by means of continuous and 24-h pulse treatments in 12 different developmental stages. Lethal concentrations (LC) of 10, 50, and 90% of continuous treatment with Cu from early blastula (S.4), complete operculum (S.

Nickel toxicity in embryos and larvae of the South American toad: effects on cell differentiation, morphogenesis, and oxygen consumption.

Nickel, a widely distributed heavy metal in the biosphere, produces systemic, carcinogenic, and teratogenic effects. The objectives of the present study are to report the acute, short-term chronic, and chronic toxicity of Ni in Rhinella arenarum embryos as well as the stage-dependent susceptibility to this heavy metal, including oxygen consumption, teratogenesis, and adverse effects on cell differentiation processes. The stages evaluated were blastula (S.

Stage-dependent toxicity of 2,4-dichlorophenoxyacetic on the embryonic development of a South American toad, Rhinella arenarum.

The acute and short term chronic toxicity of both the herbicide butyl ester of 2,4-Dichlorophenoxyacetic acid (2,4-D) and a commercial formulation (CF) were evaluated on Rhinella (= Bufo) arenarum embryos at different developmental stages. Adverse effects were analyzed by means of the isotoxicity curves for lethality, malformations, stage-dependent susceptibility, and ultrastructural features. For all experimental conditions, the CF was more toxic, up to 10 times, than the active ingredient, being the open mouth stage (S.

Acute and subchronic toxicity of arsenite and zinc to tadpoles of Rhinella arenarum both alone and in combination.

The current study evaluated acute and subchronic toxicity of arsenite (As(3+)) and zinc (Zn(2+)) to stage 25 tadpoles of Rhinella arenarum in both single and joint laboratory exposures. LC50 values obtained for As(3+) were elevated and remained within the range of 46 to 50 mg/L of As(3+) between 4 and 17 d of exposure. Growth of tadpoles was completely inhibited with 30 mg/L of As(3+), demonstrating the presence of ecologically relevant sublethal effects at concentrations lower than those resulting in lethality.

Nickel tissue residue as a biomarker of sub-toxic exposure and susceptibility in amphibian embryos.

Although low level exposure to physicochemical agents is the most common environmental scenario, their effects on living organisms are very controversial. However, there is an increasing need to integrate low level exposures from risk assessment to remediation purposes. This study focus on the possibility to employ Ni tissue residue values as biomarkers of sub-toxic exposure and susceptibility to this metal in a range of almost pristine to sub-toxic concentrations for Rhinella arenarum embryos.

Stage-dependent teratogenic and lethal effects exerted by ultraviolet B radiation on Rhinella (Bufo) arenarum embryos.

The adverse effects of ultraviolet B radiation from 547.2 to 30,096 J/m2 on morphogenesis, cell differentiation, and lethality of amphibian embryos at six developmental stages were evaluated from 24 up to 168 h postexposure. The ultraviolet B radiation lethal dose 10, 50, and 90 values were obtained for all developmental stages evaluated.

Comparative susceptibility to atrazine of three developmental stages of Rhinella arenarum and influence on metamorphosis: non-monotonous acceleration of the time to climax and delayed tail resorption.

Acute and subchronic toxicity of atrazine was evaluated in embryos (stage 4) and in premetamorphosis (stage 25) and prometamorphosis (stage 38-39) larvae of the common South American toad Rhinella arenarum (Anura: bufonidae). The influence of atrazine on the last stages of metamorphosis was also examined by exposing prometamorphosis larvae until completion of metamorphosis. Results obtained revealed that larvae in premetamorphosis are more sensitive than larvae in prometamorphosis and that these are, in turn, more sensitive than embryonic stages.

Acclimation to low level exposure of copper in Bufo arenarum embryos: linkage of effects to tissue residues.

The acclimation possibilities to copper in Bufo arenarum embryos was evaluated by means of three different low level copper exposure conditions during 14 days. By the end of the acclimation period the copper content in control embryos was 1.04 +/- 0.

Synergistic effects of copper and butylic ester of 2,4-Dichlorophenoxyacetic acid (Esternon Ultra) on amphibian embryos.

Cu2+ and butylic ester of 2,4-Dichlorophenoxyacetic acid as Esternon Ultra (2,4-D) toxicity on Bufo arenarum embryos were evaluated by means of a short-term chronic toxicity test (AMPHITOX). The NOEC values for Cu and 2,4-D were 0.02 mg/L and 2 mg/L respectively.

Evoecotoxicology: environmental changes and life features development during the evolutionary process-the record of the past at developmental stages of living organisms.

For most of evolutionary history, scientific understanding of the environment and life forms is extremely limited. In this commentary I discuss the hypothesis that ontogenetic features of living organisms can be considered biomarkers of coevolution between organisms and physicochemical agents during Earth's history. I provide a new vision of evolution based on correlations between metabolic features and stage-dependent susceptibility of organisms to physicochemical agents with well-known environmental signatures.

Estradiol uptake, toxicity, metabolism, and adverse effects on cadmium-treated amphibian embryos.

The exposure of Bufo arenarum embryos to 25 micromol/L 17beta-estradiol (E2) resulted in 100% lethality within 48 hr, whereas 10 micromol//L E2 was the no observed effect concentration value for short-term chronic (7 days) exposure. The toxicity profile curves show that lethal effects were proportional to the E2 concentration and the time of exposure. The E2 uptake resulted in 20.

Photodynamic toxicity and its prevention by antioxidative agents in Bufo arenarum embryos.

In this work we describe an experimental model to evaluate the photodynamic toxicity on amphibian embryos, as well as the protective effect of antioxidants against the lethal oxidative stress induced by photosensitization. Bufo arenarum embryos were treated with 10 mg/l methylene blue (MB) in AMPHITOX solution for 72 h and then irradiated with a red laser or white light for variable times. Both light sources affected the survival of MB-treated animals and lethal effects occurred within the initial 12 h post-irradiation.

Ecotoxicological studies of environmental samples from Buenos Aires area using a standardized amphibian embryo toxicity test (AMPHITOX).

The toxicity of 34 environmental samples from potentially polluted and reference stations were evaluated by means of the AMPHITOX test from acute to chronic exposure according to the toxicity found in each sample. The samples were obtained from surface and ground water, leaches, industrial effluents and soils. The data, expressed in acute, short-term chronic and chronic Toxicity Units (TUa, TUstc and TUc) resulted in a maximal value of 1000 TUc, found in a leach, while the lower toxicity value was 1.