Effect of metals on Daphnia magna and cladocerans representatives of the Argentinean fluvial littoral.

Chronic toxicity tests were conducted to assess the effect of Cu, Cr and Pb on Moinodaphnia macleayi and Ceriodaphnia dubia -two cladoceran species from the Argentinian Fluvial Littoral Zone (AFLZ)- and Daphnia magna -an holarctic species-. The specimens were exposed to three concentrations of each metal. As endpoints, the number of living and dead organisms, molts, neonates released, and the age of first reproduction were recorded. Chronic assays showed that Cu significantly affected the analyzed life history traits in the three species. The lowest Pb and Cr concentrations did not affect survival, molting or fecundity in D. magna. Conversely, in M. macleayi and C. dubia, survival, molting and fecundity showed highly significant differences in all the concentrations tested compared to control assay. The present study stresses the importance of using biological parameters as bioindicators, as well as the study species from the Southern Hemisphere to assess metal pollution.

Atrazine characterization: An update on uses, monitoring, effects, and environmental impact, for the development of regulatory policies in Argentina.

Atrazine (ATZ) is the third most widely used herbicide in Argentina (10 000 t year-1 ) and is approved for sugar cane, flax, corn, sorghum, and tea. An assessment of the ATZ environmental impacts was conducted at the request of the Ministry of Environment and Sustainable Development of Argentina. A review of 541 national and international technical and scientific reports and a survey among agricultural technicians, applicators, and producers was done. The survey revealed that 94% of ATZ applications are terrestrial and use diversion exists, associated mainly with soybean cultivation. Atrazine was reported at high frequencies (50%-100%) in surface and groundwater, sediments, and soils, sometimes exceeding permitted limits. Several sublethal effects induced by ATZ on invertebrate and vertebrate species were found, sometimes at concentrations lower than those in water quality guidelines (<3 µg L-1 ) or the environmental concentrations found in Argentina. Available epidemiological or human health studies of local populations are extremely scarce. This assessment also demonstrated that herbicides are ubiquitous in the environment. The investigation highlights the need for further studies assessing the adverse effects of ATZ on local species, ecosystems, and human health. Therefore, the precautionary principle is recommended to promote better application standards and product traceability to reduce volumes entering the environment and to avoid use deviation. In addition, this work concluded that there is a need for reviewing the toxicological classification, establishing buffer zones for ATZ application, introducing specific management guidelines, and expanding local studies of toxicity, ecotoxicity, and human epidemiology for environmental and health risk assessments. This study could also serve as a preliminary risk evaluation for establishing a final regulatory action and for considering ATZ inclusion in Annex III of the Rotterdam Convention. Finally, the requirements to consider its inclusion in Annex A (Elimination) or B (Restriction) of the Stockholm Convention were evaluated and discussed, and information on the potential of long-range transport was the only criterion with no information to consider. Integr Environ Assess Manag 2023;19:684-697. © 2022 SETAC.

Wastewater-Based Epidemiology: Detection of SARS-CoV-2 RNA in Different Stages of Domestic Wastewater Treatment in Santa Fe, Argentina.

The COVID-19 pandemic affected human life at every level. In this study, we analyzed genetic markers (N and ORF1ab, RNA genes) of SARS-CoV-2 in domestic wastewaters (DWW) in San Justo City (Santa Fe, Argentina), using reverse transcription-quantitative real-time PCR. Out of the 30 analyzed samples, 30% were positive for SARS-CoV-2 RNA. Of the total positive samples, 77% correspond to untreated DWW, 23% to pre-chlorination, and no SARS-CoV-2 RNA was registered at the post-chlorination sampling site. The viral loads of N and OFR1ab genes decreased significantly along the treatment process, and the increase in the number of viral copies of the N gene could anticipate, by 6 days, the number of clinical cases in the population. The concentration of chlorine recommended by the WHO (≥ 0.5 mg L-1 after at least 30 min of contact time at pH 8.0) successfully removed SARS-CoV-2 RNA from DWW. The efficiency of wastewater-based epidemiology (WBE) confirms the need to control and increase DWW treatment systems on a regional and global scale. This work could contribute to building a network for WBE to monitor SARS-CoV-2 in wastewaters during the pandemic waves and the epidemic remission phase. Supplementary Information: The online version contains supplementary material available at 10.1007/s11270-022-05772-w.

Toxicity of fluoroquinolones on the cladoceran Daphnia magna.

This study evaluates the acute and chronic toxicological effects of six fluoroquinolones on the mortality and growth of Daphnia magna. The NOECs calculated with the multivariate Probit regression model for the chronic study were 56 µg/L ciprofloxacin, 63 µg/L enrofloxacin, 78 µg/L levofloxacin, 85 µg/L marbofloxacin, 69 µg/L norfloxacin, and 141 µg/L ofloxacin. The risk quotients were determined using the measure environmental concentrations reported in water sources from different countries. The risks were low and moderate in water samples from rivers and lakes, although concentrations of ciprofloxacin, norfloxacin, and ofloxacin reported in some countries can cause toxicological damage to D. magna. In addition, urban wastewater and hospital wastewater samples constitute a threat to D. magna (high and moderate risks), requiring the treatment of these wastewater. PRACTITIONER POINTS: The NOECs calculated with the multivariate Probit model for the six fluoroquinolonas are between 56 µg/L ciprofloxacin and 141 µg/L ofloxacin. The levels of ciprofloxacin, norfloxacin, and ofloxacin in urban wastewater and hospital wastewater produce moderate and high risks for D. magna. Water and river samples from some countries containing ciprofloxacin, norlfoxacin, and ofloxacin present high risks for D. magna.

Synergy between glyphosate and cypermethrin formulations on zooplankton: evidences from a single-specie test and a community mesocosm experiment.

Agrochemicals can reach freshwater bodies by drift, leaching, or runoff, where they constitute complex mixtures. Given that glyphosate and cypermethrin are within the most worldwide used pesticides, they are likely to co-occur in freshwater bodies. The aim of this study was to analyze the interaction between glyphosate and cypermethrin formulations on the cladoceran Ceriodaphnia dubia (Richard 1894) through an acute toxicity test and on a zooplankton assemblage through a mesocosm (30 L) experiment. The 24-h LC50 of both isolated pesticides and their equitoxic mixture was obtained for C. dubia. The mesocosm was performed by exposing a zooplankton assemblage to both pesticides isolated and in combination. The acute toxicity of the equitoxic mixture in C. dubia was 3 and 4 times higher than the isolated toxicity of glyphosate and cypermethrin, respectively. The total toxic units of the mixture were 0.53, indicating a synergistic interaction. In the mesocosm experiment, both pesticides also interacted causing a synergistic negative effect in Cladocera and Copepoda abundances. No interactions between pesticides were found for Rotifera; therefore, the mixture effect was considered additive. It is suggested to continue analyzing pesticide mixture effects on the basis of complementary scales of analysis to reach more environmentally relevant information.

Water and sediment quality assessment in the Colastiné-Corralito stream system (Santa Fe, Argentina): impact of industry and agriculture on aquatic ecosystems.

The present study focuses on the evaluation of metal (chromium, copper, and lead), arsenic, and pesticide (atrazine and endosulfan) contamination in freshwater streams of one of the most important agricultural and industrial areas of central-eastern Argentina, which has not been reported earlier. The environmental fate of inorganic microcontaminants and pesticides was assessed. Samples were collected monthly for a year. Pesticide concentrations were measured in water; metal and arsenic concentrations were measured in water and sediments, and physicochemical variables were analyzed. In most cases, metals and arsenic in water exceeded the established guideline levels for the protection of aquatic biota: 98 and 56.25% of the samples showed higher levels of Cr and Pb, while 81.25 and 85% of the samples presented higher values for Cu and As, respectively. Cr, Pb, Cu, and As exceeded 181.5 times, 41.6 times, 57.5 times, and 12.9 times, respectively, the guideline level values. In sediment samples, permitted levels were also surpassed by 40% for Pb, 15% for As, 4% for Cu, and 2% for Cr. Geoaccumulation Index (Igeo) demonstrated that most of the sediment samples were highly polluted by Cr and Cu and very seriously polluted by Pb, which indicates progressive deterioration of the sediment quality. Atrazine never exceeded them, but 27% of the 48 water samples contained total endosulfan that surpassed the guidelines. The findings of this study suggest risk to the freshwater biota over prolong periods and possible risk to humans if such type of contaminated water is employed for recreation or human use. Improper disposal of industrial effluents and agricultural runoffs need to be controlled, and proper treatment should be done before disposal to avoid further deterioration of the aquifers of this area.