Alicia E. Ronco

Levels of glyphosate in surface waters, sediments and soils associated with direct sowing soybean cultivation in north pampasic region of Argentina

Levels of glyphosate were determined in water, soil and sediment samples from a transgenic soybean cultivation area located near to tributaries streams of the Pergamino-Arrecifes system in the north of the Province of Buenos Aires, Argentina. Field work took into account both the pesticide application and the rains occurring after applications. The pesticide was analysed by HPLC-UV detection, previous derivatization with 9-fluorenylmethylchloroformate (FMOC-Cl). In addition, SoilFug multimedia model was used to analyse the environmental distribution of the pesticides. In the field, levels of glyphosate in waters ranged from 0.10 to 0.70 mg/L, while in sediments and soils values were between 0.5 and 5.0 mg/Kg. Temporal variation of glyphosate levels depended directly on the time of application and the rain events. The results obtained from the application of the model are in accordance with the values found in the field.

Insecticide toxicity to Hyalella curvispina in runoff and stream water within a soybean farm (Buenos Aires, Argentina)

Toxicity to the locally dominant amphipod Hyalella curvispina was assessed in a first-order stream running through a cultivated farm. Cypermethrin, chlorpyrifos, endosulfan and glyphosate were sprayed throughout the studied period. Toxicity was assayed under controlled laboratory conditions with runoff and stream water samples taken from the field under steady state and flood conditions. Ephemeral toxicity pulses were observed as a consequence of farm pesticide applications. After pesticide application, runoff water showed 100% mortality to H. curvispina for 1 month, but no mortality thereafter. Toxicity persistence was shortest in stream water, intermediate in stream sediments and longest in soil samples. Runoff had a more important toxicity effect than the exposure to direct aerial fumigation. The regional environmental features determining fast toxicity dissipation are discussed.

Indoor-outdoor distribution and risk assessment of volatile organic compounds in the atmosphere of industrial and urban areas.

Volatile organic compounds (VOCs), which play an important part indoors and outdoors, comprise differing compound groups such as n‐alkanes, cycloalkanes, aromatic and chlorinated hydrocarbons and terpenes. In the current study, samples were analyzed from indoor (schools and houses, n = 92) and outdoor (n = 33) air in urban, industrial, semirural and residential areas from the region of La Plata (Argentine) to consider VOC exposure in different types of environments. VOCs were sampled for 1 month during winter for 3 years, with passive 3M monitors. Samples were extracted with CS2 and analyzed by GC/MS detectors. The results show significant differences in concentration and distribution between indoor and outdoor samples, depending on the study area. Most VOCs predominantly originated indoors in urban, semirural and residential areas, whereas an important outdoor influence in the industrial area was observed. In all areas alkanes and aromatic compounds dominated, even though a different chemical distribution was seen. Traffic burden was determined as the major source of outdoor VOC with a benzene/toluene ratio close to 0.5. Indoors, C9–C11 alkanes, toluene and xylenes dominated, caused by human activities. In contrast, in the industrial area higher concentrations of hexane, heptane and benzene occurred outdoors and affected the indoor air significantly. The lifetime cancer risk (LCR) associated to the benzene exposure was calculated for children from the different study areas. For all groups the study showed a LCR value greater than 1 × 10−6 related to the benzene exposure indoors as well outdoors. A value two magnitudes higher was detected indoors in the industrial area, what demonstrates the high risk for children living in this area of La Plata.

Sublethal and lethal effects on Rhinella Arenarum (Anura, Bufonidae) tadpoles exerted by the pirimicarb-containing technical formulation insecticide Aficida®

Acute toxicity, genotoxicity, and cytotoxicity of the pirimicarb-containing commercial-formulation carbamate insecticide Aficida(R) (50% pirimicarb) were evaluated on Rhinella arenarum (Anura, Bufonidae) tadpoles exposed under laboratory conditions. Lethal and sublethal effects were employed as bioassays for acute toxicity, whereas micronuclei (MNi) induction and alterations in the ratio erythrocytes:erythroblasts were employed as end-points for genotoxicity and cytotoxicity, respectively. Cr(VI) (23 mg L(-1)) and cyclophosphamide (40 mg L(-1)) were employed as positive controls for toxicity and geno-cytotoxicity assays, respectively. In Gosner stage 25 (STD25), the results revealed mean values of 402.0 and 223.6 mg Aficida L(-1) for LC-50(24)(h) and LC-50(96)(h), respectively. When STD37-39 tadpoles were exposed, the LC-50(24)(h) and LC-50(96)(h) reached values of 239.4 and 181.7 mg Aficida L(-1), respectively. Sublethal effects revealed a mean EC-50(96)(h) of 133.85 and 104.2mg Aficida in those STD25 and STD37-39 treated tadpoles, respectively. The results demonstrated that in 48-h-exposed tadpoles, a MNi increase was found only in those 80.0 mg L(-1) Aficida-treated individuals. When tadpoles were exposed to Aficida for 96h, only the 160 mg L(-1)-treated individuals showed a significant increase in MNi frequency. Concentrations ranging from 80.0 to 250.0mg Aficida L(-1) resulted in cellular cytotoxicity, revealed by a decreased proportion of circulating erythrocytes and an enhancement of erythroblasts. Accordingly, this species could provide a suitable and useful experimental model for biomonitoring aquatic ecosystems.

Toxicity of the effluent from an anaerobic bioreactor treating cereal residues on Lactuca sativa.

Effluents generated during the process of anaerobic digestion should be treated before their disposal into the environment. The aim of this study was evaluating the effectiveness of the effluent treatment system from an anaerobic bioreactor, assessing the toxicity reduction with the Lactuca sativa seed germination and root elongation inhibition test. Three sampling points were selected along the effluent treatment system: inflow into the first treatment pond, outflow from the third pond and recirculated flow to the bioreactor. Effluent dilutions tested for each sampling point were 25% and 50% (v/v), undiluted sample and controls. The pH, conductivity, temperature, dissolved oxygen, BOD₅ and COD were measured. The decrease in the organic and inorganic loads was correlated with a reduction in the phytotoxicity. The use of the seed toxicity test allows evaluating the quality and effectiveness of the studied effluent treatment system.

Reduced body condition and enzymatic alterations in frogs inhabiting intensive crop production areas.

Parameters indicative of general condition and health were compared amongst adult frogs inhabiting uncultivated lands and fields subjected to agricultural practices typical of the humid pampas of Argentina. Whereas no significant differences existed in the parasite load and external malformations prevalence rate of adult frogs from either environments, a reduced condition factor was clearly demonstrated in frogs from agricultural lands. This conclusion was reached for four frog species of different life habits: the terrestrial fossorial Rhinella fernandezae, the terrestrial Leptodactylus latinasus, the semi-aquatic Leptodactylus ocellatus, and the arborescent Hypsiboas pulchellus. A distinct pattern of enzymatic modifications was furthermore observed in L. ocellatus and H. pulchellus from agricultural lands, including elevated hepatic activities of catalase and cholinesterase, and an inhibition of liver GST activity. Further studies should investigate the causes and consequences of the systematically low condition factor observed in frogs from agricultural fields of the humid pampas of Argentina.

Geochemistry of heavy metals in bottom sediments from streams of the western coast of the rio de la plata estuary, Argentina

The fluvial system within the southwestern coastal sector of the Río de la Plata interacts with a very large and efficient mixing basin known as the Río de la Plata estuary. The region is a densely populated and productive sector of Argentina and is characterised by a temperate humid climate. The streams Carnaval, Martín, Del Gato and El Pescado of the study area drain two main geomorphologic units: a higher inner zone and the low lands of the coastal plain. In particular, the Del Gato stream receives heavily polluted discharges from agricultural, urban and industrial point and non-point sources of pollution, while the other streams collect a lower and variable discharge input. As a part of an initial assessment of the role of fluvial bottom sediments in the fate of metals through the stream ecosystems, the spatial distribution of trace and major elements related to particles in the accumulation areas was examined. Concentration of Cr, Ni, Cu, Zn, Cd, Hg, Pb, Fe and Mn, grain size, mineralogy (clay-X ray diffraction) and organic matter content were analysed in the four streams considering both geomorphologic units at different depositional time. Untreated and iron-normalised trace metal concentrations in the most polluted streams show higher levels in the upper layers of most contaminated sectors and accumulation areas associated to topographic low lands. The coastal plain sector behaves as a regional sink between the upstream area and the estuary.

Lethal and sublethal effects of cypermethrin to Hypsiboas pulchellus tadpoles

The study of the effects of the insecticide cypermethrin (CY) technical grade and its Sherpa® commercial formulation on Hypsiboas pulchellus tadpoles assessing lethality, behavior, growth, and abnormalities under standardized laboratory conditions is reported. Observed behaviors were identified and categorized by means of a ranking system according to the loss of mobility. Results of acute lethal effects indicate higher potency for Sherpa® at this level of assessment. All effects on behavior showed an increasing degree of injury as insecticide concentration increased. Organisms exposed to technical grade CY showed lower body length with respect to controls from 3.44 µg CY/L to higher concentrations, whereas those exposed to Sherpa® exhibited lower growth from 0.83 µg CY/L. Both forms of the tested insecticide caused abnormalities between 0.34 and 4.18 µg CY/L, but 100% of malformed individuals was detected from 34.4 µg CY/L for those exposed to the technical grade CY, and from 8.36 µg CY/L for those exposed to Sherpa®. This study proposes the use of easily identifiable and distinguishable sublethal end-points. The high input loads of CY in natural environments, the detected concentrations in the field, in addition to the low levels of this insecticide required to induce sublethal effects (which could eventually lead to death), allow for the conclusion that the insecticide is a risk factor for amphibians inhabiting agroecosystems.

Short and Long-Term Effects of Endosulfan, Cypermethrin, Spinosad, and Methoxyfenozide on Adults of Chrysoperla externa (Neuroptera: Chrysopidae)

ABSTRACT The susceptibility assessment of natural enemies to pesticides is relevant before the use of selective pesticides and biological control agents within the framework of integrated pest management programs. Chrysoperla externa (Hagen) (Neuroptera: Chrysopidae) is a predator considered a potential biocontrol agent of agricultural pests in the Neothropical Region. The aim of this study was to evaluate the short and long-term effects of two broad spectrum insecticides (Cypermethrin and endosulfan) and two biorational (spinosad and methoxyfenozide) registered in Argentina on young C. externa adults under laboratory conditions by ingestion through drinking water. The assessed end-points were: survivorship during preoviposition period, preoviposition time, fecundity and fertility of females, and survivorship of the progeny. Total survivorship of adults was adversely affected only by Cypermethrin that reduced the survivorship of adults irrespective of sex. Although endosulfan did not induce significant total mortality, it reduced the survivorship of females. All tested insecticides delayed the reproductive maturity of adults. Cypermethrin, endosulfan, and spinosad reduced the fecundity of females. Fertility was affected only by spinosad. Methoxyfenozide was the insecticide inducing the lowest effects on reproductive parameters. No effects were observed on the survival of progeny with any of the tested compounds. In accordance with the International Organization for Biological Control and Noxious Animals and Plants guidelines the insecticides were classified according to its lethal effects in the following toxicity classes: methoxyfenozide, spinosad, and endosulfan, class 1 (innocuous); Cypermethrin, class 2 (moderately toxic). However, if sublethal effects are taken into account, spinosad and endosulfan should not be considered innocuous.

Abnormalities in amphibian populations inhabiting agroecosystems in Northeastern Buenos Aires Province, Argentina.

The occurrence of abnormalities in amphibians has been reported in many populations, and its increase could be related to environmental pollution and habitat degradation. We evaluated the type and prevalence of abnormalities in 5 amphibian populations from agroecosystems with different degrees of agricultural disturbance (cultivated and reference areas). We detected 9 types of abnormalities, of which the most frequent were those occurring in limbs. The observed prevalence of abnormality in assessed populations from cultivated and reference areas was as follows: Rhinella fernandezae (37.1 and 10.2%, respectively), Leptodactylus latrans adults (28.1 and 9.2%) and juveniles (32.9 and 15.3%), and Hypsiboas pulchellus (11.6 and 2.8%). Scinax granulatus populations did not show abnormalities. Pseudis minuta, which was only detected in the reference area, exhibited a prevalence of 13.3%. For R. fernandezae, L. latrans, and H. pulchellus, generalized linear mixed models showed that prevalence of abnormalities was significantly higher (p < 0.05) in cultivated than in reference areas. L. latrans juveniles were more vulnerable to abnormalities than adults (p < 0.05). The presence of abnormalities in some species inhabiting different agroecosystems suggests that environmental stress factors might be responsible for their occurrence. While we detected pesticides (endosulfan, cypermethrin, and chlorpyrifos) and lower dissolved oxygen levels in ponds of the cultivated area, no data are currently available on how other factors, such as injuries from predators and parasite infections, vary by land use. Further research will be necessary to evaluate possible causes of abnormalities detected in the present study mainly in the context of factor interactions.