Radiological Analyses of 226Ra and 238U in Surface Water and Sediments from the Jackpile Member of the Morrison Formation, Pueblo of Laguna, New Mexico.

Surface water and sediments from the Jackpile mine, St. Anthony mine, Rio Paguate, Rio Moquino, and Mesita Dam areas near Pueblo of Laguna, New Mexico, were analyzed for 226Ra and U using gamma (γ) spectroscopy and inductively coupled plasma mass spectroscopy, respectively. Activity ratios for 226Ra/238U for solid samples range from 0.34 ± 0.13 to 16 ± 2.9, which reflect uranium transport and accumulation (<1), relatively pristine material in secular equilibrium (1), and removal of uranium by weathering (>1). Concentrations ranging from 80 to 225 µg L-1 U were detected in unfiltered water samples near the Jackpile mine. Water samples upstream and downstream from the mine contained concentrations ranging from 12 to 15 µg L-1 U. Water samples collected from the North Pit standing pond in the Jackpile mine contained as much as 1560 pCi L-1 of 226Ra, and passing the water through a 0.2 µM filter did not substantially reduce the activity of 226Ra in the water. 234Th and 226Ra are in secular equilibrium in this water, while radon gas was lost from the water. The results of the current study provide insight into the distribution of U-series radionuclides in the Pueblo of Laguna area, including detection of high levels of radioactivity in water at some locations within the Jackpile mine.

Greenhouse gas emission potential of tropical coastal sediments in densely urbanized area inferred from metabarcoding microbial community data.

Although benthic microbial community offers crucial insights into ecosystem services, they are underestimated for coastal sediment monitoring. Sepetiba Bay (SB) in Rio de Janeiro, Brazil, holds long-term metal pollution. Currently, SB pollution is majorly driven by domestic effluents discharge. Here, functional prediction analysis inferred from 16S rRNA gene metabarcoding data reveals the energy metabolism profiles of benthic microbial assemblages along the metal pollution gradient. Methanogenesis, denitrification, and N2 fixation emerge as dominant pathways in the eutrophic/polluted internal sector (Spearman; p < 0.05). These metabolisms act in the natural attenuation of sedimentary pollutants. The methane (CH4) emission (mcr genes) potential was found more abundant in the internal sector, while the external sector exhibited higher CH4 consumption (pmo + mmo genes) potential. Methanofastidiosales and Exiguobacterium, possibly involved in CH4 emission and associated with CH4 consumers respectively, are the main taxa detected in SB. Furthermore, SB exhibits higher nitrous oxide (N2O) emission potential since the norB/C gene proportions surpass nosZ up to 4 times. Blastopirellula was identified as the main responsible for N2O emissions. This study reveals fundamental contributions of the prokaryotic community to functions involved in greenhouse gas emissions, unveiling their possible use as sentinels for ecosystem monitoring.

Inferred drought-induced plant allocation shifts and their impact on drought legacy at a tropical forest site.

While droughts predominantly induce immediate reductions in plant carbon uptake, they can also exert long-lasting effects on carbon fluxes through associated changes in leaf area, soil carbon, etc. Among other mechanisms, shifts in carbon allocation due to water stress can contribute to the legacy effects of drought on carbon fluxes. However, the magnitude and impact of these allocation shifts on carbon fluxes and pools remain poorly understood. Using data from a wet tropical flux tower site in French Guiana, we demonstrate that drought-induced carbon allocation shifts can be reliably inferred by assimilating Net Biosphere Exchange (NBE) and other observations within the CARbon DAta MOdel fraMework. This model-data fusion system allows inference of optimized carbon and water cycle parameters and states from multiple observational data streams. We then examined how these inferred shifts affected the duration and magnitude of drought's impact on NBE during and after the extreme event. Compared to a static allocation scheme analogous to those typically implemented in land surface models, dynamic allocation reduced average carbon uptake during drought recovery by a factor of 2.8. Additionally, the dynamic model extended the average recovery time by 5 months. The inferred allocation shifts influenced the post-drought period by altering foliage and fine root pools, which in turn modulated gross primary productivity and heterotrophic respiration for up to a decade. These changes can create a bust-boom cycle where carbon uptake is enhanced some years after a drought, compared to what would have occurred under drought-free conditions. Overall, allocation shifts accounted for 65% [45%-75%] of drought legacy effects in modeled NBE. In summary, drought-induced carbon allocation shifts can play a substantial role in the enduring influence of drought on cumulative land-atmosphere CO2 exchanges and should be accounted for in ecosystem models.

While clearing the forests: The social-ecological memory of trees in the Anthropocene.

The Anthropocene concept raises awareness of human-induced planetary changes but is criticized for being 'too global'. We examined the social-ecological memory that emerges from people-tree relationships in South American temperate territories, Chile. We integrated dendrochronology (analysis of tree rings of 35 memorial trees; 17 species) with dendrography (participant observation complemented with semi-structured and go-along interviews with 14 interviewees; six women, eight men). We found that assemblages of people-tree relationships reflect marked historical changes in the territory, associated with the historical clearing of forests, which may be imprinted in both tree growth rings and in the social meanings and practices associated with memorial trees. In devastated territories, practices of tree care emphasize interconnectedness, multispecies collaborations, and the blurring of boundaries between humans and other-than-humans. We discuss some of the interdisciplinary and relational insights of our study, which may prove valuable for future research, political agendas, and educational programs in South America and beyond.

Integrating pollutant levels and biochemical biomarkers in oysters (Crassostrea rhizophorae and Crassostrea gasar) indicates anthropic impacts on marine environments along the coast of Santa Catarina state, Brazil.

This study aimed to carry out a general diagnosis of the contamination of the coastal marine environment of the Santa Catarina state (SC, Brazil) by different classes of environmental pollutants, as well as to evaluate possible adverse effects of the contaminants on biochemical biomarkers of oysters, Crassostrea gasar and Crassostrea rhizophorae. 107 chemicals were evaluated in water, sediment and oyster samples from nine sites along the coastline of SC. We also examined various biochemical biomarkers in the oysters' gills and digestive glands to assess potential effects of contaminants. In general, the northern and central regions of the littoral of SC presented higher occurrences and magnitudes of contaminants than the southern region, which is probably related to higher urbanization of center and northern areas of the littoral. The biomarker analysis in the oysters reflected these contamination patterns, with more significant alterations observed in regions with higher levels of pollutants. Our results may serve as a first baseline for future and more extensive monitoring actions and follow-up of the degree of contamination in the state, allowing for inspection actions and management of areas most affected by marine pollutants.

Functional significance of microbial diversity in arid soils: biological soil crusts and nitrogen fixation as a model system.

Microbial communities respond to changes in environmental conditions; however, how compositional shifts affect ecosystem processes is still not well-understood and it is often assumed that different microbial communities will function equally under similar environmental conditions. We evaluated this assumption of functional redundancy using biological soil crusts (BSCs) from two arid ecosystems in Mexico with contrasting climate conditions (hot and cold deserts) following an experimental approach both in the field (reciprocal transplants) and in laboratory conditions (common garden), focusing on the community's composition and potential for nitrogen fixation. Potential of nitrogen fixation was assessed through the acetylene reduction assay. Community composition and diversity was determined with T-RFLPs of nifH gene, high throughput sequencing of 16S rRNA gene amplicons and metagenomic libraries. BSCs tended to show higher potential nitrogen fixation rates when experiencing temperatures more similar to their native environment. Moreover, changes in potential nitrogen fixation, taxonomic and functional community composition, and diversity often depended on an interactive effect of origin of the communities and the environment they experienced. We interpret our results as legacy effects that result from ecological specialization of the BSC communities to their native environment. Overall, we present evidence of nonfunctional redundancy of BSCs in terms of nitrogen fixation.

Ernesto Bustamante Zuleta (1922-2021): pioneering teacher and practitioner of Colombian neurosurgery.

Ernesto Bustamante Zuleta (1922-2021) was an impactful Colombian neurosurgeon whose legacy is inextricably linked with the development of the neurosurgery specialty in Colombia. His detail-oriented approach to treatment complemented his reputation for mastery of the neurosciences. Never simply confined to the operating theater, this calm and considerate physician felt compelled to teach during his entire career. The result of his teaching made a lasting imprint on an entire generation of neurosurgeons who subsequently established a high standard of neurosurgical care in Colombia. A true pioneer, Bustamante comprehensively engaged in his field, from founding the country's first residency program in neurosurgery to successfully implementing technology in his procedures, performing many of Colombia's first neurosurgical interventions, and publishing extensively across various categories of medical science. This historical reflection highlights his enduring contributions to the field and considers his legacy through the witness testimony of many of his students and collaborators. The hope is that his contributions may be acknowledged in full, as he was a reserved person who never boasted of his own accomplishments. The authors also hope that those who did not have the opportunity to know him would be informed by the historical context of the development of Colombian neurosurgery and inspired by his conviction and altruism.

A history of Colombian neurosurgery: events, persons, and outcomes that have shaped the specialty in the country.

The history of Colombian neurosurgery is a collective legacy of neurosurgeon-scientists, scholars, teachers, innovators, and researchers. Anchored in the country's foundational values of self-determination and adaptability, these pioneers emerged from the Spanish colonial medical tradition and forged surgical alliances abroad. From the time of Colombian independence until the end of World War I, exchanges with the French medical tradition produced an emphasis on anatomical and systematic approaches to the emerging field of neurosurgery. The onset of American neurosurgical expertise in the 1930s led to a new period of exchange, wherein technological innovations were added to the Colombian neurosurgical repertoire. This diversity of influences culminated in the 1950s with the establishment of Colombia's first in-country neurosurgery residency program. A select group of avant-garde neurosurgeons from this period expanded the domestic opportunities for patients and practitioners alike. Today, the system counts 10 recognized neurosurgery residency programs and over 500 neurosurgeons within Colombia. Although the successes of specific individuals and innovations were considered, the primary purpose of this historical survey was to glean relevant lessons from the past that can inform present challenges, inspire new opportunities, and identify professional and societal goals for the future of neurosurgical practice and specialization.

"The hysteria of a little flue": effects of COVID-19 on HEIs in Brazil.

This essay will look at the key challenges public Higher Education Institutions (HEIs) faced in Brazil during the COVID-19 lockdown. The pandemic led universities to close their campuses and adopt an online interface for academic activities. However, many of these institutions do not have the technological infrastructure for such, nor did the staff and students who suffered further social exclusions. The president of Brazil referred to the pandemic as a "little flue" and later on responded to measures adopting the lockdown as a "hysteric" act that "will lead to an economic crash". Considering the lack of support from the government and the process of dismantling resources for public HE since the beginning of the new presidency elected in 2018, the COVID-19 lockdown quickly revealed the institutional racism, elitism and ableism evident in this administration's agenda. The consequence of the agenda is the cuts on research funds and lack of infrastructure to provide online classes, as examples of the severe policies that promote the erasure of marginalised groups. Such policies follow Sylvia Wynter's "Argument", revealing a code of symbolic life and death of how human order organises itself through the coloniality of power/being. In order to show how such symbolic code is engraved in the Brazilian educational system, this study explores narratives of staff and students from three universities per region of Brazil to identify how the colonial legacies are correlated with postulates of power in the Brazilian HEIs setting during the pandemic. The paper discusses the challenges experienced while keeping the HE sector active during a pandemic that the government has belittled. The conclusions advocate for organised strategies at the union and social movements level to dismantle the colonial occupation put in place in the foundation of the HEIs and reinforced by the current necropolitical administration.

Dr. Netptali Taquechel Tusiente, paradigma de la historia y la medicina cubana / Dr. Netptali Taquechel Tusiente, a paradigm of Cuban history and medicine

La vida y obra de algunos hombres y mujeres de la historia de la Medicina, transita a veces, sin artilugios, acompañadas tan solo de la humildad y la sabiduría de estos. Es por ello, que al resumir en breves líneas el tiempo de enseñanzas y heroicidades de estos paradigmas, solo se cumple con el noble objetivo de exponer a las nuevas generaciones la labor realizada por maestros, como lo fue, el Dr. Netptali Taquechel Tusiente. A través de la realización de una revisión histórica de su vida y aportes y con la obtención de los datos por medio de la entrevista, el expediente laboral y académico como fuente primaria, se procesó la información. Los aportes de este internista estuvieron centrados en la especialidad de Medicina interna y en su actividad como líder del Ministerio de Salud Pública en diversos escenarios, pero el mayor de todos fue ser considerado una figura paradigmática de la salud pública. Se concluye que este médico cubano transitó de joven revolucionario y destacado estudiante a profesor de alto reconocimiento en la educación médica y figura inolvidable para todo el que lo conoció, con un merecido puesto entre los grandes de la historia de la Medicina cubana.

The life and work of some men and women in the history of medicine sometimes pass through without any gadgets, accompanied only by their humility and wisdom. That is why, when summarizing in few lines the time of teachings and heroisms of these paradigms, the noble objective of exposing to the new generations the work carried out by teachers such as Dr. Netptali Taquechel Tusiente is fulfilled. A historical review of the life and contributions of the aforementioned doctor was carried out, and the information was processed by obtaining data from interviews as well as from his employment and academic records as a primary source. The contributions of this internist were focused on the specialty of internal medicine as well as on his activity as a leader of the Ministry of Public Health in various settings, but the greatest of all was to be considered as a paradigmatic figure of public health. It is concluded that this Cuban doctor went from being a revolutionary young man and an outstanding student to a highly recognized professor in medical education and an unforgettable figure for all who knew him, with a deserved position among the greats in the history of Cuban medicine.

The History of Neurosurgery in Puerto Rico and the Legacy of Dr. Nathan Rifkinson and the Professors at the University of Puerto Rico: Fifty Years of Education.

BACKGROUND: Dr. Nathan Rifkinson (1912-2010) was an influential neurosurgeon who dedicated his entire career to the people of Puerto Rico. In 1948, he became the first formally trained neurosurgeon to practice in Puerto Rico. Driven by incredible tenacity and with the help of several other neurosurgery professors, he created a world-class neurosurgery residency training center. METHODS: This article presents the history of neurosurgery in Puerto Rico taken from publications and personal stories recorded by a neurosurgeon who has been part of the neurosurgery program of the University of Puerto Rico for 34 years. The establishment and development of the residency training program during the last 50 years are documented. RESULTS: This recollection of events presents the history of neurosurgery in Puerto Rico and emphasizes the creation of a neurosurgery training program at the University of Puerto Rico. The University of Puerto Rico has the only residency program on the Island, preparing neurosurgeons for the last 50 years. The notable contributions of the professors in the University over the past 50 years, with special mention of Dr. Nathan Rifkinson, are described. CONCLUSIONS: In Puerto Rico, Dr. Rifkinson discovered a new niche that helped him grow to a unique iconic figure, advising physicians and government leaders on the Island. Together with all the other neurosurgery pillars and their extraordinary dedication, our professors have established an incredible legacy. Without the extreme goodness of our neurosurgery professors, neurosurgery in Puerto Rico would not be what it is now.

Evandro Pinto da Luz de Oliveira, MD, PhD (November 8, 1945-February 11, 2021): A Giant of Microneurosurgery and Neuroanatomy.

Dr Evandro de Oliveira, one of the most acclaimed and recognized names in neurosurgery, anywhere in the world, tragically left us on February 11, 2021, at the age of 75. The Rhoton Society submits an account of Dr Evandro de Oliveira's life with highlights of his personal journey, and his special contributions to the fields of microneurosurgery and neuroanatomy.

Elevated blood lead and metal/metalloid levels and environmental exposure sources in urban Ecuadorian school-age children and mothers.

BACKGROUND: Lead and other toxic and potentially toxic metals and metalloids are significant contributors to the global burden of disease and disability. Studies characterizing blood metal/metalloid levels and potential sources of environmental exposures are limited for populations living in the major urban centers of Andean-area countries. METHODS: We used ICP-MS to quantify blood levels of lead (PbB), cadmium (CdB), manganese (MnB), total arsenic (AsB), and total mercury (HgB) in school-age children (n = 47) and their reproductive-age mothers (n = 49) from low-resource households in Quito, Ecuador. These were compared to published 95th percentile reference values (RV95) and for PbB, also to CDC reference values. We used a detailed environmental questionnaire to examine the contribution of residential and neighborhood environmental exposure sources with participant blood metal/metalloid levels. We used ICP-MS to measure Pb levels in residential windowsill dust, floor dust, and drinking water samples and used XRF for paint samples. RESULTS: Forty-five percent of the mothers had PbBs ≥ 5 µg/dL; 14.3% had PbBs ≥10 µg/dL. Maternal blood levels exceeded RV95s for PbB (76%), CdB (41%), MnB (88%), HgB (57%), and AsB (90%). Of children, 68% had PbBs ≥ 5 µg/dL, and 21.3% had PbB ≥10 µg/dL. Most child blood levels exceeded the RV95s for PbB (100%), CdB (100%), MnB (94%), and total HgB (94%) and AsB (98%). Most mothers (97%) and all children had blood levels indicating exposure to multiple metal/metalloid mixtures. Maternal and child PbBs were moderately correlated with each other but the other four metals/metalloids were not. Factors associated with maternal blood metal/metalloid levels were residence in a home with an earthen floor (PbB) or bare cement block walls (MnB), living near a dirt-paved or cobblestone street (PbB), <50 m from a heavily trafficked major roadway (PbB, HgB), living in the Los Chillos (PbB) or Cotocollao neighborhoods (PbB, HgB), or in areas where street vendors grilled food using charcoal (MnB). Factors associated with child blood metal/metalloid levels were residence in a dirt floor home (PbB, CdB, AsB), living near a dirt-paved or cobblestone street (PbB), living in the El Camal or Cotocollao neighborhoods (AsB), or in local neighborhoods where scrap metal smelters (MnB) and LPG gas depositories (PbB) were present. CONCLUSIONS: The elevated blood levels of PbB, other metal/metalloids, and metal/metalloid mixtures identified mothers and children in this exploratory study is an urgent public health and clinical concern. The exposure patterns suggest that traffic-related exposures, especially the resuspension of legacy Pb in dust, as well as other anthropogenic and geogenic sources may be important environmental contributors to metal/metalloid exposures in urban Ecuadorian mothers and children. Future studies are needed to confirm these findings and explore other potential exposure sources. Biomonitoring is also needed in order to formulate effective intervention strategies to reduce population exposure to toxic levels of environmental metals/metalloids.

Map of total phosphorus content in native soils of Brazil

Knowledge of the distribution of total phosphorus (P) content in native soils provides information on the management of ecosystem, land capability for agriculture, environmental quality, and biodiversity conservation. We mapped the spatial distribution of total P concentrations in topsoils (0-30 cm) of uncultivated (native) areas in Brazil. We obtained data on native total P of the southern, south-eastern, and north-eastern regions from reports of exploratory projects developed between 1960s and 1970s by EMBRAPA and by the RADAM Brazil Project. We estimated data from the central-western and northern regions from the relationship between total P and soil properties (Fe, Al, C and clay content), based on the RADAM Brazil Project. Soil total P varied widely (< 25 to > 500 mg kg1) in all regions in Brazil. Higher concentrations (> 500 mg kg-¹) were observed in southern region compared to most of the rest of the country (< 200 mg kg-¹), while the Cerrado (Central), Amazon (North) and Caatinga (Northeast) biomes are very poor in total P. This first national native soil total P map provides a valuable baseline for understanding the historical patterns of agriculture expansion in Brazil. It allows quantifying the effect of agriculture expansion and future cropping systems on soil available P content and legacy P, targeting regional soil-crop specific strategies for optimization of ecosystem services, and mitigating potential environmental risk due to P transference to water bodies.(AU)

Map of total phosphorus content in native soils of Brazil

Knowledge of the distribution of total phosphorus (P) content in native soils provides information on the management of ecosystem, land capability for agriculture, environmental quality, and biodiversity conservation. We mapped the spatial distribution of total P concentrations in topsoils (0-30 cm) of uncultivated (native) areas in Brazil. We obtained data on native total P of the southern, south-eastern, and north-eastern regions from reports of exploratory projects developed between 1960s and 1970s by EMBRAPA and by the RADAM Brazil Project. We estimated data from the central-western and northern regions from the relationship between total P and soil properties (Fe, Al, C and clay content), based on the RADAM Brazil Project. Soil total P varied widely ( 500 mg kg1) in all regions in Brazil. Higher concentrations (> 500 mg kg-¹) were observed in southern region compared to most of the rest of the country (< 200 mg kg-¹), while the Cerrado (Central), Amazon (North) and Caatinga (Northeast) biomes are very poor in total P. This first national native soil total P map provides a valuable baseline for understanding the historical patterns of agriculture expansion in Brazil. It allows quantifying the effect of agriculture expansion and future cropping systems on soil available P content and legacy P, targeting regional soil-crop specific strategies for optimization of ecosystem services, and mitigating potential environmental risk due to P transference to water bodies.

Persistent organic pollutants (POPs) and personal care products (PCPs) in the surface sediments of a large tropical bay (Todos os Santos Bay, Brazil).

The occurrence and spatial distribution of persistent organic pollutants (POPs) and personal care products (PCPs) were investigated in surface sediments of Todos os Santos Bay. Samples were Soxhlet-extracted and analyzed by gas chromatography coupled with tandem mass spectrometry. Quantification limits (QL) ranged from 0.0025 ng g-1 for POPs to 0.25 ng g-1 for PCPs. Of the POPs studied, only PCBs and DDTs were detectable, with concentrations ranging from

Legados dos megaeventos esportivos para a proposta pedagógica do Programa Segundo Tempo / Legacies of mega sport events for the pedagogic proposal of the Program Segundo Tempo

A realização da Copa do Mundo de Futebol, em 2014, e dos Jogos Olímpicos e Paraolímpicos, em 2016, trouxeram à tona, no Brasil, a discussão sobre os legados de megaeventos esportivos, em especial sobre como os investimentos públicos nestes eventos reverteriam em prol de projetos sociais esportivos. O objetivo dessa pesquisa foi debater, a partir de seus agentes sociais, como os legados dos egaeventos esportivos se refletem no desenvolvimento das ações do Programa Segundo Tempo (PST), um programa social esportivo de dimensão nacional levado a efeito pelo Governo Federal. A pesquisa, do tipo descritiva, utilizou um questionário fechado. Participaram do estudo 513 agentes do PST, integrantes de 27 convênios situados nas cinco regiões geográficas do Brasil, envolvidos diretamente com as ações administrativas (Coordenador Geral e Coordenador Pedagógico) e interventivas (Coordenador de Núcleo e Monitores). Para a análise das respostas aos questionários, empregou-se a estatística descritiva. Os dados foram organizados em duas categorias definidas a priori: 1) Possíveis legados dos megaeventos esportivos na proposta pedagógica do PST; 2) A contemplação da Educação Olímpica na proposta pedagógica do PST. Os resultados evidenciaram que, na proposta pedagógica do PST, há indicativos de estratégias que favorecem a consolidação dos legados destes megaeventos esportivos. Entretanto, ainda se fazem necessárias ações que reforcem o trabalho com os valores no esporte, centrais na Educação Olímpica. Considerando que o país se encontra em um momento pósmegaevento, os resultados desta pesquisa reiteram o valor dos programas sociais esportivos como uma estratégia governamental para fortalecer e concretizar os legados desses eventos, especialmente os legados sociais...(AU)

The 2014 Football World Cup and the Rio 2016 Olympics and Paralympics brought to the fore in Brazil a discussion about the legacies of mega sport events, especially about how public investments in these events would revert to social sport projects. The aim of the present research is to debate, according to the perspective of its social agents, how the sports mega events legacy reflexes on the development of actions taken of the Programa Segundo Tempo (PST), a social sport program of national dimension carried out by the Brazilian Federal Government. The research, of the descriptive type, used a closed question questionnaire. The participants of the study were 513 PST agents, who integrated 27 covenants from the five geographic regions of Brazil, directly involved with the administrative (General Coordinator and Pedagogical Coordinator) and intervening actions (Core Coordinator and Monitors). For the analysis of the questionnaire's responses, descriptive statistics were sed. The data were organized in two categories defined a priori: 1) Possible legacies of the mega sport events for the pedagogical proposal of the PST; 2) The contemplation of Olympic Education in the pedagogical proposal of the PST. The results showed that, in the pedagogical proposal of the PST, there are indicatives of strategies that favor the consolidation of the legacies of these mega sport events.However, actions are still needed to strengthen the work with values in sport, central elements of the Olympic Education. Considering that the country is now in a post-mega event moment, the results of this research reiterate the value of sport social programs as a governmental strategy for strengthening andconcretizing the legacies of these events, especially the social ones...(AU)

Historical records of mercury deposition in dated sediment cores reveal the impacts of the legacy and present-day human activities in Todos os Santos Bay, Northeast Brazil.

We determined depth profiles of total mercury (T-Hg) in six 210Pb-dated sediment cores from Todos os Santos Bay to reconstruct the history of anthropogenic Hg accumulation. We also assessed superficial sediments samples from five estuaries. T-Hg concentrations (5-3500 µg kg-1) presented a large spatial and temporal variability. T-Hg concentrations in Ribeira Bay increased up to 200-fold along time, whereas the fluxes of T-Hg are substantially higher (up to 10,000 fold) than present-day wet deposition for industrialized areas. Sedimentary records indicate that a chlor-alkali plant has been the main source of Hg pollution until the present, although the T-Hg records suggest that harbor, shrimp farming, and oil refinery activities, besides Hg atmospheric depositions, are important across the bay. Sediments in the Ribeira Bay act as an important Hg sink. If sediments are eroded or disturbed, they may release Hg, thus posing a serious risk to wildlife and ecosystem health. CAPSULE: Sedimentary cores provide data on preindustrial levels and also anthropogenic fluxes of Hg for the appraisal of the magnitude, processes and potential risks of the contamination.

Ecological Risk Assessment (ERA) of pesticides from freshwater ecosystems in the Pampas region of Argentina: Legacy and current use chemicals contribution.

Agricultural production in the Pampas region is one of the most important economic activities in Argentina. However, the possible environmental effects related to the growth of this activity in the last years have not been studied enough. Particularly, the effects of pesticides mixtures are a topic of great concern both for society and regulatory authorities worldwide, given the possible additive and synergistic relationships between these chemicals and their possible effects on aquatic biota. Based on a concentration addition model, this study developed an Ecological Risk Assessment (ERA) of pesticides from freshwater ecosystems in the Pampas region. For this purpose, reported pesticides concentrations available in public bibliography and a Risk Quotients (RQs) approach were used. A cumulative risk map was established to display RQs for current use pesticides (CUPs) and legacy chemicals. The ΣRQs were calculated for 66 sites, using available reported measured environmental concentrations (MECs) and predicted no effect concentrations (PNECs) of pesticides. While ΣRQ for only CUPs resulted in a high and very high risk (ΣRQ > 1) for 29% of the sites, when legacy pesticides were incorporated this percentage reached the 41% of the sites, increasing significantly the absolute values of RQ. Herbicides like glyphosate and atrazine contributed considerably to the ΣRQCUPs while organochlorines were the major contributors for ΣRQs when legacy pesticides were incorporated. Moreover, some active ingredients (acetochlor, carbendazim and fenitrothion) which are approved for their use in Argentina but banned in EU showed high contribution to ΣRQCUPs. The present study is the first attempt to develop an ERA in surface water of the Pampas region of Argentina and it provides a starting point for a more comprehensive pesticides monitoring and a further risk assessment program.