Antofagasta Region Research Articles

Magnesium, zinc, arsenic, selenium and platinum urinary excretion from cancer patients of Antofagasta region, Chile: multi-metal approach.

ObjectivesTo evaluate the short-term 24 h urinary excretion of platinum, arsenic, selenium, magnesium and zinc in patients with lung cancer and with cancer other than lungs treated with cisplatin or/and carboplatin from Antofagasta, Chile.DesignUrine measurements of Pt and Se were made by inductively coupled plasma optical emission spectrometry, As by hydride-generation atomic absorption spectrometry and Mg and Zn by means of flame furnace atomic absorption spectrometry.SettingAll samples were provided by the Oncological Centre of Antofagasta Regional Hospital (Region of Antofagasta, Chile).ParticipantsNinety 24-h urine samples from cancer patients after the infusion of Pt-base drugs and 10 24-h urine samples from cancer patients not treated with metal-base drugs.Main outcome measuresConcentrations of Pt, Se, As, Zn and Mg coming from 24-h urine samples.ResultsPt excreted was not significantly different between patients with lung and other cancers treated with cisplatin. The excretion of Mg, Zn and Se was greater than As. Then, Pt favours the excretion of essential elements. For lung and other types of cancers treated with drugs without Pt, excretion of Mg, Zn and Se was also greater than that of As, suggesting antagonism Mg-Zn-Se–anti-cancer drug relationship.ConclusionsThe amounts of Mg, Zn and Se excreted were greater than for As either with or without Pt-containing drugs, suggesting antagonist Mg-Zn-Se–anti-cancer drug relationships. The excretion of As, Mg, Zn and Se is induced by Pt. Knowledge obtained can contribute to understanding the arsenic cancer mechanism and the As-Mg-Zn-Se-Pt inter-element association for lung cancer and other types of cancer.

The burden of oesophageal cancer in Central and South America

Rationale and objectiveOesophageal cancer shows marked geographic variations and is one of the leading causes of cancer death worldwide. We described the burden of this malignancy in Central and South America. MethodsRegional and national level incidence data were obtained from 48 population-based cancer registries in 13 countries. Mortality data were obtained from the WHO mortality database. Incidence of oesophageal cancer by histological subtype were available from high-quality population-based cancer registries. ResultsMales had higher incidence and mortality rates than females (male-to-female ratios: 2–6:1 and 2–5:1). In 2003–2007, the highest rates were in Brazil, Uruguay, Argentina and Chile. Mortality rates followed the incidence patterns. Incidence of oesophageal squamous cell carcinoma (SCC) was higher than adenocarcinoma (AC), except in females from Cuenca (Ecuador). SCC and AC incidence were higher in males than females, except in the Region of Antofagasta and Valdivia (Chile), Manizales (Colombia) and Cuenca (Ecuador). Incidence and mortality rates tended to decline in Argentina, Chile, Brazil (incidence) and Costa Rica from 1997 to 2008. ConclusionThe geographic variation and sex disparity in oesophageal cancer across Central and South America may reflect differences in the prevalence of tobacco smoking and alcohol consumption which highlights the need to implement and/or strengthen tobacco and alcohol control policies. Maté consumption, obesity, diet and Helicobacter pylori infection may also explain the variation in oesophageal cancer rates but these relationships should be evaluated. Continuous monitoring of oesophageal cancer rates is necessary to provide the basis for cancer prevention and control in the region.

Riotintoite, Al(SO4)(OH)·3H2O, A New Mineral From La Vendida Copper Mine, Antofagasta Region, Chile

The new mineral riotintoite was discovered in the abandoned La Vendida mine, near Sierra Gorda, Antofagasta Region, Atacama desert, Chile. Associated minerals are vendidaite, eriochalcite, Mg-rich aubertite, magnesioaubertite, belloite, alunite, kaolinite, and halloysite. Riotintoite forms colorless platy crystals up to 0.1 × 0.4 × 0.4 mm in size and exhibits the forms {010} (the major form), {001}, {100}, {110}, {01![Graphic][1] }, {1![Graphic][2] 0}, {2![Graphic][3] 0}, {123}, {![Graphic][4] 23}, {![Graphic][5] 31}, and {1![Graphic][6] 1}. Riotintoite is brittle, with Mohs' hardness of 2½. There are three good cleavages: {010}, {001}, and {201}. D meas = 2.13(2) g/cm3, D calc = 2.129 g/cm3. The new mineral is optically biaxial (–), α 1.513(2), β 1.522(2), γ 1.526(2), 2 V (meas.) = 62(1)°, 2 V (calc.) = 67°. The infrared spectrum is given. The chemical composition (electron microprobe, H2O by gas chromatography) is (in wt.%): Al2O3 24.36, SO3 40.69, H2O 34(2), total 99.05. The empirical formula is: Al0.93(SO4)0.99(OH)0.81·3.25H2O. The crystal structure was solved using single-crystal X-ray diffraction data ( R 1 = 0.0398). Riotintoite is triclinic, space group P ![Graphic][7] , a 5.600(2) A, b 7.450(3) A, c 7.671(3) A, α 74.785(7)°, β 86.042(8)°, γ 75.810(7)°, V 299.4(2) A3, Z = 2. The structure is based on isolated clusters which are formed by pairs of edge-shared Al(H2O)3(OH)2O octahedra (AlO6 octahedra link via common OH–OH edge and O belongs to the SO42– anion) and SO4 tetrahedra. The clusters are linked by strong hydrogen bonds between water molecules and non-bridging oxygen atoms of SO4 tetrahedra. The strongest lines of the powder X-ray diffraction pattern [ d , A ( I , %) ( hkl )] are: 6.975 (100) (010), 4.459 (40) (111), 4.391 (72) (101), 3.766 (31) (![Graphic][8] ![Graphic][9] 1), 3.695 (29) (002, 012), 3.491 (24) (021, 020), 2.552 (26) (201, ![Graphic][10] 01, 013). [1]: /embed/inline-graphic-1.gif [2]: /embed/inline-graphic-2.gif [3]: /embed/inline-graphic-3.gif [4]: /embed/inline-graphic-4.gif [5]: /embed/inline-graphic-5.gif [6]: /embed/inline-graphic-6.gif [7]: /embed/inline-graphic-7.gif [8]: /embed/inline-graphic-8.gif [9]: /embed/inline-graphic-9.gif [10]: /embed/inline-graphic-10.gif

Palynostratigraphy of the Zorritas Formation, Antofagasta region, Chile: Insights on the Devonian/Carboniferous boundary in western Gondwana

The Middle Member of the Zorritas Formation in the Antofagasta region of northern Chile, yielded terrestrial and marine palynomorph assemblages which span the Devonian/Carboniferous boundary. The assemblages show a clear predominance of terrestrial palynomorphs with 70 miospore species, 18 marine phytoplankton species, two non-marine algae and one chitinozoan species, all coming from 15 productive levels. Palynomorphs are poorly preserved and most of them are reworked. Three palynological associations are recognized based on miospores. These are assigned to the Tournaisian–Visean, Tournaisian and probable latest Famennian. Age assignments are discussed in the frame of the spore zonal schemes established for Euramerica and western Gondwana. The stratigraphical distribution of spores allows the identification of the probable position of the Devonian/Carboniferous boundary within the Zorritas Formation. This system boundary is proposed for the first time in Palaeozoic sedimentary rocks of northern Chile. The presence of Gondwanan typical miospore species indicates affinities with this palaeocontinent even though the Tournaisian and Tournaisian–Visean miospore associations support the cosmopolitanism already suggested for the early Carboniferous flora. The significant number of reworked palynomorphs together with the sedimentological analysis of the studied sections, suggest that these deposits were severely impacted by the climatic change and major sea level fluctuations. Similar conditions were recorded in coeval western Gondwana basins.

Iodine budget in surface waters from Atacama: Natural and anthropogenic iodine sources revealed by halogen geochemistry and iodine-129 isotopes

Iodine enrichment in the Atacama Desert of northern Chile is widespread and varies significantly between reservoirs, including nitrate-rich “caliche” soils, supergene Cu deposits and marine sedimentary rocks. Recent studies have suggested that groundwater has played a key role in the remobilization, transport and deposition of iodine in Atacama over scales of millions-of-years. However, and considering that natural waters are also anomalously enriched in iodine in the region, the relative source contributions of iodine in the waters and its extent of mixing remain unconstrained. In this study we provide new halogen data and isotopic ratios of iodine (129I/I) in shallow seawater, rivers, salt lakes, cold and thermal spring water, rainwater and groundwater that help to constrain the relative influence of meteoric, marine and crustal sources in the Atacama waters. Iodine concentrations in surface and ground waters range between 0.35 μM and 26 μM in the Tarapacá region and between 0.25 μM and 48 μM in the Antofagasta region, and show strong enrichment when compared with seawater concentrations (I = ∼0.4 μM). In contrast, no bromine enrichment is detected (1.3–45.7 μM for Tarapacá and 1.7–87.4 μM for Antofagasta) relative to seawater (Br = ∼600 μM). These data, coupled to the high I/Cl and low Br/Cl ratios are indicative of an organic-rich sedimentary source (related with an “initial” fluid) that interacted with meteoric water to produce a mixed fluid, and preclude an exclusively seawater origin for iodine in Atacama natural waters. Iodine isotopic ratios (129I/I) are consistent with halogen chemistry and confirm that most of the iodine present in natural waters derives from a deep initial fluid source (i.e., groundwater which has interacted with Jurassic marine basement), with variable influence of at least one atmospheric or meteoric source. Samples with the lowest isotopic ratios (129I/I from ∼215 to ∼1000 × 10−15) strongly suggest mixing between the groundwater and iodine storage in organic-rich rocks (with variable influence of volcanic fluids) and pre-anthropogenic meteoric water, while samples with higher values (∼2000–93,700 × 10−15) indicate the input of anthropogenic meteoric fluid. Taking into account the geological, hydrologic and climatic features of the Atacama region, we propose that the mean contribution of anthropogenic 129I is associated with 129I releases during nuclear weapon tests carried out in the central Pacific Ocean until the mid 1990's (129I/I = ∼12,000 × 10−15). This source reflects rapid redistribution of this radioisotope on a global scale. Our results support the notion of a long-lived continental iodine cycle in the hyperarid margin of western South America, which is driven by local hydrological and climate conditions, and confirm that groundwater was a key agent for iodine remobilization and formation of the extensive iodine-rich soils of Atacama.

Unusual Coastal Breeding in the Desert-Nesting Gray Gull (Leucophaeus modestus) in Northern Chile

Abstract. The Gray Gull (Leucophaeus modestus) has the unique habit among gulls of nesting in the interior Atacama Desert, up to 100 km from the coast. During the 2014–2015 austral breeding season, two breeding colonies were recorded on the coast within 90 m of the shoreline in the Antofagasta Region, northern Chile. The new colonies ranged in size from 40 (Playa Grande) to 150 (Playa Brava) nests. Egg laying was synchronous in both colonies and most likely occurred in late November 2014, coinciding with egg laying in desert colonies. The colony at Playa Brava was successful, but the one at Playa Grande was deserted due to feral dog (Canis familiaris) attacks. The habitat used by Gray Gulls resembled that reported for desert colonies, with flat plains covered with small rocks, which provide protection to chicks from intense solar radiation. This unusual coastal nesting behavior could result in the modification of certain life history and behavioral traits in the Gray Gull (e.g., chick growth rates, energy...

Implementation of leading practice in geotechnical and blasting performance evaluations at the Centinela sulphide mine

The Centinela sulphide mine (formerly known as Esperanza Mine) is an open pit sulphide deposit located in Chile's Antofagasta Region, 1350 km North of Santiago. One of the strategic objectives of the mine is to implement productivity improvement projects that can be monitored, adequately quantified and adhere to strict geotechnical requirements. This paper describes the implementation of leading practices to evaluate geotechnical and blasting performance. An approach based on direct measurements was developed and implemented at the mine site. The process involved measurements of near-field accelerations and gas penetration behind pre-split-lines; run of mine (ROM) fragmentation analysis and geotechnical evaluations based on the reconciliation of key geotechnical design parameters, such as bench face angle, berm width, inter-ramp angles and final slope characteristics. A geotechnical evaluation matrix was introduced to rank final results at each monitored location. From a geotechnical perspective, the best results were obtained with some of the lowest powder factor blasts monitored. Fragmentation assessment results showed that plant requirements were still being achieved at these lower powder factors. This helped confirm that in the rock mass domains of interest, reduced powder factors in production rows were more appropriate in order to maintain higher standards of quality in wall control practices.

Water Scarcity and the Impact of the Mining and Agricultural Sectors in Chile

Chile contains some of the driest areas in the world, yet human activities in these areas require large volumes of water, the result is regions experiencing high water scarcity leading to environmental degradation, conflicts and reduced industrial productivity. The aim of this paper was to quantify the water scarcity in the central and northern regions by calculating the water scarcity index—the ratio of annual water demand to availability. A focus of the paper was to determine the impact of the main industries in each region and investigate the benefit of implementing water reduction strategies within these industries. The water resources of each investigated region were found to be greatly overexploited and particularly so in the region of Antofagasta. The mining industry was found to be the greatest water consuming sector in this region and further analysis demonstrated that the degree of water scarcity could be greatly reduced by the implementation of water reduction strategies. The agricultural sector dominated water demand in all other regions and it was found that upgrading irrigation efficiency alongside reducing consumption in mining improved the situation in all regions. Nevertheless, given the scale of water scarcity, further investigation is necessary to obtain more recent and accurate data and analyze alternative strategies.

Are vertical linkages promoting the creation of a mining cluster in Chile? An analysis of the SMEs' practices along the supply chain

In regions whose industrial structure is organized around one or more large firm corporations, the best practices of small and medium enterprises depend on where firms are located in the supply chain. This paper studies 351 small and medium enterprises in the Antofagasta Region in Chile between 2007 and 2008, where multinational and public mining companies are the drivers of the local economy and the government is promoting the formation of a mining cluster. Structural equation model is used to show that first-tier small and medium enterprise mining suppliers, directly related to large corporations, follow business practices that promote international certification, quality control, and investment in innovation, while in contrast second-tier small and medium enterprises are more focused on avoiding insolvency and client orientation. These results cast doubt on the formation of a mining cluster in the region and suggest the need for differentiated policies in these two groups of small and medium enterprises, especially those related to knowledge transfer.

Magnesiovoltaite, K2Mg5Fe3+ 3Al(SO4)12·18H2O, a new mineral from the Alcaparrosa mine, Antofagasta region, Chile

Magnesiovoltaite, a new voltaite-group mineral, was discovered in the Alcaparrosa mine, Cerro Alcaparrosa, El Loa province, Antofagasta region, Chile, in two associations, one of which includes coquimbite, tamarugite, alum-(Na), rhomboclase, yavapaiite, voltaite and opal, and the other one is botryogen, opal, tamarugite, alum-(K), pickeringite, magnesiocopiapite, and jarosite. Magnesiovoltaite forms yellow, brownish-yellow or pale yellowish-greenish isometric crystals up to 2 mm across. The main crystal forms are {111} and {100}; the subordinate forms are {110} and {211}. The new mineral is brittle, with subconchoidal fracture; cleavage is not observed. Mohs’ hardness is 2½. D meas = 2.51(2) g/cm 3 , D calc = 2.506 g/cm 3 . Magnesiovoltaite is optically anomalously anisotropic, uniaxial with e = 1.584(2) and ω = 1.588(2), or biaxial (−) with α = 1.584(2), β = 1.587(2), and γ = 1.588 (2). Possible causes of the optical anomalies are discussed. The infrared spectrum is given. The chemical composition is (EDS-mode electron microprobe, all iron is considered as Fe 3+ in accordance with Mossbauer data, H 2 O by gas chromatography of ignition products, wt. %): Na 2 O 0.13, K 2 O 4.64, MgO 9.13, MnO 1.73, ZnO 0.84, Al 2 O 3 2.47, Fe 2 O 3 13.36, SO 3 50.83, H 2 O 17.6, total 100.73. The empirical formula based on 66 O atoms per formula unit ( apfu ) is (K 1.85 Na 0.08 )(Mg 4.25 Mn 0.46 Zn 0.14 )Fe 3+ 3.14 Al 0.91 (SO 4 ) 11.91 (H 2 O) 18.325 O 0.035 . The simplified formula is K 2 Mg 5 Fe 3+ 3 Al(SO 4 ) 12 ·18H 2 O. The crystal structure has been refined to R = 3.2% using 1147 unique reflections with I > 2σ( I ). Magnesiovoltaite is cubic, Fd –3 c, a = 27.161(1) A, V = 20038(2) A 3 , and Z = 16. Magnesiovoltaite is isostructural with other cubic voltaite-group minerals. The strongest lines of the powder X-ray diffraction pattern [ d , A ( I , %) ( hkl )] are: 9.56 (29) (022), 6.77 (37) (004), 5.53 (61) (224), 3.532 (68) (137), 3.392 (100) (008), 3.034 (45) (048), 2.845 (30) (139). The type material is deposited in the collections of the Fersman Mineralogical Museum of the Russian Academy of Sciences, Moscow, Russia.

Thoracic aortic aneurysm in a pre-Columbian (210 BC) inhabitant of Northern Chile: Implications for the origins of syphilis

The aim of this work is to report a probable first case of a thoracic aortic aneurysm in the remains of a pre-Columbian individual from South America and to explore the relationship of this case to the only other paleopathological case previously described. We also consider the implications of both cases for the origins of syphilis. This study is based on the macroscopical analysis of human remains recovered during excavation of the Chiu Chiu 273 prehistoric cemetery, in the Antofagasta Region of Northern Chile. Ceramic sherds from the grave have a thermoluminescence date of 2160±100 A.P. or 210 B.C. The skeletal remains of an adult individual display resorptive lesions in both the sternum and the first two thoracic vertebrae, which are suggestive of a thoracic aortic aneurysm. The lesions observed in the case described are clearly compatible with the development of an aneurysm of the thoracic aorta (ascending portion and arch). We suggest that this aneurysm has a syphilitic etiology, considering the vascular segments compromised, the type of lesions observed, and the prevalent etiology of this kind of cardiovascular pathology in pre-penicillin times. Since the only two cases of thoracic aortic aneurysms reported to date have been found in the Americas and are clearly pre-Columbian, it can be suggested that venereal syphilis was present in the Americas in times before European contact.

<i>Lupinus microcarpus</i> Growing in Arsenic—Agricultural Soils from Chile: Toxic Effects and It Potential Use as Phytoremediator Plant

Arsenic (As) is the most important contaminant of the environment in northern Chile. The purpose of the present work is to study As-toxicity symptoms on Lupino microcarpus (lupine), an annual legume plant that constitutes part of the desert community of the pre-Andean area of the Antofagasta Region, Chile. This plant species is cultivated in As-agricultural soil collected from Chiu Chiu (northern Chile) which is classified as arid soils. Control soil (0 - 20 cm depth) is collected from an area located in the central zone of Chile, which is classified as molli soil. The main physic-chemical characteristics of As-soil and the control soil are determined. Eighteen plastic pots of 1.6 L (fifteen for experimental and three for control) are filled with As-soil and control soil treatments. Two plants are cultivated in each pot and then separated leaves and roots for As-analysis. Visual As-toxicity symptoms such as foliar chlorosis, necrosis of the leaf tips and margins, leaf wilting and stunted are determined. Total As concentrations in soils where lupine is cultivated, reach levels between 5.3 - 14.2 mg·kg-1 d.w. (control soil As-level: 3.1 mg·kg-1). Roots show higher As-concentration than leaves, both experimental plants as control plants (2.28 - 9.1 mg·kg-1 d.w., and 0.76 mg·kg-1 d.w., respectively) and low values of transport index (TI) (0.16 - 0.34). All of visual As-toxicity symptoms determined is showed by lupin cultivated in As-agricultural soils. Neither control lupin plant suffers any toxicity symptoms. The results indicate that lupine plants do not resist contamination and accumulated higher levels of As in roots. Lupine can be used in the phytostabilisation of As immobilizing it by microbial activity in agricultural soil.

Mining Development and Opportunities for Poverty Reduction and Human Development in Latin America

Large-scale mining development has a potential to contribute to human development and poverty reduction in Latin America, particularly in the area of influence of mining activities. Given efficient resources management with a core objective towards sustainable development, large-scale mines are sources of long-term impacts at local and national levels. This paper analyses the effects of large-scale mining development on poverty reduction in the Antofagasta Region, Chile. By employing a simple econometric model, this research demonstrates that large-scale mining development can be an important economic engine for poverty reduction and social progress. The regression results show high correlation between the independent and dependent variables and indicate that poverty levels have decreased with every increase in mining production over the period 1990-2010. Based on these results, it is possible to conclude that: 1) there is strong evidence of causality between mining activity (represented by copper production) and poverty reduction (percentage of poverty) in Antofagasta during that period and 2) Mining activity is the most important source of poverty reduction in Antofagasta. The paper recommends that efforts need to be coordinated among policy makers, interested groups, civil society and mining companies to develop complementary policies, strategies and actions focused on specific social aspects to transform mining opportunities into effective results.

Maritime fishing during the Middle Holocene in the hyperarid coast of the Atacama Desert

The emergence of specialized fishers is often considered one of the most distinguishing traits of the Middle Holocene (ca. 8000–6000 cal BP) in the hyperarid Southern Atacama coast. Most of the evidence comes from funerary contexts and artifact typologies, but there are very few systematic zooarchaeological studies from which to understand this process. Considering the importance of marine and coastal resources for communities who inhabited this area in terms of subsistence and social organization, in this paper we analyze ichthyoarchaeological evidence from the Zapatero site (Antofagasta region of Chile), one of the most important Middle Holocene sites of the Taltal area. Our evidence shows a specialized maritime adaptation based on the exploitation of different fish resources from the area, but at the same time an important intensification in the harvesting of one specific taxon, the jack mackerel Trachurus murphyi. Through this systematic ichthyoarchaeological analysis, we reflect on the historical process of adaptation of local communities to the driest coastal desert in the world.

Paleomagnetism of Permo-Triassic and Cretaceous rocks from the Antofagasta region, northern Chile

New paleomagnetic data from Permo-Triassic and Late Cretaceous rocks yield a consistent trend of vertical-axis-tectonic-rotations which are consistent with the Central Andean Rotation Pattern (CARP). However, three sites in the Tuina Formation and one site in the Purilactis Group record large rotations (80°). These mayor rotations are probably due to dextral-transpressive deformation occurring in close relation with the Incaic tectonic phase. Consequently, it is possible to infer that previous tectonic phases Peruvian and K-T would not have produced significant tectonic rotations in the area.

Multi-layered foresight: Lessons from regional foresight in Chile

The design, management and evaluation of foresight is challenging firstly due to the vast diversity of foresight practices and secondly due to its embeddedness in the context of other policy processes. To help overcome these challenges we look at the contributions of foresight from multiple perspectives in a systemic way and propose the concept of multi-layered foresight, which analyses the contributions of foresight to knowledge, relations and capabilities on four layers: landscape, system, organisation and individual. We construct these layers building on earlier literature and illustrate them with a case example from the region of Antofagasta in Chile. We argue that foresight exercises benefit from considering multiple levels and respective different emphases in analysis. For instance, on the landscape layer the focus tends to be on contributions to knowledge while on the organisational layer it is more on capabilities. The layers help position the foresight exercise and its effects in relation to the broader context. Thus, we expect the concept of multi-layered foresight to support the design, management and evaluation of foresight.

First observations of the aquatic invertebrate fauna in ephemeral Atacama River (22° S, Antofagasta Region, Chile).

The invertebrate communities of the northern Chilean rivers are characterised by their marked endemism andspecificity of their community structure in different basins. The river systems located in the Atacama Desert are endorheicand are affected by the rainy period of January-February commonly known as the “Bolivian winter“. The present study isthe first report on the observations of arthropods in the ephemeral Atacama River during a period of the “Bolivian winter“.The Atacama River is characterised by species with poor invertebrate assemblage dominated by diapausing crustaceans(cladocera, copepod, ostracoda) and dispersing aquatic insects (ephemeroptera and diptera larvae).

Ecology and Conservation of Sea Turtles in Chile

Abstract Chilean marine habitats have supported sea turtle species since prehistorical times. Although information exists regarding their contemporary distribution and ecological role in the region, it is diffuse. This study aims to bring such data together and provide an up-to-date review of the ecology and conservation status of sea turtles in Chile. Detailed available data largely reflect interactions between Dermochelys coriacea and Caretta caretta with oceanic fisheries. Newspaper and local studies have reported the regular presence of Chelonia mydas and Lepidochelys olivacea in certain locations in northern Chile during the past decade. The latter species were particularly abundant in the area around a thermal discharge from a water-cooled power plant (Mejillones Bay, 23°S) in the Antofagasta Region, and accounts included several reports of negative interactions between these species and sea lions (Otaria flavescens). Sea turtles found in Chilean waters are probably juveniles or subadults. No estima...

Estimation of arsenic intake from drinking water and food (raw and cooked) in a rural village of northern Chile. Urine as a biomarker of recent exposure.

The aim of this study was to estimate both the contribution of drinking water and food (raw and cooked) to the total (t-As) and inorganic (i-As) arsenic intake and the exposure of inhabitants of Socaire, a rural village in Chile´s Antofagasta Region, by using urine as biomarker. The i-As intake from food and water was estimated using samples collected between November 2008 and September 2009. A 24-hour dietary recall questionnaire was given to 20 participants. Drinking water, food (raw and cooked) and urine samples were collected directly from the homes where the interviewees lived. The percentage of i-As/t-As in the drinking water that contributed to the total intake was variable (26.8–92.9). Cereals and vegetables are the food groups that contain higher concentrations of i-As. All of the participants interviewed exceeded the reference intake FAO/OMS (149.8 µg∙i-As·day−1) by approximately nine times. The concentration of t-As in urine in each individual ranged from 78 to 459 ng·mL−1. Estimated As intake from drinking water and food was not associated with total urinary As concentration. The results show that both drinking water and food substantially contribute to i-As intake and an increased exposure risk to adult residents in contaminated areas.

Elephant seal (Mirounga sp.) from the Pleistocene of the Antofagasta Region, northern Chile

ABSTRACTThe genus Mirounga is the largest living member of the Phocidae family (true seals) and includes two species: M. angustirostris and M. leonina. These species exhibit a noticeable antitropical distribution in the Northern and Southern hemispheres, respectively. The evolutionary history of elephant seals, especially in regard to establishing this antitropical pattern, is poorly known. Nearly all fossils of the genus are isolated remains from the Pleistocene of California (M. angustirostris) and South Africa (M. leonina). Here, we describe new fossil material of Mirounga sp. (incomplete maxilla, dentary, and humerus), from the middle to late Pleistocene of Antofagasta Region, northern Chile. This material constitutes the first fossil occurrence of this species in South America and suggests that during part of the Pleistocene, phocids coexisted with otariids along the eastern edge of the South Pacific Ocean, which contrasts with the current biogeographic pattern in this ocean basin, providing new information about the structure of the pinniped community during the Pleistocene of South America.