Different components of the mixed function oxidase (MFO) system and the levels of fluorescent aromatic compounds in bile (FACs) were measured in Cathorops spixii in order to assess the impact of ...polycyclic aromatic hydrocarbons (PAHs). Fish were sampled in an estuary (Santos/São Vicente) with a history of contamination by PAHs, mainly due to the presence of the industrial complex of Cubatão city and of another of low anthropogenic influence (Cananéia) on the Brazilian coast. FACs were higher in fish from the polluted site, and the PAH 5 and 6-ring metabolites were the most frequent - with 14% and 15%, respectively. Levels of the different components of the MFO system showed the same variation profile as the FACs for both estuaries. Therefore, the values found for somatic indexes and biomarkers with data of bile PAH metabolites indicate the presence of organic contaminants, especially in the area subject to the influence of the industrial complex on the Santos/São Vicente estuary.
Diferentes componentes do sistema oxidase de função mista (MFO) e os níveis de compostos aromáticos fluorescentes em bile (FACS) foram determinados em Cathorops spixii a fim de avaliar o impacto de hidrocarbonetos policíclicos aromáticos (PAHs). Os peixes foram coletados em um estuário com histórico de contaminação por PAHs (Santos/São Vicente), devido principalmente a presença do complexo industrial na cidade de Cubatão e em outro com baixa influência antropogênica (Cananéia) na costa brasileira. FACs foram maiores nos peixes oriundos da área contaminada, sendo os metabolitos de HPAs com 5 e 6 anéis, os mais representativos com 14% e 15%, respectivamente. Os níveis dos diferentes componentes do sistema MFO mostraram o mesmo perfil de variação que os FACs em ambos os estuários. Portanto, os valores encontrados para os índices somáticos e os biomarcadores considerados, em associação com os dados de metabólitos biliares de PAHs, indicam a presença de contaminantes orgânicos, principalmente na área sob influência do complexo industrial no estuário de Santos/São Vicente.
European eels (
Anguilla anguilla), crucian carps (
Carassius carassius) and catfish (
Ictalurus nebulosus) were collected in three coastal locations of the Vaccarès lagoon (French National Nature ...Reserve of Camargue). The purpose of this paper is to report results of the first biomonitoring investigation in fish living in this protected coastal wetland. Residues of organochlorine (OC) contaminants (i.e. ΣPCBs, γHCH, HCB, dieldrin,
pp′-DDE) were determined in hepatic and muscular tissues, in order to compare geographical and seasonal distribution. Total exposure levels appeared to be more important in fatty fish such as eels than in crucian carps and catfish. The highest OC concentrations in liver (ΣPCB) and in muscle (γHCH) were detected in Spring in some fish coming from a site located near the mouth of a canal draining irrigation waters of rice fields. Morphophysiological parameters (condition factor, organo-somatic indexes and lipid tissue composition) were measured concomitantly. Correlations between the hepatic and muscular burdens of OC and condition factor or organo somatic indexes were infrequent and rather negative. Localization of lipid accumulation (neutral or polar lipids) depended on metabolic rates of different species and appeared related to the fish trophic level.
Human evolutionary scholars have long supposed that the earliest stone tools were made by the genus Homo and that this technological development was directly linked to climate change and the spread ...of savannah grasslands. New fieldwork in West Turkana, Kenya, has identified evidence of much earlier hominin technological behaviour. We report the discovery of Lomekwi 3, a 3.3-million-year-old archaeological site where in situ stone artefacts occur in spatiotemporal association with Pliocene hominin fossils in a wooded palaeoenvironment. The Lomekwi 3 knappers, with a developing understanding of stone’s fracture properties, combined core reduction with battering activities. Given the implications of the Lomekwi 3 assemblage for models aiming to converge environmental change, hominin evolution and technological origins, we propose for it the name ‘Lomekwian’, which predates the Oldowan by 700,000 years and marks a new beginning to the known archaeological record.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, SBMB, SIK, UILJ, UKNU, UL, UM, UPUK
The effects of fenitrothion exposure on fourth‐instar Chironomus riparius larvae were investigated on biochemical, physiological, and population‐level parameters. Biochemical effects were ...investigated through measurements of acetylcholinesterase and cytosolic superoxide dismutase activities. Water content and dry weight of the larvae were used as physiological parameters, and the emergence rate of adults was used as a descriptor of population‐level effects. Results showed that the response of most parameters exhibited a concentration‐dependent relationship. Although biochemical parameters proved to be very sensitive, no direct relation was observed with effects at a higher level of biological organization. Perturbations of osmoregulation, as reflected by changes in water content of the larvae, were more directly related with emergence failure. This study demonstrates that the use of several biological parameters can provide complementary information about the effects of chemical exposure. Therefore, use of a multilevel approach in C. riparius seems to be a promising way to diagnose environmental quality.
Researches on the contamination by pesticides of marine organisms within coral reef trophic webs in French Polynesia.
Researches addressed in this paper have been carried out in the framework of a ...survey of the pollution levels by pesticides in French Polynesia coral reefs. A ubiquitous contamination has been shown up of critical organisms from various levels of the trophic web. Such a contamination occurs even in remote areas such as for example some atolls from the Tuamotu Archipelago where agricultural activities are very restricted. On one hand, the occurrence of organochlorine insecticides is shown widespread.
Especially worrying is our finding of chlordecone (képone®) widely present in all organisms investigated, particularly in fishes, which are commonly consumed by the local inhabitants. Some concerns arise from these data as the average residence time of chlordecone in sediment numbers in thousands of years. On the other hand, analyses have demonstrated a pervasive contamination of coral reefs trophic webs by various major families of herbicides, namely chloroacetamide and triazine derivatives, as well as diuron. These
findings are worrying with respect to the coral reefs ecosystems health, especially since their functioning is strongly dependent on the Symbiodinium zooxanthellae symbiosis with hermatypic coral, as the Symbiodinium Dinoflagellates that have proven especially sensitive to these families of herbicides. These can partially inhibit their photosynthetic activity at concentrations lower than one part per billion in seawater.
À la suite des résultats déjà publiés sur la contamination par les pesticides d’organismes de récifs coralliens de Tahiti et de Moorea en Polynésie française, l’objectif de nos investigations a été d’étendre nos connaissances sur une éventuelle contamination dans d’autres îles et sur d’autres espèces. Une contamination ubiquiste de divers organismes majeurs des réseaux trophiques récifaux a été mise en évidence même dans des biotopes reculés comme certains atolls des Tuamotu où les activités agricoles sont très réduites voire inexistantes. La présence d’insecticides organochlorés, en particulier du lindane est quasi permanente. Particulièrement préoccupante est la présence généralisée de chlordécone dans tous les types d’organismes analysés, notamment dans les poissons, qui constituent une part importante de la nourriture des populations locales. Par ailleurs, nos recherches montrent une contamination étendue des organismes des réseaux trophiques récifaux par les herbicides dérivés de l’acide trichloracétique, des dérivés des triazines et par le diuron, une urée substituée. Cette contamination est inquiétante pour la santé future des écosystèmes coralliens et leur fonctionnement, tout particulièrement pour les coraux hermatypiques fortement dépendants de leur symbiose avec les zooxanthelles, Dinoflagellés du genre Symbiodinium. Des travaux antérieurs ont, en effet, démontré que leur activité photosynthétique pouvait être partiellement inhibée par des concentrations de ces herbicides dans l’eau de mer, inférieures à la partie par milliard.
Salvat Bernard,Roche Hélène,Berny Philippe,Ramade François. Recherches sur la contamination par les pesticides d’organismes marins des réseaux trophiques récifaux de Polynésie française. In: Revue d'Écologie (La Terre et La Vie), tome 67, n°2, 2012. pp. 129-147.
In order to assess pollutant transfer in Camargue ponds from bordering agrosystems, a biomonitoring assay was conducted in irrigation and drainage channels of rice fields in the Rhone Delta (France). ...A filter-feeding bivalve, the Asian clam,
Corbicula fluminea, was used as bioindicator and caged in upstream and downstream channels of an area of conventional rice fields. After 6 weeks incubation, many lipophilic biocides were identified in
Corbicula tissues, including pesticides used in rice plantations (pretilachlor, oxadiazon), pesticides presumed in use in the Rhone basin diuron and its metabolite 3,4 dichloroaniline (3,4-DCA) and organochlorine pesticides (OCPs) banned for several decades. In addition, PCBs were highly bioaccumulated in
Corbicula. Downstream bivalves had significantly lower concentrations of OCPs, PCB and 3,4-DCA. However, the exposure biomarkers (glutathione S-transferase, catalase and propionylcholinesterase) were not correlated with the decreased concentrations. The results of this experiment raise several questions concerning the potential role of immersed plants in a retention process.
Hominin fossil evidence in the Turkana Basin in Kenya from ca . 4.1 to 1.4 Ma samples two archaic early hominin genera and records some of the early evolutionary history of Paranthropus and Homo . ...Stable carbon isotopes in fossil tooth enamel are used to estimate the fraction of diet derived from C 3 or C 4 resources in these hominin taxa. The earliest hominin species in the Turkana Basin, Australopithecus anamensis , derived nearly all of its diet from C 3 resources. Subsequently, by ca . 3.3 Ma, the later Kenyanthropus platyops had a very wide dietary range—from virtually a purely C 3 resource-based diet to one dominated by C 4 resources. By ca . 2 Ma, hominins in the Turkana Basin had split into two distinct groups: specimens attributable to the genus Homo provide evidence for a diet with a ca . 65/35 ratio of C 3 - to C 4 -based resources, whereas P. boisei had a higher fraction of C 4 -based diet ( ca . 25/75 ratio). Homo sp. increased the fraction of C 4 -based resources in the diet through ca . 1.5 Ma, whereas P. boisei maintained its high dependency on C 4 -derived resources.
Relatively few remains of Late Pliocene hominids' knapping activities have been recovered to date, and these have seldom been studied in terms of manual dexterity and technical achievements. With ...regard to early hominid technological development, the evidence provided by the data from 2.34 Myr site of Lokalalei 2C (Kenya) questions both the prior assumption of a continuous and linear evolutionary trend in lithic production and the idea that it long remained static. The level of elaboration evinced by the lithic assemblage is quite unexpected in view of its age, and seemingly more advanced that what can be surmised for other Late Pliocene East-African sites, including the nearby site of Lokalalei 1. Analysis relies mainly on the dynamic reconstruction of entire cobble reduction sequences from particularly informative refitting groups. The Lokalalei 2C knappers had already internalised the notion of planning and foresight in raw material procurement and management. Beyond simple mastery of the basic technical constraints peculiar to stone knapping, they conducted a highly controlled débitage of flakes following constant technical rules and resulting in high productivity. The data suggest that early hominids displayed distinct technical competencies and techno-economic patterns of behavior, thus pointing to an intrasite complexity and intersite diversity which are not accounted for by the existing chrono-cultural classifications.
The concentrations of organochlorine pesticides (OCPs) were determined in muscle samples of two species of fish, tilapia (Oreochromis niloticus) and the catfish (Chrysichthys nigrodigitatus) and the ...prawn (Macrobrachium vollenhovenii) found in Lake Taabo (Cote d'Ivoire). Simultaneous measurements of enzymatic biomarkers were made to evaluate the ecotoxicological risk in this hydroelectric reservoir. Lindane and endosulfan were the dominant contaminants, suggesting their current use in neighboring agricultural areas. Other organochlorine (OC) compounds were detected, including some currently banned substances. Ranked in an order of descending concentrations, we found: DDT and its metabolites (17.8-57.2 ng g super(-1) dry weight), endrin (7.17-25.0 ng g super(-1) dry weight) and heptachlor (7.36-23.6 ng g super(-1) dry weight), as well as traces of isomers of chlordane, aldrin and fipronil. The hepatic Glutathione S-Transferase (GST) activity measured in fishes was not correlated with pesticide contamination; whereas the antioxidant biomarkers demonstrated some significant associations, especially hepatic catalase with lindane (R = 0.83) and Glutathione Peroxidase (GPx) with heptachlor epoxide (R = 0.84) and with pp'DDT (R = 0.81). In the prawns, acetylcholinesterase (AChE) activity showed significant negative correlations with DDT and its metabolites (R = -0.91). The results of this study emphasize the urgent need for overall environmental risk assessment studies in the region of Taabo and other developing areas.
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