RESUMEN
Monitoring of benthic invertebrates in streams receiving acidic metal-contaminated water over an 18-yr period revealed both degraded conditions and recovery along a network of downstream locations. Compared with reference streams, and over the course of clean-up remediation efforts below an abandoned open-pit sulfur mine in the central Sierra Nevada of California, improving water quality was accompanied by recovery of benthic communities at some sites. Years of high flow resulted in degraded biological status when acid mine drainage capture was incomplete and metal loading had increased with runoff. Seasonal patterns of recovery evident in the fall after the summer treatment season reverted in the next spring after overwinter periods when sources were not captured. As the metal load has been reduced, phased recovery of community structure, function, and similarity progressed toward that of reference assemblage taxonomic composition. From impacted communities dominated by relatively tolerant midges, reassembly involved an increase in density, return of long-lived taxa, an increased ratio of sensitive-to-tolerant forms, then overall diversity and community composition, and eventually large predators and grazers reappearing along with mayfly, stonefly, and caddisfly richness. Threshold effect levels defined using several analysis methods showed that the response range of biological indicators corresponds to US Environmental Protection Agency guidelines of predicted effects utilizing cumulative criterion units (CCUs) of metal toxicity (i.e., CCU â¼ 1). All sites have shown improved function with increased density of some or all trophic groups over time. Although recovery is progressing, year-around treatment may be necessary to fully restore biological integrity in streams nearest the mine. Environ Toxicol Chem 2018;37:2575-2592. © 2018 SETAC.
Asunto(s)
Ácidos/química , Monitoreo del Ambiente , Invertebrados/efectos de los fármacos , Metales/toxicidad , Minería , Contaminantes Químicos del Agua/toxicidad , Animales , California , Chironomidae/efectos de los fármacos , Ephemeroptera/efectos de los fármacos , Geografía , Insectos/efectos de los fármacos , Invertebrados/fisiología , Nevada , Factores de TiempoRESUMEN
The biology, behaviour and venom of the ant Myrmecia nigrocincta are described. Symptoms of 15 cases of envenomation are described.
Asunto(s)
Venenos de Hormiga/toxicidad , Hormigas , Mordeduras y Picaduras de Insectos/patología , Adolescente , Adulto , Animales , Australia , Niño , Preescolar , Femenino , Humanos , Masculino , Persona de Mediana EdadRESUMEN
The biology, behaviour and venom of the ant Myrmecia nigrocincta are described. Symptoms of 15 cases of envenenomation are described. (AU)
Asunto(s)
Venenos de Hormiga/toxicidad , Mordeduras y Picaduras de Insectos , Toxicología , Patogenesia Homeopática , Materia Medica , AustraliaRESUMEN
The effects of extracts of five Australian Phyllanthus species (P. hirtellus, P. gunnii, P. gasstroemii, P. similis and P. tenellus), other plant extracts and the antiviral drug foscarnet on duck hepatitis B virus (DHBV) endogenous DNA polymerase (DNAp) activity were compared. All 5 Phyllanthus species caused 50% inhibition at concentrations of dry weight between 350-800 micrograms/ml, which is comparable with the effect described for P. amarus on the DNAp of human and woodchuck hepatitis B viruses. Incubation of P. hirtellus with 100 ID50 DHBV neutralized infection. However, neither P. gasstroemi extract, given by intraperitoneal injection (i.p.) at a dose of 20 mg/kg 3 times per week to ducklings early in the incubation period, or P. hirtellus extract, given to established DHBV carrier ducklings, prevented or eliminated infection.