The Effects of Isolation and Acid Mine Drainage on Fish and Macroinvertebrate Communities of Monday Creek, Ohio, USA

Isolated headwater streams in mined watersheds may have good water quality and fish habitat, yet be disconnected from immigration sources by stream segments impaired by acid mine drainage (AMD). Studies of fish and macroinvertebrate communities, habitat, and a number of hydrochemical parameters in Monday Creek, Ohio, show that AMD eliminates fish communities and severely limits macroinvertebrate communities in directly affected tributaries. Isolated headwaters in the heavily mined Monday Creek watershed have relatively good water quality and habitat, but poor fish communities. Comparison of isolated Monday Creek headwaters with non-isolated reaches in unmined watersheds indicates that differences in fish communities are attributable to isolation. Fish communities in isolated headwaters have lower Indices of Biotic Integrity (IBI) than comparable non-isolated communities, reduced species numbers, and lower numbers of individuals, despite suitable habitat as measured by the Qualitative Habitat Evaluation Index (QHEI). Comparison of macroinvertebrate communities shows higher Invertebrate Community Indices (ICI), and no apparent species loss, which can be attributed to the obligate flight stage in the life cycle of many macroinvertebrates, which enables them to overcome aquatic barriers. The implication of this research is that there is an opportunity for recovery of depleted fish communities in large AMD-isolated areas with good water quality, suitable habitat, and intact macroinvertebrate communities, by downstream treatment or source control of AMD to create aquatic corridors for fish immigration.     

'EUROPART'. Airborne particles in the indoor environment. A European interdisciplinary review of scientific evidence on associations between exposure to particles in buildings and health effects

The relevance of particle mass, surface area or number concentration as risk indicators for health effects in non-industrial buildings has been assessed by a European interdisciplinary group of researchers (called EUROPART) by reviewing papers identified in Medline, Toxline, and OSH. Studies dealing with dermal effects or cancer or specifically addressing environmental tobacco smoke, house dust-mite, cockroach or animal allergens, microorganisms and pesticides were excluded. A total of 70 papers were reviewed, and eight were identified for the final review: Five experimental studies involving mainly healthy subjects, two cross-sectional office studies and one longitudinal study among elderly on cardiovascular effects. From most studies, no definite conclusions could be drawn. Overall, the group concluded that there is inadequate scientific evidence that airborne, indoor particulate mass or number concentrations can be used as generally applicable risk indicators of health effects in non-industrial buildings and consequently that there is inadequate scientific evidence for establishing limit values or guidelines for particulate mass or number concentrations.     

The performance of activated sludge plants compared with the results of various bacterial toxicity tests—A study with 3,5-dichlorphenol

It was investigated whether and to what extent the results obtained by various methods of determining bacterial toxicity in waste water could be applied to conditions prevailing in activated sludge plants or in receiving water.3.5-Dichlorphenol (DCP) was studied as an example of a persistent chemical which constitutes a pollution risk to water. The bacterial toxicity limits determined by five different methods—respiration after a 20-h consumption period, consumption rate after 2-h incubation, dehydrogenase activity determined with TTC. gas formation in a fermentation tube and inhibition of the cell division of Pseudomonas—all agreed with the toxicity limit of 5 mg DCP I⁻¹ found in degradation tests in laboratory activated sludge equipment. No safety margin need be taken into account when the test results are applied to biological purification plants.In the activated sludge plants the degradation of the industrial waste water was markedly impaired only when the DCP concentration was increased to 25 mg I⁻¹. This varied in degree according to the sludge load at the beginning of the trial.Shock loads of DCP did not cause the expected fall-off in degradation but only a moderate fluctuation in its rate. The decline in degradation following continuous and also discontinuous addition of DCP was largely or completely overcome within a few weeks by the bacteria becoming adapted to DCP.In samples of river water the toxicity limit as determined by the tests was in the region of 2 mg I⁻¹.     

Characterization of particulate emissions from occupant activities in offices

This paper characterizes the relationship between occupant activities and indoor air particulate levels in a non-smoking office building. Occupant activities were recorded on video. Particulate concentrations were monitored by three optical particle counters (OPCs) in five size ranges at three heights. Particulate mass concentrations were measured gravimetrically and bioaerosol concentrations were determined by impaction methods. Occupant activities and number concentrations were determined with 1-min resolution over a 1-week period. Occupant activities such as walking past or visiting the monitoring site explained 24-55% of the variation of 1- to 25-micron diameter particle number concentrations. Statistical models associating particulate concentrations with occupant activities depended on the size fraction and included an autocorrelative term. Occupant activities are estimated to contribute up to 10 micrograms m-3 in particulate concentrations per person. Number concentrations of particles smaller than 1 micron had little correlation with indoor activities other than cigarette smoking and were highly correlated with outdoor levels. The method can be used to characterize emissions from activities if rapid measurements can be made and if activities can be coded from the video record.     

Uptake of cadmium, zinc, copper, lead and chromium in the pacific oyster. Crassostrea gigas. Grown in the tamar river. Tasmania

Hundreds of oysters and mud samples from 15 sites along the Tamar River were analysed for cadmium, copper, zinc, lead and chromium. The widely accepted concept of enrichment factors of up to several hundred thousand, describing accumulation by oysters of cadmium, zinc and copper from seawater has been found to be grossly misleading. Concentrations found for these three metals in oysters were only 10–40 times the concentrations in inhabited muds. Concentrations of metals in muds may be used to indicate whether a potential oyster bed would produce oysters that were grossly contaminated. Approximately 1 ppm cadmium in mud could result in oysters containing at least 25 ppm, i.e. 4–5 ppm wet wt. Similarly. 100 ppm zinc in mud could produce oysters containing at least 4000 ppm. i.e. 800–1000 ppm wet wt. Three heavy metal accumulation processes were discernible. Copper and chromium appeared to be absorbed up to a maximum weight that was limited by the size of the oyster and was independent of the amount of metal in the mud. Lead was not absorbed through any physiological demand, but was randomly incorporated at sites containing high concentrations in the mud. Zinc and cadmium were accumulated by a process that depended primarily on the concentrations of these metals in the mud at each site. Mean dry wt concentrations of metals in oysters and mud samples ranged from: 4.2–134 ppm and 0·4 to 5·7 ppm cadmium; 200–1700 ppm and 3–224 ppm copper: 0 135 ppm and 4–1500 ppm lead: 1–37 ppm and 2–88 ppm chromium; 1700 14.000 ppm and 20–500 ppm zinc. respectively.     

Contact flocculation-filtration of humic substances

Contact flocculation-filtration of humic dispersions with alum in medium grain (0.62 mm) sand gave short runs to breakthrough, while in coarse (1.2 mm) media clarification was inefficient. Alum with cationic polymer gave in coarse media acceptable runs, but shorter then for mineral dispersions. Analysis of results by parameters of existing filtration models showed that using the Ives-Iwasaki model and plotting filtration coefficient λ vs specific deposit σ gave different λ_max for different polymer dose, plot of λ_max vs dose goes through maximum at optimum dose.Plotting the cube root of headloss vs square root of specific deposit gave a straight line corresponding to Shektman formula.Analysis by Adin-Rebhun model showed that for contact flocculation-filtration humic dispersions attachment coefficient k₁ was similar to, detachment k₂ was many fold higher then and theoretical maximum mass capacity much lower then in case of mineral dispersions.Calculations showed that the solid content and the density of alumo-organic deposits in bed are much lower than of alumo-mineral deposits. Polymers and minerals increase the solid content, the density of deposits and the mass capacity of filter beds.