Triazine herbicide contamination of Tasmanian streams: Sources, concentrations and effects on biota

1994 ◽  
Vol 45 (2) ◽  
pp. 209 ◽  
Author(s):  
PE Davies ◽  
LSJ Cook ◽  
JL Barton
Keyword(s):  
Surface Waters ◽  
Biological Effects ◽  
Invertebrate Drift ◽  
Triazine Herbicide ◽  
Short Term ◽  
Rainfall Events ◽  
Agricultural Catchments ◽  
Stream Communities ◽  
Forestry Industry ◽  
Forestry Plantations

Concentrations of the triazine herbicides atrazine, simazine, cyanazine, metribuzin and propazine were determined in streams draining forestry and agricultural catchments in Tasmania, Australia, between 1989 and 1992. Atrazine and simazine were used extensively by the forestry industry in a winter spraying programme, and applications of the other herbicides occurred in cropped agricultural catchments during spring and summer. Of 29 streams sampled intensively for triazines, 20 contained detectable residues. Median contaminations over all samples were 2.85, 1.05, <0.05, <0.05 and <0.05 �g L-1 for atrazine, simazine, cyanazine, metribuzin and propazine, respectively. All herbicide concentrations ranged over several orders of magnitude up to 53 mg L-1, with atrazine and simazine having significantly higher concentrations than the others. Atrazine concentrations were examined in streams draining forestry plantations for periods of up to two years. A decline in concentration was observed with time, but this was strongly influenced by rainfall events. Atrazine contamination from single spraying events persisted at a low level for up to 16 months. Contamination of Big Creek with atrazine to 22�g L-1 after aerial spraying led to an increase in stream invertebrate drift only on the day of spraying and to a short-term increase in movement of brown trout. On examination of biological effects of triazines in surface waters reported in the literature, it was concluded that the observed frequent contamination of Tasmanian streams with triazines may cause occasional minor short-term disturbance to stream communities.

scholarly journals Leaching Rate of Polychlorinated Biphenyls (PCBs) from Marine Paint Chips

2021 ◽  
Author(s):  
Allen D. Uhler ◽  
Jeffery H. Hardenstine ◽  
Deborah A. Edwards ◽  
Guilherme R. Lotufo
Keyword(s):  
Polychlorinated Biphenyls ◽  
Surface Waters ◽  
Leaching Rate ◽  
Short Term ◽  
Aroclor 1254 ◽  
Maintenance And Repair ◽  
Potential Source ◽  
Vessel Bottom ◽  
Dissolved Phase ◽  
Over Time

AbstractPolychlorinated biphenyls (PCBs) were added to certain marine vessel bottom paints as a plasticizer to improve the adhesion and durability of the paint. The most common PCB formulation used to amend such paints was Aroclor 1254. Fugitive Aroclor-containing paint chips generated from vessel maintenance and repair operations represent a potential source of PCB contamination to sediments. Limited published studies indicate that Aroclor-containing paint is largely inert and exhibits low PCB leaching into water; however, the rate and degree of leaching of PCBs from paint chips have not been directly studied. This laboratory-based study evaluated the rate and extent of leaching of PCBs from paint chips into freshwater. The results of this investigation demonstrate that the rate of PCB dissolution from paint chips decreased rapidly and exponentially over time. Based on this study, it is estimated that the rate of leaching of PCBs from paint chips would cease after approximately 3 years of exposure to water. When all leachable PCBs were exhausted, it is estimated that less than 1% of the mass of PCBs in the paint chips was amenable to dissolution. The results of this experiment suggest that Aroclor-containing paint chips found in sediments are likely short-term sources of dissolved-phase PCB to pore or surface waters and that the majority of the PCBs in paint chips remain in the paint matrix and unavailable for partitioning into water. Graphic Abstract

scholarly journals Virus isolation studies suggest short-term variations in abundance in natural cyanophage populations of the Indian Ocean

2006 ◽  
Vol 86 (3) ◽  
pp. 499-505 ◽  
Author(s):  
Martha R.J. Clokie ◽  
Andrew D. Millard ◽  
Jaytry Y. Mehta ◽  
Nicholas H. Mann
Keyword(s):  
Indian Ocean ◽  
Surface Waters ◽  
Molecular Diversity ◽  
Virus Isolation ◽  
Short Term ◽  
Distinct Subgroup ◽  
Time Points ◽  
The Indian Ocean ◽  
Long Timescales ◽  
Time Point

Cyanophage abundance has been shown to fluctuate over long timescales and with depth, but little is known about how it varies over short timescales. Previous short-term studies have relied on counting total virus numbers and therefore the phages which infect cyanobacteria cannot be distinguished from the total count.In this study, an isolation-based approach was used to determine cyanophage abundance from water samples collected over a depth profile for a 24 h period from the Indian Ocean. Samples were used to infect Synechococcus sp. WH7803 and the number of plaque forming units (pfu) at each time point and depth were counted. At 10 m phage numbers were similar for most time-points, but there was a distinct peak in abundance at 0100 hours. Phage numbers were lower at 25 m and 50 m and did not show such strong temporal variation. No phages were found below this depth. Therefore, we conclude that only the abundance of phages in surface waters showed a clear temporal pattern over a short timescale. Fifty phages from a range of depths and time points were isolated and purified. The molecular diversity of these phages was estimated using a section of the phage-encoded psbD gene and the results from a phylogenetic analysis do not suggest that phages from the deeper waters form a distinct subgroup.

Patch history, invertebrate patch dynamics and heterogeneous community composition: perspectives from a manipulative stream experiment

2007 ◽  
Vol 58 (4) ◽  
pp. 307 ◽  
Author(s):  
D. A. Olsen ◽  
C. D. Matthaei ◽  
C. R. Townsend
Keyword(s):  
Community Composition ◽  
Patch Dynamics ◽  
Invertebrate Drift ◽  
Macroinvertebrate Communities ◽  
Disturbance History ◽  
Patch Type ◽  
Entire Study ◽  
Stream Communities ◽  
Different Types ◽  
Stable Control

Recent research after bed-moving flow events has shown that local disturbance history can contribute to patchiness in stream communities. Patterns of recolonisation were studied following experimental disturbances in which patches of sediment were manipulated by removing 10 cm of surface sediment (scour) or by depositing 10 cm of clean sediment (fill) on top of existing sediments. Six invertebrate samples were collected from each patch type (including stable control patches) on five occasions up to six weeks after the manipulation. Immediately after the disturbance, distinctive macroinvertebrate communities occurred in scour, fill and stable patches. Community composition in scour patches remained distinct from fill and stable patches for the entire study period. Immediately after the manipulation, scour patches contained higher densities of hypogean taxa than did fill patches, but this difference did not persist for long, indicating that the relict community had little influence on the subsequent pattern of recovery. In contrast, fill patch communities were indistinguishable from stable patches by Day 14, most likely owing to recolonisation by buried invertebrates and invertebrate drift. Differences in patterns of recolonisation following different types of disturbance can result in patchy invertebrate communities that persist for several weeks after the disturbance.

scholarly journals Biological CO2 Uptake and Upwelling Regulate the Air-Sea CO2 Flux in the Changjiang Plume Under South Winds in Summer

2021 ◽  
Vol 8 ◽  
Author(s):  
Dewang Li ◽  
Xiaobo Ni ◽  
Kui Wang ◽  
Dingyong Zeng ◽  
Bin Wang ◽  
...  
Keyword(s):  
Surface Waters ◽  
Carbon Sink ◽  
Co2 Flux ◽  
Co2 Uptake ◽  
Short Term ◽  
Biological Production ◽  
Initial Stage ◽  
Wind Event ◽  
Wind Events ◽  
Biogeochemical Parameters

The partial pressure of CO2 (pCO2) in the sea and the air-sea CO2 flux in plume waters are subject to interactions among biological production, horizontal advection, and upwelling under wind events. In this study, time series of pCO2 and other biogeochemical parameters in the dynamic Changjiang plume were presented to illuminate the controlling factors of pCO2 and the air-sea CO2 flux after a strong south wind event (July 23–24, maximum of 11.2 ms–1). The surface pCO2 decreased by 310 μatm (to 184 μatm) from July 24 to 26. Low-pCO2 waters (&lt;200 μatm) were observed in the following 2 days. Corresponding chlorophyll a and dissolved oxygen (DO) increase, and a significant relationship between DO and npCO2 indicated that biological uptake drove the pCO2 decrease. The salinity of undersaturated-CO2 waters decreased by 3.57 (from 25.03 to 21.46) within 2 days (July 27–28), suggesting the offshore advection of plume waters in which CO2 had been biologically reduced. Four days after the wind event, the upwelling of high-CO2 waters was observed, which increased the pCO2 by 428 μatm (up to 584 μatm) within 6 days. Eight days after the onset of upwelling, the surface pCO2 started to decrease (from 661 to 346 μatm within 3 days), which was probably associated with biological production. Regarding the air-sea CO2 flux, the carbon sink of the plume was enhanced as the low-pCO2 plume waters were pushed offshore under the south winds. In its initial stage, the subsequent upwelling made the surface waters act as a carbon source to the atmosphere. However, the surface waters became a carbon sink again after a week of upwelling. Such short-term air-sea carbon fluxes driven by wind have likely occurred in other dynamic coastal waters and have probably induced significant uncertainties in flux estimations.

scholarly journals Edge-of-Field Technologies for Phosphorus Retention from Agricultural Drainage Discharge

2020 ◽  
Vol 10 (2) ◽  
pp. 634 ◽  
Author(s):  
Lipe Renato Dantas Mendes
Keyword(s):  
Surface Waters ◽  
Organic Phosphorus ◽  
Freshwater Ecosystems ◽  
Phosphorus Retention ◽  
Buffer Strips ◽  
Large Variability ◽  
Agricultural Catchments ◽  
Limiting Nutrient ◽  
Phosphorus Form ◽  
Subsurface Drains

Agriculture is often responsible for the eutrophication of surface waters due to the loss of phosphorus—a normally limiting nutrient in freshwater ecosystems. Tile-drained agricultural catchments tend to increase this problem by accelerating the transport of phosphorus through subsurface drains both in dissolved (reactive and organic phosphorus) and particulate (particle-bound phosphorus) forms. The reduction of excess phosphorus loads from agricultural catchments prior to reaching downstream surface waters is therefore necessary. Edge-of-field technologies have been investigated, developed and implemented in areas with excess phosphorus losses to receive and treat the drainage discharge, when measures at the farm-scale are not able to sufficiently reduce the loads. The implementation of these technologies shall base on the phosphorus dynamics of specific catchments (e.g., phosphorus load and dominant phosphorus form) in order to ensure that local retention goals are met. Widely accepted technologies include constructed wetlands, restored wetlands, vegetated buffer strips and filter materials. These have demonstrated a large variability in the retention of phosphorus, and results from the literature can help targeting specific catchment conditions with suitable technologies. This review provides a comprehensive analysis of the currently used edge-of-field technologies for phosphorus retention in tile-drained catchments, with great focus on performance, application and limitations.

scholarly journals Effect of polyphenols on the intestinal and placental transport of some bioactive compounds

2010 ◽  
Vol 23 (1) ◽  
pp. 47-64 ◽  
Author(s):  
Fátima Martel ◽  
Rosário Monteiro ◽  
Conceição Calhau
Keyword(s):  
Bioactive Compounds ◽  
Biological Effects ◽  
Alcoholic Beverages ◽  
Short Term ◽  
Intestinal Epithelia ◽  
The Past ◽  
Cell Culture Systems ◽  
Epithelial Barriers

Polyphenols are a group of widely distributed phytochemicals present in most foods of vegetable origin. A growing number of biological effects have been attributed to these molecules in the past few years and only recently has their interference with the transport capacity of epithelial barriers received attention. This review will present data obtained concerning the effect of polyphenols upon the transport of some compounds (organic cations, glucose and the vitamins thiamin and folic acid) at the intestinal and placental barriers. Important conclusions can be drawn: (i) different classes of polyphenols affect transport of these bioactive compounds at the intestinal epithelia and the placenta; (ii) different compounds belonging to the same phenolic family often possess opposite effects upon transport of a given molecule; (iii) the acute and chronic/short-term and long-term exposures to polyphenols do not produce parallel results and, therefore, care should be taken when extrapolating results; (iv) the effect of polyphenolics in combination may be very different from the expected ones taking into account the effect of each of these compounds alone, and so care should be taken when speculating on the effect of a drink based on the effect of one component only; (v) care should be taken in drawing conclusions for alcoholic beverages from results obtained with ethanol alone. Although most of the data reviewed in the present paper refer to in vitro experiments with cell-culture systems, these studies raise a concern about possible changes in the bioavailability of substrates upon concomitant ingestion of polyphenols.

Influence of Upwellings, Storms, and Generating Station Operation on Water Chemistry and Plankton in the Nanticoke Region of Long Point Bay, Lake Erie

1990 ◽  
Vol 47 (7) ◽  
pp. 1434-1445 ◽  
Author(s):  
T. G. Dunstall ◽  
J. C. H. Carter ◽  
B. P. Monroe ◽  
G. T. Haymes ◽  
R. R. Weiler ◽  
...  
Keyword(s):  
Water Chemistry ◽  
Surface Waters ◽  
Lake Erie ◽  
Organic Nitrogen ◽  
Inorganic Nitrogen ◽  
Lake Surface ◽  
Cooling Process ◽  
Short Term ◽  
Total Inorganic Nitrogen ◽  
Reactive Phosphorus

Storms and upwellings resulted in significant alterations to the aquatic environment in the Long Point Bay region of Lake Erie, contributing to short-term variability in water chemistry and plankton. Both storms and upwellings resulted in nutrient enrichment (filtered reactive phosphorus, total inorganic nitrogen, reactive silicates and organic nitrogen) in lake surface waters during the period of lake warming, prior to mid-August. Storms and upwellings also differentially affected the distributions of specific zooplankton taxa in the lake surface stratum. The most prominent effect was the increased abundance of Diacyclops bicuspidatus thomasi during upwellings, particularly towards shore. The once-through cooling process of the generating station also affected zooplankton distributions, most notably that of D. bicuspidatus thomasi, with a nearshore increase in abundance that was similar to the influence exerted by upwelling.

Short-term experimental acidification of a Welsh stream: comparing the biological effects of hydrogen ions and aluminium

1987 ◽  
Vol 17 (2) ◽  
pp. 341-356 ◽  
Author(s):  
S. J. ORMEROD ◽  
P. BOOLE ◽  
C. P. McCAHON ◽  
N. S. WEATHERLEY ◽  
D. PASCOE ◽  
...  
Keyword(s):  
Biological Effects ◽  
Hydrogen Ions ◽  
Short Term ◽  
Experimental Acidification

scholarly journals Expression and homologous regulation of GH secretagogue receptor mRNA in rat adrenal gland

2002 ◽  
pp. 677-688 ◽  
Author(s):  
ML Barreiro ◽  
L Pinilla ◽  
E Aguilar ◽  
M Tena-Sempere
Keyword(s):  
Biological Effects ◽  
Biologically Active ◽  
Pcr Analysis ◽  
Mrna Levels ◽  
R Gene ◽  
Rt Pcr ◽  
Short Term ◽  
Opposite Pattern ◽  
Corticosterone Secretion

OBJECTIVE: GH secretagogues (GHSs) elicit a variety of biological effects in several endocrine and non-endocrine target tIssues, including activation of the hypothalamic-pituitary-adrenal axis. The latter is mainly carried out through a central hypothalamic action; yet the possibility of additional effects directly at the adrenal level cannot be ruled out. The aims of this study were to evaluate the expression and homologous regulation of the GHS-receptor (GHS-R) gene in rat adrenal and to assess the effects of synthetic (GH releasing peptide-6 - GHRP-6) and natural (ghrelin) ligands of GHS-R upon basal and ACTH-stimulated corticosterone secretion in vitro. DESIGN AND METHODS: Analysis of adrenal expression of target mRNAs (GHS-R, GHS-R1a, ghrelin, and several steroidogenic factors) was conducted by means of primer-specific, semi-quantitative RT-PCR. Evaluation of corticosterone secretion by incubated adrenal tIssue was carried out by specific RIA. RESULTS: RT-PCR analysis demonstrated expression of the GHS-R gene, but not of the gene encoding the cognate ligand ghrelin, in rat adrenal. Moreover, expression of the mRNA coding for the type 1a GHS-R (GHS-R1a), i.e. the biologically active receptor form, was demonstrated. The adrenal expression of the GHS-R message appeared under the regulation of homologous signals in vitro, as short-term incubation of adrenal samples in serum-free medium induced a significant increase in GHS-R mRNA levels that was inhibited by exposure to different doses of GHRP-6 (10(-9)-10(-5) mol/l) or ghrelin (10(-7) mol/l). Notably, an opposite pattern of homologous regulation of GHS-R gene expression was observed at the pituitary. Finally, short-term stimulation with increasing concentrations of GHRP-6 (10(-9)-10(-5) mol/l) or ghrelin (10(-7) mol/l) failed to alter basal and ACTH-stimulated corticosterone secretion in vitro, neither did it modify ACTH-stimulated mRNA expression levels of several upstream elements in the steroidogenic route: the steroidogenic acute regulatory (StAR) protein, and the enzymes P450 cholesterol side-chain cleavage (P450scc) and 3beta-hydroxysteroid dehydrogenase (3beta-HSD). CONCLUSIONS: Our study provides novel evidence for the expression and homologous regulation of the GHS-R gene in rat adrenal. However, our results cast doubts on the possibility of direct adrenal actions of ligands of the GHS-R in the regulation of corticosterone secretion in the rat.

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