An in situ assessment of mercury contamination in the Sudbury River, Massachusetts, using transplanted freshwater mussels (Elliptio complanata)

2000 ◽  
Vol 57 (5) ◽  
pp. 1103-1112 ◽  
Author(s):  
Nancy Beckvar ◽  
Sandra Salazar ◽  
Michael Salazar ◽  
Ken Finkelstein
Keyword(s):  
Freshwater Mussels ◽  
Dry Weight ◽  
Mercury Contamination ◽  
Textile Dye ◽  
Tissue Concentrations ◽  
Mussel Tissue ◽  
Elliptio Complanata ◽  
Average Temperature ◽  
Total Hg ◽  
Growth Differences

Freshwater mussels (Elliptio complanata) were transplanted into the Sudbury River, Massachusetts, to evaluate the bioavailability of total Hg and methyl mercury (MeHg) and the potential impacts to resident species. The principal Hg source is the Nyanza Superfund site, a former textile dye production facility. Mussels (initial tissue concentrations = 640 ng Hg·g dry weight-1 and 120 ng MeHg·g dry weight-1) were transplanted to eight locations in the Sudbury River watershed for 12 weeks. Tissue total Hg concentration increased significantly in mussels at the station closest to the Nyanza site (950 ng Hg·g dry weight-1). Mussel growth, which increased downstream with distance away from the site, was significantly negatively correlated with tissue concentrations of total Hg (r = -0.95) and positively correlated with average temperature (r = 0.85). Due to growth differences, uptake was best assessed by changes in content. Tissue total Hg and MeHg burdens were greatest in mussels at two stations closest to the Nyanza site, with less Hg accumulated in downstream mussels. However, the MeHg content in mussel tissue increased significantly at all Sudbury River stations, indicating that MeHg was bioavailable in all portions of the river evaluated.

Occurrence of Butyltin Compounds in Freshwater Mussels (Elliptio complanata) from Contaminated Aquatic Areas in Ontario, Canada

2001 ◽  
Vol 36 (4) ◽  
pp. 805-814 ◽  
Author(s):  
Fan Yang ◽  
R. James Maguire ◽  
Yiu K. Chau
Keyword(s):  
Freshwater Mussels ◽  
Aquatic Organisms ◽  
Aquatic Systems ◽  
Mussel Tissue ◽  
Elliptio Complanata ◽  
Antifouling Agent ◽  
Wet Weight ◽  
One Year ◽  
Butyltin Compounds

Abstract The antifouling agent tributyltin (TBT) is extremely toxic to some aquatic organisms. The accumulation of butyltin compounds in the tissues of freshwater mussels from contaminated areas in Ontario was studied in the field with caged mussels (Elliptio complanata). Mussels were placed in four sites for 11 months, and one site for 6 months, in locations of previous contamination of water and sediments. Additional cages were exposed for 5 months at two of the sites to study the effect of mussel size on accumulation. The mussels were collected at regular intervals for butyltin analysis. After almost one year of exposure at four locations, the TBT contents in tissue of mussels were 9 to 148 ng as Sn/g (wet weight). The results showed that concentrations of TBT in mussels were related to the mussel size and the concentrations of TBT in contaminated aquatic areas, and that concentrations in mussel tissue increased dramatically over winter. The results of the experiment demonstrated that caged mussels are useful for indicating the presence of TBT in aquatic systems.

Rat-dietary fructose and the intestinal distribution and growth of Moniliformis (Acanthocephala)

Parasitology ◽  
1983 ◽  
Vol 86 (1) ◽  
pp. 57-71 ◽  
Author(s):  
D. W. T. Crompton ◽  
Anne Keymer ◽  
A. Singhvi ◽  
M. C. Nesheim
Keyword(s):  
Fatty Acids ◽  
Small Intestine ◽  
Fatty Acid ◽  
Weight Gain ◽  
Sexual Development ◽  
Dry Weight ◽  
Infection Period ◽  
Dietary Fructose ◽  
Growth Differences ◽  
Maize Oil

SUMMARYThe numbers, distribution in the small intestine, sexual development and growth (dry weight) of 5-week-old Moniliformis dubius (Acanthocephala) were investigated experimentally in adult, female CFHB rats fed on theoretically isoenergetic diets containing known amounts of fructose in combination with either maize-oil fatty acids or maize oil and two concentrations of casein. There was no obvious development of M. dubius when there was no fructose in the host's diet. In contrast, estimated consumption by the host of as little as about 2 g of fructose during the 5-week infection period was accompanied by marked sexual dimorphism and weight gain in most of the M. dubius present. The dry weights of M. dubius of both sexes were positively correlated with fructose concentrations ranging from 0 to 2·5 % (w/w) in the diets containing fatty acids. Significant, but not substantial, increases in M. dubius dry weight were observed as the dietary fructose concentration was raised to 12 % (w/w). Similar trends were observed when the fructose was offered to the infected rats with maize oil, but in general, fructose added to the fatty-acid based diets supported most M. dubius growth. Differences in the distribution pattern of the worms in rats fed on the fatty-acid or maize-oil based diets were observed and their possible significance is discussed.

scholarly journals Assessment of mercury contamination of the Svitava and Svratka rivers and muscle of chub (Leuciscus cephalus L.) in the urban agglomeration of Brno in the Czech Republic

2011 ◽  
Vol 80 (2) ◽  
pp. 227-233 ◽  
Author(s):  
Kamila Kružíková ◽  
Renáta Kenšová ◽  
Jana Blahová ◽  
Zdeňka Svobodová
Keyword(s):  
Health Risk ◽  
Total Mercury ◽  
River Sediments ◽  
Hazard Index ◽  
Dry Weight ◽  
Atomic Absorption Spectrophotometry ◽  
Mercury Contamination ◽  
Acid Digestion ◽  
The Czech Republic ◽  
Leuciscus Cephalus

This study focused on the total mercury and methylmercury content in the muscle of chub (Leuciscus cephalusL.), the total mercury in the river sediments and the evaluation of health risks associated with fish contamination. Chub were caught at seven localities on the Svratka and Svitava rivers in the agglomeration of Brno in 2008. The results were compared to those obtained from the same sites in 2007. Total mercury was determined by atomic absorption spectrophotometry using an AMA 245 analyzer, and methylmercury was determined by gas chromatography (using an electron-capture detector) after acid digestion and toluene extraction in chub muscle. The highest concentrations of total mercury and methylmercury (0.12 ± 0.14 and 0.07 ± 0.02 mg·kg-1fresh weight, respectively) were found in Svratka before junction (south of Brno), whereas the lowest concentration of mercury and methylmercury in chub (0.06 ± 0.01 and 0.04 ± 0.01 mg·kg-1) was detected in Svitava before junction with the Svratka River. Total mercury in sediments ranged from 0.01 to 1.05 mg·kg-1dry weight, the highest value was detected in the sediment from Rajhradice. The lowest content (0.01 mg·kg-1) was at Kníničky. Hazard indices calculated for the selected localities showed no health risk for either a standard consumer or a fishing family. Fish from the Svitava and Svratka rivers show very low mercury concentration and hazard index and their consumption poses no health risk from total mercury and methylmercury contamination.

scholarly journals 170 The Effect of Ca: NH4 Ratio on the Growth of Sour Orange Seedlings

HortScience ◽  
2000 ◽  
Vol 35 (3) ◽  
pp. 419D-419
Author(s):  
Dariusz Swietlik
Keyword(s):  
N Uptake ◽  
Dry Weight ◽  
Sole Source ◽  
Additional Treatment ◽  
Molar Ratio ◽  
Sour Orange ◽  
Molar Ratios ◽  
Tap Root ◽  
Growth Differences ◽  
Hydroponically Grown

The purpose of this study was to determine the effect of Ca: NH4 ratio in the rhizosphere of hydroponically grown sour orange seedlings (SO) (Citrus aurantium L.) on the plants' vegetative growth and N uptake. The experiment was prompted by our observation that application of N in the form of NH4 in conjunction with CaCl2 was more efficient in eliminating N deficiency in field-grown grapefruit trees than the same rates of N applied in the form of NH4NO3 without CaCl2. About 40-cm-tall SO were pruned back to the 4th leaf and grown for 6 weeks in nutrient solutions containing 5 mm NH4+ at CaCl2: NH4+ molar ratios of 1.0, 1.3, 1.6, 1.9, 2.2, or 2.5. In an additional treatment, NO3– was used as the sole source of N at CaCl2: NO3– ratio of 1:1. The level of Ca:NH4 ratio had no effect on new leaves number, shoot growth, total and average leaf area, specific leaf weight, as well as leaf, stem, and tap root dry weight. However, lateral root dry weigh decreased at Ca: NH4 ratio of 2.5. No growth differences were found when the plants were supplied with NH4+ vs. NO3– at Ca:N molar ratio of 1:1.

scholarly journals Coir as an Alternative to Peat in Media for Tomato Transplant Production

HortScience ◽  
2002 ◽  
Vol 37 (2) ◽  
pp. 309-312 ◽  
Author(s):  
M. Arenas ◽  
C.S. Vavrina ◽  
J.A. Cornell ◽  
E.A. Hanlon ◽  
G.J. Hochmuth
Keyword(s):  
Leaf Area ◽  
Seedling Emergence ◽  
C:N Ratio ◽  
Dry Weight ◽  
Medium Composition ◽  
Stem Diameter ◽  
Tomato Seed ◽  
Root Dry Weight ◽  
Growth Differences ◽  
Summer Fruit

Sixteen media prepared from peat, coir, vermiculite, or perlite were used to determine the optimum growing media for tomato (Lycopersicum esculentum Mill.) transplants. Medium composition did not affect tomato seed emergence, although seedling emergence was higher in winter (90%) than summer (85%). Greatest transplant root dry weight, stem diameter, and leaf area were achieved in 50% to 75% peat + 25% to 50% vermiculite in summer. In winter, greatest transplant root dry weight, stem diameter, and leaf area were achieved in eight media: 100% peat, 75% peat + 25% vermiculite, 75% peat + 25% perlite, 50% peat + 50% vermiculite, 50% peat + 50% perlite, 25% peat + 50% coir + 25% vermiculite, 50% peat + 25%coir + 25% vermiculite, and 25% peat +25% coir +25% vermiculite +25% perlite. Transplants grown with >50% coir exhibited reduced plant growth compared to peat-grown transplants, a response that may be associated with high N immobilization by microorganisms and high C:N ratio. Despite transplant growth differences during the summer, fruit yields generally were unaffected by transplant media.

scholarly journals A bioassay screening Trichoderma isolates for enhancement of root development in Impatiens walleriana cuttings

2010 ◽  
Vol 63 ◽  
pp. 33-38
Author(s):  
A.M. Clouston ◽  
R.A. Hill ◽  
R. Minchin ◽  
M. Braithwaite ◽  
A. Stewart
Keyword(s):  
Root Growth ◽  
Root Development ◽  
Dry Weight ◽  
Positive Control ◽  
Trichoderma Spp ◽  
Screening Experiments ◽  
Commercial Mixture ◽  
Ideal System ◽  
Impatiens Walleriana ◽  
Growth Differences

The potential of 62 Trichoderma spp isolates to enhance root development on cuttings was evaluated in a screening bioassay using the ornamental plant impatiens (Impatiens walleriana) Increased root development and consequent growth of cuttings induced by Trichoderma treatments were compared to that of a commercial rooting hormone (indole3 butryic acid) and untreated cuttings Results recorded after 3 weeks growth indicated sufficient resolution in the bioassay to detect statistical growth differences between treatments As expected treatment with IBA (positive control) enhanced root growth in root score root dry weight and root to shoot ratio parameters assessed across all three screening experiments Six individual Trichoderma isolates and a commercial mixture of isolates were also identified as significantly improving root growth with 2065 increases in the measured growth variables relative to untreated cuttings The bioassay provided an ideal system for measuring rooting response and allowed accelerated screening of Trichoderma candidates useful for enhancing root development of cuttings

scholarly journals Comparison of Plant Establishment Method, Transplant, or Direct Seeding on Growth and Yield of Bell Pepper

1993 ◽  
Vol 118 (1) ◽  
pp. 17-22 ◽  
Author(s):  
Daniel I. Leskovar ◽  
Daniel J. Cantliffe
Keyword(s):  
Root Growth ◽  
Dry Weight ◽  
Direct Seeding ◽  
Bell Pepper ◽  
Growth And Yield ◽  
Dry Matter Partitioning ◽  
Establishment Method ◽  
Direct Seeded ◽  
Growth Differences ◽  
Stem Leaf

Transplants produced with overhead or subirrigation and plants from direct seeding using primed or nontreated `Jupiter' bell pepper (Capsicum annuum L.) seeds were evaluated for growth and yield in the field for 3 years. Early in development, overhead-irrigated (01) transplants had more basal root elongation than subirrigated (SI) transplants; however, root growth differences caused by irrigation systems in the greenhouse were minimized during late ontogeny in the field. Basal, lateral, and taproot dry weights accounted for 81%, 15%, and 4% of the total for transplants and 25%, 57%, and 18% of the total for direct-seeded plants. Direct-seeded plants maintained a more-balanced root, stem, leaf, and fruit dry matter partitioning than transplants, which allocated more dry weight (per unit of root growth) to stems, leaves, and fruits. Over all seasons, transplants exhibited significantly higher and earlier yields than direct-seeded pepper plants, and total yields were similar between SI and OI transplants and between primed and nontreated seeds.

The Fate of Hg Contaminated Sediments of the Ravenna Lagoon (Italy): Final Burial or Potential Remobilization

1993 ◽  
Vol 28 (8-9) ◽  
pp. 349-358 ◽  
Author(s):  
S. Miserocchi ◽  
L. Langone ◽  
S. Guerzoni
Keyword(s):  
Surface Sediments ◽  
Adriatic Sea ◽  
Accumulation Rate ◽  
Mercury Contamination ◽  
Northern Adriatic Sea ◽  
Northern Adriatic ◽  
Input Point ◽  
Subsurface Layers ◽  
Total Hg ◽  
Contaminated Area

In the period 1957-77 a part of 100-200 tons of mercury as industrial waste was discharged into a 10 km2 lagoon (“Pialassa Baiona”) connected to the Ravenna harbor and the Northern Adriatic Sea (Italy). Extremely high levels of Hg (up to 160 µg/g) were found in surface sediments, but the maximum values (up to 1114 µg/g) were detected in subsurface layers, down to 80 cm, close to the industrial source, and values of 1-2 µg/g were recorded in the fore-harbor, outside the lagoon. The calculation of total Hg budget in sediments gave 38 tons of Hg being stored within a contaminated area of 15 km2. The redistribution of polluted sediments would seem to be due mainly to the tidal action; more than 80% of the total Hg discharged is confined in 10% of the area, i.e. in the southern ponds close to the input point. The time necessary for a restoration of the area was estimated by using different approaches of accumulation rate calculations (210Pb, Hg peak). It appears that 40-50 years would be needed to clean the surface sediments of the Ravenna lagoon from the mercury contamination. We suggest that remedial plans should be focused on the southern ponds.

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