TOXICITY OF SIXTY-THREE METALS AND METALLOIDS TO HYALELLA AZTECA AT TWO LEVELS OF WATER HARDNESS

2005 ◽  
Vol 24 (3) ◽  
pp. 641 ◽  
Author(s):  
Uwe Borgmann ◽  
Yves Couillard ◽  
Patrick Doyle ◽  
D. George Dixon
Keyword(s):  
Water Hardness ◽  
Hyalella Azteca ◽  
Metals And Metalloids

Influence of pH and hardness on toxicity of ammonia to the amphipod Hyalella azteca

1995 ◽  
Vol 52 (10) ◽  
pp. 2078-2083 ◽  
Author(s):  
G. T. Ankley ◽  
M. K. Schubauer-Berigan ◽  
P. D. Monson
Keyword(s):  
Water Quality ◽  
North America ◽  
Sediment Toxicity ◽  
Water Hardness ◽  
Hyalella Azteca ◽  
Ammonia Toxicity ◽  
Total Ammonia ◽  
Baseline Values ◽  
Ph Dependent ◽  
Influence Of Ph

The amphipod Hyalella azteca is frequently used for freshwater sediment tests throughout North America. A common potential toxicant in sediments is ammonia. Our objective was to characterize the influence of two key water quality variables, pH and hardness, on toxicity of ammonia to the amphipod. Ninety-six hour, water-only exposures of H. azteca to ammonia were conducted using three different water types with hardnesses of 42, 100, and 270 mg/L as CaCO3 and three levels of pH (ca. 6.5, 7.5, and 8.5). In the soft water, toxicity of total ammonia was constant across test pH. As water hardness increased, toxicity of ammonia (on a total basis) to the amphipod decreased and became more pH dependent. Our data suggest that in softer water the amphipod was quite sensitive to the ionized (NH4+) form of ammonia. This contrasts with most other species that have been tested, which typically are more sensitive to un-ionized (NH3) ammonia than to NH4+. These data provide baseline values for interpreting the possible contribution of ammonia to sediment toxicity in tests conducted with H. azteca and also indicate that in some situations NH4+ may be important in determining ammonia toxicity.

Multivariate Analysis of Correlations Between Environmental Parameters and Cadmium Concentrations in Hyalella azteca (Crustacea: Amphipoda) from Central Ontario Lakes

1988 ◽  
Vol 45 (10) ◽  
pp. 1705-1710 ◽  
Author(s):  
M. Stephenson ◽  
G. L. Mackie
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Principal Components ◽  
Water Hardness ◽  
Environmental Parameters ◽  
Hyalella Azteca ◽  
Dry Mass ◽  
Cadmium Ions ◽  
Littoral Sediments ◽  
High Concentrations

Cadmium concentrations in Hyalella azteca collected from 69 central Ontario lakes ranged from 0.13 to 56.6 μg/g dry mass. Principal components analysis followed by multiple linear regression found three principal components, interpreted as water hardness, total cadmium, and dissolved organic carbon concentrations, to be significantly [Formula: see text] correlated with cadmium concentrations in H. azteca. Cadmium concentrations in H. azteca were independent of cadmium concentrations in littoral sediments. It is suggested that cadmium ions compete with calcium ions for uptake sites on the gill surfaces of H. azteca. High concentrations of dissolved organic carbon may complex free cadmium ions and reduce their concentration in solution, leading to lower cadmium concentrations in H. azteca.

DIP quality influenced by process water quality

TAPPI Journal ◽  
2014 ◽  
Vol 13 (9) ◽  
pp. 51-60
Author(s):  
DENNIS VOSS ◽  
HANS-JOACHIM PUTZ ◽  
SAMUEL SCHABEL
Keyword(s):  
Water Quality ◽  
Surface Tension ◽  
Ph Value ◽  
Water Hardness ◽  
Process Water ◽  
Test Results ◽  
Negative Effects ◽  
Water Parameters ◽  
Effects Of Ph ◽  
Contamination Levels

The need for deinking mills to reduce their fresh water consumption has resulted in higher loads of various contaminants in the process water. Lower recovered paper quality also leads to higher contamination levels in the mills. This higher load has an influence on achievable target brightness. The objective of the work was to determine and explain the main reasons for relatively poor deinked pulp quality or poor deinking potential based on the influence of recovered paper composition and process water quality. The process water parameters significantly affect the deinking potential of recovered paper. The test results showed the negative effects of increased water hardness. For standard recovered paper mixtures, flotation selectivity is higher with increasing flotation pH-value. Good results were realized for standard recovered paper with low hardness, low surface tension, and high pH-value. The results for recovered paper containing flexo newsprint could be slightly improved with low hardness, low surface tension, and low pH-value. The results of the test program using design of experiments showed interacting effects of pH-value and surface tension on luminosity and flotation selectivity.

scholarly journals Exposure to mixtures of heavy metals and metalloids in the adult population of Andalusia

2019 ◽  
Vol 3 ◽  
pp. 337
Author(s):  
Rodríguez-Barranco M ◽  
Gómez-Ariza J ◽  
García-Barrera T ◽  
Salamanca-Fernández E ◽  
Sanchez M
Keyword(s):  
Heavy Metals ◽  
Adult Population ◽  
Metals And Metalloids ◽  
Heavy Metals And Metalloids
Sign in / Sign up

Export Citation Format

Share Document