Thallium in freshwater and marine water
Toxicant default guideline values for protecting aquatic ecosystems
Extracted from Section 8.3.7 ‘Detailed descriptions of chemicals’ of the ANZECC & ARMCANZ (2000) guidelines.
The default guideline values (previously known as ‘trigger values’) and associated information in this technical brief should be used in accordance with the detailed guidance provided in the Australian and New Zealand Guidelines for Fresh and Marine Water Quality.
Description of chemical
Thallium is introduced into the environment by natural weathering and as waste from the production of other metals (CCREM 1987), and is present in trace amounts in fresh waters (McNeely et al. 1979). Thallium (I) is the predominant form of thallium in most aerobic waters; however, in waters with high oxygen content some thallium (III) may be present (USEPA 1979e). In reducing environments, thallium may be precipitated in the elemental form or as the insoluble sulfide if sulfur is present (Lee 1971, Magorion et al. 1974). Thallium is more abundant in waters of the Great Lakes than cadmium (Borgmann et al. 1998). Recent developments in chemical analysis of thallium using Laser-Excited Atomic Fluorescence Spectrometry (Cheam et al. 1996) enables direct analysis of low levels without pre-concentration. The current analytical practical quantitation limit (PQL) for cadmium is 0.01 µg/L in fresh water and 0.3 µg/L in marine water (NSW EPA 2000).
Thallium has been reported to exhibit chronic toxicity to freshwater aquatic life at concentrations of 40 µg/L (USEPA 1986). The 7-day LC50 of thallium to Hyalella azteca was around 20 g/L but was reduced in presence of potassium; the figure was 86 g/L with 1.6 to 2.0 mg K/L (Borgmann et al. 1998). The 10-week EC25 for reproduction was between 0.5 and 5.3 g/L. This places thallium as being more toxic than Ni, Cu or Zn but less toxic than Cd or Hg (Borgmann et al. 1998).
Chronic data (around 35 points) were available on six species, belonging to three taxonomic groups as follows (pH range of 7.5 to 8.6):
Fish: three species, 30-day NOEC survival and growth for Pimephales promelas of 40 µg/L to 10-day LC50 for Oncorhynchus mykiss of 1500 µg/L.
Crustaceans: two species, 70-day EC25 for reproduction for Hyalella azteca 0.5 µg/L (Borgmann et al. 1998) to 7-day immobilisation for Daphnia magna of 520 µg/L.
Algae: one species Chlorella vulgaris NOEC (growth) of 20 µg/L. Although the pH range of this test was very wide (around 2.2 to 8.0), it gives an indication of algal toxicity and its inclusion will only affect the size of the assessment factor (AF) used.
A freshwater low reliability trigger value of 0.03 µg/L was derived from the Hyalella reproduction figure with an AF of 20 (because the data were chronic).
Acute marine data (8 points) were available for five species from three taxonomic groups:
Fish: two species, 96-hour LC50, 21,000 to 31,000 µg/L. For Cyprinodon variegatus, the 96-hour NOEC was 6200 to 14,000 µg/L.
Crustaceans: two species, 96-hour LC50, 2130 µg/L (Mysidopsis bahia) to 10,000 µg/L (Crangon crangon).
Algae: one species, 5-day EC50, growth, 330 µg/L (Ditylum brightwellii).
A marine low reliability trigger value for thallium of 17 µg/L was calculated from the crustacean figure using an AF of 20 (chronic figure). These figures should only be used as indicative interim working levels.
ANZECC & ARMCANZ 2000. Australian and New Zealand Guidelines for Fresh and Marine Water Quality, Australian and New Zealand Environment and Conservation Council and Agriculture and Resource Management Council of Australia and New Zealand, Canberra.
Borgmann U, Cheam V, Norwood WP & Lechner J 1998. Toxicity and bioaccumulation of thallium in Hyalella azteca, with comparison to other metals and prediction of environmental impact. Environmental Pollution 99, 105–114.
CCREM 1987. Canadian water quality guidelines. Canadian Council of Resource and Environment Ministers, Ontario.
Cheam V, Lechner J, Desrosiers R & Sekerka I 1996. Direct determination of dissolved and total thallium in lake waters by laser-excited atomic fluorescence spectrometry. International Journal of Environmental Analytical Chemistry 63, 153–165.
Lee AG 1971. The chemistry of thallium. Elsevier Publishing Co, Amsterdam.
Magorion TR, Wood KG, Michalovic JG, Pek SL & Van Lier MM 1974. Water pollution by thallium and related metals. NTIS PB 253333, Springfield, Virginia.
McNeely RN, Neimanis VP & Dwyer L 1979. Copper. In Water quality source book. A guide to water quality parameters. Water Quality Branch, Inland Waters Directorate, Environment Canada, Ottawa.
NSW EPA 2000. Analytical Chemistry Section, Table of Trigger Values 20 March 2000, LD33/11, Lidcombe, NSW.
USEPA 1986. Quality criteria for water. US Department of Commerce, National Technical Information Service, US Environmental Protection Agency, Springfield, Virginia. PB87-226759, EPA 440/5 86-001.
USEPA 1979e. Thallium. In Introduction, technical background, metals and inorganics, pesticides, polychlorinated biphenyls, Vol. 1 of Water-related environmental fate of 129 priority pollutants. EPA-440/4-49-029a. Office of Water Planning and Standards, US Environmental Protection Agency, Washington, DC.