Microtesting appraisal of ATP and cell recovery toxicity end points after acute exposure of Selenastrum capricornutum to selected chemicals

Abstract

Employing microtesting procedures, intracellular ATP and cell recovery (96‐h cell count determinations) were appraised as toxicity end‐point responses after acute (4‐h) exposure of the green alga Selenastrum capricornutum to metals (Cu2+, Co2+, Cd2‐, Cr3+, Cr6+, Ni2+, Hg2+, Zn2+, B3+), sodium azide, and 4 organic compounds (sodium dodecyl sulphate, 2,4‐dichlorophenol, phenol, tebuthiuron). Except for B3‐, both end points were able to measure acute metal phytotoxicity effects at concentrations of 5 mg · L−1 or lower. The algal recovery test showed better metal toxicity discrimination than the ATP test on the basis of dose—response slope steepness and elevation differences. Both tests, however, supplied useful complementary information. While the ATP test reacted rapidly to chemical aggression, the recovery test offered pertinent insight into actual long‐term consequences of acute exposure. With the nonmetals, both end‐point responses were mitigated (sodium azide, sodium dodecyl sulphate, 2,4‐dichlorophenol) or insensitive (phenol, tebuthiuron), suggesting low acute exposure risk to algae by these chemicals. Based on 4‐h (ATP and cell recovery) EC50 to standard 96‐h EC50 ratio values, the algal indicator was shown to have low tolerance to 6 chemicals (Cr3+, Cr6+, Hg2‐, Cu2+, sodium dodecyl sulphate, 2,4‐dichlorophenol). When compared to acute exposure bacterial assays, the acute exposure ATP and cell recovery microtests competed well in terms of overall sensitivity to a selection of chemicals. In general, this work demonstrates the utility that short‐term algal exposure tests can provide for chemical toxicity investigations.

Potential ecotoxic effects probe (PEEP): A novel index to assess and compare the toxic potential of industrial effluents

“…With the algal bioassay, 14 of the 15 effluents are still toxic after biodegradation testing and only 5 of these exhibit a drop in toxicity. The greater sensitivity of algae toward inorganic chemicals (Chiaudani and Vighi, 1978;Rai et al, 1981;Hickey et al, 1991) presumably accounts for the fact that the phytotoxic response is less influenced by the biodegradation procedure. Organic interactions during microbial degradation of complex effluents can also give rise to toxic by-products (Atlas, 1986) and may have contributed in maintaining algal toxicity elevated as well.…”

Canadian water quality guidelines for tebuthiuron

“…A proportion (30%) in the faeces. Hoffman et al (1975) reported that rats from 2 to 18 months old excreted water : methanol (1 : 1) extraction of samples of macrophytes (Hydrilla sp.) showed measurable quantities approximately 85% of a 10 mg и kg Ϫ1 dose in urine within 24 h of ingestion.…”

“…Ring-labeled tebuthiuron was EPA 1994). McRae (1991) classified compounds on the basis of their potential to leach with the groundwater mixed with a sandy loam (1.3% organic matter) at a level corresponding to 4.5 kg и ha Ϫ1 and allowed to ''age'' ubiquity score (GUS). Tebuthiuron has a GUS of Ͼ2.8, indicating a high potential to leach through agricultural for 30 d. The soil was then added to the top of a 27 cm column of untreated soil and eluted with 40 mL of tap soil.…”

A Multivariate Biological and Chemical Characterization of Industrial Effluents Connected to Municipal Sewage Treatment Plants

“…17,1998 C. Andrén et al 99.5 5,263 2,000 5,000 10,000 500 a Cond ϭ conductivity; Cl ϭ chloride; F ϭ fluoride; BOD ϭ biochemical oxygen demand; COD ϭ chemical oxygen demand; GF/A ϭ glass fiber filter; P tot ϭ total phosphorus; N tot ϭ total nitrogen; NO 23 N ϭ nitrite-nitrate nitrogen; NH 4 N ϭ ammonium nitrogen; AOX ϭ adsorbable organic halogens; EOX ϭ extractable organic halogens; EGOM ϭ extractable gas chromatographable organic matter; PBS ϭ potentially bioaccumulating substances; OPOL ϭ nonpolar aliphatic hydrocarbons; AROM ϭ total extractable aromatic compounds; ALIF ϭ total extractable aliphatic compounds; N-inhib ϭ nitrification inhibition; Mic50-15 through Mic20-30 ϭ Microtox test with 50% effective concentration and a 15-min exposure, and so on; Sele ϭ growth inhibition test with Selenastrum capricornutum. Known causes of Microtox toxicity are many metals and many organic compounds [18][19][20]; Selenastrum is also known to be very sensitive to many metals [21]. c The analytical uncertainty expressed as relative standard deviation of quality control samples.…”