Algal Assay Research Articles

Ageing of bleached kraft mill effluent studied by degradation of chlorinated phenolic compounds and Selenastrum algal assays

Bleached kraft mill effluent (BKME) from a Finnish kraft pulp mill with a full bleaching system was aged under laboratory conditions. The ageing solutions were prepared in nutrient solution and three types of lake water. The changes in acute toxicity of the BKME were studied by Selenastrum algal assays and degradation of chlorinated phenolics. Chlorinated phenolic compounds were analysed with a gas chromatograph from the subsamples taken from the ageing solutions on the following days: 0, 4 and 7 or 8. The toxicity of the ageing solutions was bioassayed on the same days using Selenastrum capricornutum as a test organism. The response of the test algae to ageing solutions was measured by cell counting after 72 and 96 h. During the ageing period the amounts of chlorinated phenolics decreased in the following order: (1) chlorocatechols, (2) chlorophenols and (3) chloroguaiacols. After the ageing period the EC 50 values of BKME ageing solutions to Selenastrum algae ranged from 6% to 10% (v/v) depending on the test medium and the effluent sample used. The correlation between the EC 50 values and total chlorinated phenolics was not statistically significant, so it seemed that, in these studies, chlorinated phenolics were not the primary reason for the acute toxicity of the BKME to Selenastrum algae.

COMPARISONS OF SINGLE-SPECIES, MICROCOSM AND EXPERIMENTAL POND RESPONSES TO ATRAZINE EXPOSURE

Results from single-species toxicity tests form the basis for guidance about concentrations of chemicals that are likely to be environmentally hazardous. Microcosm bioassays have been proposed as better tools for this purpose under some circumstances. Rarely have comparisons been made among the responses in the various test systems and those seen in natural communities. We compared the responses among single-species algal assays, a synthetic microcosm (the Taub microcosm) and experimental ponds exposed to similar concentrations of atrazine by comparing concentrations of atrazine that reduced algal activity or biomass to 50% of control values (EC50). Eight algal species were examined; mean species EC50 values for 14C uptake ranged from 37 to 308 μg/L. For the Taub microcosm, EC50 values were 103 to 159 μg/L for 14C uptake, 126 to 165 μg/L for dissolved oxygen production and 106 to 164 μg/L for dissolved oxygen consumption. Values were dependent on the time intervals selected for calculations. In the ponds, EC50 values for 14C uptake were 100 μg/L and for chlorophyll a, 82 μg/L. The basic similarity among EC50 values across test systems suggests that results from a combination of single-species assays, or the Taub microcosm, provided a reasonable estimate of the concentration of atrazine that produced similar direct effects on more natural communities.

Comparison of algal assay systems for detecting waterborne herbicides and metals

The EPA Bottle Test was compared to a short-term algal bioassay method (Oxygen Evolution Assay) for detecting waterborne herbicides and metals. Although the Bottle Test proved to be a more sensitive assay system, the responses of the two bioassays correlated well. The Oxygen Evolution Assay may be useful as a rapid preliminary screening method for determining which chemicals should undergo further testing. In both bioassays, differences were observed in the results of experiments conducted in the standard algal growth medium and in nutrient-enriched water samples, suggesting that water chemistry plays an important role in the determination of specific toxicity thresholds for algae.

Inhibition of growth of freshwater microalgae by long-chained aliphatic amines employed in solvent extraction processes

The influence on algal growth by six long-chained aliphatic amines, used in industrial solvent extraction processes, was investigated by a conventional algal assay and, in addition, a simple assay where algae were grown in liquid medium in 250 μl cultures on microtitration plates. Loss of solvent extractants from processes to ambient water represent a potential environmental problem. The primary, secondary, tertiary and quaternary amines (with one exception) had EC50-values based on growth rate (ECr) or algal biomass (ECb) at 0.01–0.3 mg/L (20–800 nM). This makes long-chained aliphatic amines about a thousand times more toxic than short-chained amines—on a molar basis. The difference in toxicity was interpreted as being due to different modes of action between the two groups of amines. The diatomAsterionella formosa and the blue-green algaAnabaena flos-aquae were more sensitive to the amines than the green-algaeSelen-astrum capricornutum, Monoraphidium pusillum orChlorella emersonii. The maximum ECmax/ECmin ratio recorded was 19.5, for the primary amine.Anabaena flos-aquae was more sensitive by a factor 2–4 when grown under nitrogen fixation conditions than when supplied with combined nitrogen. Compared to other aquatic organisms, the algae show a particular sensitivity to amines. The microtitration test system was less sensitive than the flask test system. The low sensitivity of the microtitration test system is not an inherent property, but due to the use of an insensitive technique (visual inspection) for detection of algal biomass. The ECr50 and ECb50-values in the flask test system were both heavily time-dependent.

Biological availability of different fractions of dissolved phosphorus in two natural waters: Algal assay experiments

(1985). Biological availability of different fractions of dissolved phosphorus in two natural waters: Algal assay experiments. SIL Proceedings, 1922-2010: Vol. 22, No. 5, pp. 2898-2903.

Algal assay evaluation of trace contaminants in surface water using the nonionic surfactant, triton X-100

Triton X-100, a nonionic surfactant, has been found to be capable of neutralizing the toxic effect of selected organic compounds in algal assays using 10% Bristol's medium. This nonionic surfactant does not seem to affect specific growth rates of Chlorella cultures when it is added alone to the medium but it accelerates growth inhibition when coupled with metals. By administering a series of increasing Triton concentrations in assays with natural waters, Chlorella growth that was once arrested in the test waters became revitalized and growth was more profuse as the concentration of Triton increased. The results indicate that Triton has the ability to alleviate the toxic stresses of organic mixtures that are contaminating many southern Ontario lakes. The bioavailability of these trace organics such as PCB, DDT, chlordane and dieldrin was confirmed in the study lakewaters from bioaccumulation in fish tissues.

Effects of pH on toxicity of As, Cr, Cu, Ni and Zn to Selenastrum capricornutum Printz

Acute toxicity tests were conducted to establish the response of Selenastrum capricornutum Printz to sublethal concentrations of As, Cr, Cu, Ni and Zn at a broad range of pH levels. Cultures were incubated for a period of seven days at pH 4 in standard algal assay media containing sublethal concentrations of metals. At this low pH, growth was depressed for all metals tested. The adjustment of pH to higher levels resulted in increased growth when cultures were treated with As, Cu, or Ni and incubated for an additional 7 days. Toxicity was least at the optimum pH range for growth of the alga.

Dose-response functions in aquatic toxicity testing and the Weibull model

A linear transformation of the Weibull model for dose-response functions is developed. The transformation is analogous to the probit and logit transformations. Typical dose-response curves in aquatic toxicity testing using macroorganisms and algae are analyzed by the Weibull and probit models, and it is shown that the Weibull model generally provides at least as good a fit to experimental data as the probit model. The expansion of the Weibull model to reflect the survival fraction or yield of organisms under multiple toxicant limiting conditions leads to particularly useful expressions for simple similar joint action (concentration addition with parallel response curves for the individual toxicants) and independent joint action (response multiplication). Explicit water quality criteria are derived based on both formulations. The multiple toxicity models, expanded to include concentration addition with non-parallel response curves for the individual toxicants, are applied to algal assay data for Selenastrum capricornutum exposed to manganese, copper, and lead. The fact that the yield based on response multiplication for the manganese-lead pair is lower than that calculated from concentration addition suggests that water quality criteria based on concentration addition may not always provide safe limits.

An algal assay method for determination of copper complexation capacities of natural waters.

The complexation capacities determined for natural waters by the Davey and the biological titration methods were statistically the same. However, these two methods differ in an important way. For Davey's method only those data in the vicinity of the equivalence point are used. For the biological titration all data can be used if the complex is strong. For weaker complexes, the data for total metal concentrations similar to that of the complexation capacity will deviate from linear behavior. In these cases the data which deviate can be disregarded. The biological titration method is easier to use because it does not require that a significant number of samples have metal concentrations similar to the value of the complexation capacity.

Predicting Algal Stimulatory Properties of Wastewater

The growth response of the green alga, Selenastrum capricornutum to varying additions of either sewage or reconstituted water containing equivalent levels of inorganic nitrogen and phosphorus, was compared to algal growth levels calculated from the inorganic nutrient concentrations of these additions using the algal yield factor of the test alga. The additions resulted in a linear increase in algal growth with percent of sewage or chemical equivalent solution addition which was in close agreement to the values predicted from the total soluble inorganic nitrogen concentration in the algal cultures alone. Thus, the Algal Assay: Bottle Test (AA:BT) did not permit sufficient organic mineralization during incubation, owing to the exclusion of heterotrophic bacteria and protozoa by the test procedure. This occurrence could result in an underestimation by the AA:BT of the algal growth potential occurring from the entry of a wastewater containing inorganic and organic nitrogen and phosphorus compounds into the aq...

A new algal assay procedure for the determination of the toxicity of copper species in seawater

Abstract Algal assays using the marine diatom Nitzschia closterium were carried out in raw, unenriched seawater to avoid the complexlng of copper by silicate, colloidal ferric hydroxide and other compounds which occurs in standard culture media. The algae remained in logarithmic growth for at least 72 h in unenriched seawater. The advantages of using this simple medium for the study of the effect of copper speciation on toxicity are outlined. Copper ions inhibit the growth of Nitzschia, but not the photosynthesis; possible reasons for this decoupling of cell division and the photosynthesis apparatus are discussed.

Bioassay techniques for soil-nutrient availability

In eutrophication control programs, it is necessary to quantify all (algal available) P inputs including those derived from soil and sediment. A one-to-one correspondence between algal availability and the results of chemical analysis does not exist. This research concerned the development of laboratory algal assays for evaluating the availability of soil P as an algal nutrient.Selenastrum capricornutum is an acceptable test organism. Autoclaving soil samples does not result in a consistent, statistically significant change in algal available-P. Maximum algal available-P is achieved with direct contact between soil and algae. Multiple incubation using fresh P-free medium results in significant increases in algal available-P.

Speciation and toxicity of aluminium in a model fresh water

Abstract A new algal assay technique was used to determine the effect of the chemical form of aluminium on toxicity in a synthetic hard water. Maximum toxicity occurred at pH 5.8 to 6.2, where as little as 5 μgL‐1 of labile aluminium significantly inhibited algal growth. Algal assay and computer modelling results implicate Al(OH)2 + as the aluminium species most toxic to algae.

Aspects toxiques du cuivre sur la biomasse et la productivit� du phytoplancton de la rivi�re du Saguenay, Qu�bec

In 1979 and 1980, batch culture experiments were conducted to observe the inhibitory effect of copper ion (concentrations of 10, 50, 100, 200 and 400 µg Cu · l−1) on the standing crops and photosynthesis of phytoplankton of the Saguenay River (for 124 hours) and in Chlorella vulgaris (for 8 days). These algal assays were carried out using the surface water of the Saguenay River. In natural populatoins of phytoplankton, it was found that photosynthesis was more sensitive than growth: at the lowest concentrations, such as 10 µg Cu · 1−1, copper seemed to increase the chlorophyll concentrations whereas the rates of primary production show a decrease of 60% with respect to the control. At higher concentrations of copper, the effect is weak in chlorophyll concentrations and more pronounced in the rates of primary production (decrease of 86 to 90%). The pennate diatoms are dominant (in all the samples) and these organisms are known as relatively resistant to copper. In Chlorella vulgaris, it was observed that with 100 µg Cu · 1−1, chlorophyll concentrations and rates of photosynthesis respectively decrease by 63 and 99% with respect to the control. At higher concentrations of copper, a maximum decrease of 70% and 99% respectively for chlorophyll concentrations and rates of primaryproduction are observed.

Evaluation of some physico-chemical techniques for the determination of the fraction of dissolved copper toxic to the marine diatom nitzschia closterium

The toxicity of copper to the marine diatom Nitzschia closterium was determined by growth rate measurements in the presence of a range of copper complexing agents, both natural and synthetic. The measurements were made in raw, unenriched sea water to avoid the reaction of copper with silicate or colloidal hydrated iron(III) oxide which occurs in standard culture media. The algae remained in exponential growth for at least 72 h in unenriched sea water and, in the presence of copper, produced an exudate which decreased the concentration of labile copper. Labile copper was measured in the algal assay solutions by using anodic stripping voltammetry (a.s.v.) at different deposition potentials, by separation on iminodiacetate (Chelex-100) and thiol resins, and by extraction with hexane/n-butanol (9:1) to simulate lipid solubility. No consistent correlation was observed between the toxic fraction of copper measured by algal assay, and the labile copper determined by the physico-chemical techniques. Although some of the naturally-occurring ligands (e.g., fulvic acid and iron—humic acid colloid) gave reasonable agreement between the toxic fraction and a.s.v.-labile copper, the chelating resins usually grossly overestimated toxicity. Lipid-soluble complexes of copper with synthetic ligands (e.g., 8-quinolinol and diethyldithiocarbamate) were highly toxic; as little as 2 μg Cu l −1 in the presence of 5 × 10 −5 M 8-quinolinol caused complete depression of algal growth. It is proposed that the extreme toxicity of lipid-soluble copper complexes results from their ability to catalyse the intercellular formation of highly destructive hydroxyl free radicals (OH.) from molecular oxygen, in a Fenton-type reaction.

Assessing aquatic productivity in the housatonic river using the Algal assay:bottle test

Dense algal growth and large diurnal oxygen variations in both free flowing and impounded reaches of the Housatonic River in Connecticut and Massachusetts prompted a concentrated study to assess the need for a comprehensive basin wide phosphorus abatement program and the contribution of point source discharges to eutrophication of the river. Inorganic nutrient levels and bioassay data indicated a predominance of nitrogen limitation below Pittsfield, MA resulting from discharges of phosphorus-rich, municipal and industrial wastewater into the river. N:P ratios suggested that the nutrient status of the river varied, to some extent, even over as short an interval as 2 months and was probably attributable to flow variations in the river. Algal assays of water samples confirmed the nutrient limitation predicted by N:P ratios in 10 out of 13 cases. Additions of varying percentages of untreated, and alum-treated Pittsfield domestic wastewater treatment plant effluent to Housatonic River water, resulted in a linear increase in algal yield that was within 20% of values predicted by inorganic nutrient content. No significant reduction in algal growth response was observed, however, in the alum-treated sewage since its N:P ratio was not sufficiently shifted to phosphorus limitation after 66% phosphorus removal (Al:P equal to 1.3:1). Phosphorus removal at Best Practicable Technology levels would therefore probably not change the nutrient status of the Pittsfield wastewater to phosphorus limitation.

Comparisons of trophic state measurements

Twenty-nine methods commonly used to measure trophic state were compared with respect to their ability to rank 44 test lakes against two standards: total phosphorus, a nutrient or driving force standard and chlorophyll a, an eutrophication response standard. The phosphorus loading models had high rank correlations with phosphorus; however, they did not rank the lakes well against chlorophyll. The relative trophic ranking of many lakes differed depending upon whether primary nutrients or biological manifestations were used as the ranking mechanism. Secchi disk was very effective in ranking the lakes against phosphorus but was relatively ineffective in ranking them against chlorophyll. Total Kjeldahl nitrogen was effective in ranking the lakes against phosphorus and had the highest rank correlation of all the methods tested against chlorophyll. Methods based upon phytoplankton community structure were especially ineffective in ranking the test lakes. Algal assay control yield gave disappointing results when compared against the chlorophyll standard. Most methods were much more effective in ranking the lakes against the total phosphorus standard than the chlorophyll a standard.

Determination of Algal‐available Phosphorus on Soil and Sediment: A Review and Analysis

AbstractImportant advances have been made recently in identifying the sources of algal‐available P in soils and sediments. Algal bioassays have shown that considerable amounts of the total soil P may be algal‐available under the appropriate environmental conditions. At present, however, the reported research contains no convincing evidence that the bioassay techniques used quantitatively measured all of the algal‐available P present in the soils and sediments tested,. Although chemical fractionation procedures have shown from which fractions algae obtain P, there is no evidence that all of the chemically extracted P in those fractions is algal‐available. Quantitative assessment of algal‐available P in soils and sediments will depend upou the development of long‐term algal assay procedures.

Determination of Particulate-Nutrient Availability

A procedure for direct contact algal assay is described which provides quantitative data on phosphorus transfer from soil to algae in serial 14-day incubations. The algae/soil/liquid phases are in direct contact. The procedure requires no special equipment other than that specified for algal assays in the Selenastrum capricornutum Printz Algal Assay Bottle Test. The method is a multi-interval assay and, as a result, provides a higher and more realistic value for maximum algal available phosphorus than obtainable using single interval assays.

Toxicite des eaux de ruissellement de la fonte de neige en milieu urbain

There is a current paucity of information on the characteristics of water originating from melting snow in urbanized areas. In fact no data exist on the potential chronic toxicity of waters originating from melting snow combined with sewage waters of industrial and domestic activities. Bioassays were conducted on the green alga Selenastrum capricornutum to evaluate the composite effect of all pollutants occurring in waters originated from melting snow in urbanized areas and also to determine the long-term bioavailability of selected toxicants in these waters. The publication resumes a sampling study of two outfalls (Curotte-Papineau and Meilleur-Atlantique) from collector systems on the island of Montréal, Québec, Canada (see Fig. 1). Both sewer systems are of the combined surface runoff-wastewater type, are self contained and drain watersheds of 11.7 and 22.2 km 2 area respectively (see Table 1). The sampling program carried out in spring (March–May) 1978, was oriented towards the analysis of flow-quality relationships during two dry and three snowmelt periods. The flow from the intrusion of snowmelt into the sewage networks were due not only to high air temperature and solar radiation conditions but also to a heavy rainfall (9.67 mm; maximum intensity of 4.6 mm h −1. The principal water quality parameters studied were BOD 5, COD, Cl −, N in, P i, Pb, Cr, Zn, Cn − and SS (see Table 2). In addition a bioassay based on the fertility potential [the Selenastrum capricornutum Printz algal assay bottle test; U.S.E.P.A. (1978)] on filtered samples (1.2 μm GF/C) of waste water was used to detect any toxological qualities of the outfalls during both dry and snowmelt periods. An analysis of the relationship between chemical quality and the toxological properties of the samples from both sewage networks showed that water collected during a period of snowmelt without rain had a greater potential chronic toxicity and greater mean ratios of B EDTA/B than combined water collected during a dry climatic period (see Table 3). This toxicity is due mainly to inorganic compounds. However, the increase in water discharge rate during periods of snowmelt accompanied by rain results in an apparent dilution of the aquatic toxicants. The potential chronic toxicity of water during the latter periods is consequently reduced compared with combined waters during dry periods. Knowledge of relationships between water flow and the chronic toxicity characteristics of waste water from urban snowmelt is necessary in the planning of any future combined water treatment system.