Biodegradation of petroleum contaminants is an effective and generally inexpensive approach for reducing their concentrations in soils. However, little information is available on the toxicological status of contaminated soils and the fate of target hydrocarbons following bioremediation. Four texturally distinct soils were contaminated with diesel fuel and bioremediated in microcosms at 22°C, with moisture contents of 85% of soil water holding capacity, and nitrogen (N) and/or phosphorus (P) nutrient amendments. The progress of bioremediation was monitored using chemical and toxicological analyses. Soil toxicity was measured using five short-term bioassays: seed germination, red blood cell hemolysis, solid-phase Microtox, SOS-chromotest, and Toxi-chromotest. Reductions in target compound concentration were not always predictive of reductions in soil toxicity. Conflicting trends were indicated by the toxicity test results. For example, total petroleum hydrocarbon analysis revealed decreased hydrocarbon concentrations in all four soils following bioremediation but seed germination and seedling emergence data indicated increased soil toxicity. In contrast, the Microtox test data indicated decreased toxicity in two of the four soils. These results suggest that measurements of target contaminant concentrations should be complemented with several different soil toxicity bioassays, particularly when evaluating the ability of bioremediation to reduce the adverse effects of contaminants in soil. © 1998 John Wiley & Sons, Inc. Environ Toxicol Water Qual 13: 117–126, 1998
Temporal variability in the concentration of toxic heptapeptide microcystin was studied during the warm season of four years (1991-1994) in a hypertrophic lake (Lake Suwa) in central Honshu, Japan. Lake water samples (ca. 5 L) were filtered to separate intracellular microcystin (cell fraction) from extracellular microcystin (filtered lake water fraction). These fractions were analyzed to measure the total quantity of microcystin in lake water. Total amounts of extra-and intracellular microcystin were measured with high performance liquid chromatography. Concentrations of intracellular microcystin usually exceeded concentrations of extracellular microcystin (24 out of 26 times). High concentrations of intracellular microcystin were found during the exponential growth phase of the blooms, whereas concentrations of extracellular microcystin were highest at the end of the blooms. However, concentrations of extracellular microcystin remained very small (<4 mu g/L) compared to the levels of intracellular microcystin. The relatively higher percentages of microcystin in filtered lake water (> 20%) at the end of blooms suggests that release of microcystin from cells occurs during senescence and the decomposition period of Microcystis cells. (C) 1998 by John Wiley & Sons, Inc.
The environmental chemistry, fate, and toxicology of the herbicide, linuron, is reviewed. Linuron is a phenylurea herbicide used for selective control of annual weeds in fruit and field crops and noncrop areas. Linuron is soluble in water which suggests that it may leach readily through soils. Its log Koc for soil is 2.83, which indicates a moderate adsorption potential and a moderate mobility. Its half-life is less than 4 weeks in water and approximately 2 months in soil. The primary mode of degradation is microbial. In regions of intensive agriculture, linuron concentrations up to 1100 and 2800 μg L−1 have been detected in Canadian surface waters and ground waters, respectively. Duckweed (Lemna minor), the most sensitive freshwater species for which data were available, had a 5-d lowest-observed-effect level of 70 μg L−1 for growth inhibition. The most sensitive crop species was the tomato (Lycopersicum esculentum) with a LOEAR of 0.018 kg ha−1 for reduced fresh weight. Canadian Water Quality Guidelines (CWQG) specify levels of contaminants that should not be exceeded in order to protect and sustain the major beneficial uses of water in Canada. For linuron, sufficient toxicity data were available to derive an interim CWQG of 7 μg L−1 for the protection of freshwater life, a full CWQG of 0.071 μg L−1 for irrigation water to protect cereals, tame hays, and pasture, and an interim CWQG of 3.3 μg L−1 for irrigation water to protect other crops. © 1998 John Wiley & Sons, Inc. Environ Toxicol Water Qual 13: 1–41, 1998
To illustrate the difficulties and problems involved in assessing the effect of biodegradation processes in sediments on the toxicity potential of targeted chemicals, a study was carried out to examine the relationship of aerobic and anaerobic biodegradation (on the ecotoxicity) of two priority organic chemicals (nonylphenol and aniline). The chemicals were spiked into heavily polluted Hamilton Harbour sediments and over a period of 6 six months the changes in toxicity and genotoxicity (as assessed by 10 short-term bioassays) of the spiked sediments and their metabolites were monitored. The results indicated that under anaerobic conditions nonylphenol levels increased in concentration, while aniline quickly degraded under aerobic conditions and a little slower under anaerobic conditions. The data also revealed the inherent wide variability in toxicant distribution in homogenized sediment samples. (C) 1998 by John Wiley & Sons, Inc.
Elemental sulfur occurs naturally in marine and limnic sediments. Elemental sulfur, brought in solution in aqueous media by using organic solvents such as methanol as carrier solvent, was toxic in a bacterial luminescence test, known as the Microtox test. Previously, it has been shown that the toxicity in the luminescence test of whole sediments also was correlated to i.a. elemental sulfur using multivariate statistical analysis. Organic solvent extracts of sediments obtained in receiving waters of effluents from a pulp and paper mill was toxic in the luminescence test, and using a toxicity evaluation procedure, the toxic substance was identified as octameric cyclic sulfur, S-8. The substance dominated the toxicity in extracts of both a contaminated sediment and a sediment from a control area. Since the toxicity in the Microtox test of aqueous solutions of S-8 decreased upon storage, a conversion process of the toxic form was indicated. Acute toxicity of S-8 was not limited to the luminescent bacteria in the Microtox test, but was observed in tests with fish larvae if tested with the transient form of elemental sulfur. Tests of acute toxicity with zebra fish and perch larvae were responsive to elemental sulfur. Probably, the toxic form of elemental sulfur is the single cyclic octamer, that due to low aqueous solubility, binding to particulate sediment material or aggregation is converted into a nontoxic form. Acute toxic effects may occur in sulfur containing sediments of varying,redox potentials or where elemental sulfur deposits are turbated. (C) 1998 by John Wiley & Sons, Inc. Environ Toxicol Water Qual 13: 217-224,1998.
From November 1992 to October 1993, Billings Reservoir in Sao Paulo State was analyzed to identify its environmental quality. Several physical, chemical, biological, and microbiological parameters were evaluated, phytoplankton being among them. Phytoplankton samples were taken monthly at eight sites, including one located on the Rio Pequeno arm. From the samples taken at Rio Pequeno, a total of 69 taxa were recorded. Cylindrospermopsis raciborskii (Wolosz.) Seenaya and Subba Raju was the dominant species from November 1992 to May 1993. Then Scenedesmus quadricauda (Turp.) Breb. and S. opoliensis P. Richt (Chlorophyceae) became dominant. Another Cyanophyceae that was frequent but less expressive in terms of density and biomass was Oscillatoria sp. Physical and chemical water parameters, including pH, dissolved oxygen, transparency (Secchi disk), conductivity, water and air temperatures, depth, total organic nitrogen, nitrate, total phosphorus, aluminum, and iron also were analyzed. Water temperature, pH, dissolved oxygen, and depth were positively correlated with C. raciborskii density, while aluminum was negatively correlated. S. quadricauda and S. opoliensis densities were inversely correlated to the same factors. There was no indication of correlation between Oscillatoria sp. density and the abiotic factors analyzed. C. raciborskii seems to be favored by physical and chemical characteristics of Rio Pequeno, such as high pH and high levels of iron, and also by biological characteristics such as the capability to migrate on the water column and to fix atmospheric nitrogen. The species toxicity is another possible explanation for the dominance of C, raciborskii, through the growth suppression of other phytoplanktonic groups and protection against grazing by zooplankton. The toxicity of these algal blooms could be responsible for fish kills which occurred at the same place in 1990. C. raciborskii dominance at Rio Pequeno during most of the year advises against the use of this water for domestic supply, due to its potential toxicity, which represents risks to human health, requiring appropriate treatment. (C) 1998 by John Wiley & Sons, Inc.
An ecotoxicological study aimed at deriving practical methods for assessing the impact of complex discharges from offshore facilities has been conducted. The study focused on large volume discharges in the West Java Sea, indonesia, which exhibit limited mixing in the receiving waters and can form "ponds" of elevated concentration as a result of variable hydrodynamic flows.A number of experiments and analyses have been conducted aimed at characterizing the effluent during the process of degradation. This information has been used to determine likely body residues in test organisms used in 96-h exposure toxicity tests. The data from the toxicity tests have been correlated with the predicted body residues to provide an approach [whole effluent toxicity (WET)] to evaluate likely mortality arising from a complex mixed effluent. This semiempirical approach has been used in an integrated physicochemical transport model where time-varying exposure concentrations can be simulated and the resulting uptake into biota modelled. This permits direct assessment of the risk posed by discharges.The toxicity test results show that, at concentrations of effluent commonly found in the receiving waters, some mortality may be encountered albeit at low levels, probably not exceeding 5%. These results are confirmed by the modelled mortality using the WET approach. The groups of compounds most likely to be contributing to the toxicity include the PAHs and phenols. Contributions from each group vary between different characterized effluents from different facilities, (C) 1998 by John Wiley & Sons, Inc.
The new ColiPlate (CP) kit was evaluated comparatively with the standard membrane filter (MF) technique for enumerating total coliforms and Escherichia coli in water. In testing natural water samples, good correlations were observed for enumerating total coliforms (R-2=0.84) and E. coli (R-2=0.95). However, counts of E. coli population density estimated by CP were 47% higher than counts estimated by MF. With the water samples spiked with culture-grown E. coli cells, the correlation between the methods was strong for both total coliforms (R-2=0.95) and for E. coli (R-2=0.94), E. coli densities were estimated to be 20% higher using CP compared with MF. Samples spiked with rehydrated freeze-dried E. coli cells (with high portion of injured or weakened cells) showed a strong correlation between the two methods (R-2=0.93, for either total coliforms or E. coli). However, estimated total coliforms and E. coli densities were higher by CP than MF counts (38 and 168%, respectively). The CP test is therefore considered a more reliable method than the traditional MF for enumerating E. coli in samples with high levels of injured or weakened cells. (C) 1998 by John Wiley & Sons, Inc.
The aim of this work is to study the variation of the infectious titer and the hepatitis A virus (HAV) antigen titer at 4, 19, and 25 degrees C following artificial contamination in sterile seawater. The results show that the survival of infectious HAV depends greatly on the temperature parameter. The T-90 are 11 days at 25 degrees C and 24 days at 19 degrees C, and the infectious titer remains stable at 4 degrees C throughout the 92 day duration of the experiment. The capsidal antigen is found to survive much longer in seawater than the infectious virus. Indeed the T-90 was estimated to be 19 times greater at 19 degrees C and 7 times greater at 25 degrees C for the capsidal antigen. The capsidal antigen constitutes a marker that allows detection of the presence of HAV in seawater, although it has very low sensitivity and does not provide any information on the infectious characteristics of the virus. Indeed at 19 and 25 degrees C the antigen survives much longer than the infectious virus. (C) 1998 by John Wiley & Sons, Inc.
in recent years, the need to develop assessment techniques that could provide advanced warning of significant wetland stress or degradation has been recognized. The goal of this paper is to identify rapid, yet realistic and reliable methods for the early detection of pollutant impacts on wetland ecosystems, particularly those in the wet-dry tropics of northern Australia. In doing so, it describes the ideal attributes of early warning indicators and their subsequent selection for wetland research. It then evaluates the potential of existing methods of assessment as early warning indicators of wetland degradation due to pollutant impacts. Particular attention is paid to rapid assessment techniques, covering a range of trophic levels and levels of biological organization.Due to a number of favorable characteristics, phytoplankton were considered to be potentially the most promising indicators of wetland degradation, and thus the scope of application of toxicity assessment and monitoring methods warrants further investigation. Rapid toxicity bioassays using invertebrates and vertebrates were also considered to be an essential part of an early detection program for wetlands, while biomarkers represented a promising tool for achieving true "early warning" of potential pollutant impacts. Given further refinement and development, rapid methods of monitoring aquatic community assemblages were also considered potentially useful tools for the early detection of wetland degradation. Finally, to gain effective use from an early warning system for wetlands, its incorporation into an ecological risk assessment framework was recommended. (C) 1998 by John Wiley & Sons,* Inc.
Toxkits are a relatively new generation of microbiotests developed by the research teams of Professor Guide Persoone at the University of Ghent, Belgium. They are an effective and cost-efficient way to perform, for example, regulatory acute aquatic toxicity screening tests of effluents, aimed at maintaining water quality and protecting biota of receiving waters. To date there are seven Toxkits on the market with different test species of different phylogenetic groups. The protocols for several of these kits (e.g., Daphtoxkit(TM) and the Algaltoxkit(TM)) adhere to national or international guidelines for toxicity testing. Supported by the Sustainable Management Fund (SMF) of the Ministry for the Environment (New Zealand), research into the development of ecotoxicity test protocols using native indicator species has been underway since 1995 at the National Institute for Water and Atmospheric Research Ltd. NZ (NIWA). The Resource Management Act of 1991 requires local authorities and industry to apply for consent to discharge effluent to water or land. Ecotoxicity testing is now being included in these consent requirements. Also supported by a grant from the SMF, Wellington Polytechnic has begun comparative sensitivity tests, using split effluent samples, with Toxkit organisms and native species. NIWA is contracted to carry out the toxicity testing with native species. Six Toxkit protocols and the IQ Toxicity Test(TM) (rapid microbiotest using fluorescing enzyme split substrate) marketed by Aqua Survey USA are being used in the comparison. In addition a round-robin intercalibration exercise will be carried out using selected Toxkits, in regional diagnostic laboratories. Information from the comparative sensitivity tests and the intercalibration exercise will be used to determine overall effectiveness and cost-efficiency of the Toxkits, under New Zealand conditions, and to make recommendations to regional authorities about their potential role as Tier I ecotoxicity screening tests in consents to discharge effluent. The research design is explained, preliminary results are presented, and an update of recent advances in Toxkit technology and their increased application in European countries is given, (C) 1998 by John Wiley & Sons, Inc.
The effects of a fungicide (VITAVAX 200 FF) were studied on the reproduction of captive mallards living in an outdoor environment. In the first experiment, the fungicide was fed (2.5 g/kg duck food) during the sexually inactive period (October–November) and in a second group at the beginning of reproduction (February–March). The plasma levels of testosterone (T), progesterone (P4) and 17-β-estradiol (E2) were measured and egg production and sexual behavior were studied in both groups. In the autumn-treated group, only males showed a decrease in T level in the spring and in P4 during the molting period. T levels in spring-treated drakes and E2 levels in females were lower than in the control during the peak of reproduction. P4 decreased only in males during molting. Egg production was lower in both the autumn- and spring-treated groups. In the second experiment, the treatment was applied at the peak of egg laying (March). Sexual steroids, gonadal weights, egg production, and sexual behavior were studied. The steroid levels showed only a slight tendency of change, but atretic follicles and decreased weights of ovaries and oviducts were observed. The weight of testicles, phallus, and liver was higher in treated drakes. On the basis of these results, it is possible that VITAVAX's damaging effect manifests itself as a decrease in the oogenetic function of the ovary, which is not always or immediately related to the decline of sexual steroid levels. To interpret the increase in the weight of testicles and liver in drakes needs further histological and steroid receptor studies. © 1998 John Wiley & Sons, Inc. Environ Toxicol Water Qual 13: 133–141, 1998
The elimination of microcystin-LR (MCYST-LR) and microcystin-RR (MCYST-RR) by reverse osmosis from tap and salt (3000 ppm NaCl) water was examined. The average retention rates for the microcystins of three different membrane types were determined by measuring the MCYST-LR and MCYST-RR concentrations in both the permeate and the retentate. The effectiveness of the reverse osmosis apparatus was assured by conductivity measurements. Using high performance liquid chromatography analysis the detection limit for both MCYST-LR and MCYST-RR was 0.2 mu g/L and the quantification limits were 0.9 and 0.8 mu g/L for MCYST-LR and MCYST-RR, respectively.Under the experimental conditions applied, the average retention rates for MCYST-LR and MCYST-RR in tap water were in the range of 96.7% to 99.9% and in salt water between 98.5 and 99.9%. There was no significant difference between salt and tap water for either compound. (C) 1998 by John Wiley & Sons, Inc.
Hyalella azteca are presently used in toxicity tests designed to evaluate adverse biological effects associated with exposure to contaminated sediments. Biological endpoints examined in a sediment test include changes in survival, as well as sublethal effects such as changes in growth, and reproduction. Length and weight, two methods used routinely to measure growth, were compared using H. azteca recovered from a 10-day sediment toxicity test. Length of individual organisms was measured using an image analyzer and dry weight of organisms was determined using an electronic microbalance. Statistical analysis was conducted using one-way analysis of variance to compare treatment sites. Length measures were shown to have greater power, a small minimum detectable difference, and smaller amount of underlying variability. The results indicate that length, measured using an image analyzer, was a more sensitive means to detect significant changes in growth and can be conducted with a greater degree of statistical confidence than use of weight measures. (C) 1998 by John Wiley & Sons, Inc. Environ Toxicol Water Qual 13: 243-248, 1998.
Copper-sensitive bacteria were isolated from a tropical river water sample and used to develop a simple, inexpensive bioassay for the determination of copper bioavailability in freshwaters. The 48-h bioassay, which has an EC50 for inorganic copper of 7.1 mu g/L, involved addition of copper-sensitive bacteria to filtered water samples amended with growth-stimulating nutrients and measurement of growth. Matrix-matched control solutions were prepared by adding the metal complexing agent EDTA to a portion of each sample tested. In order to optimize sensitivity of the bioassay, a nutrient medium was developed, which stimulated bacterial growth, but did not appreciably alter copper speciation of the sample. This necessitated omission of many organic compounds commonly incorporated in growth media because of their ability to complex copper. Performance of the bacterial bioassay was evaluated on freshwater samples from tropical and temperate river systems. Bacterial 48-h EC15 values ranged from 5.0 to 25.0 mu g Cu/L. and were much higher than the observed EC15 value of 2.8 mu g/L for inorganic copper in deionized water (no organic matter present). A linear correlation (r = 0.93, p less than or equal to 0.005) was observed between the measured EC15 values and the copper complexation capacities of river water samples determined by anodic stripping voltammetry. This confirmed the role of natural organic matter in ameliorating copper toxicity. Results of this study provide further evidence that the bioavailability of copper in freshwaters is significantly reduced in the presence of natural organic matter. A generic protocol for development of metal-sensitive bacterial bioassays was developed as part of the work. (C) 1998 by John Wiley & Sons, Inc. Environ Toxicol Water Qual 13: 263-271, 1998.
Cyanobacterial bloom samples were collected in the warm season during 1992–1995 from the 12 lakes in Korea. Six species each of Microcystis and Anabaena, and two of Oscillatoria were identified in these lakes. The cyanotoxins of 47 samples collected from the lakes were identified as microcystins-RR, -YR, -LR; desmethyl-7-microcystin-LR (7-DMLR), plus anatoxin-a. Microcystins were the main components of these cyanotoxins, while anatoxin-a was detected in samples from a few lakes. Thirty-four of the 47 samples, included microcystins and the total amounts of microcystin ranged between 20–1500 μg/g freeze-dried bloom material. In four of the 26 samples, the samples contained anatoxin-a, though the amounts varied. The total microcystin concentration in 30 samples from the lakes was equal to the cellular microcystin in these lakes because no extracellular microcystin was detected. All the lakes except for Lakes Younglang and Mijae are a source of drinking water, so the presence of cyanotoxin can be a potential threat and requires more attention to water treatment. © 1998 John Wiley & Sons, Inc. Environ Toxicol Water Qual 13: 225–234, 1998
The industrial and sanitary use of dithiocarbamates (DTCs) is on the rise, and the synthesis of new derivatives has increased the field of their application. Both positive and negative pharmacological and toxicological effects have been documented for DTCs. The development and application of new DTCs must be accompanied by the study of their toxicity, beginning with the performance of simple and rapid biological screening tests. The objective of our study was to apply the IGEC biotest (inhibition of growth of Escherichia coli) and the acetylcholinesterase (AChE) inhibition test to a group of newly synthesized DTCs with possible applications in the area of public health. The substances studied were (−)-ephedrine-DTC, (+)-pseudoephedrine-DTC, N-ethylbenzyl-DTC, diethyl-DTC, and dimethyl-DTC, and the corresponding amines used in their synthesis: (−)-ephedrine, (+)-pseudoephedrine, N-ethylbenzylamine, diethylamine, and dimethylamine. The parameters for the minimal effective concentration tested (MEC), median effective concentration (EC50), and no observed effect concentration (NOEC) of each chemical were determined using the IGEC biotest. The AChE inhibition test was carried out for all the DTCs as well. Of the synthesized DTCs, (+)-pseudoephedrine-DTC showed the lowest toxicity (NOEC=30 μg mL−1 and EC50=301 μg mL−1) and N-ethylbenzyl-DTC showed the highest toxicity (EC50=26 μg mL−1). Although (−)-ephedrine-DTC exhibited a minimal inhibitory effect on AChE, the results obtained indicate a generalized absence of AChE inhibition for the DTCs. © 1998 John Wiley & Sons, Inc. Environ Toxicol Water Qual 13: 165–174, 1998
We studied the effects of common first-row transition metal ions, Mn(II), Fe(III), Co(II), Cu(II), Zn(II), on the respiration of a mixed microbial population enriched for toluene degradation. Dissolved oxygen consumption, i.e., respiration rate, was used to measure metabolic activity of a slow-growing consortium of toluene-enriched microorganisms. Respiration rates decreased within 30 s of exposure to the metal ions and did not measurably recover during observation times (< 80 min.). Metal ion toxicity increased with metal-phosphate binding affinities, consistent with cell damage by conformational changes in the phospholipid bilayer membrane to accommodate geometry requirements of complexes with transition metal ions. Changes in normalized metabolic activity (A(N)) with aqueous composition were compared with an equilibrium free-ion toxicity mechanism relating the fraction of membrane phosphatic ligands affected by metal ion chemisorption to diminished metabolic activity. A(N) measurements agreed with model predictions that the toxicity function (A(N)(-1) - 1) is proportional to the free metal ion concentration when hydrogen ions do not compete with metal ions for the phosphatic membrane sites and proportional to the square root of the free metal ion concentration if hydrogen ions effectively compete with metal ions for membrane phosphate ligands. Transition metal ion uptake and toxicity were diminished by concentrations of competing Ca(II) and Mg(II) metal ion concentrations an order of magnitude larger than concentrations of transition metal ion. The Cu(II)-EDTA complex was nontoxic compared to Cu(II) ions. Metabolic inhibition produced by Cu(II) ions was not significantly reversed by sequestering Cu(II) ions using EDTA, suggesting that membrane damage is irreversible. (C) 1998 by John Wiley & Sons, Inc. Environ Toxicol Water Qual 13: 249-261, 1998.
The use of data on the water concentration of total petroleum hydrocarbons (TPH) in hazard evaluation for marine biota is hindered by the lack of justified water quality criteria for TPH. Using ecotoxicology data for marine organisms and U.S. EPA guidelines (1985, 1994), numerical criteria for TPH were derived. Acute and chronic toxicity data for marine organisms exposed to water-soluble fractions of oil products were obtained from published materials and the author's investigations. Out of 310 data reviewed and sorted, 82 data for the test temperatures of 20-32 degrees C were selected and analyzed. The genus mean acute values (GMAV) were calculated for 15 animal genera belonging to the phyla Chordata, Arthropoda, Mollusca, Annelida. Plant values were obtained for six species of the algae classes Diatom, Chlorophyta and Dinophyta. The GMAVs ranged from 0.2 to 13.1 mg/L TPH. The considerable variability of data was attributed to differences in toxicity test designs. The EC50 values were adjusted by taking into account the fact that average test concentrations drop during courses of static-renewal and static toxicity tests. These adjustments resulted in a GMAV range of 0.2-5.2 mg/L with acceptable intergeneric variability. The final acute value derived as the fifth percentile of the set of 15 GMAVs for animals was in the range of 0.168-0.198 mg/L for the triangular, logistic, and normal distribution models. The advisory water quality criterion (AWQC) derived from these values was 0.007 mg/L. According to the criterion definition, to protect warm water marine organisms from unacceptable effects, an ambient concentration of TPH must not exceed AWQC of 0.007 mg/L. (C) 1998 by John Wiley & Sons, Inc.
The development of industry in towns and cities can give rise to effluents arriving at sewage treatment works that are inhibitory to carbonaceous oxidation and nitrification processes or that can release toxins that will incorporate onto sewage sludge. Accidental or illegal discharges in sewers and in rivers can also cause treatment problems at the receiving sewage treatment and water treatment works. U.K. Water companies have identified a need to develop technologies and tests that enable them to monitor sewage treatment and water treatment works intakes in order to identify and apply consent limits on sources of pollution or to automatically switch to enhanced processes or diversion mechanisms to prevent disruption to treatment processes. This paper will describe developments relating to such respiration inhibition tests and nitrification inhibition tests, which can be applied to legal consents to discharge. Developments relating to on-line technologies utilizing the bioluminescent response of naturally occurring and genetically engineered bacteria, as a broad based toxicity sensor, will also be discussed. (C) 1998 by John Wiley & Sons, Inc.
