Assessment of wastewater effluent quality in Thessaly region, Greece, for determining its irrigation reuse potential

Antineoplastic drugs in urban wastewater: Occurrence, nanofiltration treatment and toxicity screening

Antineoplastic drugs are pharmaceuticals that have been raising concerns among the scientific community due to: (i) their increasing prescription in the fight against the disease of the twentieth century (cancer); (ii) their recalcitrance to conventional wastewater treatments; (iii) their poor environmental biodegradability; and (iv) their potential risk to any eukaryotic organism. This emerges the urgency in finding solutions to mitigate the entrance and accumulation of these hazardous chemicals in the environment. Advanced oxidation processes (AOPs) have been taken into consideration to improve the degradation of antineoplastic drugs in wastewater treatment plants (WWTPs), but the formation of by-products that are more toxic or exhibit a different toxicity profile than the parent drug is frequently reported. This work evaluates the performance of a nanofiltration pilot unit, equipped with a Desal 5DK membrane, in the treatment of real WWTP effluents contaminated (without spiking) with eleven pharmaceuticals, five of which were never studied before. Average removals of 68 ± 23% were achieved for the eleven compounds, with decreasing risks from feed to permeate for aquatic organisms from receiving waterbodies (with the exception of cyclophosphamide, for which a high risk was estimated in the permeate). Aditionally, no significative impact on the growth and germination of three different seeds (Lepidium sativum, Sinapis alba, and Sorghum saccharatum) were determined for permeate matrix in comparison to the control.

Concentration of potentially harmful elements (PHEs) in eggplant vegetable (Solanum melongena) irrigated with wastewater: a systematic review and meta-analysis and probabilistic health risk assessment

The main objectives of this study were PHEs concentration meta-analysis (Fe, Zn, Cr, Ni, Cu, Pb, and Cd) in eggplant irrigated by wastewater and the following estimation of non-carcinogenic (n-CR) risk for the consumers based on countries. According to the results, the rank order of PHEs concentration in eggplant was Fe (88.3 mg/kg -dry weight) > Zn (10.1 mg/kg -dry weight) > Pb (3.0 mg/kg -dry weight) > Ni (2.7 mg/kg -dry weight) > Cu (1.1 mg/kg -dry weight) > Cd (0.9 mg/kg -dry weight) > Cr (0.05 mg/kg -dry weight). Moreover, n-CR risk showed that all investigated countries (China, India, Pakistan, Turkey, and Jordan) except for United Arab Emirates (UAE) had a considerable n-CR in both age groups (adults and children).

Description of a Fe/Al Electrocoagulation Method Powered by a Photovoltaic System, for the (Pre-)Treatment of Municipal Wastewater of a Small Community in Northern Greece

Small and insular communities are sometimes not served by an efficient Wastewater Treatment Plant, and this is a hazard for both the environment and public health. A wastewater treatment apparatus based on the electrocoagulation process (EC) was tested with municipal wastewater from a small community in Northern Greece with a maximum of 6500 population equivalents. COD decrease was assessed under various parameters: current intensity, time duration, pH and use of Fe or Al electrodes. A simulation of meeting the community’s electricity needs with this apparatus was tested through RETScreen software. The results showed a satisfactory COD decrease through electrocoagulation which was affected by all the parameters mentioned; Fe electrodes could efficiently be used at 300 mA for 60 min for 55% COD removal. It was also shown that a photovoltaic panel system covers the electricity needs of the apparatus, thus no external electricity source is needed for its use. This apparatus could be used effectively by this community, so that the running costs are minimal.

Chemical and biological tracking in decentralized sanitation systems: The case of artificial constructed wetlands

Given that the social and economic sustainability of rural areas is highly based on the protection of natural resources, biodiversity and human health, simple-operated and cost-effective wastewater treatment systems, like artificial constructed wetlands (CWs), are widely proposed for minimizing the environmental and human impact of both water and soil pollution. Considering that the optimization of wastewater treatment processes is vital for the reduction of effluents toxic potential, there is imperative need to establish appropriate management strategies for ensuring CW performance and operational efficiency. To this end, the present study aimed to assess the operational efficiency of a horizontal free water surface CW (HFWS-CW) located in a world heritage area of Western Greece, via a twelve-month duration Toxicity Identification Evaluation (TIE)-like approach, including both chemical and biological tracking tools. Conventional chemical tracking, by means of pH, conductivity, total COD, and nitrogen-derived components, like nitrates and ammonia-nitrogen, were monthly recorded in both influents and effluents to monitor whether water quality standards are maintained, and to assess potent CW operational deficiencies occurring over time. In parallel, Whole Effluent Toxicity (WET) bioassays were thoroughly applied, using freshwater algae and higher plant species (producers), crustaceans and rotifers (consumers), as well as human lymphocytes (in terms of Cytokinesis Block Micronucleus assay) to evaluate the acute and short-term toxic and hazardous potential of both influents and effluents. The integrated analysis of abiotic (physicochemical parameters) and biotic (toxic endpoints) parameters, as well as the existence of "cause-effect" interrelations among them, revealed that CW operational deficiencies, mainly based on poorly removal rates, could undermine the risk posed by treated sewage. Those findings reinforce the usage of WET testing, thus giving rise to the importance of applying appropriate water management strategies and optimization actions, like oxygen enrichment of surface and bottom of HFWS-CW basins, expansion of the available land, the enhancement of bed depth and seasonal harvesting of plants, for ensuring sewage quality, in favor of water resources protection and sustainable growth in rural areas.

Effects of municipal wastewater treatment plant effluent quality on aquatic ecosystem organisms

The management and quality monitoring of wastewater have an important role in sustainable development. A recent approach in environmental protection involves the ecotoxicological assessment of effluents to complement the usual chemical evaluations. This study assessed the impacts of wastewater treatment plant (WWTP) effluent quality in a location in Western Cape province, South Africa using organisms that bear different ecosystem-level function responsibilities like the Pseudokirchneriella subcapitata (microalgae), Daphnia magna (crustaceans), and Tetrahymena thermophila (protozoan) in addition to the physicochemical parameters. The effluent showed values of chemical oxygen demand (COD; 41-83 mg L^-1), dissolved oxygen (DO; 2.7-3.1 mg L^-1), Redox potential (189-265 mV), and total dissolved solids (TDS; 656-718 ppm). The protozoan Tetrahymena thermophila ecotoxicity test exhibited toxic effects of the effluents within 24-h with a mean lethal value (LC₅₀) of 1.12% for the winter season. The findings of this study revealed that analyzed physicochemical parameters are within the regulatory water quality acceptable standard thresholds with few exceptions, while the biotests were able to determine the toxicity levels and sensitivities of each test. The results showed that the WWTP whole effluent exerted toxicity to test organisms, but dilution can mitigate the effects considerably. The use of ecotoxicological assessment methods for municipal WWTP effluent may enhance existing water management strategies.

Chemical and ecotoxicological assessment of sludge-based biosolids used for corn field fertilization

Sludge-based biosolids can be used for crop fertilization and for soil enrichment with organic matter. The prerequisites for their application are laid out in 86/278/EEC which sets limits for metals of toxicological concern in the biosolid and in the recipient soil. In this context, three kinds of sludge-based biosolids from a municipal wastewater treatment plant were submitted to the leaching tests EN 12457-2 and ΝΕΝ 7341. The leachates were examined for their physicochemical, chemical, and ecotoxicological characteristics four times within a year. Even in the more aggressive metal leaching method (ΝΕΝ 7341), results were much lower than the limits set in Council Directive 86/278/EEC. Correlations were noted between numerous parameters and principal component analysis grouped them in 3 components explaining 76% of total variation. These leaching tests were also performed on soil-biosolid samples from another investigative research in which two of the three kinds of biosolids had been incorporated in corn fields at doses 0, 20, and 40 tn/ha. EN 12457-2 leaching tests indicated that Ni and Cd leaching was affected by biosolid incorporation in soil, in relation to the type of the receiving soil (clay or sand). The leachates from the soil-biosolid mixtures were practically not toxic for the organisms tested (D. magna, V. fischeri, higher plants). In summary the biosolids were considered of low environmental risk when utilized in the field. A detailed risk assessment encompassing both chemical and ecotoxicological analysis is necessary for integrated evaluation of biosolids.

Identification, assessment and prioritization of ecotoxicological risks on the scale of a territory: Application to WWTP discharges in a geographical area located in northeast Lyon, France

The ecotoxicological risk assessment methodologies developed up to now mainly focus on local pollution and do not incorporate an evaluation and prioritization of the different risk situations present in the same territory. This article presents the different phases of formulating an innovative methodology developed to fill this gap, and its application to all the 18 WasteWater Treatment Plants (WWTP) of a geographical area located northeast of Lyon, France. The aim was also take into account emerging pollutants that are very often "forgotten" in ecotoxicological risk assessments. The results of the study show the extreme diversity of the ecotoxicity of the pollutants present in discharges, with "minimum" PNEC values in the region of a millionth of a microgram (10^-6 μg/l) and "maximum" PNEC values in the region of several tens of micrograms. They also show very considerable diversity of the flows of the receiving watercourses in the territory concerned (from several m³/s to 600 m³/s). The Risk Quotients (RQ) resulting from these 2 datasets, calculated for each WWTP and for each of the 10 pollutants most implicated in ecotoxicological risks (Diclofenac, Amoxicillin, Trimethoprim, Roxithromycin, 17β-estradiol, 17α-Ethynylestradiol, Estrone, Nonylphenol, Octylphenol, Nickel, et NH₄⁺), vary from 0.000002 to 187.7 when using the median concentration values of these pollutants, and from 0.000007 to 3750 when using their maximum concentration values. Globally, they show that: (1) the risks are higher for small streams that receive WWTP discharges of average size, (2) the risks are low to very low for discharges into watercourses with high flow rates.

Microbiological Impact of the Use of Reclaimed Wastewater in Recreational Parks

Reclaimed wastewater for irrigation is an opportunity for recovery of this natural resource. In this study, microbial risk from the use of treated wastewater for irrigation of recreational parks in the city of Chihuahua, evaluating the effect of distribution distance, season, and presence of storage tanks, was analyzed. Escherichia coli, Salmonella, and multidrug-resistant bacteria were recovered from samples of reclaimed water and soils at recreational parks in Chihuahua by the membrane filtration method, using selected agars for microbial growth. Samples were taken at three different seasons. No correlation in the presence of microbial indicators and multidrug-resistant bacteria (p > 0.05) was found between the distance from the wastewater treatment plant to the point of use. Presence of storage tanks in parks showed a significant effect (p < 0.05) with a higher level of E. coli. The highest count in wastewater occurred in summer. We isolated 392 multidrug-resistant bacteria from water and soil; cluster analysis showed that the microorganisms at each location were of different origins. Irrigation with reclaimed wastewater did not have a negative effect on the presence of microbial indicators of the quality of soils in the parks. However, the prevalence of multidrug-resistant bacteria still represents a potential risk factor for human health.

Concentration of heavy metals and trace elements in soils, waters and vegetables and assessment of health risk in the vicinity of a lignite-fired power plant

The pollution of agricultural soils, waters and products in the regions of lignite mines and fired power plants is of great importance. The concentration of As, Βa, Co, Cr, Sr, Sc, Th, U, Zn in soils and waters in the vicinity of a lignite-fired power plant in Northern Greece was determined using Instrumental Neutron Activation Analysis. The determination frequency was every three months during a period of one year in order to evaluate the seasonal impact of the pollution to the environment. Measurements were performed in three locations around the lignite mine as well as in one reference location at a certain distance from the mine. The results, which exhibited a slight seasonal variation, were compared, where possible, with literature values from other countries. The obtained data in most of the cases did not exceed the normal levels and indicated that the investigated area was only slightly contaminated. The concentration of heavy and trace metals was also measured in three common garden crops (tomato, cucumber and parsley) grown in this area. The calculated transfer factors (TF) from soil to vegetables and health risk quotients (HQ) do not denote a health risk.

Phytotoxic effects of irrigation water depending on the presence of organic and inorganic pollutants

Irrigation is one of the most important uses of surface waters in the agricultural region of Vojvodina province (Serbia). The aim of the study was to assess the quality of water from Stara Tisa meander, based on the levels of pollution with metals, volatile compounds (VOC), pharmaceuticals, pesticides, and pathogenic bacteria, on sunflower, cabbage, cucumber, maize, barley, buckwheat, sorghum, radish, beans, and white mustard. Microbiological analysis was carried out using the dilution method and phytotoxicity assay according to ISTA filter paper method (germination energy (GE), germination (G), root and shoot length, fresh and dry weight). The sample was slightly contaminated with domestic, industrial, and agricultural xenobiotics and had low levels of nitrogen substances, metals, and organic micropollutants. Pesticides, metolachlor, tebuconazole, propiconazole, imidacloprid, and thiametoxam were detected at levels exceeding the maximum admissible concentrations (MACs), i.e., the sum value for neonicotinoids. The number of saprophytic (2.27 × 10(6) CFU mL(-1)) and coliform bacteria (5.33 × 10(2) CFU mL(-1)) was very high. The total number of sulphite reducing clostridia (10 cells mL(-1)) and Escherichia coli (5 cells mL(-1)) was very low. The GE and G of all tested plants, except sunflower, were not influenced by the total chemism of water sample. However, it inhibited root lengths of sunflower, cucumber, maize, and barley and stimulated shoot lengths of all species except maize and white mustard. These results indicate that it can be used for irrigation of cabbage and radish from the chemical point of view, but the microbiological traits should be considered prior to consumption since they are consumed raw. The overall results suggest that water from Stara Tisa should be purified before using for agricultural purposes.

Is the step-wise tiered approach for ERA of pharmaceuticals useful for the assessment of cancer therapeutic drugs present in marine environment?

Methotrexate (MTX) and tamoxifen (TMX) cancer therapeutic drugs have been detected within the aquatic environment. Nevertheless, MTX and TMX research is essentially bio-medically orientated, with few studies addressing the question of its toxicity in fresh water organisms, and none to its' effect in the marine environment. To the authors' knowledge, Environmental Risk Assessments (ERA) for pharmaceuticals has mainly been designed for freshwater and terrestrial environments (European Medicines Agency-EMEA guideline, 2006). Therefore, the purpose of this research was (1) to assess effect of MTX and TMX in marine organism using the EMEA guideline, (2) to develop an ERA methodology for marine environment, and (3) to evaluate the suitability of including a biomarker approach in Phase III. To reach these aims, a risk assessment of MTX and TMX was performed following EMEA guideline, including a 2-tier approach during Phase III, applying lysosomal membrane stability (LMS) as a screening biomarker in tier-1 and a battery of biochemical biomarkers in tier-2. Results from Phase II indicated that MTX was not toxic for bacteria, microalgae and sea urchin at the concentrations tested, thus no further assessment was required, while TMX indicated a possible risk. Therefore, Phase III was performed for only TMX. Ruditapes philippinarum were exposed during 14 days to TMX (0.1, 1, 10, 50 μg L(-1)). At the end of the experiment, clams exposed to environmental concentration indicated significant changes in LMS compared to the control (p<0.01); thus a second tier was applied. A significant induction of biomarkers (activity of Ethoxyresorufin O-deethylase [EROD], glutathione S-transferase [GST], glutathione peroxidase [GPX], and lipid peroxidation [LPO] levels) was observed in digestive gland tissues of clams compared with control (p<0.01). Finally, this study indicated that MTX was not toxic at an environmental concentration, whilst TMX was potentially toxic for marine biota. This study has shown the necessity to create specific guidelines in order to evaluate effects of pharmaceuticals in marine environment which includes sensitive endpoints. The inadequacy of current EMEA guideline to predict chemotherapy agents toxicity in Phase II was displayed whilst the usefulness of other tests were demonstrated. The 2-tier approach, applied in Phase III, appears to be suitable for an ERA of cancer therapeutic drugs in the marine environment.

Dissolved organic matter removal during coal slag additive soil aquifer treatment for secondary effluent recharging: Contribution of aerobic biodegradation

Recycling wastewater treatment plant (WWTP) effluent at low cost via the soil aquifer treatment (SAT), which has been considered as a renewable approach in regenerating potable and non-potable water, is welcome in arid and semi-arid regions throughout the world. In this study, the effect of a coal slag additive on the bulk removal of the dissolved organic matter (DOM) in WWTP effluent during SAT operation was explored via the matrix configurations of both coal slag layer and natural soil layer. Azide inhibition and XAD-resins fractionation experiments indicated that the appropriate configuration designing of an upper soil layer (25 cm) and a mixture of soil/coal slag underneath would enhance the removal efficiency of adsorption and anaerobic biodegradation to the same level as that of aerobic biodegradation (31.7% vs 32.2%), while it was only 29.4% compared with the aerobic biodegradation during traditional 50 cm soil column operation. The added coal slag would preferentially adsorb the hydrophobic DOM, and those adsorbed organics could be partially biodegraded by the biomass within the SAT systems. Compared with the relatively lower dissolved organic carbon (DOC), ultraviolet light adsorption at 254 nm (UV-254) and trihalomethane formation potential (THMFP) removal rate of the original soil column (42.0%, 32.9%, and 28.0%, respectively), SSL2 and SSL4 columns would enhance the bulk removal efficiency to more than 60%. Moreover, a coal slag additive in the SAT columns could decline the aromatic components (fulvic-like organics and tryptophan-like proteins) significantly.

Assessment of the ecotoxicological risk of combined sewer overflows for an aquatic system using a coupled "substance and bioassay" approach

Very few tools are available for assessing the impact of combined sewer overflows (CSOs) on receiving aquatic environments. The main goal of the study was to assess the ecotoxicological risk of CSOs for a surface aquatic ecosystem using a coupled "substance and bioassay" approach. Wastewater samples from the city of Longueuil, Canada CSO were collected for various rainfall events during one summer season and analyzed for a large panel of substances (n = 116). Four bioassays were also conducted on representative organisms of surface aquatic systems (Pimephales promelas, Ceriodaphnia dubia, Daphnia magna, and Oncorhynchus mykiss). The analytical data did not reveal any ecotoxicological risk for St. Lawrence River organisms, mainly due to strong effluent dilution. However, the substance approach showed that, because of their contribution to the ecotoxicological hazard posed by the effluent, total phosphorus (Ptot), aluminum (Al), total residual chlorine, chromium (Cr), copper (Cu), pyrene, ammonia (N-NH4 (+)), lead (Pb), and zinc (Zn) require more targeted monitoring. While chronic ecotoxicity tests revealed a potential impact of CSO discharges on P. promelas and C. dubia, acute toxicity tests did not show any effect on D. magna or O. mykiss, thus underscoring the importance of chronic toxicity tests as part of efforts aimed at characterizing effluent toxicity. Ultimately, the study leads to the conclusion that the coupled "substance and bioassay" approach is a reliable and robust method for assessing the ecotoxicological risk associated with complex discharges such as CSOs.

A tool for a comprehensive assessment of treated wastewater quality

The main goal of a wastewater treatment plant (WWTP) is to comply with the treated wastewater (TWW) quality requirements. However, the assessment of this compliance is a rather complex process for WWTPs in the EU Member States, since it requires the integration of a large volume of data and several criteria according to EU Directives 91/271/EEC and 2000/60/EC. A tool for a comprehensive assessment of TWW quality in this context is herein presented. The tool's novelty relies on an integrated analysis of performance indicators (PIs) and new performance indices (PXs). PIs integrate the several compliance criteria into a single framework, supported by flowcharts for a straightforward assessment of TWW compliance by practitioners. PXs are obtained by applying a performance function to the concentration values analysed in the TWW for discharge or reuse. PXs are dimensionless and the scale adopted (0-300) defines three performance levels: unsatisfactory, acceptable and good performance. The reference values proposed for these levels and for the PIs were based on the EU legislation. The PXs complement the information provided by the PIs. While the latter assess the plant effectiveness in a given year (i.e. the TWW compliance with the requirements), PXs tackle the plant reliability, i.e. they allow to easily compare the performance of different parameters over the time and to identify when the performance did satisfy or fail the pre-established objectives and the distance that remains to achieve these targets. The tool was tested in 17 WWTPs and the most representative results are herein illustrated.

Developmental toxicity of treated municipal wastewater effluent on Bombina orientalis (Amphibia: Anura) embryos

Amphibian populations have been decreasing in urban freshwater systems in Korea. To elucidate the biological safety of treated wastewater effluent (TWE) in the Tancheon basin, the capital area of Korea, a 7-d-exposure Bombina orientalis embryo developmental toxicity assay was examined during the breeding season. In March, there were no significant differences in embryonic survival or malformation among the water samples. In July, following monsoon precipitation, embryonic lethality in TWE was significantly higher than in the upstream water sample. Malformation in TWE and TWE-mixed waters was significantly higher than in the control and upstream water samples. Tail muscle height of tadpoles also significantly decreased in TWE and TWE-mixed waters. Heavy metals were not detected in any samples. Total nitrogen, total phosphorous, and chemical oxygen demand in TWE markedly increased together with a decrease in dissolved oxygen in July. The increase in organic and inorganic loading following precipitation could have made TWE and TWE-mixed water not suitable for embryonic development. Though being managed based on physicochemical criteria, the water quality of TWE may not be sufficient to assure normal development of amphibian embryos. An amphibian developmental toxicity assay would be helpful for the water-quality management of TWE and urban freshwater systems in Korea.

Reclamation of used urban waters for irrigation purposes--a review of treatment technologies

The worldwide fresh water scarcity is increasing the demand for non-conventional water resources. Despite the technology being available for application of treated wastewater in irrigation, the use of effluent in agriculture is not being properly managed in the majority of cases. Industrial countries, where financial resources are available but restricted, face difficulties in some cases related to the lack of a complete definition of irrigation water quality standards, as well as to the lack of monitoring components that determine if the effluent is suitable for such use. The present paper presents a critical review on urban reclamation technologies for irrigation. The technologies are presented by the four most important parameters for irrigation water quality: salinity, pathogens, nutrients and heavy metals. An overview is given of the current, on-going evaluation of different reclamation technologies for irrigation.

Evaluation of Shiraz wastewater treatment plant effluent quality for agricultural irrigation by Canadian Water Quality Index (CWQI)

BACKGROUND

Using treated wastewater in agriculture irrigation could be a realistic solution for the shortage of fresh water in Iran, however, it is associated with environmental and health threats; therefore, effluent quality assessment is quite necessary before use. The present study aimed to evaluate the physicochemical and microbial quality of Shiraz wastewater treatment plant effluent for being used in agricultural irrigation. In this study, 20 physicochemical and 3 microbial parameters were measured during warm (April to September) and cold months (October to march). Using the measured parameters and the Canadian Water Quality Index, the quality of the effluent was determined in both warm and cold seasons and in all the seasons together.

RESULTS

The calculated index for the physicochemical parameters in the effluent was equal (87) in warm and cold months and it was obtained as 85 for the seasons all together. When the microbial parameters were used in order to calculate the index, it declined to 67 in warm and cold seasons and 64 in all the seasons together. Also, it was found that three physicochemical parameters (TDS, EC, and NO3) and three microbial parameters (Fecal coliform, Helminthes egg, and Total coliform) had the most contribution to the reduction of the index value.

CONCLUSIONS

The results showed that the physicochemical quality of Shiraz Wastewater Treatment Plant Effluent was good for irrigation in the warm, cold, and total of the two kinds of seasons. However, by applying the microbial parameter, the index value declined dramatically and the quality of the effluent was marginal.

Implementation of a minimal set of biological tests to assess the ecotoxic effects of effluents from land-based marine fish farms

Environmental monitoring plans (EMP) that include chemical analysis of water, a battery of bioassays and the study of local hydrodynamic conditions are required for land-based marine aquaculture. In this study, the following standardized toxicity tests were performed to assess the toxicity of effluents from eight land-base marine fish farms (LBMFFs) located on the northwest coast of Spain: bacterial bioluminescence (with Vibrio fischeri at 15 and 30 min), microalgal growth (with Phaeodactyllum tricornutum and Isochrysis galbana) and sea urchin larval development (with Paracentrotus lividus and Arbacia lixula). These bioassays were evaluated for inclusion in routine fish farm monitoring. Effective concentrations (EC(5), EC(10), EC(20), EC(50)) for each bioassay were calculated from dose-response curves, obtained by fitting the bioassay results to the best parametric model. Moreover, a graphical method of integrating the results from the battery of bioassays and classifying the toxicity was proposed, and the potential ecotoxic effects probe (PEEP) index was calculated. The bacterial bioluminiscence test at 30min, growth of I. galbana and larval development of A. lixula were found to be the most sensitive and useful tests. Graphical integration of these test results enabled definition of the ecotoxicological profiles of the different farms. The PEEP index, considering EC(20), efficiently reflected the toxic loading potential of LBMFF effluents. In conclusion, a battery of bioassays with species from different low trophic levels is recommended as a rapid and cost-effective methodology for assessing LBMFF discharges. The graphical integration method and the PEEP index are proposed for consideration in EMPs for such farms.

Phytotoxkit: a critical look at a rapid assessment tool

Terrestrial plant toxicity testing contributes critical information to many site risk assessments, but standardized tests can be labor-intensive, use large amounts of soil, and employ long test durations. The Phytotoxkit (MicroBioTests, Environmental Bio-Detection Products) minimizes the time and cost associated with terrestrial plant testing with a unique test setup, a shorter test duration, and less soil. However, the sensitivity of the test remains an open question. In this research, the Phytotoxkit and the standardized Environment Canada terrestrial plant toxicity test (definitive test) are compared using a parallel testing approach. Three different scenarios were examined: a multiconcentration test, in which an inhibiting concentration (ICp) was derived from chemically amended soils; a soil remediation test, in which plant growth in a remediated soil was compared to the original contaminated soil; and a site soil test, in which plant growth in a contaminated soil was compared to a reference soil. The contaminants tested were boric acid, Cr(VI) with cyclodextrin as a remediation agent, and petroleum hydrocarbons. Trifolium pratense (red clover) was used in the first and second scenarios, and six different plant species were used in the third scenario. In the first scenario, the Phytotoxkit results compared well with the definitive test results after 5 and 7 d of exposure. In the second scenario, the Phytotoxkit results agreed with the definitive test when evaluating the effectiveness of remediation. In the third scenario, the Phytotoxkit results were often not in agreement with the results from the definitive test. The reduced sensitivity of the Phytotoxkit in the third scenario may be driven by test unit design, as plant roots are separated from soil by filter paper.