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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Movement of copper from in-ground root control fabrics

Kosuta, Sonja A. January 1998 (has links)
No description available.
12

Effects on Survival, Reproduction and Growth of Ceriodaphnia dubia following Single Episodic Exposure to Copper or Cadmium

Turner, Philip K. 08 1900 (has links)
Effects of episodic exposures have gained attention as the regulatory focus of the Clean Water Act has shifted away from continuous-flow effluents. Standardized laboratory toxicity tests require that exposure be held constant. However, this approach may not accurately predict organism responses in the field following episodic exposures such as those associated with rain-driven runoff events or accidental pollutant discharge. Using a modified version of the 7-day short-term chronic test recommended by the US Environmental Protection Agency, Ceriodaphnia dubia were exposed to copper or cadmium for durations ranging from 1 minute to 24 hours. In addition, adult reproductive recovery and effects on second generation individuals was assessed following select copper exposures. Finally, cadmium exposures were compared in reconstituted hard water (RHW) and municipal treated wastewater effluent (TWE). Following exposure, organisms were transferred to clean RHW or TWE and maintained for the remainder of the test. No- and lowest observed effect concentrations (NO- and LOECs) increased logarithmically with respect to logarithmic decreases in duration regardless of metal, endpoint or water type. Effective concentrations of cadmium however, were usually higher than those of copper, especially in TWE. LOECs for C. dubia survival following 24-hour and 5-minute exposures to copper were 116 and 417 µg/L, respectively. LOECs for fecundity were 58 and 374 µg/L, respectively. Neonate production of first generation adult C. dubia appeared to recover from pulsed copper exposure upon examination of individual broods. Cumulative mean neonate production however, showed almost no signs of recovery at exposure durations ≥3 hours. Pulse exposure to copper also resulted in diminished fecundity of unexposed second generation individuals. Such effects were pronounced following parental exposure for 24 hours but lacking after parental exposures ≤3 hours. LOECs for C. dubia survival following 24-hour and 5-minute exposures to cadmium in RHW were 44 and 9000 µg/L, respectively. LOECs for fecundity were 16 and 5000 µg/L, respectively. In TWE, LOECs for C. dubia survival were 83 and >10,000 µg/L, respectively. LOECs for fecundity in TWE were 48 and 7000 µg/L, respectively. Runoff pollution is site and event specific, however, data presented herein may be useful as a predictive tool under various conditions.
13

The impact of copper on filamentous fungi and yeasts present in soil

Cornelissen, Stephanie 04 1900 (has links)
Thesis (MSc)--University of Stellenbosch, 2004. / ENGLISH ABSTRACT: Numerous workers studied the impact of pollutants and agricultural chemicals, containing heavy metals such as copper (Cu), on soil microbes. It was found that elevated soil Cu levels do have a detrimental effect on soil bacterial populations however the filamentous fungi seemed to be less affected. Most of these studies were conducted in soils containing already relatively high Cu levels and the effect of this heavy metal on the nonfilamentous fungi (i.e. yeasts) was never investigated. The aim of this study was therefore to determine the impact of elevated Cu levels on filamentous fungi and yeasts occurring in soils containing relatively low natural Cu levels. A synthetic selective medium containing glucose as carbon source, thymine as nitrogen source, vitamins, minerals and chloramphenicol as anti-bacterial agent (TMV-agar), was used to enumerate ascomycetous and basidiomycetous Cu resistant yeasts in a sample of virgin soil containing ~ 2ppm Cu. Media that were used to enumerate Cu resistant filamentous fungi were malt extract agar, malt extract agar with streptomycin sulfate, maltyeast- extract-peptone agar with chloramphenicol and streptomycin sulfate, benomyl–dichloran-streptomycin medium for the enumeration of hymenomycetous fungi and two selective media for the isolation of mucoralean fungi. Cu resistant fungi able to grow on all of the above mentioned solid media supplemented with 32 ppm Cu occurred in the soil sample. To obtain an indication of the level of Cu tolerance of fungi present in this soil sample, a number of fungal isolates were screened for the ability to grow on a series of agar plates, prepared from glucose-glutamate-yeast extract agar, containing increasing concentrations of Cu. It was found that filamentous fungi and yeasts that were able to grow on this agar medium containing up to 100 ppm Cu were present in the soil. A series of soil microcosms was subsequently prepared from the soil sample by experimentally contaminating the soil with increasing amounts of copper oxychloride, were after fungal populations in the microcosms, including Cu resistant fungi, were monitored using plate counts. At the end of the incubation period, after 245 days, fungal biomass in the microcosms was compared by determining the concentrations of the fungal sterol, ergosterol, inthe soil. Generally, Cu had little impact on the numbers of filamentous fungal colony forming units on the plates, as well as on the ergosterol content of the soil. The numbers of filamentous fungi in the soil, including the Mucorales and hymenomycetes, seemed to be less affected by the addition of copper oxychloride than the numbers of soil yeasts able to grow on TMV-agar. The focus of the next chapter was on the response of yeasts in different soils to elevated levels of Cu in the soil. TMV-agar was used to enumerate yeasts in soil microcosms prepared from four different soil samples, which were experimentally treated with copper oxychloride resulting in Cu concentrations of up to 1000 ppm. The selective medium supplemented with 32 ppm Cu was used to enumerate Cu resistant yeasts in the microcosms. The results showed that the addition of Cu at concentrations ≥ ~1000 ppm did not have a significant effect on total yeast numbers in the soil. Furthermore, it was found that Cu resistant yeasts were present in all the soil samples regardless of the amount of Cu that the soil was challenged with. At the end of the incubation period, yeasts in the microcosms with zero and ~1000 ppm additional Cu were enumerated, isolated and identified using sequence analyses of the D1/D2 600-650bp region of the large subunit of ribosomal DNA. Hymenomycetous species dominated in the control soil, while higher numbers of the urediniomycetous species were found in the soil that received Cu. These observations suggest that urediniomycetous yeasts may play an important role in re-establishing overall microbial activity in soils following perturbations such as the addition of Cu-based fungicides. / AFRIKAANSE OPSOMMING: Vele navorsers het al die impak van besoedelingstowwe en landbouchemikalieë wat swaarmetale soos koper (Cu) bevat, op grond-mikrobes bestudeer. Dit is gevind dat verhoogde Cu vlakke ‘n nadelige effek het op grond-bakteriese populasies, maar dat die filamentagtige fungi geneig is om minder geaffekteer te word. Meeste van hierdie studies is gedoen met gronde wat alreeds relatief hoë Cu vlakke bevat het en die effek van hierdie swaarmetaal op die nie-filamentagtige fungi (d.i. giste) is nooit ondersoek nie. Die doel van hierdie studie was dus om die impak van verhoogde Cu vlakke op filamentagtige fungi en giste in gronde, wat natuurlike lae vlakke van Cu bevat, te bepaal. ‘n Sintetiese selektiewe medium wat glukose as koolstofbron, timien as stikstofbron, vitamiene, minerale asook chloramfenikol as anti-bakteriese agent bevat (TMV-agar), is gebruik om askomisete en basidiomisete Cu weerstandbiedende giste in ‘n monster ongeskonde grond, bevattende ~ 2dpm Cu, te tel. Media wat gebruik is om Cu weerstandbiedende filamentagtige fungi te tel, was mout-ekstrak agar, moutekstrak agar met streptomisiensulfaat, benomiel-dichloran-streptomisien medium vir die tel van hiemenomiseetagtige fungi en twee media vir die isolasie van mukoraliese fungi. Cu-weerstandbiedende fungi wat op al die bogenoemde media, aangevul met 32 dpm Cu, kon groei, het in die grondmonster voorgekom. Om die mate van Cu-weerstandbiedendheid van fungi wat in die grondmonster voorkom, te bepaal, is ‘n getal fungus-isolate op agarplate, voorberei met glukose-glutamaat-gis ekstrak agar, bevattende verhoogde konsentrasies Cu, nagegaan. Daar is gevind dat daar filamentagtige fungi en giste in die grond voorkom wat die vermoë het om op media bevattende 100 dpm Cu te groei. ‘n Reeks grond mikrokosmosse is dus voorberei vanaf die grondmonster deur om dit eksperimenteel te kontamineer met verhoogde hoeveelhede koper oksichloried, waarna die fungus-populasies asook die Cu-weerstandbiedende fungi in die mikrokosmos gemoniteer is deur middel van plaattellings. Aan die einde van die inkubasie periode, 245 dae, is die fungus biomassa in al die mikrokosmosse bereken deur die konsentrasie van die fungus sterool ergosterool te bepaal en dit met mekaar te vergelyk. Oor die algemeen het Cu min impak ten opsigte van diegetal filamentagtige fungi kolonie vormende eenhede die plate, asook op die ergosterool inhoud van die grond gehad. Dit wil voorkom of die getal filamentagtige fungi in die grond, insluitende die Mucorales en die hymenomisete, minder geaffekteer is deur die toediening van koperoksichloried as die aantal grondgiste wat op die TMV-agar kan groei. Die fokus van die volgende hoofstuk was dus op die reaksie wat giste in verskillende grondtipes gehad het op verhoogde Cu in die grond. TMV-agar is gebruik om die getal giste te bepaal in die grond mikrokosmosse van die vier verskillende grondmonsters, wat voorberei is deur om dit eksperimenteel met koper oksikloried te kontamineer tot en met Cu konsentrasies van 1000 dpm. Die selektiewe medium wat gesupplementeer is met 32 dpm Cu, is gebruik om Cu weerstandbiedende giste in die mikrokosmosse te bepaal. Die resultate toon dat die toevoeging van Cu by konsentrasies ≥ ~1000 dpm nie enige beduidende effek op die totale gis getalle gehad het nie. Daar is ook gevind dat daar Cu weerstandbiedende giste in die grond monsters voorkom gekom het ten spyte van die hoeveelheid Cu wat tot die grond toegevoeg is. Aan die einde van die inkubasie periode is die giste wat die die mikrokosmosse bevattende nul en ~1000 dpm Cu getel, geïsoleer en geïdentifiseer deur gebruik te maak van DNA volgorde bepaling van die D1/D2 600-650 bp areas geleë in die groter subeenheid van die ribosonale DNA. Hymenomisete spesies het in die grond kontrole gedomineer, terwyl hoër getalle uredinomisete spesies in die grond met addisionele Cu gevind is. Die resultate dui daarop dat uredinomisete giste dalk ‘n belangrike rol kan speel in die hervestiging van die oorwegende mikrobiese aktiwiteit in grond na skoktoestande soos die aanwending van Cu-gebaseerde fungisiede.
14

Die ultrastruktuur van sperme van die rooibok Aepyceros melampus (Lichtenstein, 1812) in die Nasionale Krugerwildtuin met spesiale verwysing na die invloed van koperbesoedeling

Ackerman, Dirk J. (Dirk Jacobus) 08 1900 (has links)
Thesis (PhD) -- Stellenbosch University, 1995. / ENGLISH ABSTRACT: Graling in the Kruger National Park. south of Phalaborwa Gate, is contaminated with copper, probably from a nearby copper refinery. Cattle in the neighbourhood have died from copper poisoning while the average copper concentration in the livers of impala in the Krgler National Park, was found to be abnormally high. The possibility exists that the ultrastructure of spermatozoa may serve as an indicator of environmental conditions. To examine this statement further, the purpose of this study includes the following: - To describe the ultrastructure of normal impala sperm as well as their abnormalities. - To quantify the sperm abnormalities of each experimental animal and to relate the abnormalities with the copper concentration in the impala liver, in order to determine whether any correlation exists between these two variables. Impala have been terminated monthly, from 1992.06.09 to 1993.05.15. in the vicinity of Phalaborwa Gate and in the Skukuza area for other research projects. Their sperm were made available for this study. The control group consisted of 20 animals which comprised 14 animals from an area, not contaminated with copper, along the Nwaswitshaka spruit near Skukula and 6 animals originally from the same area but which had been kept in captivity at Skukuza on a diet, not contaminated with copper. The experimental group consisted of 44 animals which comprised 32 animals from copper contaminated grazing along the Tshutshi spruit south of Phalaborwa Gate and 12 animals captured along the Nwaswitshaka spruit which were kept on a copper contaminated diet in captivity at Skukuza. Sperm from the epididymis of each animal were collected and fixed in a temporary laboratory. The sperm were processed at the Electron Microscopy Unit of the Faculty of Veterinary Science of the University of Pretoria and studied by means of scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The copper concentration in the liver was analyzed and bone marrow collected of each animal in order to determine the condition of the animal. The external morphology of a normal impala sperm was documented by means of SEM and the dimensions of the sperm determined. SEM micrographs of observed sperm abnormalities were taken. Percentages for normal sperm and the percentages of some abnormalities of a control group (Average liver copper concentration - ALCC = 37.9 ppm WB) were calculated. The same percentages were also calculated for an experimental group (ALCC = 104 ppm WB). The control group and the experimental group exhibited 91.6% and 93.6% normal sperm respectively. The difference in percentage sperm abnormalities of the two groups was of the same order. The increased copper in the livers of the experimental group has thus not lead to an increase of the percentage macro-abnormalities observed with SEM. The ultrastructure of normal impala sperm were described and documented with micrographs by means of TEM. The deviations of the normal sperm ultrastructure were also recorded on micrographs. Percentages were calculated for the normal sperm sections, as well as the abnormalities of some sperm sections of a contrl group (ALCC = 33.86 ppm WB). The same percentages were also calculated for an experimental group (ALCC = 122.5 ppm WB). For the control group the average percentage sperm neck sections with vacuoles was : 31.5% and for the experimental group this percentage was : 57.9%. The increased copper concentrations in the livers of the experimental group thus led to an increase of the percentage of sperm necks with vacuoles. There is also reason to believe that the difference of the percentages of sections of the sperm head, in the control and experimental group, should be remarkably greater. A graphic analysis of the TEM-data has also shown that a statistically significant correlation exists between the percentage of sperm with vacuoles in the neck and the copper concentrations in the livers of impalas. The conclusion is that high level copper concentrations exert a detrimental effect on the ultrastructure of the sperm neck. The possibility also exists that copper concentrations in impala liver > 500 ppm WB. will show a correlation with the percentages of some of the other abnormalities observed. / AFRIKAANSE OPSOMMING: Die weiding suid van Phalaborwahek in die Krugerwildtuin word waarskynlik vanaf 'n nabygeleë kopersmeltery met koper besoedel. Van die plaasdiere in die omgewing het reeds van kopervergiftiging gevrek en die gemiddeIde koperkonsentrasie in die lewers van rooibokke is abnormaal hoog. Die moontlikheid bestaan dat die ultrastruktuur van spermatozoa as 'n indikator van omgewingstoestande kan dien. Om bogenoemde moontlikheid verder te ondersoek was die doelwit van hierdie studie die volgende: Om die ultrastruktuur van normaIe rooiboksperme en hulle abnormaliteite te beskryf en die spermabnormaliteite van elke proefdier te kwantifiseer en met die koperkonsentrasie in die lewer in verband te bring om sodoende te bepaal of daar 'n korrelasie tussen die twee veranderlikes bestaan. Rooibokke wat maandeliks vanaf 1992.06.09 tot 1993.05.15 vir ander navorsingsprojekte in die omgewing van Phalaborwahek en Skukuza getermineer is, se sperme is vir die studie beskikbaar gestel. Die kontrolegroep het bestaan uit 20 diere wat saamgestel is uit 14 diere afkomstig van die Nwaswitshakaspruit naby Skukuza, uit 'n gebied wat nie met koper besoedel is nie en 6 diere uit 'n groep wat oorspronklik uit dieselfde gebied gekom het, maar wat te Skukuza in aanhouding geleef het op voedsel wat nie met koper besoedel was nie. Die eksperimentele groep het bestaan uit 44 diere waarvan 32 in die omgewing van die Tshutshispruit suid van Phalaborwahek versamel is en die ander 12 diere is langs die Nwaswitshakaspruit gevang en op 'n koperbesoedelde dieet te Skukuza aangehou. Sperme uit die epididymis van elke dier is in 'n tydelike laboratorium versamel en gefikseer. By die Elektronmikroskopie Eenheid van die Fakutreit van Veeartsenykunde van die Universiteit van Pretoria is die sperme voorberei en met behulp van skandeerelektronmikroskopie (SEM) en transmissie-elektronmikroskopie (TEM) bestudeer. Die koperkonsentrasie in die lewer is bepaal en murgvet is versamel om die kondisie van die diere te bepaaI. Met SEM is die uitwendige morfologie van 'n normale rooiboksperm met mikrograwe gedokumenteer en die mates van die sperm bepaal. Mikrograwe van waargeneemde spermabnormaliteite is met SEM geneem. Persentasies is vir normale sperme en die abnormaliteite van sommige sperme van 'n kontrolegroep (Gemiddelde lewerkoperkonsentrasie - GLKK =37.9 dpm NB) bereken. Dieselfde persentasies is ook vir 'n eksperimentele groep (GLKK = 104 dpm NB) bereken. Van die kontrolegroep het 91.6% en van die eksperimentele groep 93.6% sperme normaal vertoon. Die verskil in persentasies spermafwykings van die twee groepe was ook van dieselfde orde. Die verhoogde koperkonsentrasie in die lewers van die eksperimentele groep het dus nie gelei tot 'n verhoging van die persentasie makro-abnormaliteite wat met SEM waargeneem is nie. Die ultrastruktuur van 'n normale rooiboksperm is met behulp van TEM beskryf en met mikrograwe gedokumenteer. Die afwykings van die spermultrastruktuur is ook op mikrograwe vasgelê. Persentasies is vir die normale spermsneë en die abnormaliteite van sommige spermsneë van 'n kontrolegroep (GLKK = 33.86 dpm NB) bereken. Dieselfde persentasies is ook vir 'n eksperimentele groep (GLKK = 122.5 dpm NB) bereken. Vir die kontrolegroep was die persentasie neksneë met vakuoles = 31.5% en vir die eksperimentele groep was die persentasie = 57.9%. Die verhoogde koperkonsentrasie in die lewer van die eksperimentele groep het dus gelei tot 'n verhoging van die persentasie neksneë met vakuoles. Rede bestaan om te glo dat die verskil van die persentasies kopsneë van die kontrole- en eksperimentele groep ook aansienlik hoër behoort te wees. 'n Grafiese analise van die TEM-data het ook getoon dat daar 'n statisties betekenisvolle korrelasie tussen die persentasie spermnekke met vakuoles en die koperkonsentrasie in die lewer van rooibokke bestaan. Die bevinding is dat hoë lewerkoperkonsentrasies 'n nadelige invloed op die ultrastruktuur van die spermnek uitoefen. Die moontlikheid bestaan ook dat koperkonsentrasies in die lewer > 500 dpm NB ook 'n korrelasie met sommige van die ander abnormaliteite sal toon.
15

The assessment of copper and zinc removal from highway stormwater runoff using Apatite II™

Huang, Hsiao-Wen 31 May 2012 (has links)
Copper and zinc are heavy metals commonly present in highway stormwater runoff. Discharge of these metals to surface waters inhabited by sensitive aquatic species including threatened and endangered salmonids has necessitated the need for improved treatment techniques. Although copper is of the greater toxicological concern, zinc is often present at concentrations several times higher than copper and may compete with copper during adsorptive treatment processes. In the current study, the ability biogenic fish-bone based alternative adsorbent, Apatite II™, for copper and zinc removal from synthetic stormwater runoff was evaluated. Batch experiments were employed to examine equilibrium removal and rapid small scale column tests (RSSCT) were used to simulate dynamic operation in continuous systems. In both batch and continuous systems, the release of phosphate and calcium were observed, and Apatite II™ achieved high removal efficiencies. The removal of copper and zinc was likely due to a combination of processes including adsorption, ion exchange and precipitation. Precipitation played a dominant role in copper removal and the release of phosphate and pH buffering appear to drive this process. While precipitation was also quite important for zinc removal, adsorptive removal also played a role. The findings from the current study provide a general understanding of the performance of copper and zinc removal from stormwater runoff using Apatite II™. / Graduation date: 2012
16

The influence of copper, lead and iron on stream sediment nitrification

Reising, Nicholas C. 04 May 2013 (has links)
Metals are naturally found in ecosystems but can also enter via human activity such as fossil fuel combustion, and disposal of metal products. Copper, lead, and iron have frequently been detected throughout Indiana freshwaters based on historical samples. Since microbial activity is a holistic measure of ecosystem function, changes in microbial activity in response to metals may indicate potential areas of concern. Metal concentrations in seven streams of the Upper White River watershed of central Indiana were measured during spring (May) and summer (August) in conjunction with measurement of sediment nitrification rates using the nitrapyrin-inhibition technique. Additionally, the influence of copper, lead, and iron on microbial nitrification was studied using in vitro mesocosms inoculated with stream sediment from selected sites. Copper, lead, and iron concentrations in stream sediment and water varied among sites with sediment concentrations ranging 654 – 1985 mg Fe/kg sediment and 1.00 - 2.91 mg Cu/kg sediment. Water concentrations ranged from below detection to 0.10 mg Fe /L, and 0.01 – 0.02 mg Cu/L. Lead concentrations were below detection at all sites except in May at one site (Pleasant Run Creek 0.47 mg Pb/kg sediment) and in August at one site (Mud Creek 0.38 mg Pb/ kg sediment). Stream sediment nitrification rates were positively correlated to stream sediment copper concentration (r = 0.78, p = 0.001). There was no significant correlation between sediment nitrification rates and stream sediment iron, pH, dissolved iron, or total dissolved solids (TDS; p > 0.05). Positive correlations were found between nitrification response rates and total Fe (r = 0.61, p = 0.02) and Cu (r = 0.74, p = 0.002) concentrations. Experimental mesocosms indicate metal addition of 127 mg/L may reduce stream sediment nitrification rates though stream physiochemical characteristics and history of metal exposure likely dictate microbial response. Further, metal concentrations in the stream sediment may have more of an influence on nitrifying microbes than dissolved metal in the water column. / Department of Biology
17

Cellular biomarkers of exposure to the fungicide copper oxychloride, in the common garden snail Helix aspersa, in Western Cape vineyards

Snyman, Reinette Georgenie 03 1900 (has links)
Thesis (PhD(Agric)(Botany and Zoology))--University of Stellenbosch, 2001. / Copper oxychloride (Cu2CI(OH)3) is a broad-spectrum fungicide, intensively sprayed in many South African vineyards and orchards. It is necessary to find accurate and effective methods of monitoring the effects of this fungicide on the biota of the agricultural environment. The use of biomarkers may be a possible method to employ for this purpose. This study investigated the effects of copper, as a result of copper oxychloride exposure, on the biology of the common garden snail Helix aspersa, as welI as a number of cellular responses to exposure to the fungicide. The possible use ofthese responses as biomarkers was also investigated. Two groups of snails were exposed to 80 and 240 tJg g-! copper oxychloride respectively, for six weeks. A third group served as control. On a weekly basis, body mass, number of eggs produced, neutral red retention (NNR) times of haemocytic lysosomes, and body copper concentrations were determined for each individual. At the end of the experiment, the digestive glands, ovotestes and hermaphrodite ducts of a number of snails were prepared for histological analysis. The following parameters were investigated: tubule area, epithelium height and area in the digestive gland, spermatozoan area in the vesicula seminalis and ovotestis, as wen as oocyte numbers in the ovotestis. To test the validity of the laboratory results, a field survey was conducted. Snails were colIected from an uncontaminated vineyard and on two occasions from a contaminated vineyard in the Western Cape. The same cellular responses were investigated as in the laboratory study. The results showed that growth, egg production and hatching success in Helix aspersa were affected by experimental exposure to copper oxychloride. In both the laboratory study and field survey, copper in the body of H. aspersa was shown to be compartmentalized and the digestive gland was the most important site of copper accumulation. NNR times of haemocytic Iysosomes were shown to be affected by copper oxychloride exposure, already during the first week of exposure. A time evolution of copper accumulation and lysosomal damage existed. Epithelium height and area of digestive gland tubules, and spermatozoan and oocyte densities in the ovotestis, were also affected by copper oxychloride exposure and the concomitant copper burdens in the respective organs. Through the field survey it was ascertained that these histopathological changes were largely dependent on exposure time. It was concluded that lysosomal response of H. aspersa haemocytes, as measured by the NNR time assay, could be considered a useful biomarker of copper oxychloride exposure, since it provides an early warning of stress induced by this fungicide. Changes in digestive gland epithelium cells, and gametes in the ovotestis, can also possibly serve as biomarkers of copper oxychloride exposure. However, these can not serve as an early warning. All of the cellular responses identified in the present study can be used in combination with other cellular and physiological parameters and toxicological endpoints in order to improve the reliability and accuracy of interpretations regarding cause and effect.

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