Fusarium mycotoxin content and Fusarium species presence in Czech organic and conventional wheat

Deoxynivalenol and zearalenone content and the presence of Fusarium species in organically and conventionally grown wheat harvested in the Czech Republic during 2015-2017 were studied. Mycotoxin contamination was compared using two approaches. The first was based on samples taken from randomly selected farms in individual regions of the Czech Republic, both organic (154 samples) and conventional (330 samples). In the second approach, a sample set of conventional wheat compatible with organic one was formed, with samples paired according to the preceding crop and region of harvest. Using the first approach, mycotoxins were shown to be higher in conventional wheat; however, there was no difference in mycotoxin contamination between organic and conventional wheat using the second approach. Eight wheat samples with mycotoxin content above the EU limits were found, seven for deoxynivalenol (2.1%) and one for zearalenone (0.3%), all of them originated from conventional farming system. Six of them had maize as the preceding crop. The presence of five Fusarium species (Fusarium avenaceum, Fusarium culmorum, Fusarium graminearum, Fusarium poae and Fusarium sporotrichioides) was compared for the compatible wheat sample sets (second approach). The predominant species were found to be F. poae and F. graminearum in both the organic and conventional wheat. Harvest year significantly influenced both the occurrence of the main Fusarium species and the level of mycotoxin contamination. The study confirmed that (a) organic farming system was able to keep mycotoxin contamination of wheat at a low level, (b) in studies on the significance of organic/conventional agricultural practice on mycotoxin levels in cereals, it is important to pay attention to common production and environmental variables.

Mycotoxins content and its association with changing patterns of Fusarium pathogens in wheat in the Czech Republic

Mycotoxin content in 244 samples of wheat ears randomly collected during 2014 and 2015 from various localities in the Czech Republic was analysed using liquid chromatography coupled to mass spectrometry (LC-MS). Mean mycotoxin concentration in 2014 was highest for deoxynivalenol (DON; 760 μg/kg), followed by zearalenone (ZEA; 115 μg/kg), 3-acetyldeoxynivalenol (3-ADON; 88 μg/kg), deoxynivalenol-3-glucoside (83 μg/kg), and enniatins (ENNs; 102 μg/kg). In 2015, DON (66 μg/kg) also had the highest concentration level, followed by ENNs (35 μg/kg), nivalenol (2 μg/kg), and beauvericin (2 μg/kg). The maximum limit for DON in the European Union (1,250 μg/kg) was exceeded in 2% of samples, and the maximum limit for ZEA (100 μg/kg) was exceeded in 0.8% of samples. Fusarium species causing head blight were identified using PCR assays. During 2014-2015, Fusarium poae considerably dominated (48.7% average value of occurrence in the samples). Other species were detected in much lower frequencies in both years: Fusarium graminearum (average frequency of occurrence 13.7%), Fusarium avenaceum (11.9%), Fusarium culmorum (4.2%), and Fusarium equiseti (2.9%). Fusarium langsethiae was identified only in 2015, at a frequency of 10.2%, and Fusarium sporotrichioides was present only sporadically in 2014.

Occurrence of Fusarium species and mycotoxins in wheat grain collected in the Czech Republic

Random collections of ears of winter wheat cultivars grown within the Czech Republic were made during 2004-2013. The ears were assessed for Fusarium head blight symptoms on a 0-9 scale and grain samples were analysed for deoxynivalenol (DON) content by enzyme-linked immunosorbent assay. Samples from 2011-2013 were analysed in greater detail, including to detect Fusarium species using polymerase chain reaction assays and determine mycotoxin content (including ‘emerging’ mycotoxins) using ultra-high performance liquid chromatography coupled with tandem mass spectrometry. The 10-year survey reveals a significant adverse effect from maize as the preceding crop on the accumulation of DON. Most endangered were those areas situated in the eastern part of the country. The study revealed prevailing occurrence of Fusarium poae and Fusarium graminearum within the Czech Republic. The occurrence of F. poae increased greatly in 2012 (with 93.3% of samples infected) in association with relatively warmer and drier weather. These investigations provide abundant evidence as to the presence of so-called ‘emerging’ mycotoxins, particularly enniatins. The survey also shows that increased content of ‘emerging’ mycotoxins could be accompanied by high DON content through mixed infections. Among examined toxins, only DON and DON-3-glucoside (DON-3G) were positively correlated (r=0.800; P<0.001) while levels of the remaining toxins were independent of one another. DON production by both DON-producing species F. graminearum and Fusarium culmorum was significantly higher in mixed infections with other species. The presence of Fusarium avenaceum with other species appeared markedly to promote the production of 5 out of 6 mycotoxins, namely DON, DON-3G, nivalenol, enniatins, and beauvericin. These five mycotoxins profited also from contamination by F. poae. Moreover, the presence of F. graminearum and F. culmorum appeared to be decisive for zearalenone accumulation, which was not correlated with DON levels.

Mechanisms of resistance to acetolactate synthase-inhibiting herbicides in populations of Apera spica-venti from the Czech Republic

BACKGROUND

This study investigates the mechanisms of resistance to acetolactate synthase-inhibiting herbicides in populations of Apera spica-venti (L.) P.B. from the Czech Republic.

RESULTS

The proportion of resistance due to mutant acetolactate synthase (ALS) alleles was estimated by genotyping individuals from each of three populations for the eight ALS mutations known to confer resistance. Four resistance-conferring ALS mutations were identified: Pro-197-Ala, Pro-197-Thr, Trp-574-Leu and previously unreported Trp-574-Met substitution. Two populations (R1, R3) have amino acid substitution at positions Pro-197 and Trp-574. Individuals from the R3 population had two different resistance alleles. In the R2 population, only the resistant Trp-574-Met substitution was detected. Ten other single point mutations were identified, but these were not related to resistance. The cytochrome malathion decreased chlorsulfuron resistance in the resistant populations that were examined. Although malathion increased mortality, the GR50 values were too high to conclude that non-target-based mechanism was the main one for the resistance in Apera spica-venti populations tested in this study.

CONCLUSIONS

Individuals of Apera spica-venti populations tested in this study possess the target-site ALS resistance mutation and an additional so far unknown resistance mechanism(s).

Detection of organophosphate and pyrethroid resistance alleles in Czech Leptinotarsa decemlineata (Coleoptera: Chrysomelidae) populations by molecular methods

BACKGROUND

Pyrethroids and organophosphates are the most frequently used insecticides for Colorado potato beetle, Leptinotarsa decemlineata (Say), control in the Czech Republic. Based on molecular methods, organophosphate and pyrethroid resistance alleles have been detected in samples from three sites. The accuracy of restriction fragment length polymorphism (RFLP) and bidirectional polymerase chain reaction amplification of specific alleles (Bi-PASA) for detection of resistance alleles is compared.

RESULTS

Leptinotarsa decemlineata from three sites showed higher frequencies of resistance alleles to organophosphates than to pyrethroids. The rates of occurrence of individuals homozygous resistant (RR) to pyrethroids ranged from 20.0 to 22.9%, while the rates of occurrence of individuals RR to organophosphates ranged from 52.9 to 66.7%. The incidences of individuals with resistance alleles to both organophosphates and pyrethroids ranged from 8.6 to 13.6%. No relationship was found between incidence of the pyrethroid resistance allele and site, while incidence of the organophosphate resistance allele differed significantly according to site.

CONCLUSION

Both RFLP and Bi-PASA were suitable for detecting resistance alleles to pyrethroids, and in most cases also for detecting resistance alleles to organophosphates. In contrast to Bi-PASA, RFLP was also suitable for samples with lower DNA quality when testing for the resistance allele to pyrethroids. On the other hand, RFLP was not as accurate as Bi-PASA in detection of the organophosphate resistance allele.

Horseweed with reduced susceptibility to glyphosate found in the czech republic

The physiological and molecular basis of apparent resistance to glyphosate in horseweed (Conyza canadensis L. Cronq.) plants that had survived being sprayed with the herbicide at Prague-Bubny railway station in the Czech Republic was investigated. For the sake of comparison, plants expected to be susceptible were collected in areas where no herbicides had been used. Plants of both sets were treated, at the rosette stage (10-25 leaves, diameter of 3-5 cm), with herbicide at the rate recommended for use in the Czech Republic to control horseweed (960 g of glyphosate-IPA/ha; Roundup Klasik, Monsanto, 480 g of glyphosate-IPA ae L(-1)). Phytotoxic symptoms of the treated plants varied substantially, both between and within these sets of plants. Leaves of susceptible (S) plants wilted and turned yellow, and the plants subsequently died; leaves of plants with reduced susceptibility (RS) remained green, or new leaves were created in the center of their rosettes a few weeks after glyphosate application. There were no significant differences in the accumulation of shikimate between S and RS plants 3 days after treatment (DAT). However, the time course of changes in shikimic acid contents differed between the two biotypes; from 3 to 10 DAT, they decreased more than 4-fold in RS plants, while in S plants, they increased (3-fold, on average) from 3 to 7 DAT. A conserved region of the epsps gene, in which mutations are known to confer resistance in several plant species, was amplified from samples of both S and RS plants and sequenced, but no changes in the encoded amino acid sequence were found, indicating that mutations at another epsps site were responsible for the observed resistance, or that the mechanism may be at least partially non-target-based. Our results suggest that the reduced susceptibility to glyphosate may be due to impaired herbicide translocation, as previously found in studies of horseweed in the United States.

Quantitative trait loci meta-analysis of Plum pox virus resistance in apricot (Prunus armeniaca L.): new insights on the organization and the identification of genomic resistance factors

Plum pox virus (PPV) is responsible for sharka disease, one of the most detrimental stone fruit diseases affecting Prunus trees worldwide. Only a few apricot cultivars have been described as resistant, most originating from North American breeding programmes. Several PPV resistance quantitative trait loci (QTLs) have been mapped in various progenies, consistently highlighting the contribution to the resistance of the upper part of linkage group 1 (LG1). However, to date, no consensus has been reached on the precise number of QTLs linked to the resistance to PPV in apricot and P. davidiana or on their accurate position on the genetic linkage map. In the present study, the quantitative resistance of cultivar 'Harlayne' was analysed over five growth periods in a large F1 population. Four QTLs were identified, three mapping on LG1, explaining between 5% and 39% of the observed phenotypic variance. In an effort to further this analysis of PPV resistance in apricot, these results were merged in a single QTL meta-analysis with those of five other PPV resistance analyses available in the literature. Three consensus QTL regions were identified on LG1 and a putative fourth region on LG3. QTL meta-analysis also revealed the contribution of each resistant cultivar to metaQTLs, providing interesting comparative data on the resistance factors shared between the resistance sources used in the various studies. Finally, it was shown that one of the metaQTLs co-localizes with the eukaryotic translation initiation factor eIF4E, thus providing new hypotheses on the mechanisms of PPV resistance in apricot.

First Report of Anthracnose Caused by Colletotrichum acutatum on Strawberry in the Czech Republic

Colletotrichum acutatum J. H. Simmond is the causal agent of anthracnose rot and strawberry blackspot. This pathogen is listed by the EPPO as a regulated (formerly quarantined) organism for all European countries and is widely distributed throughout Europe (e.g., the United Kingdom, France, and Germany) (2). In the autumn of 2005, typical symptoms of anthracnose caused by C. acutatum (circular, dark, and sunken spots on fruit, dark, sunken lesions on petioles, and withering of the leaf, buds, and flowers) were repeatedly observed on field-grown strawberry plants in the Mělník Region of central Bohemia and Břeclav Region in southern Moravia, Czech Republic. Strawberry fruits and petioles showing typical symptoms were surface sterilized (30 s in 70% ethanol, 1 min in 10% NaOCl, and 15 s in 70% ethanol), rinsed in sterile water, dissected under aseptic conditions, and plated on 2% malt extract agar or placed in wet chambers and incubated at room temperature (18 to 20°C) for 10 days. All isolated strains were independently identified by morphological characteristics, plate-trapped antigen enzyme-linked immunosorbent assay (PTA-ELISA) (1), and PCR with the C. acutatum-specific primers ITS4 and CaInt2 (3). Morphological studies of C. acutatum were carried out on potato dextrose agar (4). The colonies were white, cream, grayish, or rose-orange before sporulation and the colony reverse was cream to orange with brown spots. The mycelial growth rate was 7.5 mm per day at 25°C. The conidia were one-celled, hyaline, cylindrical, 11.3 to 19.7 × 3.6 to 5.5 μm, and the majority of conidia were pointed at either or both ends. The appresoria were brown, globose to ellipsoidal, 5.0 to 7.5 × 5.0 to 6.2 μm, and the sclerotia were absent. Ten strawberry plants with green fruits of each cultivar Elsanta and Kama were sprayed with 500 ml of suspension of C. acutatum conidia (10⁴ conidia per ml). This test was carried out in the glasshouse under quarantine conditions at 20 to 25°C. C. acutatum caused withering of the flowers or dark brown spots on green fruits on five plants of cv. Elsanta and on four plants of cv. Kama after a 6-week incubation period. Isolation and identification of the pathogen from the diseased tissues were done as described above. C. acutatum was reisolated from three fruits, four leaf blades, and four petioles from five plants of cv. Elsanta and four fruits, four leaf blades, and two petioles from four plants of cv. Kama. The fungus was not reisolated from the control strawberry plants. In three cases, the pathogen was detected in the crown of plants of cv. Elsanta by PCR and ELISA. References: (1) Anonymous. OEPP/EPPO Bull. 34:155, 2004. (2) I. M. Smith and L. M. F. Charles, eds. Distribution Maps of Quarantine Pests for the European Union and for the European and Mediterranean Plant Protection Organization. CABI Publishing, Wallingford, UK, 1998. (3) S. Sreenivasaprasad et al. Plant Pathol. 45:650, 1996. (4) P. Talhinhas et al. Phytopathology 92:986, 2002.

[Evaluation and occurrence of high-risk pollutants in animal feed factories]

Concentrations of some hazardous pollutants were studied in dust deposit samples (n = 30) taken from the indoor equipment of two feed mixture plants (FMP) in Hodonín district in 1995 and 1996; the pollutants involved mercury, cadmium, lead, hexachlorobenzene (HCB), alpha and beta hexachlorocyclohexane (HCH), lindane (gamma HCH), DDT sum, DDT isomers, polychlorinated biphenyls (Delor 103, Delor 106, PCB indicator congeners). The statistically significantly higher (P < 0.01) average concentration of mercury (0.028 mg/kg) was recorded in dust depositions (n = 15) in FMP K. in comparison with FMP R. Increased concentrations of cadmium (more than 0.5 mg/kg) were determined in dust depositions in FMP K. in 1 sample (0.582 mg/kg), of lead (more than 5.0 mg/kg) in 1 sample (7.540 mg/kg), of HCB (more than 0.01 mg/kg) in two samples (0.034 and 0.036 mg/kg), of beta HCH (more than 0.005 mg/kg) in 4 samples (0.021; 0.022; 0.023 and 0.046 mg/kg), higher DDT sum (more than 0.05 mg/kg) were determined in FMP K. in 3 samples (0.072; 0.085 and 0.190 mg/kg) and of PCB sum (more than 0.05 mg/kg) in 4 samples (0.054; 0.059; 0.074 and 1.085 mg/kg). In comparison with FMP K., dust depositions (n = 15) in FMP R. showed the statistically significantly higher (P < 0.05) average concentration of lead (5.241 mg/kg). Increased concentrations of lead were determined in dust depositions in FMP R. in 7 samples (5.040; 5.230; 6.760; 7.590; 7.620; 8.450 and 15.650 mg/kg), of beta HCH in 7 samples (0.006; 0.008; 0.022; 0.024; 0.026; 0.029 and 0.049 mg/kg), higher DDT sum were recorded in 3 samples (0.053; 0.074 and 0.126 mg/kg) and higher PCB sum in 8 samples (0.057; 0.066; 0.101; 0.134; 0.164; 0.426; 0.821 and 1.202 mg/kg). The highest average concentration of hazardous pollutants in dust depositions (n = 30) in both feed mixture plants was determined in lead (4.122 mg/kg), in a descending order followed by PCB sum (0.151 mg/kg), cadmium (0.127 mg/kg), DDT sum (0.030 mg/kg), mercury (0.019 mg/kg), lindane (0.013 mg/kg), beta HCH (0.010 mg/kg), HCB (0.004 mg/kg and alpha HCH (0.001 mg/kg). Out of PCB indicator congeners, dust depositions contained the highest quantities of congener 138 (0.022 mg/kg), congener 180 (0.018 mg/kg) and congener 153 (0.015 mg/kg). Isomer p,p-DDT was dominant in dust depositions among DDT isomers (0.019 mg/kg). Dust depositions sampled from the indoor equipment of feed mixture plants are a promising indicator of produced feed mixtures contamination with hazardous pollutants. To seek sources of feed mixtures contamination is a permanent task of veterinary service.

Effects of environmental pollutants on the porcine and bovine immune systems

Immunological examinations were done in 30 fattening pigs from three swine farms (D., M., T.) and 20 dairy cows from one cattle farm (N.) in the district of Hodonín in 1994. At the same time, samples of stable dust deposits collected in the four farms were analysed for the contents of mercury, cadmium, lead, gamma-HCH (lindane), and total DDT and polychlorinated biphenyls (PCB). Decreased blood level of lysozyme (0.92 mg/l) was found in the swine herd D. Ten percent of the pigs in the herd were affected with purulent skin lesions. The concentrations of the pollutants under study in the dust deposits collected in the herd D. were low. An increased concentration of PCB (0.263 mg/kg) in stable dust but no adverse effects on the immune system were found in the swine herd M. Eosinophilia (6.2%), increased extensity of Ascaris suum infection (25%) and a high content of lead in stable dust (11.2 mg/kg) were typical of the swine herd T. A high content of lindane (0.139 mg/kg) and an extremely high content of lead (214 mg/kg), which can participate in the immunosuppression of lymphocytes, were found in the cattle herd N. The activity of lymphocytes was depressed in 35% of the cows and the mean value was at the lower limit of the physiological range. Hazardous pollutants can affect the immune system of farm animals and their penetration into the stable environment should be prevented.

Campylobacter spp. and Salmonella spp. in black-headed gulls (Larus ridibundus)

Cloacal examination of 41 juvenile black-headed gulls (Larus ridibundus) by cultivation demonstrated Campylobacter jejuni in 26 (63%) and Salmonella typhimurium in 21 (51%) of them. All the bird samples were collected in a breeding colony near the town Hodonin, South Moravia, Czech Republic in 1996. Twenty six Campylobacter isolates were tested for antibiotic and drug sensitivity: all were resistant to at least three agents (Penicillin, Tetracyclin and Sulfomethoxazol-trimethoprim) while all were sensitive to Augmentan, Cefotaxim, Ciprofloxacin, Erythromycin, Nitrofurantoin and Cephazidine. Four percent of isolates were resistant to Ampicillin and Nalidixic acid. Of the 21 S. typhimurium isolates tested, 33% were sensitive to all drugs assayed, proportions of the strains resistant to Sulfomethoxazol-trimethoprim, Tetracyclin and Streptomycin were 58%, 16% and 8%, respectively.

[Occurrence of harmful pollutants in fattened pigs]

Fourteen fattened pigs (age of 240-250 days, live weight 110-120 kg) were examined on three farms (D., M. and T.) in Hodonin district in 1994 for the content of some harmful pollutants (mercury, cadmium, lead, lindane, DDT sum, DDT isomers, lower and higher chlorinated biphenyls, PCB congeners) in the muscle, liver, kidneys and subcutaneous fat. Maximum allowable quantities (MAQ) of extraneous matters were slightly exceeded in mercury only, in 5 samples of the muscle (0.012-0.022 mg/kg). In comparison with the average contents of extraneous matters in pigs in the Czech Republic in 1994, higher concentrations of mercury (0.009 mg/kg), lead (0.124 mg/kg), lindane (0.060 mg/kg fat) and DDT sum (0.083 mg/kg) were observed in the muscle of pigs from Hodonín district. The liver of the pigs contained the highest average concentrations of lead (0.141 mg/kg), lindane (0.280 mg/kg fat), DDT sum (0.323 mg/kg fat), p,p'-DDE (0.106 mg/kg fat), p,p'-DDT (0.057 mg/kg fat). PCB-Delor 103 (0.415 mg/kg fat), PCB-Delor 106 (0.561 mg/kg fat) and PCB 118 congener (0.029 mg/kg fat). The highest average values of mercury (0.014 mg/kg) and cadmium (0.147 mg/kg) were determined in the kidneys of pigs. The ratio of lower-chlorinated biphenyls (Delor 103) to higher-chlorinated biphenyls (Delor 106) was approximately 1 : 3 in the muscle, 1 : 1 in the liver and 1 : 2 in subcutaneous fat. The per cent share of three PCB congeners, 101, 138 and 153, was highest in the muscle, liver and subcutaneous fat of pigs. The pigs from Hodonín district exhibited in 1994 the greater load of mercury, lead, lindane and DDT than in other regions of the Czech Republic, but these values did not mostly exceed the hygienic limits in force. It is desirable to observe the spectrum of indicator PCB congeners for objective evaluation of PCB load in pigs, as they indicate the contamination level with lower- and higher-chlorinated biphenyls (Delor 103 to Delor 106). Greater attention should be paid to the congener PCB 118, which is the most toxic out of the indicator congeners concerned.

[Occurrence of harmful chemical elements (Hg, Cd, Pb) in pig stalls]

The presence of harmful chemical elements (Hg, Cd, Pb) in the stable environment for fattened pigs was compared in Hodonin district in the years 1984 and 1994. These data were recorded for the year 1994 in comparison with 1984: 1, mercury content in feed mixtures for pigs decreased 102 times (0.510 and/or 0.005 mg/kg), cadmium content 8 times (0.400 and/or 0.048 mg/kg) and lead content 6 times (2,680 and/or 0.420 mg/kg); 2. mercury content in stable dust deposition decreased 27 times (0.480 and/or 0.018 mg/kg) and cadmium content 6 times (1.370 and/or 0.248 mg/kg), but lead content slightly increased (5.980 and/or 8.569 mg/kg); 3. mercury content in the bristles dropped 20 times (0.440 and/or 0.022 mg/kg), cadmium content 5 times (0.080 and/or 0.015 mg/kg) and lead content 10 times (1.690 and/or 0.195 mg/kg). In addition, the presence of Hg, Cd and Pb in pig manure and road dust was investigated. Road dust exhibited an increased lead concentration (22.800 mg/kg), so it is not possible to exclude lead penetration from the stable surroundings to the internal environment of the stable. After application to arable land, pig manure can be a vector of some amounts of heavy metals (Hg 0.003; Cd 0.024; Pb 0.518 mg/kg dry matter). It is a positive result that there has been a significant decrease in mercury and cadmium contents in the stable environment for fattened pigs in the last decade. This fact reduces the health risk not only for pigs but also for their tenders.

[Occurrence of chlorinated pesticides and polychlorinated biphenyls in the stalls and outdoor environment in pig-fattening farms]

Contents of some pesticides (lindane, DDT sum, o,p'-DDE, p,p'-DDE, o,p'-DDD, p,p'-DDD, o,p'-DDT, p,p'-DDT) and polychlorinated biphenyls (Delor 103, Delor 106, PCB congeners: 28, 52, 101, 118, 138, 153, 180) were investigated on three farms of fattened pigs (D., M. and T) in Hodonín district in 1994, as occurring in feed mixtures (n= 15), drinking water (n = 10), stable sedimented dust (n = 14), slurry (n = 10) and pavement dust (n = 5). Maximum permissible contents (MPC) of extraneous matters in feed mixtures were exceeded in lindane (two samples) and polychlorinated biphenyls (PCB). MPC of extraneous matters were not exceeded in drinking waters in any of the samples examined. Feed mixtures were found to have the highest average lindane content (0.054 mg/kg) and PCB sum (0.24 mg/kg); the ratio of lower chlorinated biphenyls (Delor 103) to higher chlorinated biphenyls (Delor 106) was 12:1; out of the PCB congeners, the highest amounts were determined for congeners 28 (0.067 mg/kg) and 52 (0.022 mg/kg); among the DDT isomers, isomer p,p'-DDT was prevailing (0.008 mg/kg). Drinking water had the 1:1 ratio of lower chlorinated to higher chlorinated biphenyls; out of the PCB congeners, the highest amounts were found out for congeners 28 (2.574 ng/l) and 101 (2.066 ng/l); among the DDT isomers, isomer p,p'-DDE was prevailing (1.887 ng/l). Stable dust was found to have the highest average level of DDT sum (0.026 mg/kg); the ratio of lower chlorinated to higher chlorinated biphenyls was 1:7; out of the PCB congeners, the highest amounts were determined for congeners 138 (0.036 mg/kg) and 153 (0.030 mg/kg); among the DDT isomers, isomer p,p'-DDE was prevailing (0.012 mg/kg). Slurry showed the 1:6 ratio of lower chlorinated to higher chlorinated biphenyls; out of the PCB congeners, the highest amounts were found out for congeners 138 (0.016 mg/kg dry matter) and 153 (0.014 mg/kg dry matter); among the DDT isomers, isomer p,p'-DDT was prevailing (0.005 mg/kg dry matter). Pavement dust had the 1:5 ratio of lower chlorinated to higher chlorinated biphenyls; out of the PCB congeners, the highest amounts were found out for congeners 138 (0.016 mg/kg) and 153 (0.012 mg/kg); among the DDT isomers, isomer p,p'-DDE was prevailing (0.005 mg/kg). Examination of feed mixtures and drinking waters will provide basic data on pollutant inputs to the stable environment. Stable sedimented dust is considered as an outstanding indicator of pollutant contamination of stable environment, regardless whether it comes from feed or other sources. Slurry examination will provide additional information on the total pollutant load of pig farms, informing us about outputs of extraneous matters residues from pig farms. Pavement dust examination indicates the level of pollutant load of outside stable environment as the pollutants can occasionally penetrate to the internal stable environment.

Mutagenicity of stable dust and drinking water on swine and cattle farms

Single pilot examinations of mutagenicity of stable dust and drinking water were made on three swine farms (D., M., T.) and one cattle farm (N.) in the district of Hodonín in summer 1994. The mutagenicity was examined by the Ames test using the indicator strains Salmonella typhimurium TA 98 and TA 100 with (+S9) or without (-S9) metabolic activation. At the same time the contents of selected pesticides (PES) and polychlorinated biphenyls (PCB) in stable dust and drinking water and that of polycyclic aromatic hydrocarbons in stable dust were determined. Increased mutagenicity was demonstrated in drinking water (strain TA 98 with metabolic activation; index Rt/Rk 3.6-7.7) and stable dust (strain TA 100 with metabolic activation; index Rt/Rk 2.2) collected on the swine farm M. High contents of PAH (8.246 mg/kg) and PCB (0.263 mg/kg) were also found in the dust samples collected on this farm. Only drinking water showed mutagenic activity (strain TA 98 without metabolic activation; index Rt/Rk 2.6) on the swine farm D. On both the farms, the number of revertants was dose-dependent. Increased content of PAH (2.553 mg/kg) was also demonstrated on the dust samples collected on the farm D. No significant increase (twofold or higher when compared with negative controls) of mutagenic activity of stable dust or drinking water was demonstrable on the swine farm T. and the cattle farm N. Substances responsible for the mutagenicity of drinking water on the farms D. and M. have not yet been identified. Anyway, the increase of mutagenicity of stable dust and drinking water should be taken as a warning that mutagens that can jeopardise animal and human health have penetrated into the stable environment.