Efficacy of five 'sporicidal' surface disinfectants against Clostridioides difficile spores in suspension tests and 4-field tests.

BACKGROUND: A sporicidal surface disinfection is recommended both for the outbreak and the endemic setting but a comparative evaluation on the efficacy of 'sporicidal' surface disinfectants using suspension tests and 4-field tests has not been performed. AIM: To determine the efficacy of five 'sporicidal' surface disinfectants (three ready-to-use wipes (A, B, E), two concentrates (C, D) based on peroxides or aldehydes against C. difficile spores. METHODS: The efficacy was determined under clean conditions using a suspension test and the 4-field test. Each test was performed in duplicate in two separate laboratories. Wipes were wrung to collect the solution for the suspension tests. RESULTS: Product A (peracetic acid; 5 min), product C (peracetic acid; 2% solution in 15 min or 1% solution in 30 min) and product D (peracetic acid; only 2% solution in 15 min) were effective with at least a 4 log10-reduction of C. difficile spores in suspension and on surfaces. Product B (hydrogen peroxide) was not effective in suspension (0.9 log10 after 15 min; 3.2 log10 after 1 h) and on surfaces (2.8 log10 after 15 and 60 min). Product E based on glutaraldehyde, (ethylendioxy)dimethanol and DDAC demonstrated 0.9 log10 after 4 h in suspension and 4.5 log10 after 4 h on surfaces. CONCLUSIONS: Not all surface disinfectants with a sporicidal claim were effective against C. difficile spores in standardized suspension tests and in the 4-field test. In clinical practice preference should be given to products that reliably pass the efficacy criteria of both types of tests.

Effects of low frequency noise on man--a case study.

Based on a real case effects of long-term exposure of infrasound on man are outlined. Beside a description of the background of the case together with remarks on the occurred health problems, the main view lies on the proceeding in identifying the special kind of exposure just as possible technical causes. As a source of annoyance a small heating plant was identified, which immitted into the house of the exposed people very low frequency airborne sound far below the common hearing thresholds. The results show clearly the general deficit of research on the effects of low level infrasound on man.

A standardized test to assess the impact of different organic challenges on the antimicrobial activity of antiseptics.

This paper presents a suggestion for determining the antimicrobial efficacy of antiseptics in a phase 2/step 1 assay. Emphasis is placed on specific organic challenges to evaluate the efficacy of antiseptics used to rinse the oral cavity, mucous membranes, or wounds for either prophylactic or therapeutic reasons. Basic data are given concerning ready-to-use products based on Poly(1-vinyl-2-pyrrolidone-)iodine-complex (PVP-iodine), chlorhexidine, octenidine, or cetylpyridinium chloride. Hydrogen peroxide (3.0%) was included to assess a product with known limited efficacy only. Using Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Enterococcus faecium, and Candida albicans, a 10(5)-fold reduction can be achieved in 10 min without interfering substances. In the presence of 10% albumin, 10% sheep blood, or 1% mucin, a 10(3)-fold reduction is yielded using products based on PVP-iodine, octenidine, or chlorhexidine. The combination of 4.5% albumin, 4.5% sheep blood, and 1% mucin was the most difficult organic challenge and only the products based on PVP-iodine, octenidine, or chlorhexidine remained active. The cetylpyridinium-based product and hydrogen peroxide were less effective. Based on these data, a proposal for a phase 2/step 1 assay for antiseptics is presented to promote the standardization efforts.

Do cancer patients with chemotherapy-induced leukopenia benefit from an antiseptic chlorhexidine-based oral rinse? A double-blind, block-randomized, controlled study.

Patients undergoing cancer chemotherapy frequently suffer from mucositis, particularly if they become leukopenic (leucocytes <1000/microL). To identify a possible benefit from antiseptic rinsing of the oral cavity, 47 patients were randomized to rinse either with a chlorhexidine-based product (chlorhexidine concentration 0.3%; N=24) or with an amine-stannous fluoride combination (control group; N=23). Patients were asked to rinse three times a day for 30s from the beginning of chemotherapy until the end of leukopenia. Before rinsing, as well as during and after leukopenia, aerobic and anaerobic bacteria in the oral cavity were counted. At the same time, the patients were assessed for mucositis. In the chlorhexidine-based group, a significant decrease of the aerobic (P=0.042) and anaerobic (P=0.008) bacterial flora was identified. In the control group, the numbers of aerobic and anaerobic bacteria remained unchanged (P>0.05). Fifteen patients in the chlorhexidine-based group had a C-reactive protein (CRP) increase >50mg/L, compared with only eight patients in the control group [odds ratio: 3.13, confidence interval (CI) 0.82-12.39]. Nine patients in the chlorhexidine-based group but only two patients in the control group developed severe mucositis. This difference was statistically significant with an odds ratio of 6.30 (CI: 1.02-49.67). As not all of the 47 patients developed severe leukopenia, a separate analysis was carried out for patients with <1000 leucocytes/microL for a minimum of three days. The results of the microbial counts were very similar, with a clear reduction in the chlorhexidine group and no major alterations in the control group. Twelve of 15 patients in the chlorhexidine-based group had a CRP >50mg/L whereas only eight of 15 patients did so in the control group, which can be regarded as a slightly elevated risk for a CRP increase in the former group. Seven of 15 patients developed severe mucositis in the chlorhexidine-based group, but only two of 15 patients in the control group. These differences were not significant, but patients treated with chlorhexidine-based product seemed to have more problems with inflammation of the oral mucous membranes, resulting in an elevated mucositis score and a CRP increase. Other parameters such as body temperature or application of antibiotics did not differ between the two groups. We conclude that treatment with the chlorhexidine-based product did not provide a clinical benefit for cancer chemotherapy patients. On the contrary, the risk of mucositis and clinical sequelae seems to be enhanced, although the counts of micro-organisms on the oral mucous membranes are significantly reduced.

The effect of a polyhexamethylene biguanide mouthrinse compared to an essential oil rinse and a chlorhexidine rinse on bacterial counts and 4-day plaque regrowth.

OBJECTIVES: For various clinical applications, polyhexamethylene biguanide hydrochloride (PHMB) has been used for many years as an antiseptic in medicine. Recently, a 0.04% PHMB mouthwash was shown to inhibit plaque regrowth and to reduce oral bacterial counts. In this study, a 0.12% PHMB mouthrinse (A) was compared with a negative control placebo rinse (10% ethanol, flavour) (B), a positive control 0.12% chlorhexidine rinse (C), and a commercially available mouthrinse containing essential oils (Listerine) (D). MATERIALS AND METHODS: The study was a double-blind, randomised 4-replicate 4 x 4 Latin square cross-over design in which plaque regrowth was measured. The in vivo antibacterial effect was assessed by taking bacterial counts from the tooth surface and mucosa 4 h after the first rinse with the preparations on day 1 and prior to the clinical examination on day 5. 16 volunteers participated and, on day 1 of each study period, were rendered plaque-free, ceased toothcleaning, and rinsed 2x daily with the allocated mouthrinse. On day 5, plaque was scored and smears were collected according to the protocol. Washout periods were 9 days. Data were analysed using ANOVA with Bonferroni HSD adjustment for multiple comparisons (significance level alpha=0.05). RESULTS: The 0.12% PHMB mouthrinse (A) was significantly more effective in inhibiting plaque than the placebo (B) but no significant differences could be observed between A and 0.12% chlorhexidine (C), or between A and Listerine (D). Bacterial count reductions on the tooth surface with PHMB (A) were significantly greater compared to the placebo (B) after 4 h and significantly greater compared to B and D after 5 days. Chlorhexidine (C) was more effective than A after 5 days. On the mucosa, chlorhexidine (C) was significantly more effective in reducing bacterial counts than the other 3 treatments at both time points investigated. PHMB (A) was significantly more effective in reducing bacterial counts than the placebo (B) after 4 h and after 5 days, and than D after 4 h. CONCLUSION: Consistent with a previous study, a PHMB mouthrinse was shown to inhibit plaque recolonisation and to reduce oral bacterial counts, indicating that PHMB may find applications in the prevention of plaque-associated diseases.

Effect of a polyhexamethylene biguanide mouthrinse on bacterial counts and plaque.

OBJECTIVES: For various clinical applications, polyhexamethylene biguanide (PHMB) has been used for many years as an antiseptic in medicine. Little is known, however, of its antibacterial activity in the oral cavity and its ability to inhibit plaque formation. In this study, a 0.04% PHMB mouthrinse (A) was compared with a negative control placebo rinse (10% ethanol, flavour) (B) and 2 positive control chlorhexidine rinses, one of which was a 0.12% aqueous solution (C) and the other a commercially available mouthrinse (Skinsept mucosa) diluted to a chlorhexidine concentration of 0.12% (D). MATERIAL AND METHODS: The study was a double-blind, randomised 4-replicate 4 x 4 Latin square cross-over design. Plaque regrowth was assessed with the Turesky et al. modification of the Quigley and Hein plaque index. The in vivo antibacterial effect was assessed by taking bacterial counts from the tooth surface (smears from the lingual surface of 16) and mucosa (smears from the buccal mucosa) 4 h after the 1st rinse with the preparations on day 1 and prior to the clinical examination on day 5. 16 volunteers participated, and on day 1 of each study period were rendered plaque-free, ceased toothcleaning, and rinsed 2x daily with the allocated mouthrinse. On day 5, plaque was scored and smears were collected according to the protocol. Washout periods were 9 days. Data were analysed using ANOVA with Tukey HSD adjustment for multiple comparisons (significance level alpha=0.05). RESULTS: Mouthrinses A, C, and D were significantly more effective in inhibiting plaque than the placebo (B). Mouthrinse C was significantly better than mouthrinses A and D, while mouthrinses D and A were equally effective in inhibiting plaque. Bacterial count reductions on the tooth surface with mouthrinse C were significantly greater compared to mouthrinse A and the placebo (B). The reduction of bacterial counts on the mucosa with C was significantly greater than with A and B after 4 h and significantly greater than with A, B and D after 5 days. Mouthrinse A reduced bacteria on the mucosa significantly more effectively than the placebo (B) after 4 h and 5 days, while mouthrinse D was more effective than the placebo (B) after 4 h. CONCLUSION: The results indicate that a 0.04% PHMB mouthwash inhibits plaque regrowth and reduces oral bacterial counts, and may be used in preventive applications in the oral cavity.

Filamentous fungi and yeasts on mattresses covered with different encasings.

Besides mites, filamentous fungi and yeasts play an important role as domestic allergens. Among different allergen avoidance strategies the efficacy of synthetic mattress encasings has been demonstrated for the reduction of house dust mites. Whether these synthetic encasings are also able to reduce the growth of fungi on the mattress under domestic conditions has not been assessed so far. To determine if the fungal growth on mattresses can be reduced by the use of synthetic encasings we assessed the fungal colonisation of mattresses covered either by conventional cotton encasings or by polyurethane encasings impermeable to particles > 3 mum. Within a 12-month period dust samples were obtained from the mattresses. Fungal quantities were measured by counting colonies on agar plates incubated at 20 degrees C and 37 degrees C. The counts of fungi were significantly higher on mattresses with cotton encasings. Penicillium spp. and Aspergillus spp. were isolated most frequently. Therefore the application of synthetic encasings with similar properties to the encasings used in this investigation is recommended as part of an allergen avoidance strategy for patients sensitised to fungal allergens.

Efficacy of cetylpyridinium chloride used as oropharyngeal antiseptic.

Cetylpyridinium chloride, (CPC, CAS 123-03-5) as active ingredient of antiseptic oral mouthrinses has a broad antimicrobial spectrum with a rapid bactericidal effect on gram-positive pathogens and a fungicide effect on yeasts in particular. There are gaps in its effectiveness against gram-negative pathogens and mycobacteria. Application of CPC at a concentration of 0.05% as a mouthrinse results in an immediate reduction in bacterial counts of 2.0 to 2.5 log steps (which is adequate to > 99%). This reverts to about 1 log step (= 90%) 1 h after application. The ability of CPC to inhibit plaque and thereby reduce gingivitis is assured. In comparison to chlorhexidine, CPC has a lower residual effect, and as a result a lesser effect against plaque and gingivitis. The efficacy of CPC against oropharyngeal candidiasis is assured. CPC mouthrinses can significantly reduce infectious aerosols in dental practice, thereby protecting both staff and the patient. The balance of intra-oral bacterial flora is not disturbed even in the case of relatively long-term use of CPC (up to six weeks). Taking these properties into consideration, CPC may be considered as an alternative active ingredient in the case of chlorhexidine intolerance in the treatment and prevention of bacterial or fungal disorders of the oropharyngeal cavity. It is also of interest as an element for combination in the development of new types of oropharyngeal antiseptics.

Transmission of a multiresistant Pseudomonas aeruginosa strain at a German University Hospital.

Over 15 months, 60 patients at a German University Hospital became infected or colonized by a multiresistant Pseudomonas aeruginosa strain, which was isolated from tracheal secretions, blood, urine, venous catheters, ascites and several wounds. Most patients had undergone invasive treatment (surgery, cancer therapy). The genetic relationship of the isolates was investigated by pulsed field gel electrophoresis. The isolates were resistant to beta-lactam antibiotics, including carbapenems and aztreonam, to aminoglycosides and quinolones. The only in vitro susceptibility was to polymyxin B. Extensive sampling was carried out to identify contaminated medical devices, surfaces or media (water, food). Samples were taken from doctors and nursing staff and various treatment procedures were observed for several weeks. The handling of respirators, resuscitation tubes, urine bottles, and bedpans resulted in the contamination of the patients' environment, although most devices were cleaned and disinfected with automatic washer/disinfectors. Several wash basins on the intensive care unit were contaminated, but none of the drinking water samples showed any growth of P. aeruginosa. We recommend the strict use of gloves and strict application of alcoholic hand disinfectants immediately after discarding the gloves. The chain of infection ceased after strict cohort isolation and the subsequent introduction of the specific hygiene regime.

Assessment of the activity of antiperspirants added to surgical hand disinfectants: methodological aspects and first observations.

Due to the risk of sensitization caused by glove powder, the use of unpowdered latex gloves is increasing. These unpowdered gloves need a special inner-surface layer which makes it easier for the applicant to put the glove on the hand and to remove it again. However, many users report difficulties with removing the gloves because of sweat production within the glove. Therefore, a method has been developed to evaluate the efficacy of antiperspirants which may be added either to the inner-surface layer of the glove or to hand disinfectants or to skin-care products used before the gloves are put on. The paper describes various trials to optimize this method.

[Reduction of colonization of new mattresses with bacteria, moulds and house dust mites by complete mattress covers]. / Reduktion der Besiedlung neuwertiger Matratzen mit Bakterien, Schimmelpilzen und Hausstaubmilben durch Matratzenganzbezüge.

BACKGROUND AND OBJECTIVE: We investigated if the colonisation of new mattresses with house dust mites, bacteria, and fungi could be reduced by using synthetic mattress covers as compared to common cotton covers. PATIENTS/METHODS: 84 healthy volunteers were assigned to two groups. Group A (n = 43) received the cotton covers, group B (n = 41) the synthetic covers which were made of a polyester microfaser with a polyurethane surface layer (Pro-Tex, Germed, Schwarzenbek, Germany). RESULTS: The mite antigen concentration after six months was significantly lower in group B. Three months after the start of the study counts of bacteria and moulds were significantly higher in group A compared to group B. CONCLUSIONS: It can be recommended that patients suffering from an allergy to mites or moulds may reduce their domestic allergen exposure by using the synthetic mattress covers tested in this study. Since cotton covers are very likely to become colonised by bacteria and moulds, they must be cleaned periodically (at least every 2nd-3d month).

Prophylactic and therapeutic application of antimicrobial agents in the oral cavity.

Antimicrobial substances are used for many prophylactic and therapeutic reasons in the oral cavity. They are used as mouthrinses, for the irrigation of specific oral locations, in form of gels, or varnishes. Different antimicrobial agents are available and some preparations are complex compositions of these compounds. Although it has been proven that several agents are suited to achieve a considerable reduction of oral microorganisms many questions concerning the clinical benefit are yet to be answered. This report summarises the evidence of the efficacy of oral antiseptics (especially chlorhexidine, pvp-iodine, and Listerine) depending on different indications, which is the basis for clinical and practical recommendations.

[Air pollution by volatile organic compounds (VOC) and health complaints]. / Raumluftbelastung durch flüchtige organische Verbindungen (VOCs) und gesundheitliche Beschwerden.

BACKGROUND AND OBJECTIVE: Complaints of well-being and health after moving in a new or redeveloped building occur quite frequently. If these complaints persist for several months and are indicated by the majority of occupants, an examination of the air quality is required. However, the interpretation of these data can be difficult since different recommendations but no threshold limit values for the indoor contamination with volatile organic compounds (VOC's) exist. PATIENTS AND METHODS: This report presents a case with serious health complaints (14 males, average age 40.4 years; 44 females, average age 37.9 years) after moving in a completely redeveloped building. Complaints of well-being and health were investigated by a standardised questionnaire and compared with a control group (11 males, average age 41.4 years; 12 females, average age 33.3 years). The VOC-contamination was analysed by various measurements. RESULTS: Two months after moving into the building a total VOC-concentration of 2000-3000 micrograms/m3 was registered, after 10 months the concentration decreased to 900-1300 micrograms/m3 due to intense airing. The following symptoms showed the clearest differences between exposed persons and the control group: soreness of throat (odds ratio: 10.72; 95%-confidence interval: 1.46-465.2), irritations of mucous membranes (OR: 10.45; 95%-CI: 1.43-453.8), headache (OR: 9.9; 95%-CI: 1.35-430.9) and increased weariness (OR: 7.55; 95%-CI: 1.55-71.2). As a consequence extensive redevelopment measures were initiated. CONCLUSION: Contamination of the indoor air with 900 micrograms/m3 VOC's (total value) can induce serious complaints of well-being and health. Rooms with VOC-concentrations > 1200-1500 micrograms/m3 are not suited for regular stay of unprotected people.

Formaldehyde neurotoxicity in animal experiments.

The aim of this study was to determine whether the inhalation of formaldehyde has a neurotoxicological impact. Forty Wistar rats (Lew.1/K) were trained to find food in a maze within a particular time. When all animals were at an equal level, 13 rats inhaled 2.6 ppm and 13 others inhaled 4.6 ppm formaldehyde 10 min/d, 7 d/week for 90 d. The control group comprised 14 animals inhaling water steam according to the same exposure pattern. During the exposure period and the post-trial observation stage (30 d), the time required to find the food and the number of mistakes made on the way were recorded. Between the animals exposed to formaldehyde and the control group a statistically significant difference for both parameters was observed (p < 0.05). The animals exposed to formaldehyde needed more time and made more mistakes than the animals of the control group while going through the maze. The results underline the necessity for a systematic observance of precautions in case of occupational or dwelling-related formaldehyde exposure, and allow us to classify formaldehyde as "probably neurotoxic". Further investigations are required to assess the neurotoxicologic impact of subchronic formaldehyde exposure.

The integrity of latex gloves in clinical dental practice.

BACKGROUND: The aim of the study was to assess the integrity of non-sterile latex gloves (Biogel Diagnostic (A), Biogel Dental (B), Gentle Skin (C) and Manufix (D)) in clinical dental practice. MATERIALS AND METHODS: After use, the gloves were collected and examined for perforations using the water inflation test according to the EN 455-1 Standard. Over a 12-month period 847 used gloves were collected and assessed. The mean duration of use for gloves A/B/C/D was 175/112/78/79 min respectively. In spite of these differences favoring gloves C and D, 16% of glove A, 14% of glove B, 21% of glove C and 29% of glove D were found to leak. The proportion of perforated gloves increased slightly if a hygienic handrub using an alcoholic hand disinfectant had been carried out immediately prior to gloving. CONCLUSION: The results indicate striking differences between the quality of medical gloves. As all the gloves comply with the European regulations in terms of integrity, it is very difficult for the user to distinguish between gloves of superior or inferior quality. In a clinical setting it is therefore recommended that the appropriate glove should be determined for each situation. Hands must be thoroughly dry if they are disinfected prior to gloving, since hands still wet with alcoholic disinfectant may increase the risk of glove perforation.

Antimicrobial efficacy of antiseptic mouthrinse solutions.

OBJECTIVE: To assess the activity of different mouthrinse solutions compared to sterile water and sage tea against aerobe bacteria in the oral cavity. METHODS: The extent and the duration of the salivary bacterial count reduction were determined using a uniform model that allows a direct comparison of the different products. In contrast to previous investigations the antimicrobial activity of the tested products was stopped by specific neutralizers immediately after sampling. RESULTS: The obtained results allowed us to classify four categories of mouthrinse solutions according to their antimicrobial properties: Products without any active antimicrobial effect (sterile water, sage tea, Fluomint-Lysoform), products with a weak and temporary effect that does not exceed a salivary bacterial count reduction of 1.5 log of colony forming units (cfu) immediately and 1.0 log cfu 1 h after application (hydrogen peroxide, Meridol, Listerine, Lavasept), products with a strong immediate effect (> or =1.5 log cfu) but no prolonged activity (Betaisodona solution, acriflavine) and finally products that exert a sustained effect of at least 1.0 log cfu 1 h after application (Chloramine T, Gurfix, Skinsept mucosa, Corsodyl, Dobendan, Octenisept). CONCLUSION: The method used in this investigation allows an easy and reproducible evaluation of antimicrobial efficacy and may be part of a future test guideline for efficacy testing of antiseptics.

A large outbreak of multiresistant Pseudomonas aeruginosa strains in north-eastern Germany.

Multiply-resistant Pseudomonas aeruginosa were first detected in north-eastern Germany at the end of 1996; since then they have been isolated predominantly from patients in intensive care units. Colonization/infection, especially of the respiratory tract, has been demonstrated in 80 patients, with strains resistant to beta-lactams, carbapenems, aminoglycosides and quinolones. Amikacin showed in-vitro synergy with cefepime, ceftazidime or piperacillin/tazobactam. Horizontal transfer of strains was followed by PFGE and identical strains were detected in the environment, but the source of infection was not established. Rigorous infection control and restricted clinical use of carbapenems limited further dissemination of this outbreak.

[The efficacy of repeated disinfection of disposable gloves during usage]. / Untersuchungen zur wiederholten Desinfizierbarkeit von Einweghandschuhen während des Tragens.

The efficacy of disinfecting medical gloves with isopropanol 60% (v/v) while they are worn was assessed for 4 different brands of latex gloves (Biogel Diagnistic (A), Safeskin Satin Plus (B), Safeskin LPE (C) and Baxter Non-Sterile Latex Exam Gloves (D)) and one latex-free nitrile glove (100% Nitrile N-Dex (E)). Even in the presence of coagulated blood disinfection of the gloves was more efficient than disinfection of the bare hand. The efficacy of the disinfection of glove C, D and E decreased if 10 disinfections were carried out successively. An increase of perforations detected with the water inflation test according to EN 455-1 was found for brand E. As gloves of brand C and D became tacky after 10 disinfections, they were inappropriate for manual work. As a result, disinfection with isopropanol 60% (v/v) can be recommended for gloves of brand A and B only. Disinfection of these gloves is admissible e.g. after indirect patient contact, taking blood samples or laboratory work if no visible contamination or perforation has occurred. However, after contact with patients suffering from an infectious disease or carrying multiresistant organisms the gloves have to be changed. The same holds true if the gloves might be contaminated with naked viruses (e.g. Poliomyelitis virus), since virucidal alcoholic hand disinfectants require high concentration thus leading to materials incompatibility.

Risk assessment of a former military base contaminated with organoarsenic-based warfare agents: uptake of arsenic by terrestrial plants.

Organoarsenic-based chemical warfare agents (CWAs) such as the sternutators diphenylchloroarsine (CLARK I), diphenylcyanoarsine (CLARK II) or phenyldichloroarsine (PFIFFIKUS) still pose a notable risk in countries where former military bases that have stored these weapons have not yet been reclaimed. In fact, this is the case for many countries of Eastern Europe and the CIS. One of the most important military bases of the former Third Reich, the Heeresmunitionsanstalt I and II, is situated close to the German-Polish border at Loecknitz (Fig. 1). The German army stored and decanted different compounds of CWAs at this military base until 1945. When the Soviet Army destroyed the base in 1946, large amounts of CWAs and other organoarsenic compounds polluted the soil. Today up to 250 g (!) of arsenic may be found in 1 kg of soil at some places in this area. Since 1991, a Government Working Group has been working on the risk assessment in order to define the scope of reclamation measures. This study investigates the contamination and the uptake of arsenic by plants because little is known about the bioavailability and metabolism of sternutators and their constituents. The total arsenic concentration of nine different species of terrestrial plants with at least six samples per species is presented. In spite of the considerable arsenic contamination of the soil (mean value 923 mg arsenic/kg soil) the plant contamination remained comparably low. The median value of arsenic contamination of the above-ground organs of velvet grass, Holcus lanatus, was 0.7 mg/kg dry wt. and the mean value was 4.3 mg/kg dry wt. due to some highly contaminated samples. The highest arsenic concentration registered was 26 mg/kg dry wt. in a sample of H. lanatus, which was most probably caused by soil particles adhering to the plant. The chemical structure of the arsenic compounds carried by the above-ground plant organs has been determined by gas chromatographic investigations and showed an uptake of triphenyl arsine by the plants.