Environmental risk assessment of PPP application in European soils and potential ecosystem service losses considering impacts on non-target organisms.

The use of Plant Protection Products (PPPs) is leading to high exposure scenarios with potential risk to soil organisms, including non-target species. Assessment of the effects of PPPs on non-target organisms is one of the most important components of environmental risk assessment (ERA) since they play crucial functions in ecosystems, being main driving forces in different soil processes. As part of the framework, EFSA is proposing the use of the ecosystem services approach for setting specific protection goals. In fact, the services provided by soil organisms can be impacted by the misuse of PPPs in agroecosystems. The aim of this work was to assess PPPs potential risk upon ecosystem services along European soils, considering impacts on earthworms and collembola. Four well-known (2 insecticides-esfenvalerate and cyclaniliprole- and 2 fungicides - picoxystrobin and fenamidone-) worst case application (highest recommended application) were studied; exploring approaches for linked observed effects with impacts on ecosystem services, accounting for their mode of action (MoA), predicted exposure, time-course effects in Eisenia fetida and Folsomia sp. and landscape variability. The selected fungicides exerted more effects than insecticides on E. fetida, whereas few effects were reported for both pesticides regarding Folsomia sp. The most impacted ecosystem services after PPP application to crops appeared to be habitat provision, soil formation and retention, nutrient cycling, biodiversity, erosion regulation, soil remediation/waste treatment and pest and disease regulation. The main factors to be taken into account for a correct PPP use management in crops are discussed.

Toxicity interaction between chlorpyrifos, mancozeb and soil moisture to the terrestrial isopod Porcellionides pruinosus.

A main source of uncertainty currently associated with environmental risk assessment of chemicals is the poor understanding of the influence of environmental factors on the toxicity of xenobiotics. Aiming to reduce this uncertainty, here we evaluate the joint-effects of two pesticides (chlorpyrifos and mancozeb) on the terrestrial isopod Porcellionides pruinosus under different soil moisture regimes. A full factorial design, including three treatments of each pesticide and an untreated control, were performed under different soil moisture regimes: 25%, 50%, and 75% WHC. Our results showed that soil moisture had no effects on isopods survival, at the levels assessed in this experiment, neither regarding single pesticides nor mixture treatments. Additivity was always the most parsimonious result when both pesticides were present. Oppositely, both feeding activity and biomass change showed a higher sensitivity to soil moisture, with isopods generally showing worse performance when exposed to pesticides and dry or moist conditions. Most of the significant differences between soil moisture regimes were found in single pesticide treatments, yet different responses to mixtures could still be distinguished depending on the soil moisture assessed. This study shows that while soil moisture has the potential to influence the effects of the pesticide mixture itself, such effects might become less important in a context of complex combinations of stressors, as the major contribution comes from its individual interaction with each pesticide. Finally, the implications of our results are discussed in light of the current state of environmental risk assessment procedures and some future perspectives are advanced.

Molluscicide baits impair the life traits of Folsomia candida (Collembola): Possible hazard to the population level and soil function.

The application of molluscicides baits on the soil surface is the most common practice to control terrestrial gastropods. There seems to be a gap in the accurate evaluation of molluscicidal baits effects to soil arthropods, since their hazard to non-target organisms has been considered low after mixing baits into soil. In this work the ecotoxicological effects of two molluscicide baits (metaldehyde and methiocarb) to the collembolan Folsomia candida were evaluated using two different approaches: (1) molluscicidal baits were applied to the top soil once and only at the beginning of the exposure and avoidance behaviour and reproduction were evaluated; and (2) baits were replaced by new ones after 14-d of exposure, simulating the recommended application rate recommended by the manufacturer and reproduction was assessed (repeated/pulse exposure). A preference for the side contaminated for methiocarb was observed but the distribution of collembolans in the avoidance test with metaldehyde was random. Exposure to metaldehyde resulted in a significant increase in mortality. For methiocarb, a reduction in the juveniles produced but no acute effects were observed. In the bait pulse test, the toxic effects of each chemical was significantly increased compared with the single exposure test, for all treatments used (both reproduction and mortality). In summary, molluscicides have an adverse effect on F. candida, with severe effects on their behaviour (only for methiocarb), reproduction and survival (for both), which can lead to population collapse with time.

Biomarkers and energy reserves in the isopod Porcellionides pruinosus: the effects of long-term exposure to dimethoate.

Terrestrial isopods from the species Porcellionides pruinosus were exposed to the recommended field dose application (0.4 mg/kg soil) and a sublethal concentration (10mg/kg soil) of dimethoate at two temperatures that can be generally found in several countries (20°C and 25°C) and are commonly used as reference temperatures. The organisms were exposed for 28 days and sampled at the following time points: 24h, 48 h, 96 h, 7 days, 14 days, 21 days, 28 days; organisms were then changed to clean soil for a recovery period of 14 days during which organisms were sampled on day 35 and 42. For each sampling time, the enzyme activities of acetylcholinesterase (AChE), glutathione-S-transferases (GST), catalase (CAT), lactate dehydrogenase (LDH) were determined as well as the following: total lipid, carbohydrate and protein content; energy available (Ea); energy consumption (Ec); cellular energy allocation (CEA) and lipid peroxidation rate (LPO). The integrated biomarker response (IBR) was calculated for each sampling time and for each of the above parameters. Mortality was also recorded during the study. The results obtained showed that dimethoate causes toxicity by several mechanisms. This study found evidence for the inhibition of the acetylcholinesterase enzyme, which has been previously reported, and also evidence of oxidative stress, which altered the levels of GST, CAT or LPO. In addition, the study showed that the two concentrations used of dimethoate caused the activation of different general detoxification mechanisms, and also that the same concentration at different temperatures induced different toxicity responses.

Evaluation of the joint effect of glyphosate and dimethoate using a small-scale terrestrial ecosystem.

In the present work a small-scale terrestrial ecosystem (STEM) containing a soil collected from an agricultural field in Central Portugal was used to evaluate the effects of the combination of the herbicide glyphosate and the insecticide dimethoate. Earthworms (Eisenia andrei), isopods (Porcellionides pruinosus), turnip seeds (Brassica rapa), and bait-lamina strips were placed in the STEM. The results showed that the application of the recommended field dose of both pesticides did not cause any effect on the weight variation of earthworms and growth of the plants. The application of the herbicide, even at 5 and 10 times the field dose, increased feeding activity in soil (bait-lamina test), although the application of dimethoate led to a decrease in feeding activity in all concentrations tested. The binary mixtures performed showed that according to the Independent Action model, synergism (higher effect than expected from the single exposures) was observed in both the shoot length and fresh weight of B. rapa at 5 times the field dose, but antagonism was observed at 10 times the field dose. Regarding the germination success, synergism was observed at the field dose, but antagonism was detected at 5 times and 10 times the field dose. There was a decrease on the earthworm's weight in all concentrations tested, although no statistical differences were observed in any of the treatments made. Regarding depth distribution of E. andrei, worms were found in the upper layer more than it was predicted for all concentrations. In the mixtures with the field and 5 times the field dose there was a decrease in the feeding activity (bait-lamina consumption) by the soil fauna. From the four biomarkers assessed on the isopods (Catalase, Acetylcholinesterase, Glutathione-S-transferase, and Lipid peroxidation), only a significant decrease in the Acetylcholinesterase activity upon dimethoate and the binary mixtures exposures performed with the field dose was observed and on Lipid peroxidation at the field doses of single and binary exposures.

Amplified ribosomal DNA restriction analysis as a routine tool to assess toxicant driven changes in hindgut bacterial populations of Porcellio dilatatus (Crustacea: Isopoda).

Changes in saprophytic organism's gut microbial communities may present a threat to organic matter breakdown which can ultimately lead to soil function impairment. In this study, Amplified Ribosomal DNA Restriction Analysis (ARDRA) was evaluated as a potential simple molecular tool to assess shifts in bacterial community structure in hindgut populations of Porcellio dilatatus exposed to contaminated food. This prospective tool can also be used for a variety of purposes and samples prior to the use of more specific and sophisticated methods.

Joint effects of three plant protection products to the terrestrial isopod Porcellionides pruinosus and the collembolan Folsomia candida.

The effects of simultaneous application of plant protection products are of concern since the uses of different products pose an additional risk to non-target soil organisms. The effects of binary combinations of dimethoate, glyphosate and spirodiclofen, an insecticide an herbicide and an acaricide, on the avoidance behaviour of the terrestrial isopod Porcellionides pruinosus and the reproductive effort of Folsomia candida were assessed using the two reference models of concentration addition (CA) and independent action (IA). Results of single exposure to the three pesticides indicated a clear dose related avoidance response of the isopods in the highest concentrations tested of the three as well as a strong decrease in collembolan adult survival and concomitant number of juveniles produced. In the combined experiments, antagonism was found in 7 out of the 12 combinations, four combinations followed the reference models, and only in one combination synergism was detected (lower doses of glyphosate and spirodiclofen applied to P. pruinosus). In conclusion, it seems that mixing and applying these products, at the recommended field application rate, does not lead to enhanced toxicity, hence limited risk is associated with the joint application of these pesticides.

Influence of treatment with zidovudine (ZDV) on the long-term survival of AIDS patients.

The influence of treatment with zidovudine (ZDV) and other factors on long-term survival of AIDS patients was analyzed in a cohort of 629 adults. A total of 434 (69%) were diagnosed before ZDV became routinely available in Spain (December 1987) or refused the drug, while the remaining 195 (31%) received ZDV (starting at a dose of 750-1,200 mg/day). A total of 412 (65.5%) were parenteral drug addicts and 217 (34.5%) male homosexuals. Two hundred thirty-two (36.9%) presented with a tuberculosis, 303 (48.2%) with other opportunistic infections, 69 (11%) with Kaposi's sarcoma, and the remaining 25 (4%) with a lymphoma. By December 1990, 251 (39.9%) of the 629 have already died with a cumulative survival probability of 50.6% after 2 years (45.3-55.9%; 95% confidence interval). When patients receiving ZDV were compared with those untreated, the estimated survival probability was significantly (p less than 0.0001) higher (89% vs. 59% after 1 year, 69% vs. 48% after 2 years, and 55% vs. 40% after 3 years). Moreover, treatment with ZDV (p less than 0.0001) together with being less than 45 years old (p less than 0.0001), being a parenteral drug addict (p = 0.016), and presenting with tuberculosis (p less than 0.0001) were the factors selected by the multivariate analysis as independently improving the prognosis. In conclusion, adult AIDS patients (homosexual or drug addicts) may benefit from treatment with ZDV, at least during 3 years.

Comparison of the nephrotoxicity and auditory toxicity of tobramycin and amikacin.

A total of 157 patients were treated with tobramycin or amikacin in a controlled prospective randomized trial. Dosages were adjusted to renal function according to a nomogram. Trough and peak aminoglycoside levels were available at the end of the trial. Of the above total, 113 recipients of nine or more doses of tobramycin or six or more doses of amikacin, without other apparent cause of renal failure, were evaluated for nephrotoxicity. Thirty-six patients were evaluated for auditory toxicity. The patients in groups evaluated for either nephrotoxicity or auditory toxicity were similar with respect to intensity and etiology of bacterial disease, concurrent exposure to other antimicrobial drugs, age and sex distribution, initial serum creatinine level, and total dose and duration of antimicrobial therapy. Nephrotoxicity of similar severity developed in 4 of 59 (6.8%) recipients of tobramycin and in 7 of 54 (13.1%) recipients of amikacin (P greater than 0.05). Mild auditory toxicity developed in 3 of 19 (15.7%) recipients of tobramycin and in 2 of 17 (11.7%) recipients of amikacin (P greater than 0.05). When patients with abnormally high mean trough or peak aminoglycoside levels were excluded from comparison, nephrotoxicity was 6.12 and 5.12% (P greater than 0.05) and auditory toxicity was 17.6 and 7.69% (P greater than 0.05) in the groups given tobramycin and amikacin, respectively. We conclude that the nephrotoxicity and auditory toxicity of amikacin and tobramycin are not significantly different and that such toxicities are indeed infrequent events when the dosages of these drugs are adjusted to hold blood levels within the safe boundaries suggested by the studies of others.

Oxymetholone effect of acute myeloblastic leukemia cells in vitro.

The possibility that oxymetholone might induce or enhance leukemia after androgen therapy for aplastic anemia prompted us to study the direct action of oxymetholone on the DNA synthesis of AML cells in vitro. The peripheral blasts of 10 patients, 8 with AML and 2 with CML in blast crisis have been studied. The DNA synthesis of the leukemic cells with and without oxymetholone was measured by the 3H-methyl-thymidine incorporation determined by liquid scintillation. The results have been shown a wide variation of DNA synthesis from patient to patient with a range from 2,000 to 40,000 cpm but no significant difference between test and control cultures. We may conclude that oxymetholone does not increase directly the proliferation capacity of the peripheral AML cells cultured in vitro.