Usefulness of oxidative stress biomarkers in native species for the biomonitoring of pesticide pollution in a shallow lake of the Austral Pampas, Argentina.

Pesticide contamination and its adverse effects on native freshwater species continue to be a worldwide major concern, mainly in developing countries. Passive biomonitoring of pesticide pollution in shallow lakes may be achieved by the simultaneous use of fish and wetland plants. Thus, the present study aimed to evaluate the occurrence of current-use pesticides in the surface water of a shallow lake of the Austral Pampas region (Buenos Aires Province, Argentina) surrounded by intensive agricultural activities and its relationship with a battery of biomarkers, including oxidative stress and genotoxicity, in two native species, the fish Oligosarcus jenynsii and the macrophyte Bidens laevis. A total of 26 pesticide residues were analyzed, and the main ones detected were glyphosate and its metabolite aminomethylphosphonic acid (AMPA), chlorpyrifos, and imidacloprid. In O. jenynsii, hydrogen peroxide (H2O2) content in the liver increased with chlorpyrifos occurrence, while malondialdehyde (MDA) levels in the brain and liver increased with the presence of both chlorpyrifos and glyphosate. In B. laevis, H2O2 and MDA levels in leaves and roots increased with AMPA occurrence. Also, leaf H2O2 contents and root MDA levels increased with chlorpyrifos concentration. In contrast, catalase and peroxidase activities in roots decreased with AMPA and chlorpyrifos occurrence. In both species, mainly H2O2 and MDA levels demonstrated their sensitivity to be used as biomarkers in the biomonitoring of current-use pesticide pollution in shallow lakes. Their use may provide information to plan strategies for environmental conservation by government institutions or decision-makers, and to assess the biota health status.

Effect of on-farm poultry litter composting processes on physicochemical, biological, and toxicological parameters and reduction of antibiotics and antibiotic-resistant Escherichia coli.

Poultry litter is a valuable source of nutrients for crop production, but its use in agriculture can lead to environmental and public health concerns due to the presence of pollutants, antibiotic-resistant bacteria (ARB) and antibiotic-resistant genes (ARGs). We compared the effect of different on-farm poultry litter composting processes on physicochemical, biological, and toxicological parameters, as well as on the occurrence of antibiotics and resistant Escherichia coli. The composting treatments consisted of passively-aerated piles C:N = 19 (PAC19), mechanically-aerated piles C:N = 19 (MAC19), and mechanically-aerated piles C:N = 30 (MAC30). Poultry litter composting led to a significant reduction of antibiotic residues, enteroparasites and antibiotic resistant E. coli. The conditions of the process, such as extra C source and mechanical aeration influence the quality of the final product. MAC19 is a low-cost effective method to reduce the potential risks associated with poultry litter use in agriculture and produce good quality compost.

Influence of exposure time, physicochemical properties, and plant transpiration on the uptake dynamics and translocation of pharmaceutical and personal care products in the aquatic macrophyte Typha latifolia.

Typha latifolia is widely used as a phytoremediation model plant for organic compounds. However, the dynamic uptake and translocation of pharmaceutical and personal care products (PPCPs) and their relationship with physicochemical properties, such as lipophilicity (LogKow), ionization behavior (pKa), pH-dependent lipophilicity (LogDow), exposure time and transpiration, are scarcely studied. In the current study, hydroponically grown T. latifolia was exposed to carbamazepine, fluoxetine, gemfibrozil, and triclosan at environmentally relevant concentrations (20 µg/L each). Eighteen out of thirty-six plants were exposed to the PPCPs and the other eighteen were untreated. Plants were harvested at 7, 14, 21, 28, 35, and 42 days and separated into root, rhizome, sprouts, stem, and lower, middle, and upper leaf sections. Dry tissue biomass was determined. PPCP tissue concentrations were analyzed by LC-MS/MS. PPCP mass per tissue type was calculated for each individual compound and for the sum of all compounds during each exposure time. Carbamazepine, fluoxetine, and triclosan were detected in all tissues, while gemfibrozil was detected only in roots and rhizomes. In roots, triclosan and gemfibrozil mass surpassed 80% of the PPCP mass, while in leaf carbamazepine and fluoxetine mass represented 90%. Fluoxetine accumulated mainly in the stem and the lower and middle leaf, while carbamazepine accumulated in the upper leaf. The PPCP mass in roots and rhizome was strongly positively correlated with LogDow, while in leaf it was correlated with water transpired and pKa. PPCP uptake and translocation in T. latifolia is a dynamic process determined by the properties of contaminants and plants.

Atrazine uptake, translocation, bioaccumulation and biodegradation in cattail (Typha latifolia) as a function of exposure time.

The extensive use and environmental persistence of atrazine has resulted in its ubiquitous occurrence in water resources. Some reports have described atrazine bioaccumulation and biodegradation pathways in terrestrial plants, but few have done so in aquatic macrophytes. Thus, in this study, we aimed to analyze morphological changes, uptake, translocation and bioaccumulation patterns in tissues of the aquatic macrophyte Typha latifolia (cattail) after long-term atrazine exposure and to determine the presence of atrazine biodegradation metabolites, desethylatrazine (DEA) and desisopropylatrazine (DIA), in tissues. Plants were hydroponically exposed to 20 µg/L atrazine (18 exposed and 18 non-exposed) for 7, 14, 21, 28, 35 and 42 days. Plants were separated into root, rhizome, stem, and lower, middle and upper leaf sections. Atrazine was analyzed by LC-MS/MS and DIA and DEA by LC-DAD. Plants showed reductions in weight (after 21 days) and transpiration (after 28 days), both symptoms of chronic phytotoxicity. The distribution of atrazine within tissues, expressed as concentration levels (µg/kg dry weight), was as follows: middle leaf (406.10 ± 71.77) = upper leaf (339.15 ± 47.60) = lower leaf (262.43 ± 7.66) = sprout (274.53 ± 58.1) > stem (38.63 ± 7.55) = root (36.00 ± 3.49) = rhizome (26.15 ± 3.96). In submerged tissues, DEA and DIA were detected at similar concentrations. In leaves, DIA was the main metabolite identified. Results indicated that atrazine was taken up from roots to shoots and induced phytotoxicity effects that reduced the translocation to shoots. Typha likely is able to biodegrade atrazine via different metabolic pathways.

Contaminants of emerging concern (CECs) in Zea mays: Uptake, translocation and distribution tissue patterns over the time and its relation with physicochemical properties and plant transpiration rate.

Passive uptake of contaminants of emerging concern (CECs) and its relationship with physicochemical properties, such as lipophilicity (LogKow), ionization behavior (pKa), distribution coefficient (LogDow) and transpiration rate are scarcely studied. In the current study, hydroponically grown corn (Zea mays) was exposed to carbamazepine (CBZ), fluoxetine (FLX), gemfibrozil (GBZ), triclosan (TRI) and atrazine (ATZ)) at environmentally relevant concentrations (20 µg/L each one). Plant tissue concentrations of CECs were determined several times over 21 days. Eighteen plants were used, nine exposed to the CECs and nine untreated. Whole plants were harvested at 7, 14 and 21 days and separated into roots, stem, leaf and male bud flower (only at 21 days). Hydroponic solution was maintained at pH 5.5 throughout the study. CECs concentrations in the exposure solution and tissues were determined by LC-MS/MS. ATZ metabolites desisopropylatrazine (DIA) and desethylatrazine (DEA) were determined by LC-DAD. In shoot tissues, CBZ, FLX and ATZ were detected, while TRI and GBZ were detected only in roots. Root concentrations were related with LogKow (R2ROOT = 0.415). Leaf and stem concentrations of CBZ, FLX and ATZ were linked with LogKow and strongly linked with pKa. Transpiration was related with CBZ and ATZ in shoot, but not related with FLX shoot levels. Neutral compounds such as CBZ (pKa = 13.94; 100% neutral) and ATZ (pKa = 1.6; 85% neutral) were taken up passively with transpiration. Root accumulation was related with CECs lipophilicity, while translocation and bioaccumulation in shoot were not only related with lipophilicity, but also with CECs ionization behavior and transpiration.

Ecological risk assessment of current-use pesticides and biocides in soils, sediments and surface water of a mixed land-use basin of the Pampas region, Argentina.

The present study aimed to assess the ecological risk of 30 current-use agricultural pesticides and biocides in the soil, sediments and aquatic organisms of a mixed land-use basin located in the Depressed Pampas Region of Argentina. Risk Quotients (RQs) were used to evaluate the chronic risk in soil and aquatic organisms, while Toxic Units (TUs) were used to assess the acute risk in sediment-dwelling organisms and aquatic biota. Acetochlor, hydroxy-atrazine, glyphosate, AMPA, metolachlor, imidacloprid and tebuconazole were the only pesticide residues detected (>30%) and quantified in all the matrices evaluated. Glyphosate and AMPA showed the highest concentrations, being their mean and maximum levels 27.90-176.00 µg kg-1 and 270-712.50 µg kg-1 in soils, 8.28-32.0 µg kg-1 and 6.85-17.50 µg kg-1 in sediments, and 1.88-4.36 µg L-1 and 0.66-1.03 µg L-1 in surface water. The RQs in soils showed high chronic risk, mainly due to AMPA and imidacloprid. The TUs in sediments showed acute risk in dwelling organisms, mainly due to glyphosate and imidacloprid. RQs assessment showed a range of chronic risk levels according to the site/sampling event, with higher contribution of atrazine and its metabolites, and acetochlor, whereas TUs assessment showed no acute risk in aquatic biota. In contrast to Europe, in Argentina, there are no restrictions regarding the use of atrazine, acetochlor, imidacloprid and glyphosate to protect aquatic life. Thus, it is recommended that the current Argentine pesticide regulations should be modified to prevent ecological risk and protect ecosystems.

Monensin occurrence in surface water and its impact on aquatic biota in a stream of the southeast Pampas, Argentina.

Monensin is an ionophore antibiotic used as a feed additive and growth promoter in cattle production worldwide. The occurrence of monensin in aquatic surficial ecosystems is of concern due to its possible detrimental effects on human health and native biota. Argentina is one of the most important cattle beef producers worldwide; however, there is little knowledge on the environmental occurrence of monensin and the associated risks to aquatic biota. In this study, we developed a method for the extraction and quantification of monensin in surface water; then, we evaluated the occurrence of monensin in a stream impacted by different animal husbandry's operations, and then, we analyzed the ecological implications of monensin residues on aquatic organisms using the risk quotient (RQ) method. Sampling was carried out on August 2017 from the headwaters to the floodplain of the El Pantanoso stream, Buenos Aires province, Argentina. Monensin detection frequency was 75% (n = 20). The median level was 0.40 µg/L and the maximum concentration was 4.70 µg/L. The main input of monensin was from a cattle slaughterhouse, an activity that has not been considered before in the literature as a source of emission of veterinary pharmaceuticals into the environment. The RQ assessment showed that monensin levels could have potential negative effects on aquatic biota in the sampling site closest to the cattle slaughterhouse. The data obtained in this study shows that monensin was present in El Pantanoso surface waters at levels of high ecotoxicological risk to aquatic biota.

Presence of the point mutations Val1016Gly in the voltage-gated sodium channel detected in a single mosquito from Panama.

BACKGROUND: In Panama, arboviroses such as dengue fever, and more recently chikungunya fever and Zika disease, are transmitted by Aedes aegypti and Aedes albopictus. Their control is based on the elimination of breeding sites and fogging with pyrethroid insecticides. However, one of the significant issues derived from the prolonged use of pyrethroid insecticide is the development of resistance mechanisms, such as knockdown resistance or kdr. The objective of this study was to evaluate the presence of kdr mutations in a partial region of the VGSC gene in samples of wild-caught Aedes mosquitoes from different locations of the Metropolitan Region of Panama. RESULTS: Based on the analysis of 194 sequences of the VGSC gene, two kdr mutations (Ile1011Met and Val1016Gly) were detected in a specimen of Ae. aegypti. The frequency of kdr mutations in the evaluated samples of Ae. aegypti was 0.01. CONCLUSIONS: This study provides evidence for a low frequency of kdr mutations in Ae. aegypti populations in Panama. It is possible that these changes have no impact on vector control interventions. To our knowledge, we report, for the first time in America the Val1016Gly mutation documented in Asia. In general terms, this result is highly relevant to the Aedes Control Programme in Panama since it constitutes a feasible approach for the timely detection of resistance as well as for the development of strategies.

Non-point source pollution of glyphosate and AMPA in a rural basin from the southeast Pampas, Argentina.

We measured the occurrence and seasonal variations of glyphosate and its metabolite, aminomethylphosphonic acid (AMPA), in different environmental compartments within the limits of an agricultural basin. This topic is of high relevance since glyphosate is the most applied pesticide in agricultural systems worldwide. We were able to quantify the seasonal variations of glyphosate that result mainly from endo-drift inputs, that is, from direct spraying either onto genetically modified (GM) crops (i.e., soybean and maize) or onto weeds in no-till practices. We found that both glyphosate and AMPA accumulate in soil, but the metabolite accumulates to a greater extent due to its higher persistence. Knowing that glyphosate and AMPA were present in soils (> 93% of detection for both compounds), we aimed to study the dispersion to other environmental compartments (surface water, stream sediments, and groundwater), in order to establish the degree of non-point source pollution. Also, we assessed the relationship between the water-table depth and glyphosate and AMPA levels in groundwater. All of the studied compartments had variable levels of glyphosate and AMPA. The highest frequency of detections was found in the stream sediments samples (glyphosate 95%, AMPA 100%), followed by surface water (glyphosate 28%, AMPA 50%) and then groundwater (glyphosate 24%, AMPA 33%). Despite glyphosate being considered a molecule with low vertical mobility in soils, we found that its detection in groundwater was strongly associated with the month where glyphosate concentration in soil was the highest. However, we did not find a direct relation between groundwater table depth and glyphosate or AMPA detections. This is the first simultaneous study of glyphosate and AMPA seasonal variations in soil, groundwater, surface water, and sediments within a rural basin.

Personal Hygiene Practices among Urban Homeless Persons in Boston, MA.

Persons experiencing homelessness in the United States experience significant barriers to self-care and personal hygiene, including limited access to clean showers, laundry and hand washing facilities. While the obstacles to personal hygiene associated with homelessness may increase risk of infectious disease, hygiene-related behaviors among people experiencing homelessness has received limited attention. We conducted a cross-sectional study of individuals experiencing homelessness in Boston, MA (n = 194) to identify hygiene-related self-care practices and risk factors for reduced hygiene in this population. Most participants (72%) reported taking a daily shower. More than 60% reported hand washing with soap five or more times each day, and use of hand sanitizer was widespread (89% reported using sanitizer in the last week). A majority (86%) used a laundromat or laundry machine to wash clothing, while 14% reported washing clothing in the sink. Heavy drinking, injection drug use, and sleeping outdoors were identified as significant risk factors for reduced hygiene practices. People experiencing homelessness who also engage in these activities may be among the most difficult to reach for intervention, yet targeted efforts may decrease illness risk associated with reduced hygiene. Housed friends and family play a critical role in assisting homeless individuals maintain hygiene by providing showers and laundry facilities.

Can an aquatic macrophyte bioaccumulate glyphosate? Development of a new method of glyphosate extraction in Ludwigia peploides and watershed scale validation.

Glyphosate is intensively used in agricultural fields and it is frequently detected in non-target wetland ecosystems. The floating hydrophyte Ludwigia peploides is widely distributed in American streams and it is an abundant species. Therefore, our objectives were (1) to establish and validate an extraction and quantification methodology for glyphosate in L. peploides and (2) to evaluate the role of this species as a potential glyphosate biomonitor in an agricultural watershed. We developed a new method of glyphosate extraction from leaves of L. peploides. The method recovery was 117± 20% and the matrix effect 20%. To validate the method using environmental samples, plants of L. peploides were collected in March 2016 from eight monitoring sites of El Crespo stream. Surface water and sediment samples were collected at the same time to measure glyphosate and to calculate bioconcentration factors (BCFs) and biota-sediment accumulation factors (BSAFs). Glyphosate was detected in 94.11% in leaves, the concentrations ranging between 4 and 108 µg/kg. Glyphosate was detected in surface water and sediments at 75% and 100% of the samples, at concentrations that varied between 0 and 1.7 µg/L and 5-10.50 µg/kg dry weight, respectively. The mean BCFs and BSAFs were 88.10 L/Kg and 7.61, respectively. These results indicate that L. peploides bioaccumulates glyphosate mainly bioavailable in the surface water. In this sense, L. peploides could be used as a biomonitor organism to evaluate glyphosate levels in freshwater aquatic ecosystems because, in addition to its capacity to bioconcentrate glyphosate, it is easy to sample and it has a restricted mobility.

Spatial and temporal trends and flow dynamics of glyphosate and other pesticides within an agricultural watershed in Argentina.

In the present study, we evaluated the spatial and temporal trends of current-use pesticides in surface water and sediments as well as their relationship with hydrological stream dynamics within the agricultural watershed of El Crespo stream (Buenos Aires Province, Argentina). We sampled 2 contrasting sites: site 1 (upstream), surrounded by agricultural lands, and site 2 (downstream), surrounded by natural grasslands. Most of the applied pesticides (glyphosate, 2,4-D, atrazine, tebuconazole, and imidacloprid) were detected at high frequencies in surface water samples at both sites. However, only glyphosate and aminomethylphosphonic acid (AMPA) were present at high concentrations and had a significant spatial-temporal trend. The highest concentrations were found during spring 2014 at site 1, in association with the intense rains that occurred in that season. The fact that glyphosate and AMPA concentrations were higher than the rest of the studied compounds is closely related to the land use within the watershed, as glyphosate was the most applied herbicide during the fallow period of glyphosate-resistant crops (soybean, maize). The pesticide mixture had a significant spatial-temporal trend, reaching the highest levels during storm flow events in spring 2014. The intensive rains in spring 2014 could be the main factor influencing stream hydrology and pesticide behavior at El Crespo watershed. The estimated annual pesticide losses were 3.11 g/ha at site 1 and 0.72 g/ha at site 2. This result indicates that an attenuation process could be decreasing pesticide loads during downstream transport from site 1 to site 2. Environ Toxicol Chem 2017;36:3206-3216. © 2017 SETAC.

Genetic and biochemical biomarkers in the macrophyte Bidens laevis L. exposed to a commercial formulation of endosulfan.

Previous studies in the wetland macrophyte Bidens laevis L have demonstrated that the insecticide endosulfan induces a high frequency of somatic chromosome aberrations in anaphase-telophase (CAAT) but no DNA changes as determined by the single cell gel electrophoresis (Comet) assay. Thus, cytogenetic biomarkers appear to be more sensitive to the toxic effects of the insecticide than the DNA molecule in the studied species. For this reason, the goals of this study were to use cytogenetic biomarkers--CAAT and abnormal metaphase--and defense biomarkers such as the activity of the antioxidant enzymes--guaiacol peroxidases (POD), glutathione reductase, and microsomal and cytosolic (m- and c-) glutathione-S-transferase (GST)--to evaluate in B. laevis effects caused by a commercial formulation of endosulfan. The frequency of CAAT was increased at 5, 10, 50, and 100 µg/L endosulfan with respect to the negative controls by 3.1, 2.5, 2.5, and 3.2-fold, respectively while the frequency of abnormal metaphases was also increased at the same concentrations by 3.5, 2.8, 3.2, and 11.3-fold, respectively. In addition to these aneugenic effects, other abnormalities such as C-mitosis and chromosome clumping were observed at 10 µg/L endosulfan. On the other hand, POD induction at 0.02, 0.5, 5, and 10 µg/L and m-GST inhibition at 0.5, 10, and 50 µg/L in plants exposed during 24 h to endosulfan were observed but all of these responses were highly variable. In conclusion, only cytogenetic biomarkers like CAAT in B. laevis can serve potentially as early warning systems to detect environmentally relevant concentrations of endosulfan in aquatic ecosystems.

Root-to-Shoot transfer and distribution of endosulfan in the wetland macrophyte Bidens laevis L.

Endosulfan is genotoxic in somatic cells of Bidens laevis, and reproduction could be affected if translocated from roots to flower buds. Hydroponic experiments were conducted to quantify this transfer. While the root uptake of [(14) C] endosulfan and its transfer to aboveground tissues was relatively low, the resulting average flower bud concentration (1.01 ± 0.76 ng/g) after 30 d of exposure to an aqueous concentration of 5 µg/L could still represent a genotoxic risk for germ cells.

Genotoxicity evaluation of the insecticide endosulfan in the wetland macrophyte Bidens laevis L.

The frequency of micronuclei (MN) and chromosome aberrations in anaphase-telophase (CAAT) was determined in root tips of the wetland macrophyte Bidens laevis exposed to environmentally relevant concentrations of endosulfan (0.01, 0.02, 0.5 and 5microg/L) for 48h. MN frequency varied from 0 in negative controls and plants exposed to 0.01microg/L endosulfan to 0-3 in plants exposed to 5microg/L. Moreover, a significant concentration-dependent increase of CAAT was observed. The higher proportion of laggards and vagrand chromosomes observed at 5microg/L would indicate that endosulfan interacts with the spindle interrupting normal chromosome migration. Endosulfan resulted genotoxic to B. laevis, a species of potential value for bioassays and in situ monitoring of environmental contamination by pesticides.