Assessment of DNA damage in Brazilian workers occupationally exposed to pesticides: a study from Central Brazil

We evaluated 41 rural workers occupationally exposed to pesticides and 32 subjects as a control group, using the micronucleus (MN) and the comet assay. For the comet assay, we evaluated the peripheral blood, and for the MN, we sampled cells from the oral epithelium. Damage to DNA was measured by tail length, % DNA in tail (% tail), olive tail moment (OTM), and tail moment (TM). The exposed group presented an 8× increase in MN frequency, when compared to the control group (p <0.05). When we contrasted the MN frequencies between the individuals that use and do not use personal protective equipment, we found a mean of 7.5 MN (57 % variance) and 12.1 MN (130 % variance), respectively. The binucleated cells were 0.04 and 0.005, in the exposed and control groups, respectively, indicating 8× increase in the number of binucleated cells, when comparing the groups (p <0.05). In the comet assay, we demonstrated statistically significant differences in three parameters (% DNA, OTM, and TM) indicating that the rural workers presented high levels of genomic damages. Our results indicate that occupational exposure to pesticides could cause genome damage in somatic cells, representing a potential health risk to Brazilian rural workers that deal constantly with agrochemicals without adequate personal protection equipment.     

Quantitative Ethnobotany in an Atlantic Forest Fragment of Northeastern Brazil – Implications to Conservation

Two new methods for assessing temporal trends in stream-solute concentrations at specific streamflow ranges were applied to long (40 to 50-year) but sparse (bi-weekly to quarterly sampling) stream-water quality data collected at three forested mesoscale basins along an atmospheric deposition gradient in the northeastern United States (one in north-central Pennsylvania, one in southeastern New York, and one in eastern Maine). The three data sets span the period since the implementation of the Clean Air Act in 1970 and its subsequent amendments.Declining sulfate (O ₄ ^2-) trends since the mid 1960s were identified for all 3 rivers by one or more of the 4 methods of trend detection used. Flow-specific trends were assessed by segmenting the data sets into 3-year and 6-year blocks, then determining concentration-discharge relationships for each block. Declining sulfate (O ₄ ^2-) trends at median flow were similar to trends determined using a Seasonal Kendall Tau test and Sen slope estimator. The trend of declining O ₄ ^2- concentrations differed at high, median and low flow since the mid 1980s at YWC and NR, and at high and low flow at WR, but the trends leveled or reversed at high flow from 1999 through 2002. Trends for the period of record at high flows were similar to medium- and low-flow trends for Ca²⁺+ Mg²⁺ concentrations at WR, non-significant at YWC, and were more negative at low flow than at high flow at NR; trends in nitrate (NO₃ ^-), and alkalinity (ALK) concentrations were different at different flow conditions, and in ways that are consistent with the hydrology and deposition history at each watershed. Quarterly sampling is adequate for assessing average-flow trends in the chemical parameters assessed over long time periods (∼decades). However, with even a modest effort at sampling a range of flow conditions within each year, trends at specified flows for constituents with strong concentration-discharge relationships can be evaluated and may allow early detection of ecosystem response to climate change and pollution management strategies.     

Comparative diversity and heavy metal biosorption of myxomycetes from forest patches on ultramafic and volcanic soils

Ultramafic and volcanic soils are exploited for industrial activities such as mining due to their high metal content, thus it is important that species in these areas are documented before irreversible environmental damage sets in. In this study, aerial and ground leaf litter, dead vines and twigs from six forest patches on volcanic and ultramafic soils in the provinces of Bataan, Pangasinan and Zambales in the Philippines were cultured in moist chambers (MC) and assessed for myxomycete diversity. From the 77% positive MC for myxomycetes, a total of 40 species from 14 genera were identified. Despite the higher heavy metal content, forest patches on ultramafic soils had greater species diversity as compared to volcanic soils. In this study, 10 species were abundant in both forest patches, namely Arcyria cinerea, Diachea leucopodia, Diderma effusum, D. hemisphaericum, Didymium ochroideum, Perichaena chrysosperma, P. corticalis, P. depressa, P. dictyonema and Physarum melleum. Selected myxomycetes tested for Cr and Mn content had equal or higher heavy metal levels than that of their leaf substrate. The study hypothesised that the presence of Mn⁷⁺ in fruiting bodies of myxomycetes was due to the phagocytosis of food bacteria inhabiting the substrates on the forest soil laden with heavy metal.     

环渤海区域典型河流下游水体中抗生素赋存状况及风险评估

利用高效液相色谱-串联质谱法分析了环渤海区域典型河流下游水体中6类58种抗生素的赋存特征,采用生态风险模型和人类健康风险模型分别评估了抗生素对生态和人体的健康风险.结果显示:环渤海区域4大典型河流(小凌河、滦河、黄河和大辽河)下游水体中有6类50种抗生素被检出,青霉素G浓度水平最高,最高浓度为353.13ng/L.β-...     

Strategies to optimize monitoring schemes of recreational waters from Salta,Argentina: a multivariate approach

Several recreational surface waters in Salta, Argentina, were selected to assess their quality. Seventy percent of the measurements exceeded at least one of the limits established by international legislation becoming unsuitable for their use. To interpret results of complex data, multivariate techniques were applied. Arenales River, due to the variability observed in the data, was divided in two: upstream and downstream representing low and high pollution sites, respectively, and cluster analysis supported that differentiation. Arenales River downstream and Campo Alegre Reservoir were the most different environments, and Vaqueros and La Caldera rivers were the most similar. Canonical correlation analysis allowed exploration of correlations between physicochemical and microbiological variables except in both parts of Arenales River, and principal component analysis allowed finding relationships among the nine measured variables in all aquatic environments. Variable’s loadings showed that Arenales River downstream was impacted by industrial and domestic activities, Arenales River upstream was affected by agricultural activities, Campo Alegre Reservoir was disturbed by anthropogenic and ecological effects, and La Caldera and Vaqueros rivers were influenced by recreational activities. Discriminant analysis allowed identification of subgroup of variables responsible for seasonal and spatial variations. Enterococcus, dissolved oxygen, conductivity, E. coli, pH, and fecal coliforms are sufficient to spatially describe the quality of the aquatic environments. Regarding seasonal variations, dissolved oxygen, conductivity, fecal coliforms, and pH can be used to describe water quality during dry season, while dissolved oxygen, conductivity, total coliforms, E. coli, and Enterococcus during wet season. Thus, the use of multivariate techniques allowed optimizing monitoring tasks and minimizing costs involved.     

Study of the spatial variation of the biodegradation rate of the herbicide bentazone with soil depth using contrasting incubation methods

Vertical and horizontal spatial variability in the biodegradation of the herbicide bentazone was compared in sandy-loam soil from an agricultural field using sieved soil and intact soil cores. An initial experiment compared degradation at five depths between 0 and 80 cm using sieved soil. Degradation was shown to follow the first-order kinetics, and time to 50% degradation (DT(50)), declined progressively with soil depth from 56 d at 0-10 cm to 520 d at 70-80 cm. DT(50) was significantly correlated with organic matter, pH and dehydrogenase activity. In a subsequent experiment, degradation rate was compared after 127 d in sieved soil and intact cores from 0 to 10 and 50 to 60 cm depth from 10 locations across a 160x90 m portion of the field. Method of incubation significantly affected mean dissipation rate, although there were relatively small differences in the amount of pesticide remaining in intact cores and sieved soil, accounting for between 4.6% and 10.6% of that added. Spatial variability in degradation rate was higher in soil from 0 to 10 cm depth relative to that from 50 and 60 cm depth in both sieved soil and intact core assessments. Patterns of spatial variability measured using cores and sieved soil were similar at 50-60 cm, but not at 0-10 cm depth. This could reflect loss of environmental context following processing of sieved soil. In particular, moisture content, which was controlled in sieved soil, was found to be variable in cores, and was significantly correlated with degradation rate in intact topsoil cores from 0 to 10 cm depth.     

北极耐冷石油降解菌的筛选、鉴定及其碳源利用广谱性

从北极不同海底沉积物样品中富集、分离得到50株能以石油作为唯一碳源和能源的北极耐冷石油降解菌株,命名为BJ1、BJ2…BJ50,用红外分光光度法测定培养基中剩余油含量,选出降解率较高的菌株BJ1、BJ9和BJ19;通过形态学观察、生理生化试验和16S rDNA序列分析,将BJ1、BJ9和BJ19鉴定为假交替单胞菌属(Pseudoalteromonas,P.);以常见石油产品和石油中典型直链烷烃和芳香烃为唯一碳源培养的结果表明,该三株菌能在低温下利用多种碳源。研究结果表明,BJ1、BJ9和BJ19均为海洋耐冷石油降解菌,且对碳源的利用具有广谱性。     

南极生态环境及管理现状研究

南极作为世界上最后一块“净土”,其丰富的自然资源和内在的科研、美学等价值受到了越来越多国家的关注。在全球变暖与人类活动（科学考察、商业捕捞、旅游等）因素的影响下,南极出现了海冰面积区域性增减,南极生物物种数量波动,环境污染加重等问题。而现有的以“南极条约体系”为基础的管理政策因理念抽象等问题尚不能完全规范人类活动,南极生态环境保护的形势日益严峻。国际社会应通过跨学科间的国际协作,加强科学研究与管理之间的联系,完善南极生态环境管理政策,最大限度减少人类对南极生态环境的破坏。     

Techno-economic-environmental characteristics of polyurethane composite to thermal insulation for building with flame resistance: corroborative effect recycled of PVC and aluminum oxide

Journal of Material Cycles and Waste Management - In this article, we present the results of the composite development obtained from polyurethane (PU), polyvinyl chloride (PVC), and aluminum...     

Short-term variability in the photosynthetic activity of microphytobenthos as detected by measuring rapid light curves using variable fluorescence

Short-term variability in the photosynthetic activity of microphytobenthos assemblages was studied by measuring chlorophyll fluorescence rapid light curves (RLC), using pulse amplitude modulated (PAM) fluorometry. Measurements carried out on undisturbed samples under dark–light cycles revealed large diel oscillations in both the initial slope of the RLC () and in the maximum relative electron transport rate (ETR_m). Short-term variations in RLC parameters were also observed, closely following changes in incident photon irradiance (E). Increases in irradiance were followed by decreases in and increases in ETR_m, resulting in significant correlations between the light-saturation parameter E_k and E. These results were interpreted as resulting from the onset of reversible energy-dissipating, non-photochemical quenching mechanisms and of compensatory high light-induced activation of carbon metabolism activity. Short-term RLC variability was shown to result mainly from physiological causes and to be detectable only by using short (10–20 s) light steps during RLC construction. Dark-adapted samples kept under constant conditions exhibited apparently endogenous rhythms in RLC parameters and in the maximum quantum yield, F_v/F_m, coincident with vertical migratory movements occurring during subjective photoperiods. These fluctuations appeared to result from the interaction between migratory rhythms and the physiological responses, and from the endogenous activation of processes affecting both the efficiency of energy transfer from light-harvesting antennae to the photosystem II (PSII) reaction centres or from non-radiative pathways (F_v/F_m, ) and the reactions downstream of PSII (ETR_m).Communicated by M. Kühl, Helsingør