A real-time,dynamic early-warning model based on uncertainty analysis and risk assessment for sudden water pollution accidents

A real-time, dynamic, early-warning model (EP-risk model) is proposed to cope with sudden water quality pollution accidents affecting downstream areas with raw-water intakes (denoted as EPs). The EP-risk model outputs the risk level of water pollution at the EP by calculating the likelihood of pollution and evaluating the impact of pollution. A generalized form of the EP-risk model for river pollution accidents based on Monte Carlo simulation, the analytic hierarchy process (AHP) method, and the risk matrix method is proposed. The likelihood of water pollution at the EP is calculated by the Monte Carlo method, which is used for uncertainty analysis of pollutants’ transport in rivers. The impact of water pollution at the EP is evaluated by expert knowledge and the results of Monte Carlo simulation based on the analytic hierarchy process. The final risk level of water pollution at the EP is determined by the risk matrix method. A case study of the proposed method is illustrated with a phenol spill accident in China.     

Water quality assessment of the Tubarão River through chemical analysis and biomarkers in the Neotropical fish Geophagus brasiliensis

The Tubarão River rises in Santa Catarina, Brazil, and has been historically affected by coal mining activities around its springhead. To evaluate its water conditions, an investigation regarding a possible decontamination gradient associated with the increased river flow toward the estuary, as well as the influence of seasonality over this gradient was performed through a series of biomarkers (vitellogenin, comet assay, lipid peroxidation, protein carbonylation, gluthatione, gluthatione S-transferase, acetylcholinesterase, light microscopy in liver, and scanning electron microscopy in gills) and chemical analysis (polycyclic aromatic hydrocarbons (PAHs) in bile and metal analysis in sediment) in the cichlid Geophagus brasiliensis. Two collections (summer and winter) were made in four distinct sites along the river, while sediments were sampled between those seasons. As expected, the contamination linked exclusively to mining activities was not observed, possibly due to punctual inputs of contaminants. The decontamination gradient was not observed, although seasonality seemed to have a critical role in the responses of biomarkers and availability of contaminants. In the summer, the fish presented higher histopathological damages and lower concentrations of PAHs, while in the winter they showed both higher genetic damage and accumulation of PAHs. The Tubarão suffers impacts from diverse activities, representing health risks for wild and human populations.     

Strategies to evaluate biodegradability: application to chlorinated herbicides

The biodegradability of nitrochlorinated (diuron and atrazine) and chlorophenoxy herbicides (2,4-D and MCPA) has been studied through several bioassays using different testing times and biomass/substrate ratios. A fast biodegradability test using unacclimated activated sludge yielded no biodegradation of the herbicides in 24 h. The inherent biodegradability test gave degradation percentages of around 20–30 % for the nitrochlorinated herbicides and almost complete removal of the chlorophenoxy compounds. Long-term biodegradability assays were performed using sequencing batch reactor (SBR) and sequencing batch membrane bioreactor (SB-MBR). Fixed concentrations of each herbicide below the corresponding EC₅₀ value for activated sludge were used (30 mg L^?1 for diuron and atrazine and 50 mg L^?1 for 2,4-D and MCPA). No signs of herbicide degradation appeared before 35 days in the case of diuron and atrazine and 21 days for 2,4-D, whereas MCPA was partially degraded since the early stages. Around 25–36 % degradation of the nitrochlorinated herbicides and 53–77 % of the chlorophenoxy ones was achieved after 180 and 135 days, respectively, in SBR, whereas complete disappearance of 2,4-D was reached after 80 days in SB-MBR.     

A new bioseed for determination of wastewater biodegradability: analysis of the experimental procedure

A new bioassay proposed in the patent P201300029 was applied to a pre-treated wastewater containing a mixture of commercial pesticides to simulate a recalcitrant industrial wastewater in order to determine its biodegradability. The test uses a mixture of standardized inoculum of the lyophilized bacteria Pseudomonas putida with the proper proportion of salts and minerals. The results highlight that biodegradation efficiency can be calculated using a gross parameter (chemical oxygen demand (COD)) which facilitates the biodegradability determination for routine water biodegradability analysis. The same trend was observed throughout the assay with the dehydrated and fresh inoculums, and only a difference of 5 % in biodegradation efficiency (E _f) was observed. The obtained results showed that the P. putida biodegradability assay can be used as a commercial test with a lyophilized inoculum in order to monitor the ready biodegradability of an organic pollutant or a WWTP influent. Moreover, a combination of the BOD₅/COD ratio and the P. putida biodegradability test is an attractive alternative in order to evaluate the biodegradability enhancement in water pre-treated with advanced oxidation processes (AOPs).     

Vertical and horizontal distributions of microbial abundances and enzymatic activities in propylene-glycol-affected soils

The natural microbial activity in the unsaturated soil is vital for protecting groundwater in areas where high loads of biodegradable contaminants are supplied to the surface, which usually is the case for airports using aircraft de-icing fluids (ADF) in the cold season. Horizontal and vertical distributions of microbial abundance were assessed along the western runway of Oslo Airport (Gardermoen, Norway) to monitor the effect of ADF dispersion with special reference to the component with the highest chemical oxygen demand (COD), propylene glycol (PG). Microbial abundance was evaluated by several biondicators: colony-forming units (CFU) of some physiological groups (aerobic and anaerobic heterotrophs and microscopic fungi), most probable numbers (MPN) of PG degraders, selected catabolic enzymatic activities (fluorescein diacetate (FDA) hydrolase, dehydrogenase, and β-glucosidase). High correlations were found between the enzymatic activities and microbial counts in vertical soil profiles. All microbial abundance indicators showed a steep drop in the first meter of soil depth. The vertical distribution of microbial abundance can be correlated by a decreasing exponential function of depth. The horizontal trend of microbial abundance (evaluated as total aerobic CFU, MPN of PG-degraders, and FDA hydrolase activity) assessed in the surface soil at an increasing distance from the runway is correlated negatively with the PG and COD loads, suggesting the relevance of other chemicals in the modulation of microbial growth. The possible role of potassium formate, component of runway de-icers, has been tested in the laboratory by using mixed cultures of Pseudomonas spp., obtained by enrichment with a selective PG medium from soil samples taken at the most contaminated area near the runway. The inhibitory effect of formate on the growth of PG degraders is proven by the reduction of biomass yield on PG in the presence of formate.     

Persistently elevated AFP and AChE in amniotic fluid from a normal fetus following demise of its twin

Intrauterine fetal demise (IUFD) in one of twins at 12 weeks of gestation was accompanied by markedly elevated maternal serum alpha-fetoprotein (AFP) at 17 and 18 weeks. Amniotic fluid AFP from the healthy surviving twin's sac at 18·5 and 23 weeks was also greatly increased along with a positive acetylcholinesterase (AChE) band. Persistently elevated AFP and positive AChE so long after fetal demise–-6·5 and 11 weeks post IUFD–-has not, to our knowledge, been previously described. In similar cases, high level ultrasound and careful placental examination at birth should be utilized to search for fetal abnormalities or multiple pregnancy with IUFD.     

Estimated crop yield losses due to surface ozone exposure and economic damage in India

In this study, we estimate yield losses and economic damage of two major crops (winter wheat and rabi rice) due to surface ozone (O₃) exposure using hourly O₃ concentrations for the period 2002–2007 in India. This study estimates crop yield losses according to two indices of O₃ exposure: 7-h seasonal daytime (0900–1600 hours) mean measured O₃ concentration (M7) and AOT40 (accumulation exposure of O₃ concentration over a threshold of 40 parts per billion by volume during daylight hours (0700–1800 hours), established by field studies. Our results indicate that relative yield loss from 5 to 11 % (6–30 %) for winter wheat and 3–6 % (9–16 %) for rabi rice using M7 (AOT40) index of the mean total winter wheat 81 million metric tons (Mt) and rabi rice 12 Mt production per year for the period 2002–2007. The estimated mean crop production loss (CPL) for winter wheat are from 9 to 29 Mt, account for economic cost loss was from 1,222 to 4,091 million US$ annually. Similarly, the mean CPL for rabi rice are from 0.64 to 2.1 Mt, worth 86–276 million US$. Our calculated winter wheat and rabi rice losses agree well with previous results, providing the further evidence that large crop yield losses occurring in India due to current O₃ concentration and further elevated O₃ concentration in future may pose threat to food security.