Environmental risk assessment for trisodium [S,S]-ethylene diamine disuccinate, a biodegradable chelator used in detergent applications

Environmental safety data are presented for [S,S]-Ethylene Diamine Disuccinate ([S,S]EDDS), a new, biodegradable, strong transition metal chelator. An environmental risk assessment for its use in detergent applications, which takes into account the chelating properties of [S,S]-EDDS, is proposed.

A property of [S,S]-EDDS that distinguishes it from other strong transition metal chelators is its, “ready” and transparent (no recalcitrant metabolites) biodegradation profile. Because its sorption to activated sludge solids is low ( Kp of 40 1/kg), removal of [S,S]EDDS during sewage treatment, which is greater than 96% as determined by the Continuous Activated Sludge test , is mainly ascribed to biodegradation. At projected use volumes in detergent applications [S,S] - EDDS predicted steady-state concentration in rivers leaving the mixing zone will be below 5 pg/I due to rapid biodegradation. [S,S]-EDDS exhibits low toxicity to fish and Daphnia ( both EC₅₀s> 1000 mg/l). By contrast, due to limitation of the algal test for chelators apparent toxicity was observed (EC₅₀ = 0.290 mg/l, NOEC - No observable Effect Concentration = 0.125 mg/l). Schowanek et al. [1] demonstrated that this is not toxicity sensu stricto but a chelation effect of trace metals in the test medium and of resulting essential nutrients limitation. This requires specific attention when the results of algal toxicity are to be extrapolated to a field situation to perform realistic risk assessment. Metal speciation calculations, using MINEQL+, show that at the predicted environmental concentrations of [S,S] - EDDS (1–5 μg/l), such a chelation effect would be insignificant. These calculations allow to estimate the NOEC for chelation effects in the field to be in the range of 0.250-0.500 mg/l, depending on the background water chemistry. These values are well above the laboratory NOEC.

An environmental risk assessment was performed using the EUSES (1.0) program. EUSES is currently the EU recommended tool for conducting risk assessments (TGD 1995). It was applied to estimate the river water and soil concentrations from production, formulation and private use life stages. The estimated PEC/PNEC ratio in all relevant environmental compartments is smaller than 1, indicating “no immediate concern” at the anticipated usage level.     

Water leaching of titanium from ore flotation residue

Copper ore tailings were tested for the stability of titanium submitted to water leaching in three different reactor systems (agitated vessel, bioreactor and percolated fixed-bed column). For each of these systems, titanium extraction did not exceed 1% of the available metal. Biomass removed from ore residue adsorbed a small part of the titanium with sorption capacities below 20-30 mg g(-1), but most of this biomass was sequestered in the ore residue. Oxygen and carbon dioxide concentrations were monitored and changes in concentration correlated with bacteria development at the initial stage of the process and to fungal development in the latter stages.     

Environmental risk assessment of phosphonates,used in domestic laundry and cleaning agents in The Netherlands

In the long-term cooperative project Voluntary Plan of Action (1990) between the Dutch Soap and Detergent Association (NVZ) and the Dutch Ministry of Housing, Spatial Planning and the Environment (VROM) environmental risk assessments of several main components of laundry cleaning formulations were completed. As a part of that project the environmental risk assessment of HEDP, ATMP, EDTMP and DTPMP phosphonates used in detergent applications has been carried out according to the EU Technical Guidance Document for Environmental Risk Assessment for New and Existing Chemicals. All PEC/PNEC ratios were well below 1. Results of this assessment based on the total industry volumes from 1995 and 1998 indicate that the environmental risk of these phosphonates is low in The Netherlands with properly functioning sewage treatment plants.     

Biosensors for pathogen surveillance

Biologists, chemists, and physicists are collaborating to develop highly sensitive and specific biosensors for pathogen detection in the food, healthcare, and environmental sectors. Those novel biosensors allow quick detection and are thus expected to solve the issues of the emergence of highly virulent or antibiotic-resistant pathogens. This article reviews different types of biosensors used for pathogen detection, classified based on the type of transducer used. Optical biosensors integrate labeled means, e.g., fluorophores, quantum dots, and carbon dots to overcome photobleaching. Surface plasmon resonance is also used for enhanced sensitivity. Mechanical biosensors with piezoelectric crystals and cantilevers are adapted for the detection of food pathogens without sample preparation or labels. Conventional methods using electrodes for the measurement of electrochemical changes with differential pulse voltammetry or impedance spectroscopy are fast and highly sensitive. Immunosensors are developed for pathogen detection at trace levels using sample enrichment, signal amplification, and new visual detection techniques.     

我国环境监测体制改革探讨

本文分析了目前我国环境监测工作中普遍存在的体制不顺、职责不明、行政干预、重复监测、资源浪费、信息混乱等问题,提出监测机构垂直管理,调整监测职能,打破条块分割,整合社会监测资源,引入第三方检测的具体构想。     

Occurrence of pesticides and polychlorinated biphenyls in water of the Nile river at the estuaries of Rosetta and Damiatta branches,north of delta,Egypt

Abstract

A study was conducted from summer 1995 to summer 1997 to assess the seasonal occurrence of pesticide residues and other organic contaminants, polychlorinated biphenyls (PCBs), in water at the estuaries of Rosetta and Damiatta branches of the Nile river. The results indicated that organochlorine compounds (OCs) including HCB, lindane, p,p‘‐DDE, p,p‘DDD, p,p‘‐DDT, aroclor 1254 and aroclor 1260 were present in all the water samples at concentration levels ranging between 0.195–0.240, 0.286–0.352, 0.035–0.067, 0.019–0.033, 0.024–0.031, 0.390–0.70 and 0.166–0.330 μg/l, respectively. The levels of these compounds were higher in water of Damiatta branch than those found in water of Rosetta branch. Aldrin, dieldrin and endrin were not detected in all water samples. Only 4 compounds from 36 organophosphorus insecticides, fungicides and s‐triazine herbicides tested were detected in water samples collected during summer and autumn seasons from Rosetta branch. The concentration levels of these detected compounds, dimethoate, malathion, captan, and ametryne, ranged from 0.011 to 0.340 μg/l, respectively. Similar compounds during the same seasons as found in water of Rosetta branch were also detected in water of Damiatta branch except ametryne. The levels of the detected compounds (dimethoate, malathion and captan) ranged between 0.030 and 0.330 μg/l. The levels of detected organophosphorus insecticides, fungicides and s‐triazine herbicides were in the order: dimethoate > malathion > captan > ametryne.     

Energy efficiency during conventional and novel sintering processes: the case of Ti–Al2O3–TiC composites

The conventional (hot pressing or HP) and the novel (spark plasma sintering or SPS) consolidation techniques were compared when processing Ti–Al₂O₃–TiC powders obtained by self-propagating high-temperature synthesis (SHS). It was found that the two different methods are able to produce similar materials, in some cases (Vickers hardness and wear rate) slightly better for SPSed samples. However, SPS does not need sintering temperatures as high as HP to obtain fully dense products. Most significantly, processing times were strongly reduced when adopting the SPS technique instead of HP, i.e. 4–7 min and about 5 h, respectively. Finally, when the total energies required during each SPS or HP experiment were compared, it was found that the use of the SPS technology allowed for an energy saving in the order of 90–95%. This fact makes SPS significantly advantageous from environmental and economical points of view compared to HP.     

Issues and practices in the use of effects data from FREDERICA in the ERICA Integrated Approach

The ERICA Integrated Approach requires that a risk assessment screening dose rate is defined for the risk characterisation within Tiers 1 and 2. At Tier 3, no numerical screening dose rate is used, and the risk characterisation is driven by methods that can evaluate the possible effects of ionising radiation on reproduction, mortality and morbidity. Species sensitivity distribution has been used to derive the ERICA risk assessment predicted no-effect dose rate (PNEDR). The method used was based on the mathematical processing of data from FRED (FASSET radiation effects database merged with the EPIC database to form FREDERICA) and resulted in a PNEDR of 10 microGy/h. This rate was assumed to ascribe sufficient protection of all ecosystems from detrimental effects on structure and function under chronic exposure. The value was weighed against a number of points of comparison: (i) PNEDR values obtained by application of the safety factor method, (ii) background levels, (iii) dose rates triggering effects on radioactively contaminated sites and (iv) former guidelines from literature reviews. In Tier 3, the effects analysis must be driven by the problem formulation and is thus highly case specific. Instead of specific recommendations on numeric values, guidance on the sorts of methods that may be applied for refined effect analysis is provided and illustrated.