Treatment of Arctic wastewater by chemical coagulation,UV and peracetic acid disinfection

Conventional wastewater treatment is challenging in the Arctic region due to the cold climate and scattered population. Thus, no wastewater treatment plant exists in Greenland, and raw wastewater is discharged directly to nearby waterbodies without treatment. We investigated the efficiency of physicochemical wastewater treatment, in Kangerlussuaq, Greenland. Raw wastewater from Kangerlussuaq was treated by chemical coagulation and UV disinfection. By applying 7.5 mg Al/L polyaluminium chloride (PAX XL100), 73% of turbidity and 28% phosphate was removed from raw wastewater. E. coli and Enterococcus were removed by 4 and 2.5 log, respectively, when UV irradiation of 0.70 kWh/m³ was applied to coagulated wastewater. Furthermore, coagulated raw wastewater in Denmark, which has a chemical quality similar to Greenlandic wastewater, was disinfected by peracetic acid or UV irradiation. Removal of heterotrophic bacteria by applying 6 and 12 mg/L peracetic acid was 2.8 and 3.1 log, respectively. Similarly, removal of heterotrophic bacteria by applying 0.21 and 2.10 kWh/m³ for UV irradiation was 2.1 and greater than 4 log, respectively. Physicochemical treatment of raw wastewater followed by UV irradiation and/or peracetic acid disinfection showed the potential for treatment of arctic wastewater.     

Reconnecting with nature for sustainability

Calls for humanity to ‘reconnect to nature’ have grown increasingly louder from both scholars and civil society. Yet, there is relatively little coherence about what reconnecting to nature means, why it should happen and how it can be achieved. We present a conceptual framework to organise existing literature and direct future research on human–nature connections. Five types of connections to nature are identified: material, experiential, cognitive, emotional, and philosophical. These various types have been presented as causes, consequences, or treatments of social and environmental problems. From this conceptual base, we discuss how reconnecting people with nature can function as a treatment for the global environmental crisis. Adopting a social–ecological systems perspective, we draw upon the emerging concept of ‘leverage points’—places in complex systems to intervene to generate change—and explore examples of how actions to reconnect people with nature can help transform society towards sustainability.     

Documenting lemming population change in the Arctic: Can we detect trends?

Lemmings are a key component of tundra food webs and changes in their dynamics can affect the whole ecosystem. We present a comprehensive overview of lemming monitoring and research activities, and assess recent trends in lemming abundance across the circumpolar Arctic. Since 2000, lemmings have been monitored at 49 sites of which 38 are still active. The sites were not evenly distributed with notably Russia and high Arctic Canada underrepresented. Abundance was monitored at all sites, but methods and levels of precision varied greatly. Other important attributes such as health, genetic diversity and potential drivers of population change, were often not monitored. There was no evidence that lemming populations were decreasing in general, although a negative trend was detected for low arctic populations sympatric with voles. To keep the pace of arctic change, we recommend maintaining long-term programmes while harmonizing methods, improving spatial coverage and integrating an ecosystem perspective.     

Irrigation of treated wastewater in Braunschweig, Germany: an option to remove pharmaceuticals and musk fragrances

In this study the fate of pharmaceuticals and personal care products which are irrigated on arable land with treated municipal wastewater was investigated. In Braunschweig, Germany, wastewater has been irrigated continuously for more than 45 years. In the winter time only the effluent of the sewage treatment plant (STP) of Braunschweig is used for irrigation, while during summer digested sludge is mixed with the effluent. In the present case study six wells and four lysimeters located in one of the irrigated agricultural fields were monitored with regard to the occurrence of 52 pharmaceuticals and two personal care products (PPCPs; e.g. betablockers, antibiotics, antiphlogistics, carbamazepine, musk fragrances, iodinated contrast media (ICM) and estrogens). No differences in PPCP pollution of the groundwater were found due to irrigation of STP effluents with and without addition of digested sludge, because many polar compounds do not sorb to sludge and lipophilic compounds are not mobile in the soil-aquifer. Most of the selected PPCPs were never detected in any of the lysimeter or groundwater samples, although they were present in the treated wastewater irrigated onto the fields. In the groundwater and lysimeter samples primarily the ICM diatrizoate and iopamidol, the antiepileptic carbamazepine and the antibiotic sulfamethoxazole were detected up to several mugl(-1), while the acidic pharmaceuticals, musk fragrances, estrogens and betablockers were likely sorbed or transformed while passing the top soil layer. Potential estrogenic effects are likely to disappear after irrigation, since the most potent steroid estrogens were not measurable.     

巴西雨林自然保护区河流中杀虫剂残毒:对水生生物和人类健康的影响评价

1998年11月、1999年3月和2000年元月分别在巴西雨林自然保护区河流的水体、沉积物和鱼体中检测杀虫剂残毒,每种杀虫剂浓度与基于急性毒性测试的生态毒理基准进行了比较,并且还与规定标准进行比较,以确定它们对水生生物和人类潜在影响的程度.在所有的7个调查地点都检测出杀虫剂及其代谢产物,在水体以及沉积物样品中检测出总共27种杀虫剂及其代谢物的残毒,鱼类富集其中某些最持久稳固的残毒.水体和沉积物中检测出的杀虫剂残毒浓度表明水生生物保护的问题需要引起重视,水体中的几种杀虫剂含量超过了巴西以及欧盟当局规定的指标,表明对人类的健康也有影响.     

Do plant density, nutrient availability, and herbivore grazing interact to affect phlorotannin plasticity in the brown seaweed Ascophyllum nodosum

Plants have different strategies to cope with herbivory, including induction of chemical defences and compensatory growth. The most favourable strategy for an individual plant may depend on the density at which the plants are growing and on the availability of nutrients, but this has not been tested previously for marine plant–herbivore interactions. We investigated the separate and interactive effects of plant density, nutrient availability, and herbivore grazing on the phlorotannin (polyphenolic) production in the brown seaweed Ascophyllum nodosum. Seaweed plants grown at low or high densities were exposed either to nutrient enrichment, herbivorous littorinid gastropods (Littorina obtusata), or a combination of nutrients and herbivores in an outdoor mesocosm experiment for 2 weeks. Seaweeds grown at a low density tended to have higher tissue nitrogen content compared to plants grown at a high density when exposed to elevated nutrient levels, indicating that there was a density dependent competition for nitrogen. Herbivore grazing induced a higher phlorotannin content in plants grown under ambient, but not enriched, nutrient levels, indicting either that phlorotannin plasticity is more costly when nutrients are abundant or that plants responded to herbivory by compensatory growth. However, there were no significant interactive or main effects of plant density on the seaweed phlorotannin content. The results indicate that plants in both high and low densities induce chemical defence, and that eutrophication may have indirect effects on marine plant–herbivore interactions through alterations of plant chemical defence allocation.     

Pesticide pollution remains severe after cleanup of a stockpile of obsolete pesticides at Vikuge, Tanzania

High levels of DDT residues and hexachlorocyclohexanes (HCHs) were found in soil, well water, and surface water around a collapsed pesticide storage shed at Vikuge Farm, Tanzania. Residues of DDT and HCHs were found at three soil depths down to 50 cm. Surface soil samples contained up to 28% total DDT and 6% total HCH residues. Water samples had concentrations of up to 30 microg L(-1) of organochlorine pesticides. Other compounds detected were aldrin, azinphos-methyl, carbosulfan, gamma-chlordane, chlorprofam, heptachlor, hexazinone, metamitron, metazachlor, pendimethalin, and thiabendazole. Although the visible remains of pesticides have been removed, the remaining soil is itself hazardous waste and poses a risk to the environment and the inhabitants of the surrounding villages. These findings show the necessity to follow up the environmental situation at former storage sites of obsolete stocks of pesticides, and that the environmental problems are not necessarily solved by removing the visible remains.     

Leaching of pesticides through normal-tillage and low-tillage soil--a lysimeter study. I. Isoproturon

Isoproturon is a herbicide, which was used in Denmark against grass weeds and broad-leaved weeds until 1998. Isoproturon has frequently been detected in ground water monitoring studies. Leaching of isoproturon (N,N-dimethyl-N'-(4-(1-methylethyl)-phenyl)urea) and its metabolites, N'-(4-isopropylphenyl)-N-methylurea and N'-(4-isopropylphenyl)urea was studied in four lysimetres, two of them being replicates from a low-tillage field (lysimeter 3 and 4), the other two being replicates from a normal tillage field (lysimeter 5 and 6). In both cases the soil was a sandy loam soil with 13-14% clay. The lysimetres had a surface area of 0.5 m2 and a depth of 110 cm. Lysimeter 3 and 4 were sprayed with unlabelled isoproturon while lysimeter 5 and 6 was sprayed with a mixture of 14C-labelled and unlabelled isoproturon. The total amount of isoproturon sprayed onto each lysimeter was 63 mg, corresponding to 1.25 kg active ingredient per ha. The lysimeters were sprayed with isoproturon on October 26, 1997. The lysimetres were installed in an outdoor system in Research Centre Flakkebjerg and were thus exposed to normal climatic conditions of the area. A mean of 360 l drainage water were collected from lysimeter 3 and 4 and a mean of 375 litres from lysimeter 5 and 6. Only negligible amounts of isoproturon and its primary metabolites were found in the drainage water samples, and thus no significant difference between the two lysimeter sets was shown. In a total of 82 drainage water samples, evenly distributed between the four lysimetres isoproturon was found in detectable amounts in two samples and N'-(4-isopropylphenyl)urea was found in detectable amounts in two other samples. The detection limit for all the compounds was 0.02 microg/l. 48% and 54% of the added radioactivity were recovered from the upper 10 cm soil layer in lysimeter 5 and 6, respectively, and 17 and 14% from 10-20 cm's depth. By extraction first with an aquatic CaCl2 solution 0.49% of the added radioactivity was extracted from the upper 10 cm layer in lysimeter 5. In the subsequent extraction with acetonitril, 1.19% of the added radioactivity was extracted. In lysimeter 6, upper 10 cm, 0.2% were extracted with water and 0.56% were extracted with acetonitril. Below 10 cm's depth no measurable amounts could be extracted.     

Laboratory shake flask batch tests can predict field biodegradation of aniline in the Rhine

The aim of this study was to compare degradation rates of aniline in laboratory shake flask simulation tests with field rates in the river Rhine. The combined events of a low flow situation in the Rhine and residual aniline concentrations in the effluent from the BASF treatment plant in Ludwigshafen temporarily higher than normal, made it possible to monitor aniline at trace concentrations in the river water downstream the wastewater outlet by means of a sensitive GC headspace analytical method. Aniline was analyzed along a downstream gradient and the dilution along the gradient was calculated from measurements of conductivity, sulfate and a non-readily biodegradable substance, 1,4-dioxane. Compensating dilution, field first-order degradation rate constants downstream the discharge of BASF were estimated at 1.8 day⁻¹ for two different dates with water temperatures of 21.9 and 14.7 °C, respectively. This field rate estimate was compared with results from 38 laboratory shake flask batch tests with Rhine water which averaged 1.5 day⁻¹ at 15 °C and 2.0 day⁻¹ at 20 °C. These results indicate that laboratory shake flask batch tests with low concentrations of test substance can be good predictors of degradation rates in natural water bodies––at least as ascertained here for short duration tests with readily degradable compounds among which aniline is a commonly used reference.     

Assessment of the importance of sorption for steroid estrogens removal during activated sludge treatment

Distribution coefficients (K(d)) between water and activated sludge particles (f(oc)=27.7+/-0.1%) were measured for the steroid estrogens (SE), estrone (E1), 17beta-estradiol (E2) and 17alpha-ethinylestradiol (EE2) in batch experiments. Experimental concentration levels ranged from environmentally realistic low ng/l to the high microg/l. In this range K(d)s were independent of their water concentration. The experimentally obtained K(d)s (with 95% confidence intervals) were 402+/-126 l/kg, 476+/-192 l/kg and 584+/-136 l/kg for E1, E2 and EE2, respectively. K(d)s were used to estimate the fraction of the total SE concentration that is expected to be sorbed in the activated sludge treatment tanks of a typical STP assuming equilibrium conditions. Assuming a suspended solids concentration of 4 g/l dissolved solids (ds), it was estimated that 61+/-9%, 66+/-13% and 70+/-6% of the total concentration of E1, E2 and EE2, respectively, would be sorbed during activated sludge treatment. The fraction of the SEs that was expected to be sorbed to suspended sludge particles in the effluents from a typical Danish STP was estimated to be only 0.20+/-0.06%, 0.24+/-0.10% and 0.29+/-0.07% of the total concentration of E1, E2 and EE2, respectively, at a suspended solids concentration of 5 mg/lds. For a typical STP the removal of steroid estrogens with excess sludge was estimated to be only 1.5-1.8% of the total loading if equilibrium conditions exists. Sorption is therefore not important for the fate of SEs in STPs compared to biodegradation.