Accumulation of arsenic, lead, copper, and zinc, and synthesis of phytochelatins by indigenous plants of a mining impacted area

Several native plants, able to grow in an unconfined mining impacted area that is now in close vicinity with urban areas, were evaluated for their ability to accumulate heavy metals. The main soil contaminants were As, Pb, Cu, and Zn. Sampling of the rhizospheric metal polluted soil showed that Euphorbia prostrata Aiton, Parthenium incanum Kunth, and Zinnia acerosa (DC.) A. Gray were able to grow in the presence of high amounts of mixtures of these elements. The plants accumulated the metals in the above ground parts and increased the synthesis of thiol molecules. E. prostrata showed the highest capacity for accumulation of the mixture of elements (588 μg g DW^?1). Analysis of the thiol-molecules profile showed that these plants synthesized high amounts of long-chain phytochelatins, accompanied by low amounts of monothiol molecules, which may be related to their higher resistance to As and heavy metals. The three plants showed translocation factors from roots to leaves >1 for As, Pb, Cu, and Zn. Thus, by periodically removing aerial parts, these plants could be useful for the phytoremediation of semi-arid and arid mining impacted areas, in which metal hyper-accumulator plants are not able to grow.     

Temporal trends of organochlorine contamination in Black Guillemots in Iceland from 1976 to 1996

The levels of several different persistent organochlorines (OCs) in Black Guillemots Cepphus grylle, collected during the summers of 1976-1996 at Breioafj?rour in W-Iceland, were investigated. The levels of about 40 different organochlorines (PCBs, DDTs, chlordanes, toxaphenes, HCH, HCB) were compared with respect to age, sex, fat content, and year of collection. The levels of PCBs correlated very closely with those of DDE, indicating long-range transport as the major source of these contaminants in Iceland, with the ratio PCBs/DDE mostly in the range of 2-5. Unlike the Gyrfalcon Falco rusticolus, the organochlorine levels did not seem to accumulate substantially with age, neither in males nor females. The variation in the levels of OCs at the age of 2 years was even greater than the variation in OC levels over an age range of 12 years. In immature birds the levels of PCBs, DDE, HCB and beta-HCH declined very slowly (T(1/2) from 12 to 20 years) over the years 1976-1996, whereas the levels of alpha-HCH and p,p'-DDT declined much faster. The levels of trans-nonachlor, alpha-chlordane, gamma-chlordane, oxychlordane, and toxaphene did not correlate with the year of collection. As the Black Guillemot is mostly a resident seabird, feeding mainly on small fish and invertebrates, this investigation should give a good indication of the temporal trends of organochlorine pollution at Breioafj?rour, Iceland, during this 20 year period and is likely to reflect baseline trends in the marine environment of the North-Atlantic Ocean.     

Influence of pre-treatment step on PAHs analyses in contaminated soils

There is no specific standardization for the pre-treatment of a soil sample for PAHs analyses. The ISO/FDIS 14507 method for soil quality gives a guidance for sample pre-treatment before measurement of organic contaminants in soil. It refers to cryogenic crushing which is not so easy to carry out. So, analysts lead to develop in house methods which can be very different from a laboratory to another and can involve deviations in the pollution quantification. This study has explored different ways of drying, grinding and sieving in order to determine the influence of the soil sample handling on the measured pollutant concentration. It appears that the influence of pre-treatment depends on the soil nature and on the PAHs distribution. As a conclusion, it is advised "light" drying ways like air drying or drying at 40 degrees C in a drying oven instead of more "drastic" ways (freeze-drying, cryogenic crushing) which can induce some losses. Crushing and sieving are also recommended for more reproducible measures.     

Interpretation of heavy metal data from mussel by use of multivariate classification techniques

Different strategies of multivariate analysis of metals concentrations (Mn, Fe, Ni, V, Co, Cu, Cd, Hg, Pb, Na, K) in mussel samples from different spanish markets are used to interpret a data base and identify differences between species and origin of the samples. Principal Component Analysis and Potential curves are applied to properly classify unknown samples from representative mussels samples (Mytilus edulis and Perna canaliculus). Also, Principal Components Analysis is used as display method to visualize the relation between the variables and objects of interest.     

Measurements of selected PCBs in open urban ambient air of Madrid (Spain)

The focus of this study was to characterize the concentration levels of selected PCBs and compare them to compiled data in order to contribute to the international database. The sampling site is located in the outskirts of Madrid and can be considered an open urban area. 32 samples of air were taken from February 1998 to June 1998 by using a high volume air sampler. Glass fiber filters and polyurethane foam (PUF) were used to collect the paniculate and gas phase material, respectively. PUF plugs were Soxhlet extracted and filters were ultrasonically extracted by using pesticide-grade hexane and dichloromethane, respectively. The cleanup procedure was carried out on a florisil column with hexane and hexane/dichloromethane as elution solvents. GC/MS in a selected ion monitoring mode was used for quantification and 29 selected PCBs congeners were analyzed.     

Concentrations and fluxes of organic compounds in the atmosphere of the Swedish west coast

Measurements of organic compounds in air and deposition have been carried out in parallel on the Swedish west coast. In this investigation the importance of long-range transport for the occurrence of organic compounds in deposition has been studied. Air samples were collected using a high volume sampler (HVS) and the deposition was sampled on a 1 m² Teflon-coated horizontal surface with runoff for the precipitation to an adsorbent. The samples were analyzed in order to identify and quantify different semivolatile compounds such as PAH and petrogenic hydrocarbons and chlorinated compounds such as PCB, HCH and HCB. Qualitative differences between the content of organic compounds in air and deposition during periods with varying levels of air pollution and different meteorological conditions have been studied and a comparison with other air pollutants, such as soot, has been carried out. The results of the measurements show that deposition of PAH and other hydrocarbons takes place continuously but the greatest amounts are measured in the deposition in connection with episodes together with heavy precipitation. The highest concentrations of PCB and HCH in the air were obtained during a warm dry period in May and the greatest amounts were deposited in a period in May with heavy precipitation.     

Integrated catalytic wet air oxidation and aerobic biological treatment in a municipal WWTP of a high-strength o-cresol wastewater

This study examines the feasibility of coupling a Catalytic Wet Air Oxidation (CWAO), with activated carbon (AC) as catalyst, and an aerobic biological treatment to treat a high-strength o-cresol wastewater. Two goals are pursued: (a) To determine the effect of the main AC/CWAO intermediates on the activated sludge of a municipal WasteWater Treatment Plant (WWTP) and (b) To demonstrate the feasibility of coupling the AC/CWAO effluent as a part of the influent of a municipal WWTP. In a previous study, a high-strength o-cresol wastewater was treated by AC/CWAO aiming to establish the distribution of intermediates and the biodegradability enhancement. In this work, the biodegradability, toxicity and inhibition of the most relevant intermediates detected in the AC/CWAO effluent were determined by respirometry. Also, the results of a pilot scale municipal WWTP study for an integrated AC/CWAO-aerobic biological treatment of this effluent are presented. The biodegradation parameters (i.e. maximum oxygen uptake rate and oxygen consumption) of main AC/CWAO intermediates allowed the classification of the intermediates into readily biodegradable, inert or toxic/inhibitory compounds. This detailed study, allowed to understand the biodegradability enhancement exhibited by an AC/CWAO effluent and to achieve a successful strategy for coupling the AC/CWAO step with an aerobic biological treatment for a high-strength o-cresol wastewater. Using 30%, as COD, of AC/CWAO effluent in the inlet to the pilot scale WWTP, the integrated AC/CWAO-biological treatment achieved a 98% of total COD removal and, particularly, a 91% of AC/CWAO effluent COD removal without any undesirable effect on the biomass.     

ESPR subject area 5 ‘Environmental Microbiology, (Bio)Technologies, Health Issues’

Goal, Scope and Background  Aquaculture activities are well known to be the major contributor to the increasing level of organic waste and toxic compounds in the aquaculture industry. Along with the development of intensive aquaculture in China, concerns are evoked about the possible effects of everincreasing aquaculture waste both on productivity inside the aquaculture system and on the ambient aquatic ecosystem. Therefore, it is apparent that appropriate waste treatment processes are needed for sustaining aquaculture development. This review aims at identifying the current status of aquaculture and aquaculture waste production in China. Main Features  China is the world’s largest fishery nation in terms of total seafood production volume, a position it has maintained continuously since 1990. Freshwater aquaculture is a major part of the Chinese fishery industry. Marine aquaculture in China consists of both land-based and offshore aquaculture, with the latter mostly operated in shallow seas, mud flats and protected bays. The environmental impacts of aquaculture are also striking. Results  Case studies on pollution hot spots caused by aquaculture have been introduced. The quality and quantity of waste from aquaculture depends mainly on culture system characteristics and the choice of species, but also on feed quality and management. Wastewater without treatment, if continuously discharged into the aquatic environment, could result in remarkable elevation of the total organic matter contents and cause considerable economy lost. Waste treatments can be mainly classified into three categories: physical, chemical and biological methods. Discussion  The environmental impacts of different aquaculture species are not the same. New waste treatments are introduced as references for the potential development of the waste treatment system in China. The most appropriate waste treatment system for each site should be selected according to the sites’ conditions and financial status as well as by weighing the advantages and disadvantages of each system. Strategies and perspectives for sustainable aquaculture development are proposed, with the emphasis on environmental protection. Conclusions  Negative effects of waste from aquaculture to aquatic environment are increasingly recognized, though they were just a small proportion to land-based pollutants. Properly planned use of aquaculture waste alleviates water pollution problems and not only conserves valuable water resources but also takes advantage of the nutrients contained in effluent. It is highly demanding to develop sustainable aquaculture which keeps stocking density and pollution loadings under environmental capacity. Recommendations and Perspectives  The traditional procedures for aquaculture waste treatment, mainly based on physical and chemical means, should be overcome by more site-specific approaches, taking into account the characteristics and resistibility of the aquatic environment. Further research needs to improve or optimize the current methods of wastewater treatment and reuse. Proposed new treatment technology should evaluate their feasibility at a larger scale for practical application. ESS-Submission Editor: Dr. Ding Wang (wangd@ihb.ac.cn)     

Heavy metals in untreated/treated urban effluent and sludge from a biological wastewater treatment plant

Background, Aim and Scope

The presence of heavy metals in wastewater is one of the main causes of water and soil pollution. The aim of the present study was to investigate the removal of Cd, Cu, Pb, Hg, Mn, Cr and Zn in urban effluent by a biological wastewater treatment, as well as to quantify the levels of As, Be, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Sn, Tl, V and Zn in dewatering sludge from the Biological Wastewater Treatment Plant to Ribeirão Preto (RP-BWTP), Brazil.

Materials and Methods

Concentrations of Cd, Cr, Cu, Mn and Pb in wastewater and those of Ni in sludge were determined by atomic absorption spectrophotometry with graphite furnace atomization. Mercury concentrations in wastewater were measured by hydride generation atomic spectrophotometry, and Zn levels were determined by atomic absorption spectrophotometry using acetylene flame. In sludge, the levels of As, Be, Cd, Cr, Cu, Fe, Hg, Mn, Pb, Sn, Tl, V and Zn were determined by inductively coupled plasma-mass spectrometry.

Results

The percentages of removal efficiency (RE) were the following: Hg 61.5%, Cd 60.0%, Zn 44.9%, Cu 44.2%, PB 39.7%, Cr 16,5% and Mn 10.4%. In turn, the mean concentrations (mg/kg) of metals in dewatering sludge followed this increasing order: Tl (<0.03), Hg (0.31), Be (0.43), As (1.14), Cd (1.34), V (59.2), Pb (132.1), Sn (166.1), Cr (195.0), Mn (208.1), Ni (239.4), Cu (391.7), Zn (864.4) and Fe (20537).

Discussion

The relationship between metal levels in untreated wastewater, as well as the removal efficiency are in agreement with previous data from various investigators, It is important to note that metal removal efficiency is not only affected by metal ion species and concentration, but also by other conditions such as operating parameters, physical, chemical, and biological factors.

Conclusions

Metal values recorded for treated wastewater and sludge were within the maximum permitted levels established by the Environmental Sanitation Company (CETESB), São Paulo, Brazil.

Recommendations

There is an urgent need for the authorities who are responsible for legislation on sludge uses in agriculture of establishing safety levels for As, Be, Hg, Sn, Tl and V.

Perspectives

According to the current metal levels, RP-BWTP sludge might be used for agriculture purposes. However, for an environmentally safe use of sewage sludge, further studies including systematic monitoring are recommended. Annual metal concentrations and predicted variations of those elements in the sludge should be monitored.