Occurrence and risk assessment of pharmaceutically active compounds in wastewater treatment plants. A case study: Seville city (Spain)

The occurrence of four anti-inflammatory drugs (diclofenac, ibuprofen, ketoprofen and naproxen), an antiepileptic drug (carbamazepine) and a nervous stimulant (caffeine) in influent and effluent samples from four wastewater treatment plants (WWTPs) in Seville was evaluated. Removal rates in the WWTPs and risk assessment of the pharmaceutically active compounds have been studied. Analytical determination was carried out by high performance liquid chromatography (HPLC) with diode array (DAD) and fluorescence (Fl) detectors after sample clean up and concentration by solid phase extraction. All pharmaceutically active compounds, except diclofenac, were detected not only in wastewater influents but also in wastewater effluents. Mean concentrations of caffeine, carbamazepine, ketoprofen and naproxen ranged between 0.28-11.44 microg l(-1) and 0.21-2.62 microg l(-1) in influent and effluent wastewater, respectively. Ibuprofen was present in the highest concentrations in the range 12.13-373.11 microg l(-1) and 0.78-48.24 microg l(-1) in influent and effluent wastewater, respectively. Removal rates of the pharmaceuticals ranged between 6 and 98%. Risk quotients, expressed as ratios between the measured environmental concentration (MEC) and the predicted no effect concentrations (PNEC) were higher than 1 for ibuprofen and naproxen in influent wastewater and for ibuprofen in effluent wastewater.     

Environmental fate of alkylphenols and alkylphenol ethoxylates--a review

Alkylphenol ethoxylates (APEs) are widely used surfactants in domestic and industrial products, which are commonly found in wastewater discharges and in sewage treatment plant (STP) effluents. Degradation of APEs in wastewater treatment plants or in the environment generates more persistent shorter-chain APEs and alkylphenols (APs) such as nonylphenol (NP), octylphenol (OP) and AP mono- to triethoxylates (NPE1, NPE2 and NPE3). There is concern that APE metabolites (NP, OP, NPE1-3) can mimic natural hormones and that the levels present in the environment may be sufficient to disrupt endocrine function in wildlife and humans. The physicochemical properties of the APE metabolites (NP, NPE1-4, OP, OPE1-4), in particular the high K(ow) values, indicate that they will partition effectively into sediments following discharge from STPs. The aqueous solubility data for the APE metabolites indicate that the concentration in water combined with the high partition coefficients will provide a significant reservoir (load) in various environmental compartments. Data from studies conducted in many regions across the world have shown significant levels in samples of every environmental compartment examined. In the US, levels of NP in air ranged from 0.01 to 81 ng/m3, with seasonal trends observed. Concentrations of APE metabolites in treated wastewater effluents in the US ranged from < 0.1 to 369 microg/l, in Spain they were between 6 and 343 microg/l and concentrations up to 330 microg/l were found in the UK. Levels in sediments reflected the high partition coefficients with concentrations reported ranging from < 0.1 to 13,700 microg/kg for sediments in the US. Fish in the UK were found to contain up to 0.8 microg/kg NP in muscle tissue. APEs degraded faster in the water column than in sediment. Aerobic conditions facilitate easier further biotransformation of APE metabolites than anaerobic conditions.     

Disinfection of wastewater with peracetic acid: a review

Peracetic acid is a strong disinfectant with a wide spectrum of antimicrobial activity. Due to its bactericidal, virucidal, fungicidal, and sporicidal effectiveness as demonstrated in various industries, the use of peracetic acid as a disinfectant for wastewater effluents has been drawing more attention in recent years. The desirable attributes of peracetic acid for wastewater disinfection are the ease of implementing treatment (without the need for expensive capital investment), broad spectrum of activity even in the presence of heterogeneous organic matter, absence of persistent toxic or mutagenic residuals or by-products, no quenching requirement (i.e., no dechlorination), small dependence on pH, short contact time, and effectiveness for primary and secondary effluents.Major disadvantages associated with peracetic acid disinfection are the increases of organic content in the effluent due to acetic acid (AA) and thus in the potential microbial regrowth (acetic acid is already present in the mixture and is also formed after peracetic acid decomposition). Another drawback to the use of peracetic acid is its high cost, which is partly due to limited production capacity worldwide. However, if the demand for peracetic acid increases, especially from the wastewater industry, the future mass production capacity might also be increased, thus lowering the cost. In such a case, in addition to having environmental advantages, peracetic acid may also become cost-competitive with chlorine.     

The analysis of free chlorine in the presence of nitrogenous organic compounds

Comparative analyses for aqueous chlorine using Standard Methods indicated that in chlorinated solutions containing nitrogenous organic compounds, none of these methods gave a reliable measurement of free available chlorine. Examination of the cyanuric acid-aqueous chlorine system showed that combined chlorine reacted as if it were free chlorine in all the Standard Methods. The implication of these studies for water and wastewater chlorination is that in waters containing nitrogenous organic compounds, N-Chloro compounds form which may result in an overestimation of the disinfecting potential of the added chlorine, when free chlorine is measured by Standard Methods.     

Nonylphenol in the environment: a critical review on occurrence, fate, toxicity and treatment in wastewaters

Nonylphenol is a toxic xenobiotic compound classified as an endocrine disrupter capable of interfering with the hormonal system of numerous organisms. It originates principally from the degradation of nonylphenol ethoxylates which are widely used as industrial surfactants. Nonylphenol ethoxylates reach sewage treatment works in substantial quantities where they biodegrade into several by-products including nonylphenol. Due to its physical-chemical characteristics, such as low solubility and high hydrophobicity, nonylphenol accumulates in environmental compartments that are characterised by high organic content, typically sewage sludge and river sediments, where it persists. The occurrence of nonylphenol in the environment is clearly correlated with anthropogenic activities such as wastewater treatment, landfilling and sewage sludge recycling. Nonylphenol is found often in matrices such as sewage sludge, effluents from sewage treatment works, river water and sediments, soil and groundwater. The impacts of nonylphenol in the environment include feminization of aquatic organisms, decrease in male fertility and the survival of juveniles at concentrations as low as 8.2 mug/l. Due to the harmful effects of the degradation products of nonylphenol ethoxylates in the environment, the use and production of such compounds have been banned in EU countries and strictly monitored in many other countries such as Canada and Japan. Although it has been shown that the concentration of nonylphenol in the environment is decreasing, it is still found at concentrations of 4.1 mug/l in river waters and 1 mg/kg in sediments. Nonylphenol has been referred to in the list of priority substances in the Water Frame Directive and in the 3rd draft Working Document on Sludge of the EU. Consequently there is currently a concern within some industries about the possibility of future regulations that may impose the removal of trace contaminants from contaminated effluents. The significance of upgrading sewage treatment works with advanced treatment technologies for removal of trace contaminants is discussed.     

Human hair as a potential biomonitor for assessing persistent organic pollutants

To explore human biomonitor of persistent organic pollutants (POP) for public health risk assessment, extractable organohalogens (EOX), extractable persistent organohalogens (EPOX) and some selected organochlorine pesticides (OCP) and polychlorinated biphenyls (PCB) in children hair from urban and rural regions of Beijing, China, were measured by instrumental neutron activation analysis (INAA) and gas chromatography-electron capture detector (GC-ECD). The results indicated that about 96% of the total halogens existed as water-soluble polar compounds; about 25 to 50% of EOX were sulfuric acid-resistant EPOX; organochlorines were the major fraction of the organohalogens; and 88 to 99.6% of extractable persistent organochlorines (EPOCl) cannot be attributed to the selected OCP and PCB. HCH, DDT and 2-5CB were the major contributors to hair OCP and PCB. Further, gamma-HCH, p,p'-DDE, p,p'-DDT and PCB-52 were the predominant individuals of HCH, DDT and 2-5CB, respectively. The concentration distributions of EPOCl, HCH, DDT and PCB in children hair were generally in the order of urban>rural and girls>boys, except for PCB congeners with random distributions between genders. Pearson positive correlations between hair lipid and the detected parameters of hair gamma-HCH (p<0.01), DDT (p<0.01), EOCl (p<0.05), as well as EPOCl (p<0.05) were observed. Also, the ratios of hair alpha/gamma and p,p'-DDE/p,p'-DDT suggested that fresh input of HCH and DDT might exist in Beijing area. Hair can reflect body's integral exposure to POP from endogenous and exogenous sources, which, thus, can be used as a potential biomonitor in assessing POP exposure for public health purposes.     

A review of the significance and formation of chlorinated N-organic compounds in water supplies including preliminary studies on the chlorination of alanine,tryptophan, tyrosine,cytosine, and syringic acid

Nitrogenous organic compounds are of environmental significance because of their potential as both trihalomethane (THM) and nonpurgeable organic halide (NPOX) precursors. They additionally lead to falsely positive tests for free available chlorine (FAC) and are components in the reaction of chlorine to form dihaloacetonitriles (DHANs). A large number of naturally occurring nitrogenous compounds additionally react readily with aqueous chlorine exerting significant chlorine demand. Such reactions generally involve the substitution of chlorine for hydrogen on a nitrogen atom. Additionally, N-chloroorganic materials may be produced even when the precursor concentration is low owing to the rapid specific rate of formation. While previous attention has been largely focused on nonpolar chlorinated organic contaminants such as THMs, the wide distribution of N-organic compounds in water, as well as their general reactivity towards aqueous chlorine, warrant further attention and study to this group of materials. Preliminary studies on the chlorination of several N-organic compounds at a few chlorine-to-compound molar ratios at pH 7 and 4.7 over several reaction intervals are presented. NPOX formation was quite rapid and comprised the greatest proportion of the total organic halide formed for the conditions studied.     

Groundwater contamination by microbiological and chemical substances released from hospital wastewater: Health risk assessment for drinking water consumers

Contamination of natural aquatic ecosystems by hospital wastewater is a major environmental and human health issue. Disinfectants, pharmaceuticals, radionuclides and solvents are widely used in hospitals for medical purposes and research. After application, some of these substances combine with hospital effluents and, in industrialised countries, reach the municipal sewer network. In certain developing countries, hospitals usually discharge their wastewater into septic tanks equipped with diffusion wells. The discharge of chemical compounds from hospital activities into the natural environment can lead to the pollution of water resources and risks for human health. The aim of this article is to present: (i) the steps of a procedure intended to evaluate risks to human health linked to hospital effluents discharged into a septic tank equipped with a diffusion well; and (ii) the results of its application on the effluents of a hospital in Port-au-Prince. The procedure is based on a scenario that describes the discharge of hospital effluents, via septic tanks, into a karstic formation where water resources are used for human consumption. COD, Chloroform, dichlomethane, dibromochloromethane, dichlorobromomethane and bromoform contents were measured. Furthermore, the presence of heavy metals (chrome, nickel and lead) and faecal coliforms were studied. Maximum concentrations were 700 NPP/100 ml for faecal coliforms and 112 mg/L for COD. A risk of infection of 10^? 5 infection per year was calculated. Major chemical risks, particularly for children, relating to Pb(II), Cr(III), Cr(VI) and Ni(II) contained in the ground water were also characterised. Certain aspects of the scenario studied require improvement, especially those relating to the characterisation of drugs in groundwater and the detection of other microbiological indicators such as protozoa, enterococcus and viruses.     

Aerobic degradation of 2,4,6-TCP content in ECF bleached effluent

Elemental chlorine-free (ECF) bleach effluents from kraft mill are characterised by: a chemical organic demand/biological organic demand (COD/BOD(5)) ratio of 4, chlorophenol content with low chlorine substitution, and toxicity. The effect of increasing the concentration of 2,4,6-trichlorophenol (2,4,6-TCP) content in ECF bleaching sequence effluent on the degradative activity of bacterial communities present in an aerobic system treatment was studied. An aerobic lagoon (AL) was used as a typical secondary treatment of kraft-mill effluent. AL displays a high performance of BOD(5) degradation (up to 90%); however, only 40% of the COD was removed. Simultaneously, the AL system shows a high ability to biodegrade 2,4,6-TCP up to 237 mg/l day. Kinetic parameters of the 2,4,6-TCP biodegradation by aerobic bacteria were determined. The K(s) and K(i) values were 34.3 and 50 mg/l 2,4,6-TCP, respectively. Moreover, the tolerance of aerobic bacteria was observed up to 1.3 g/l 2,4,6-TCP.     

Toxicological effects of disinfections using sodium hypochlorite on aquatic organisms and its contribution to AOX formation in hospital wastewater

Sodium hypochlorite (NaOCl) is often used for disinfecting hospital wastewater in order to prevent the spread of pathogenic microorganisms, causal agents of nosocomial infectious diseases. Chlorine disinfectants in wastewater react with organic matters, giving rise to organic chlorine compounds such as AOX (halogenated organic compounds adsorbable on activated carbon), which are toxic for aquatic organisms and are persistent environmental contaminants. The aim of this study was to evaluate the toxicity on aquatic organisms of hospital wastewater from services using NaOCl in pre-chlorination. Wastewater samples from the infectious and tropical diseases department of a hospital of a large city in southeast of France were collected. Three samples per day were collected in the connecting well department at 9 a.m., 1 p.m. and 5 p.m. during 8 days from 13 March to 22 March 2001, and a mixture was made at 6 p.m. with the three samples in order to obtain a representative sample for the day. The toxicity test comprised the 24-h EC50 on Daphnia magna and a bioluminescence assay using Vibrio fischeri photobacteria. Fecal coliforms and physicochemical analyses such as total organic carbon (TOC), chloride, AOX, total suspended solids (TSS) and chemical oxygen demand (COD) were carried out. Wastewater samples highlighted considerable acute toxicity on D. magna and V. fischeri photobacteria. However, low most probable numbers (MPN), ranging from <3 to 2400 for 100 ml, were detected for fecal coliforms. Statistical analysis, with a confidence interval of 95%, gave a strong linear regression assessed with r=0.98 between AOX concentrations and EC50 (TU) on daphnia. The identification of an ideal concentration of NaOCl in disinfecting hospital wastewater, i.e. its non-observed effect concentration (NOEC) on algae and D. magna, seems to be a research issue that could facilitate the control of AOX toxicity effects on aquatic organisms. Therefore, it would be necessary to monitor the biocide properties of NaOCl on fecal coliforms at various doses and its toxicity effects on aquatic organisms.     

Ultraviolet irradiation of municipal wastewater: Evaluation of effects on organic constituents

A comparison of chromatograms derived from the UV-absorbing and oxidizable constituents present in primary and secondary municipal wastewater effluents indicates that exposure to UV irradiation at disinfection levels results in only slight chemical changes. The most pronounced chemical effects to nonvolatile organic constituents in wastewater effluents have been observed at irradiation levels in excess of those necessary for disinfection. Aliquots of effluents before and after exposure to varying levels of UV irradiation were concentrated by lyophilization prior to liquid chromatographic (LC) analysis. Anion-exchange chromatographic techniques utilizing a modified ultraviolet detector coupled in series with a cerate oxidative monitor provided excellent resolution and sensitivity in the determination of chemical changes occurring in the effluents as a result of exposure to different irradiation levels. The total coliform counts for each irradiated effluent were determined by the membrane-filter technique to evaluate the effectiveness of UV irradiation as a disinfection process for municipal wastewaters. Changes in biochemical oxygen demand (BOD), chemical oxygen demand (COD), total organic carbon (TOC), and total Kjeldahl nitrogen (TKN) at different levels of exposure to UV irradiation are presented. The results of these determinations and the gas chromatography/mass spectrometry data characterizing the observed chemical changes are discussed.     

Environmental significance of nitrogenous organic compounds in aquatic sources

The presence of nitrogenous organic compounds in raw water sources for municipal supplies is of environmental concern because many of them exert significant chlorine demand, while some produce complex stable mutagenic products upon chlorination or are precursors to haloform formation. Seven N-organic compounds have been identified in municipal water concentrates (adenine, 5-chlorouracil, cytosine, guanine, purine, thymine, and uracil) at concentrations ranging from 20 to 860 μg/L. Eight compounds (adenine, cytosine, purine, pyrrole, thymine, tryptophan, tyrosine, and uracil) have been found in filtrates from cultures of either Anabaena flos aquae or Oscillatoria tenuis. Calculated CHCl₃ levels which might have formed at pH 7 in the water supplies were well below the maximum contaminant level (MCL) of 0.1 mg/L proposed by the U.S. Environmental Protection Agency (USEPA) for total trihalogenated methanes. Calculated levels of CHCl₃ which might have been formed under more alkaline conditions, however, were more than 10% of the MCL and were therefore significant. Calculated levels of combined forms of chlorine yielding falsely positive tests for free chlorine in some samples were slightly less or exceeded the 0.5 mg/L free chlorine residual generally taken as an acceptable level of disinfection. The demonstration of a parallel increase in organic nitrogen content with population density in two laboratory grown blue-green algal cultures, and the finding of elevated organic nitrogen values in a water supply sample collected during the occurrence of a blue-green algal bloom, suggested that summer algal bloom occurrence can add considerably to the organic nitrogen content and the trihalomethane potential of water supplies.     

Levels and distribution of organochlorines in fish from Indonesia

Organochlorines such as PCBs, DDTs, HCHs, CHLs and HCB were determined in pooled whole body homogenized of fish samples collected from five locations during 1998 and 2003 in order to understand their contamination status, temporal and spatial variation in Indonesian waters. PCBs and DDTs were the predominant contaminants with concentrations from 9.7 to 2700 ng/g lipid wt. and 12 to 1100 ng/g lipid wt., respectively, while HCHs (nd-24 ng/g lipid wt.), CHL compounds (nd-81 ng/g lipid wt.) and HCB (0.22-28 ng/g lipid wt.) were one to two orders of magnitude lower. Among the locations, PCBs and CHLs were higher in the samples from highly industrialized and thickly populated-locations, whereas OC pesticides such as DDTs and HCHs were particularly more prominent in suburban and rural areas. Levels of OCs observed in the waters surrounding Java Island were higher than those in Sumatra Island, implying significant use of OCs in highly populated Java Island. Concentrations of PCBs and DDTs in fish from Jakarta Bay were significantly lower in the samples collected in 2003 as compared to fish in 1998, indicating decreasing trend of these compounds in the Indonesian environment. Recent estimated average daily intakes of PCBs (0.81 microg/person/day), DDTs (1.1 microg/person/day), HCHs (0.018 microg/person/day), CHLs (0.010 microg/person/day) were much lower than the threshold values recommended by various agencies, suggesting minimal risk of this compound via fish ingestion to Indonesians.     

Natural and synthetic endocrine disrupting compounds (EDCs) in water, sediment and biota of a coastal lagoon

We report a survey on the occurrence and distribution of natural (17beta-estradiol, E2; estrone, E1) and synthetic (nonylphenol, NP; nonylphenol monoethoxylate carboxylate, NP1EC; bisphenol-A, BPA; benzophenone, BP; mestranol, MES; 17alpha-ethinylestradiol, EE2; diethylstilbestrol, DES) endocrine disrupting compounds (EDCs) in water, sediment and biota (Mediterranean mussel, Mytilus galloprovincialis) in the Venice lagoon, a highly urbanized coastal water ecosystem that receives both industrial and municipal wastewater effluents. The survey was preceded by the development of tailor made extraction and clean-up procedures for the simultaneous HPLC-ESI-MS determination of all examined EDCs in sediment and biota samples. Satisfactory extraction performances and method detection limits (MDLs) were obtained for almost all EDCs. Most of the selected compounds were found in water and sediment (concentration range: 2.8-211 ng/L, and 3.1-289 microg/kg, d.w., respectively), while only 17alpha-ethinylestradiol and nonylphenol were recorded in biota samples (conc. range: 7.2-240 ng/g, d.w.). 17beta-estradiol and ethinylestradiol contributed mostly to the water estradiol equivalent concentration (EEQ) (1.1-191 ng/L, average: 25 ng/L), while synthetic EDCs (17alpha-ethinylestradiol, diethylstilbestrol) were mainly responsible of the sediment EEQ (1.1-191 microg/kg, average: 71 microg/kg, d.w.). Whenever diethylstilbestrol was not recorded in the sediment, water EEQs were similar to sediment EEQs. A remarkable increase of nonylphenol was observed in sediments over the last decade.     

Residues and source identification of persistent organic pollutants in farmland soils irrigated by effluents from biological treatment plants

Sewage and industrial effluents from biological treatment plant have been widely used for agricultural irrigation in north part of China. However, effluents after biological treatment still contain heavy metals and persistent organic contaminants. The persistent organic contaminants accumulated in soil may transfer through the food chains and cause adverse health effects on human or biological effects on soil fauna and flora after long-term application. In present study, field surveys were carried out in the farmlands irrigated by effluents from biological treatment plants that receive sewage wastewater and industrial discharges. Residues of polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides (OCPs) in the soils irrigated using both ground water and effluents were compared. The origins of PAHs in the soils were discussed. The results showed that wastewater irrigation could cause accumulation of PAHs in soils close to the pollution discharge. Significantly higher concentrations of PAHs were observed in the sampling sites close to the entrance of main channel in contrast to those along branches and the reference sites. There was no significant relationship between the accumulation of persistent organic pollutants and organic matter content in soil (TOC). Soil contamination of these persistent organic pollutants as affected by effluent irrigation was characterized by the dominant accumulation of high-molecular-weight PAHs (HMW-PAHs). In the case study, concentration of benzo[a]pyrane (BaP, 45.6 ng/g), indeno[1,2,3-cd]pyrene (IcP, 86.3 ng/g), benzo[g,h,i]perlene (BgP, 66.9 ng/g) could exceed the limits of the soil quality standard for biodegraded soils. In identification of the sources, the IcP/BgP values of PAHs in soils were more close to that in air particulates from coal/coke source (1.09+/-0.03 ng/g) [Dickhut RM, Canuel EA, Gustafson KE, Liu K, Arzayus KM, Walkers E, et al. Automotive sources of carcinogenic polycyclic aromatic hydrocarbons associated with particulate matter in the chesapeake bay region. Environ Sci Technol 2000;34:4635-40]. Therefore, both of the PAHs residues in effluents and emission from a nearby coal/coke plant were responsible. Also in this case study, low levels of the OCPs were observed and were not of significant concern in this wastewater irrigation area. Among the different OCPs analyzed, DDTs (mean 8.41 ng/g) and HCHs (mean 2.91 ng/g) were the major components. From the ratios of DDT/DDTs and beta-HCH/HCHs, it indicated that OCPs residues should be from historical usage.     

A case study on identification of airborne organic compounds and time courses of their concentrations in the cabin of a new car for private use

The cabin of an automobile can be considered to be a part of the living environment because many people spend long periods of time during business, shopping, recreation or travel activities. However, little is known about the interior air contamination due to organic compounds diffusing from the interior materials used in the interior of automobiles. In the present study, the compounds in the interior air of a new car were identified, and the time courses of their concentrations were examined for over 3 years after the delivery (July, 1999). A total of 162 organic compounds, involving many aliphatic hydrocarbons and aromatic hydrocarbons, were identified. High concentrations of n-nonane (458 microg/m(3) on the day following delivery), n-decane (1301 microg/m(3)), n-undecane (1616 microg/m(3)), n-dodecane (716 microg/m(3)), n-tridecane (320 microg/m(3)), 1-hexadecene (768 microg/m(3)), ethylbenzene (361 microg/m(3)), xylene (4003 microg/m(3)) and 2,2'-azobis(isobutyronitrile) (429 microg/m(3)) were detected, and the sum of the concentrations determined for all compounds excluding formaldehyde (TVOC) was approximately 14 mg/m(3) on the day after the delivery. The concentrations of most compounds decreased with time, but increased with a rise of the interior temperature. The TVOC concentration in the next summer (July, 2000) was approximately one-tenth of the initial concentration. During the 3-year study period, the TVOC concentrations in summer exceeded the indoor guideline value (300 mug/m(3)) proposed by [Seifert B. Volatile organic compounds. In: Maroni M, Seifert B, Lindvall T, editors. Indoor air quality. A comprehensive reference book. Air quality monographs, vol. 3. Netherlands: Elsevier Science; 1995. p. 819-21]. The interior temperature and days lapsed after delivery were the main factors affecting the interior concentrations of most compounds according to multiple linear regression analysis. The results of this study offer useful fundamental data for investigations on air pollution in automotive cabins due to the organic compounds diffusing from the interior materials.     

Thallium: a review of public health and environmental concerns

Thallium (Tl) is a rare but widely dispersed element. All forms of thallium are soluble enough to be toxic to living organisms. Thallium is more toxic to humans than mercury, cadmium, lead, copper or zinc and has been responsible for many accidental, occupational, deliberate, and therapeutic poisonings since its discovery in 1861. Its chemical behavior resembles the heavy metals (lead, gold and silver) on the one hand and the alkali metals (K, Rb, Cs) on the other. It occurs almost exclusively in natural waters as monovalent thallous cation. The solubility of thallous compounds is relatively high so that monovalent thallium is readily transported through aqueous routes into the environment. Tl can be transferred from soils to crops readily and accrues in food crops. The fascinating chemistry and high toxicity potential make thallium and its compounds of particular scientific interest and environmental concern. Thallium was detected in base-metal mining effluents. The conventional removal of heavy metals from wastewater has little effect on thallium. In this review, various treatment options and removal technologies are enumerated in order to protect the environment from thallium toxicity.     

Comprehensive study of endocrine disrupting compounds using grab and passive sampling at selected wastewater treatment plants in South East Queensland, Australia

Chemical (gas chromatography-mass spectrometry, GC-MS) and biological (E-Screen assay) analyses were used to determine the concentrations of 15 endocrine disrupting compounds (EDCs) and estrogen equivalent (EEq) in grab and passive samples from five municipal wastewater treatment plants (WWTPs) in South East Queensland, Australia. EEq concentrations derived by E-Screen assays for the grab samples were between 108-356 ng/L for the influents and < 1-14.8 ng/L for the effluents with the exception of one effluent sample which was at 67.8 ng/L EEq. The EDC concentrations and EEq values for the passive samples were several times lower than those of the grab samples: a decrease probably caused by, but not limited to biofouling, low flow rate, biodegradation and temperature which can progressively reduce the uptake of compounds into the sampler. At this stage, grab sampling is the most reliable method for field monitoring; nevertheless, passive sampler is a useful sampling tool but the method requires more research to ensure that the information obtained can be interpreted appropriately. Although alkylphenols and phthalates were detected at higher concentrations in the wastewater samples as compared to natural hormones, the environmental risk may be negligible as their estrogenic potencies are several orders of magnitude lower than that of the natural estrogens. In most wastewater samples, the natural estrogens contributed to 60% or more of the EEq value. Removal efficacy of most estrogenic and xenoestrogenic compounds from the conventional activated sludge or biological nutrient removal (BNR) WWTPs monitored in this study was in the range of 80-> 99%. The efficiency of the WWTPs in removing estrogenic activity was > 95%. The EEqs of the E-Screen and those calculated from the results of extensive chemical analyses using the estradiol equivalency factors were comparable for most of the WWTPs samples.     

Pharmaceuticals in soils of lower income countries: Physico-chemical fate and risks from wastewater irrigation

Population growth, increasing affluence, and greater access to medicines have led to an increase in active pharmaceutical ingredients (APIs) entering sewerage networks. In areas with high wastewater reuse, residual quantities of APIs may enter soils via irrigation with treated, partially treated, or untreated wastewater and sludge. Wastewater used for irrigation is currently not included in chemical environmental risk assessments and requires further consideration in areas with high water reuse. This study critically assesses the contemporary understanding of the occurrence and fate of APIs in soils of low and lower-middle income countries (LLMIC) in order to contribute to the development of risk assessments for APIs in LLMIC. The physico-chemical properties of APIs and soils vary greatly globally, impacting on API fate, bioaccumulation and toxicity. The impact of pH, clay and organic matter on the fate of organic ionisable compounds is discussed in detail. This study highlights the occurrence and the partitioning and degradation coefficients for APIs in soil:porewater systems, API usage data in LLMICS and removal rates (where used) within sewage treatment plants as key areas where data are required in order to inform robust environmental risk assessment methodologies.     

The potential impact of environmental variation on the concentrations and ecological effects of pollutants in a marine avian top predator

Concentrations of organochlorine contaminants (OCs) and associations between OCs and fitness components were examined in great black-backed gulls (Larus marinus) in three colonies along the coast of northern Norway. In one of the colonies, data were collected in two subsequent seasons. Concentrations of four OCs (HCB, oxychlordane, DDE and PCB) were measured in blood (n=260) and fitness components (reproductive variables and adult return rate between breeding seasons) were recorded. In the first year, in two of the colonies, body condition and reproductive performance among the gulls were poor compared to the third colony, suggesting spatial variation in environmental conditions, especially food availability. However, in the third colony, body condition and reproductive performance were even better in the second season; i.e. environmental conditions varied temporally. OC residues were higher in the colonies where environmental conditions were poor, but much of this variation was explained by differences in body condition among colonies. Moreover, concurrent with improved body condition from one season to the next, the concentrations of OCs were halved. In the two colonies where environmental conditions were poor, female OC residues were negatively related to egg-laying date, egg size and nesting success, and in the colony where the concentrations of OC were highest, gulls with elevated DDE residues had low probability of returning between breeding seasons. In comparison, in the colony where environmental conditions were better in the first year, other types of adverse relationships between OCs and fitness components were found; i.e. chicks from females with high OC concentrations were in poor condition at hatching, suggesting maternal transfer of OCs to the eggs, and males with high OC residues had poor nesting success and chick survival, suggesting OC-mediated behavioural changes. With improved environmental conditions and lower OC concentrations in the second season, no significant adverse relationships between OCs and fitness components were found. This study thus suggests that there are complex interrelationships between both concentrations and ecological effects of OCs, and the environment, indicating that effects of OCs in nature may only be assessed after considering environmental variation.