Auditing the quality of effluent discharges

The public and their elected representatives want to see whether they get Value-for-Money from investment in preventing pollution. For many rivers, the achievement of good water quality is a matter of regulating the discharges from wastewater treatment plants. The effective audit of the quality of such discharges is a good basis for measuring progress in controlling pollution. To prove that control is effective, the techniques which underpin the following tasks must be sound and consistent:

- the standards for rivers must be devised so that the environmental objectives are met with the required reliability; the form of the standards will be constrained by the procedures available to monitor compliance;

- the standards worked out for effluents must have the correct mathematical relation with the river targets, and they too must be consistent with the options available for auditing performance;

- the assessment of compliance must be objective; and,

- statistics used to summarise the performance of a region (or a Nation) must be simple, stable, clear, and consistent with the results for individual sites.

     

Background environmental pollution of the Eurasian continent

1. The interest to studying pollution of environmental media on the background level has grown in the recent years. There arose a necessity to establish a specialized observational system for conducting observations of changes in the state of the environment, and of ecological consequences of pollution as well as to produce assessments of the current and predicted states. The realized program of background monitoring and first results of integrated background measurements have already been published. The paper presented illustrates time-and-space features of the background pollution of natural environmental media according to data from various background stations.
2. Long-term systematic measurements at the ‘Borovoe’ station (Kazakh SSR) commenced in 1976 have been supplemented with the results of the background pollution studies carried out in Berezinskyi, Caucasian, Central-Chernozem, Sary-Chelek, and Repetek Biosphere Reserves and in locations of the background stations in Hungary and Czechoslovakia. The data from the Hungarian and Czechoslovak stations were obtained during joint expeditions. Details are given in the relevant publications.
3. Ozone. Ozone measurements show the diurnal variation with the day-time maxima from 35 up to 160 μg m^?3. The correlation between day-time and nocturnal concentrations is a good indicator of the anthropogenic effect.
4. Sulphur dioxide and sulphates. The annual variation of sulphur dioxide characterised by winter maximum and summer minimum indicates the direct dependence on the amount of fuel burnt in the given region. Mean values of the sulphur dioxide content in the surface layer of the atmosphere correlates with the extent of the region urbanization and varies within 0.2–12.5 μg m^?3. The value of sulphur dioxide and sulphates correlation in the atmosphere is rather stable and varies within 0.18–0.37 μg m^?3.
5. Heavy metals. The annual cycle of the atmospheric content of lead, cadmium and arsenic is well expressed by winter maximum and summer minimum (which is opposite in case of mercury). As for lead and mercury, their annual variation is more distinct than that of cadmium and arsenic; their time-and-space variation is also more distinct. The content of these metals in the urbanized regions of Europe is 5 times higher than in Asia and the Caucasus. Atmospheric contents of arsenic and cadmium vary insignificantly from region to region. The content of all these metals in other environmental media (soil, water, vegetation) is of insignificant spatial variability. Observations in the Caucasian Biosphere Reserve showed minimum levels of the background atmospheric pollution: lead-16 μg m^?3, mercury-5 ng m^?3, arsenic-3.9 ng m^?3, cadmium-0.5 ng m^?3.
6. Organochloride pesticides. Concentrations of DDT and its metabolites and hexachlorocyclohexane isomers in the environmental media of European background regions are 3 times higher than those in Asia (‘Borovoe’).
7. PAH. Atmospheric content of BaP has a well expressed annual variation with winter maximum; the difference between winter and summer periods reaches the magnitude of an order. Background concentrations in European regions (Hungary, Berzinskyi Biosphere Reserve) are noticeably higher than in Asia; the difference reaches 3–5 times.
8. Comparisons with literature data on the background pollution show that observational materials from the background monitoring stations supplement to a considerable extent, and extent, the current notions on the background pollution and show the effects of the man-made impact on the background regions.

     

Chemical speciation in waters influenced by lead–zinc metallurgical industry

The Lead–Zinc Company region, Kardjali city, Bulgaria, is known to be highly polluted with heavy metals from its pyrometallurgical activities. The polluted levels and the chemical speciation in surface natural waters in the region as well as in the wastewaters of the factory were investigated in January 2008 by application of monitoring studies, thermodynamic modeling, and interpretation in terms of the “softness–hardness” factor. It was found that the levels of trace metals pollution of surface waters were lower than the legislation limits for the regions with Pb and Zn production. The wastewater treatment facilities of the company were found to operate properly, and the quality of the cleaned waters in station Kar4 was comparable to the other surface waters studied (e.g., station Kar5). The trace metals were divided into three groups: (1) Fe^3?+? and Al^3?+?, being “hard” acids, existed in all the studied waters as hydroxy species Fe(OH) $_{2}^{+}$ , AlOH^2?+?, and Al(OH) $_{2}^{+}$ , followed by the phosphate species AlPO $_{4}^{0}$ and Al₂(OH)₂PO $_{4}^{+}$ ; (2) Mn^2?+?, Zn^2?+?, and Cd^2?+? being “soft” acids with crystal field stabilization energy (CFSE) = 0 were present in natural waters mainly as free Me^2?+? ions. Small concentrations of their MeSO $_{4}^{0}$ , MeCO $_{3}^{0}$ species, and of MeCl $_{2}^{0}$ (Me = Zn, Cd) species were also calculated. In the wastewaters, two more species [Me(SO $_{4})_{2}^{2-}$ and Me(SO $_{4})_{3}^{4-}$ ] of the softer Zn and Cd metals were also calculated; (3) Cu^2?+? and Pb^2?+?, as “soft” acids with CFSE $\ne $ 0 preferentially coordinated with softer CO $_{3}^{2-}$ ions and in natural waters existed mainly as MeCO $_{3}^{0}$ and PbHCO $_{3}^{+}$ , followed by free Me^2?+?ions and MeOH^?+?. In the wastewaters, MeSO $_{4}^{0}$ and Pb(SO $_{4})_{2}^{2-}$ species increased at the expense of the free Me^2?+? ions. The highest self-cleaning capability of natural waters was found with respect to Al and Fe, followed by Mn and Cd. The lowest corresponded to Pb, Cu, and Zn.     

Planning for implementation of long-term resource monitoring programs

Guidelines for the early stages of developing a monitoring program are presented. Jumping right into a monitoring program based on standard protocols and a number of commonly monitored parameters is an attractive idea, but it is unlikely to lead to an intelligent allocation of time and money. Rather, a number of well-defined planning steps must be followed before monitoring is begun:

1. Objectives for the program should be well defined.
2. The attributes to be monitored in order to meet objectives should be listed.
3. Methods of monitoring these attributes should be developed.
4. A pilot study should be conducted to determine spatial and temporal variability of the attributes being monitored and the cost of sampling.
5. The results of the pilot study should be carefully evaluated to determine whether program objectives can be met for an acceptable cost.
6. Objectives, attributes to be monitored, and methods should be revised in accordance with the results of the pilot study.

     

Approaches to standardization of atmospheric pollution undergoing long-range and transboundary transport

The authors consider some possible ways of regulating three types of atmospheric emission of pollutants:

1. emission of substances causing pollution of the natural environment on the global scale (global pollutants);
2. emission of substances causing pollution on a regional scale, most often including territories of several countries (international pollutants);
3. emission of substances causing negative effects in a relatively limited region, for example within border area of two adjoining countries.

Substances (gaseous, as a rule) of a long life-time in the atmosphere that can contaminate natural media on a global scale irrespective of the place of emission refer to the first class of pollutants that are subject to emission regulation at an international level and to quota establishement for individual countries. They are carbon dioxide, freon, krypton-85. Various approaches to determining permissible emission and to quota establishing are discussed in the paper. The second group includes substances of a limited, yet rather long, life-time whose emission intensity makes a notable contribution to environmental pollution of a large region including territories of several countries. Here it is needed to regulate internationally not the atmospheric emission as it is but pollutant transport over national boundaries (sulphur and nitrogen oxides, pesticides, heavy metals). The third group includes substances of relatively short time of life producing local effects. Emission regulation in such cases should be based upon bilateral agreements with due account of countries' mutual interests.     

Background monitoring and its role in global estimation and forecast of the state of the biosphere

1. Scientific grounds and the concept of monitoring as the system for observations, assessment and prediction of man-induced changes in the state of natural environment, the program and aims of the background monitoring were developed by the author in 1972–1980. These questions were discussed in detail at the International Symposium on Global Integrated Monitoring (Riga, U.S.S.R., December, 1978). It should be stressed that along with significant anthropogenic loading on large cities and industrial areas, natural ecosystems covering most of the Earth's territory are also exposed to quite extended, though insignificant anthropogenic effects. This paper proposes to consider the ways of the background information use for the biosphere state assessment and prediction.
2. Classification of objects for monitoring from the point of view of the consequences of the man-made impact, pollution in the first hand, is as follows:
3. population (public health);
4. ecosystem elements employed by man whose production is used by population (soil, water bodies, forest, etc.);
5. biotic elements of ecosystems (without the immediate consumed production);
6. abiotic constituents of natural ecosystems, considerable components of the biosphere, climatic system.
7. Historically, monitoring in all countries involves the first two spheres. The background monitoring also extends on the next two spheres. It should differentially take into account physical, chemical and biological factors of impacts. Indentification of biological effects is most complex and vital. Human impact at the background level proceeds indirectly through a general (global or regional) deterioration of the state of the biosphere.
8. Gradually the background monitoring is being practiced on a larger and larger scale. It is shown that the long-range atmospheric transport of pollutants in various regions leads to a gradual general increase of all the natural media pollution and to perceptible biological effects (soil and water acidification and resulting disturbances in the composition of soil and water organisms). The levels of the background impact differ. Thus, the background concentrations of a number of anthropogenic pollutants in Central Europe is 10–20 times higher than in Central Asia.
9. The area of priority in the background monitoring of the biosphere pollution has become evident: compounds of sulphur, mercury and their derivatives, organochloride pesticides, some radioactive substances (e.g., krypton-85 in the atmosphere).
10. The World Ocean is practically all contaminated on a global scale. Biological effects of the World Ocean pollution cause special concern. Particularly important consequences, including climate impact, may be caused by disturbances in energy and matter transfer between environmental media (water-air, water-bottom, etc.). The priority of the impact factors can be allocated here as well: oil products, metals, organochloride compounds, polycyclic aromatic hydrocarbons.
11. One of the most effective possibilities of environmental quality control is standardization which consists in elaboration of permissible ecological loadings upon ecosystems and natural media. The approach to ecological standardization differs from that of hygienic control in principle. The objective of ecological standardization is to ensure the integrity of the given ecosystem and natural environment on the whole.
12. Ecological standardization in its turn requires knowledge related to the damage from this or another impact because in such a case there is a possibility to compare ecological standards for the same ecosystem in the case when impacts are of different origin (e.g., different pollutants).

     

Non-radiological contaminants from uranium mining and milling at Ranger,Jabiru, Northern Territory,Australia

Protection from the hazards from radioactivity is of prime importance in the management of uranium mine and mill wastes. Such wastes also contain non-radiological contaminants (heavy metals, acids and neutralising agents) which give rise to potential long-term health and environmental hazards and short-term hazards to the aquatic ecosystem, e.g. as a result of release of waste water. This study seeks to identify non-radiological contaminants (elements) transferred to waste water at the Ranger uranium mine/mill complex at Jabiru, which are likely to hazardous to the aquatic environment. The two principal sources of contaminants are:

1. ore and waste rock mobilised from mining; and
2. process reagents used in the milling and mineral extraction process.

These substances may or may not already be present in the natural environment but may lead to deleterious effects on the aquatic environment if increased above threshold levels. Rhenium, derived from the ore body, was found to be significantly enriched in waste water from Ranger, indicating its suitability as an indicator element for water originating from the mining and milling process, but only uranium, likewise derived from the ore, and magnesium, manganese and sulfur (as sulfate) from the milling process were found to be significant environmental contaminants.     

Soil sampling and analysis for volatile organic compounds

Concerns over data quality have raised many questions related to sampling soils for volatile organic compounds (VOCs). This paper was prepared in response to some of these questions and concerns expressed by Remedial Project Managers (RPMs) and On-Scene Coordinators (OSCs). The following questions are frequently asked:

1. Is there a specific device suggested for sampling soils for VOCs?
2. Are there significant losses of VOCs when transferring a soil sample from a sampling device (e.g., split spoon) into the sample container?
3. What is the best method for getting the sample from the split spoon (or other device) into the sample container?
4. Are there smaller devices such as subcore samplers available for collecting aliquots from the larger core and efficiently transferring the sample into the sample container?
5. Are certain containers better than others for shipping and storing soil samples for VOC analysis?
6. Are there any reliable preservation procedures for reducing VOC losses from soil samples and for extending holding times?

Guidance is provided for selecting the most effective sampling device for collecting samples from soil matrices. The techniques for sample collection, sample handling, containerizing, shipment, and storage described in this paper reduce VOC losses and generally provide more representative samples for volatile organic analyses (VOA) than techniques in current use. For a discussion on the proper use of sampling equipment the reader should refer to other sources (Acker, 1974; U.S. EPA, 1983; U.S. EPA, 1986a). Soil, as referred to in this report, encompasses the mass (surface and subsurface) of unconsolidated mantle of weathered rock and loose material lying above solid rock. Further, a distinction must be made as to what fraction of the unconsolidated material is soil and what fraction is not. The soil component here is defined as all mineral and naturally occurring organic material that is 2 mm or less in size. This is the size normally used to differentiate between soils (consisting of sands, silts, and clays) and gravels. Although numerous sampling situations may be encountered, this paper focuses on three broad categories of sites that might be sampled for VOCs:

1. Open test pit or trench.
2. Surface soils (<5 ft in depth).
3. Subsurface soils (>5 ft in depth).

     

Effects of Cu2+, Pb2+ and Zn2+ on voltage-activated currents in Helix pomatia L. Neurons

Effects of Cu²⁺, Pb²⁺ and Zn²⁺ were studied on voltage-activated Na-, Ca-, and K-currents in snail neurons. It was found that: 1. In normal physiological saline Cu²⁺, Pb²⁺ and Zn²⁺ ions exerted complex changes on the total ionic currents; 2. All three metal ion have depressed the inward Na-currents but with different K _D , moreover Pb ²⁺ increased Na-current at low concentrations (5 M); 3. The inward Ca-current was also reduced. The sequence of the blocking effect of metals was different: Pb>Cu>Zn, however the steady-state inactivation was influenced only by Cu²⁺; 4. Outward currents were decreased in all neurons by Cu²⁺, but the effects of Pb²⁺ and Zn²⁺ were either depression or enhancement in different indentified neurons; 5. The possibility of binding heavy metals to wide variety of membrane proteins and the observed effects on different ionic channels suggest that the metal effect is complex and cannot be taken as a specific one to a single channel type or site of location.     

Monitoring bio-available marine contaminants with mussels (Mytilus edulis L) in the Netherlands

After discussing the usefulness of mussels (e.g. Mytilus edulis) for investigating contamination in the marine environment, four cases are presented:

1. A survey of Cu bioavailability in and around the Eastern Scheldt during one winter (1974–1975);
2. A surveillance with a six years interval (1974; 1980) of the bioavailability of Zn along the Dutch North Sea coast.
3. A monitoring programme over the period 1972–1980 showing the decrease in bioavailable Hg in the water column of the Ems-Dollard estuary after decreased emissions at Delfzijl.
4. Retrospective monitoring of two PCB's, as a background for the effectiveness of legal restrictions to PCB use.

These four cases are considered a first step in understanding the effects of pollutants in marine ecosystems. In depth physiological, histological and biochemical studies could lay the basis for improved routine biological effect monitoring.     

Ionic and heavy metal composition of respirable particulate in Madurai, India

Airborne particulate matter (PM₁₀) was collected for a period of 1 year at six locations in Madurai city, India. The chemical analyses on PM₁₀ samples were carried out for the estimation of heavy metals and ions using atomic absorption spectroscopy and ion chromatography respectively. The average PM₁₀ concentrations varied from 97.2 to 152.5 μg/m³, which were found to be below the Indian air quality standards. While industrial areas had the highest concentrations of heavy metals such as Fe, Zn and Cr and also the $\text{SO}_{4}^{2-}$ ions, traffic areas with relatively higher traffic densities in the city endured highest concentrations of Cd and the $\text{NO}_{3}^{-}$ ion. As gaseous pollutants serve as precursors of ionic particles in the atmospheric environment, gaseous pollution control is necessitated along with particulate with special reference to heavy metal and ion pollution abatement for the sustainable development of Madurai city.     

Harmonization problems in the implemention of the EEC directive on air quality limit values and guide values for sulphur dioxide and suspended particulates

This report deals with the implementation of Article 10 of the Directive on air quality limit values and guide values for sulphur dioxide and suspended particulates (80/779/EEC). For this purpose the Commission, in cooperation with the Member States, has prepared a ‘Common Measurement Programme’ which basically provides for:

1. examination and improvement of the reference measurement methods,
2. examination of the comparability of the measuring procedures and equipment used for monitoring purposes in the Member States,
3. the provision of guidelines and the carrying out of measurements to determine the corresponding stringency of the limit values laid down in Annexes IV and I of the Directive.

     

Chemical speciation in mining affected waters: the case study of Asarel-Medet mine

The inorganic chemical species in Maresh and Luda Yana rivers affected by the Cu– Mo Asarel-Medet mine, Bulgaria were determined during a low-flow and a high-flow period. The mining activities, the weathering and the oxidation processes strongly influenced the physicochemical processes in the whole water system. The main pollution source was a small lake receiving the acid effluents of the mining activities. High levels of SO₄ ^2???, Cu, Mg, Al, Mn and Fe were determined at the mining polluted and affected stations. Cu^2?+? and CuCO₃ ⁰ species (1:1) were present in the reference waters and Cu^2?+? and CuSO₄ ⁰ species (1:1) in the polluted and affected waters; Cu^2?+? species was dominating downstream. Me^2?+? followed by $\rm{MeSO}_{4}^{\kern3pt{0}}$ (Me = Mn, Zn, Cd and Pb), $\rm{PbCO}_{3}^{\kern3pt{0}}$ and $\rm{PbHCO}_{3}^{\kern3pt{+}}$ species as well as $\rm{Fe(OH)}_{2}^{\kern3pt{+}}$ , $\rm{Al(OH)}_{4}^{\kern3pt{-}}$ , $\rm{Al(OH)}_{2}^{\kern3pt{+}}$ , $\rm{Al(OH)}_{3}^{\kern3pt{0}}$ were prevailing in the system. $\rm{MeSO}_{4}^{\kern3pt{+}}$ and $\rm{Me(SO}_{4})_{2}^{\kern3pt{-}}$ (Me = Fe, Al), $\rm{Me(SO}_{4})_{2}^{\kern3pt{2-}}$ (Me = Zn, Cd and Pb), $\rm{Me(SO}_{4})_{3}^{\kern3pt{4-}}$ (Me = Zn, Cd) and $\rm{Cd(SO}_{4})_{4}^{\kern3pt{6-}}$ species polluted and affected waters. The major elements K and Na were mainly Me^?+? species, whereas Ca and Mg were Me^2?+? and $\rm{MeSO}_{4}^{\kern3pt{0}}$ species in different ratios. The concentration of concentration of $\rm{NO}_{2}^{\kern3pt{-}}$ , $\rm{NO}_{3}^{\kern3pt{-}}$ and $\rm{NH}_{4}^{\kern3pt{+}}$ species as well as complex phosphorous species such as H₂ $\rm{PO}_{4}^{\kern3pt{-}}$ , $\rm{FeHPO}_{4}^{\kern3pt{+}}$ , $\rm{HPO}_{4}^{\kern4pt{2-}}$ , $\rm{CaPO}_{4}^{\kern3pt{-}}$ , $\rm{CaHPO}_{4}^{\kern3pt{0}}$ and $\rm{MgHPO}_{4}^{\kern3pt{0}}$ were also calculated. The trace element concentrations decreased downstream due to dilution, sorption processes and precipitation, but the percentage of free metal species, which are more toxic, increased. An exception was iron and aluminum of which the dominant hydroxy colloidal and sulphate species were easily incorporated into the suspended phase.     

Acidic and basic properties and buffer capacity of airborne particulate matter in an urban area of Beijing

Particles with aerodynamic diameters <10  $\upmu $ m (PM₁₀) and particles with aerodynamic diameters <2.5  $\upmu $ m (PM_2.5) were sampled during summer 2006 in Beijing and mass concentrations, water-soluble ionic compounds concentrations, and acidic buffer capacity were analyzed. Results show that the mass concentration ranges of PM₁₀ and PM_2.5 were from 56.4 to 226.6  $\upmu $ g/m³ and from 31.3 to 200.7  $\upmu $ g/m³ during sampling days, respectively. Concentrations of F^???, Cl^???, NO $_{3}^{\,\,-}$ , NO $_{2}^{\,\,-}$ , SO $_{4}^{\,\,2-}$ , Ac^???, Ca^2?+?, Na^?+?, K^?+?, Mg^2?+?, and NH $_{4}^{\,\,+}$ in particles were analyzed by ion chromatography. Microtitration was adapted to determine the acidic?Cbasic property and the change of the buffering systems in different pH of the aqueous solution in which the PM is suspended. The major alkalinity and buffer capacity of particles were analyzed and calculated. The average carbonate buffer capacity was 0.3 mmol/g in PM_2.5 and 0.7 mmol/g in PM₁₀. The average acetic acid buffer capacity was 0.1 mmol/g in PM_2.5 and 0.3 mmol/g in PM₁₀. Carbonate and acetic acid are the main species for the buffer capacity in the particle phase. The average mass of carbonate was 71.0 mg/g in PM₁₀ and 46.7 mg/g in PM_2.5. The average mass of acetic acid was 11.2 mg/g in PM_2.5 and 20.0 mg/g in PM₁₀.     

Assessment of dissolved heavy metal in the Yangtze River estuary and its adjacent sea, China

The purpose of this paper is to determine the concentrations of dissolved heavy metals namely mercury (Hg), lead (Pb), cadmium (Cd), and copper (Cu) and to investigate the relationships between nutrients (nitrate-nitrogen and phosphate) and dissolved heavy metals. For this purpose, the concentrations of dissolved heavy metals were measured through 51 voyages form 1984 to 2006 in the Yangtze river estuary and its adjacent sea. Results analysis showed that dissolved heavy metals were not the main pollutants in the Yangtze river estuary, and the main source of heavy metal contamination was industrial wastewater from terrestrial pollution during the past 20 years. Heavy metal values showed significant abundance in the south branch of the Yangtze River estuary and Hangzhou Bay. In addition, Pb showed negative correlation with nutrients, while the positive correlations between Hg, Cd, and nutrients were shown. The obtained molar ratios, $\Delta \mbox{Cd}/\Delta \mbox{N} = 1.68 \times 10^{-5}$ and $\Delta \mbox{Cd}/\Delta \mbox{P} = 1.66 \times 10^{-4}$ , are close to those in plankton, showing the biogeochemical behavior and process of dissolved cadmium.     

Urban stream syndrome in a small,lightly developed watershed: a statistical analysis of water chemistry parameters,land use patterns,and natural sources

The relationships among land use patterns, geology, soil, and major solute concentrations in stream water for eight tributaries of the Kayaderosseras Creek watershed in Saratoga County, NY, were investigated using Pearson correlation coefficients and multivariate regression analysis. Sub-watersheds corresponding to each sampling site were delineated, and land use patterns were determined for each of the eight sub-watersheds using GIS. Four land use categories (urban development, agriculture, forests, and wetlands) constituted more than 99 % of the land in the sub-watersheds. Eleven water chemistry parameters were highly and positively correlated with each other and urban development. Multivariate regression models indicated urban development was the most powerful predictor for the same eleven parameters (conductivity, TN, TP, NO $_{3}^-$ , Cl^?, HCO $_{3}^-$ , SO $_{4}^{2-}$ , Na⁺, K⁺, Ca²⁺, and Mg²⁺). Adjusted R ² values, ranging from 19 to 91 %, indicated that these models explained an average of 64 % of the variance in these 11 parameters across the samples and 70 % when Mg²⁺ was omitted. The more common R ², ranging from 29 to 92 %, averaged 68 % for these 11 parameters and 72 % when Mg²⁺ was omitted. Water quality improved most with forest coverage in stream watersheds. The strong associations between water quality variables and urban development indicated an urban source for these 11 water quality parameters at all eight sampling sites was likely, suggesting that urban stream syndrome can be detected even on a relatively small scale in a lightly developed area. Possible urban sources of Ca²⁺ and HCO $_{3}^-$ are suggested.     

Groundwater hydrogeochemistry of Trikala municipality, central Greece

Sixty-four samples from the groundwater resources of Trikala municipality, central Greece, were collected during two periods (2006 and 2007) and analyzed for physico-chemical parameters (temperature, pH, specific electrical conductivity, and total dissolved solids), major ions (Ca²⁺, Cl^?, HCO ₃ ^? , K⁺, Mg²⁺, Na⁺, NO ₃ ^? , SO ₄ ^2? ), and several potentially toxic elements (Al, B, Ba, Br, Ca, Ce, Cl, Cr, Cu, Fe, K, La, Li, Mg, Mn, Mo, Na, Nd, Ni, P, Pb, Rb, S, Sc, Si, Sn, Sr, U, V, Y, Zn). European Council directives and USEPA guidelines were used to assess the water quality. The results indicate that all samples are fresh water, suitable for human consumption. All basic ions and physico-chemical parameters have average concentrations below their recommended optimum limits with the exception of electrical conductivity, for January 2007, and nitrate for October 2006 and January 2007 sampling periods. This exceedance is the result of dissolution of minerals such as calcite and dolomite that are present in the surrounding rocks and the application of fertilizers, respectively. Lead is the only element with an average value that exceeds the recommended EC guideline, while special attention should be paid to one borehole (T9) which has elevated NO ₃ ^? values which may pose a risk to human health.     

Specific absorption and backscattering coefficients of the main water constituents in Poyang Lake, China

Obtaining and analyzing the specific inherent optical properties (SIOPs) of water bodies is necessary for bio-optical model development and remote sensing-based water quality retrievals and, further, for related ecological studies of aquatic ecosystems. This study aimed to measure and analyze the specific absorption and backscattering coefficients of the main water constituents in Poyang Lake, China. The specific absorption and/or backscattering coefficients of the main water constituents at 85 sampling sites (47 in 2010 and 38 in 2011) were measured and analyzed as follows: (1) the concentrations of chlorophyll a (C _CHL), suspended particulate matter (C _SPM) (including suspended particulate inorganic matter (C _SPIM) and suspended particulate organic matter (C _SPOM)), and the absorption coefficients of total particulate (a _p), phytoplankton (a _ph), and non-pigment particulate (a _d) were measured in the laboratory; (2) the total backscattering coefficients at six wavelengths of 420, 442, 470, 510, 590, and 700 nm, including the contribution of pure water, were measured in the field with a HydroScat-6 backscattering sensor, and the backscattering coefficients without the contribution of pure water (b _b) were then derived by subtracting the backscattering coefficients of pure water from the total backscattering coefficients; (3) the specific absorption coefficients of total particulate ( $ a_{\mathrm{p}}^{ * } $ ), phytoplankton ( $ {a_{{\mathrm{ph}}}}^{ * } $ ), and non-pigment particulate ( $ a_{\mathrm{d}}^{ * } $ ) were calculated by dividing a _p, a _ph, and a _d by C _SPM, C _CHL, and C _SPIM, respectively, while the specific backscattering coefficients of total suspended particulate matter ( $ b_{\mathrm{b}}^{ * } $ ) were calculated by dividing b _b by C _SPM; and (4) the $ {a_{{\mathrm{ph}}}}^{ * } $ , $ a_{\mathrm{d}}^{ * } $ , $ a_{\mathrm{p}}^{ * } $ and $ b_{\mathrm{b}}^{ * } $ of the remaining samples (46 in 2010 and 36 in 2011) were visualized and analyzed, and their relations to C _CHL, C _SPIM or C _SPM were studied, respectively. The main results are summarized as follows: (1) the $ {a_{{\mathrm{ph}}}}^{ * } $ values at 440 nm were 0.0367–0.7203 m²?mg^?1 with a mean of 0.1623?±?0.1426 m²?mg^?1 in 2010 and 0.0319–0.7735 m²?mg^?1 with a mean of 0.3145?±?0.1961 m²?mg^?1 in 2011; there existed significant, negative, and moderate correlations between $ {a_{{\mathrm{ph}}}}^{ * } $ and C _CHL at 400–700 nm in 2010 and 2011 (p?<?0.05); (2) The $ a_{\mathrm{d}}^{ * } $ values at 440 nm were 0.0672–0.2043 m²?g^?1 with a mean of 0.1022?±?0.0326 m²?g^?1 in 2010 and 0.0559–0.1347 m²?g^?1 with a mean of 0.0953?±?0.0196 m²?g^?1 in 2011; there existed negative correlations between $ a_{\mathrm{d}}^{ * } $ and C _SPIM, while the correlations showed overall decreasing and increasing trends before and after around 575 nm with increasing wavelengths, respectively; (3) The $ a_{\mathrm{p}}^{ * } $ values at 440 nm were 0.0690–0.1929 m²?g^?1 with a mean of 0.1036?±?0.0298 m²?g^?1 in 2010 and 0.0571–0.1321 m²?g^?1 with a mean of 0.1014?±?0.0191 m²?g^?1 in 2011, and the negative correlations between $ a_{\mathrm{p}}^{ * } $ and C _SPM were found in both years; (4) The $ b_{\mathrm{b}}^{ * } $ at the six wavelengths generally decreased with increasing wavelengths, while the $ b_{\mathrm{b}}^{ * } $ values at 420 nm were lower than those at 442 nm for some samples; the correlation between $ b_{\mathrm{b}}^{ * } $ and C _SPM increased with increasing wavelength. Such results can only represent the SIOPs during the sampling time periods, and more measurements and analyses considering different seasons need to be carried out in the future to comprehensively understand the SIOPs of Poyang Lake.