Monitoring Of Organic Pollutants Research Articles

Main findings and conclusions of the implementation of Directive 76/464/CEE concerning the monitoring of organic pollutants in surface waters (Portugal, April 1999-May 2000).

The purpose of this paper is to relate the implementation of Directive 76/464/CEE concerning the survey of priority dangerous substances and indicate the main priority pollutants encountered throughout a systematic monitoring program carried out in Portugal during a period of 14 months (April 1999-May 2000). Contrary to what it seems, the implementation of such a Directive is not straightforward owing to the large number of compounds and samples to be analyzed at trace levels. During this period of time, 115 priority semivolatile organic compounds (SVOCs), 41 volatile organic compounds (VOCs), six organotin compounds, 14 heavy metals, phosphate, nitrates, nitrites and ammonia were determined in 644 surface water samples (corresponding to 14 months and 46 sites). In addition, priority SVOCs were also determined in sediment, mussels and fish (muscle and liver). This paper reports the procedure and analytical tools used and necessary to determine the levels of 115 priority toxic and persistent semivolatile organic compounds selected from the EC Council Directive list (76/464/EEC). An advanced analytical protocol was developed involving enrichment of water samples in Oasis solid-phase extraction cartridges (SPE) in the Lisbon laboratory with a Gilson ASPEC XL automated extraction system and by sending the enriched cartridges to Barcelona by aeroplane at 4 degrees C, where elution and analysis were performed. Final determination was performed with gas chromatography-electron ionization mass spectrometry (GC-EI-MS). Acidic herbicides were determined by liquid chromatography with diode array detection. Owing to the great amount of data generated throughout the monitoring study, statistical analysis of the more representative contaminants was performed, allowing the identification of the more relevant contamination sources, percentages of findings and the description of their temporal and spatial (geographical) distributions. Recommendations and compounds that should be included in future monitoring programs are given.

Biochemical mediator demand--a novel rapid alternative for measuring biochemical oxygen demand.

The biochemical oxygen demand (BOD) test (BOD5) is a crucial environmental index for monitoring organic pollutants in waste water but is limited by the 5-day requirement for completing the test. We have optimised a rapid microbial technique for measuring the BOD of a standard BOD5 substrate (150 mg glucose/l, 150 mg glutamic acid/l) by quantifying an equivalent biochemical mediator demand in the absence of oxygen. Elevated concentrations of Escherichia coli were incubated with an excess of redox mediator, potassium hexacyanoferrate(III), and a known substrate for 1 h at 37 degrees C without oxygen. The addition of substrate increased the respiratory activity of the microorganisms and the accumulation of reduced mediator; the mediator was subsequently re-oxidised at a working electrode generating a current quantifiable by a coulometric transducer. Catabolic conversion efficiencies exceeding 75% were observed for the oxidation of the standard substrate. The inclusion of a mediator allowed a higher co-substrate concentration compared to oxygen and substantially reduced the incubation time from 5 days to 1 h. The technique replicates the traditional BOD5 method, except that a mediator is substituted for oxygen, and we aim to apply the principle to measure the BOD of real waste streams in future work.

Determination and Monitoring of Polar Compounds and Acidic Herbicides Using a Modified Samos System

A system for the automated monitoring of organic pollutants in surface waters (SAMOS) has been developed over the last 5 years to monitor for the presence of organic contaminants in surface water. It uses a solid-phase extraction (SPE) trace enrichment step followed by on-line elution and separation by HPLC. Detection and provisional identification is obtained with diode array detection. For pesticide and herbicide analysis, mainly medium volatile, neutral compounds such as carbamates, triazines and phenyl ureas have been reported. Ionic species such as phenoxy acid herbicides are poorly preconcentrated at normal river pH. These ionic/polar compounds frequently show breakthrough from the SPE cartridge prior to complete loading of the sample. Any retained polar analytes are also often obscured by the presence of co-extracted humic substances in river water samples. The paper presents the required changes to the original SAMOS system to allow ionised and polar pollutants to be successfully analysed. These changes involve allowing the ionic/polar compounds to break through from the loading onto the primary cartridge (PLRP-S), allowing all but the last few ml of sample to go to waste. When breakthrough of the relevant analytes is achieved, the remaining sample is switched automatically on-line to a secondary cartridge (again PLRP-S) with acid being added just prior to this to neutralise the compounds This secondary cartridge effectively preconcentrates the ionic/polar compounds. The two cartridges are desorbed in two subsequent gradient elution LC-DAD runs. Analysis of several major classes of compounds is achieved, notably members of the triazine, phenyl urea, phenol and acid herbicide groups. The system has been designed and tested in the laboratory and applied at an installation remote from the laboratory on a river site as part of an intake protection programme. Details of the method performance, experiences of operation and access of the system via telemetry are discussed.

Biosensor technology for determination of BOD

Biochemical oxygen demand (BOD) is an important index for monitoring organic pollutants in water. The conventional standard method (5-day BOD test, BOD5), however, is a complicated and time-consuming procedure, including a 5-day incubation, and also requires considerable experience and skill to get reproducible results. To overcome these problems, microbial biosensors allowing the rapid estimation of BOD have been developed. One such BOD sensor system has already been commercialized and another highly sensitive BOD sensor, suitable for use in environmental monitoring in situations where BOD levels are low, is now being investigated. Some examples of these novel BOD sensors are described below. © 1998 John Wiley & Sons, Inc. Field Analyt Chem Technol 2: 333–340, 1998

A survey of organic contaminants in drinking water, mineral water and natural water in Eastern and Central European countries

Monitoring of organic pollution is becoming more and more important, because the toxicity of many commonly used organic chemicals such as solvents, pesticides and their metabolites are similar to that of toxic heavy metals. In this study we analyzed the organic sum parameters, adsorbable organic halogen and total organic carbon, in drinking, mineral, river and lake waters collected from 20 countries in Europe from 117 locations. Analyses were done according to the standard methods. We found that the East European and Hungarian drinking waters contained more organic halogen and carbon than the West European ones. The mineral water wells in the North Slopes of the Caucasus Mountains in Russia are endangered, the water of some of the wells is not potable. The rivers and lakes of Europe are polluted with organic halogens mainly from multisources. To our knowledge this is the first survey of organic sum parameters in this part of Europe.

Selective and sensitive detection of organic contaminants in water samples by on‐line trace enrichment–gas chromatography–mass spectrometry

AbstractLiquid chromatographic (LC) type trace enrichment is coupled online with capillary gas chromatography (GC) with mass spectrometric (MS) detection for the analysis of aqueous samples. A volume of 1–10 ml of an aqueous sample is preconcentrated on a trace‐enrichment column packed with a polymeric stationary phase. After cleanup with HPLC‐grade water the precolumn is dried with nitrogen and subsequently desorbed with ethyl acetate. A fraction of 60 μl is introduced on‐line into a diphenyltetramethyldisilazane‐deactivated retention gap under partially concurrent solvent evaporation conditions and using an early solvent vapor exit. The analytes are separated and detected by means of GC–MS. The potential of the LC–GC–MS system for monitoring organic pollutants in river and drinking water is studied. Target analysis is carried out with atrazine and simazine as model compounds; the detection limits achieved under full‐scan and multiple ion detection conditions are 30 pg and 5 pg, respectively. Identification of unknown compounds (non‐target analysis), is demonstrated using a river water sample spiked with 168 pollutants varying in polarity and volatility.

Geochemical Analysis of Stream Sediments as a Tool for Environmental Monitoring: A Pigyard Case Study

A geochemical analysis of 11 chemical elements in stream sediments in the vicinity of a pig farm shows that geochemical exploration methods can be used for regional environmental monitoring of organic pollution. In a 5-sq-mi (12.95 km 2 ) area in southern Ontario, contaminated stream sediments showed definite increases in Mg, Ca, Na, K, and Zn. Changes in Cu content were inconclusive; Pb, Co, Ni, Fe, and Mn showed background averages. The study showed that stream sediments are affected by large-scale agricultural operations within a short period of time. It is conclusive that ground water will be affected as contamination continues.