Systems and technologies of the early biological notification of the general toxicity of air

It is known that requirements of the nature protection and sanitary and epidemiologic legislation regulate obligatory carrying out routine control of maintenance of pollutants in emissions and dumpings into a circumambient, in a zone of influence of the enterprises, on border of a sanitary protection zone of objects of environmental management.

Programs for routine control of quality of a free air on large enterprises usually cover rather large number of sources of emissions on sewer both waterworks and auxiliary production sites. The list of chemicals in emissions in a free air is different and depends on the technologies applied at the enterprises. Commissioning of plants on burning of a deposit of drain waters led to extension of programs of routine control over quality of a free air, by creation of technologies of a constant control behind contents characteristic of emissions from plant on burning of a deposit of contaminants: dust, nitrogen dioxide, sulfur dioxide and dioxine.

Lack of negative impact on a free air has to be confirmed by respect for maximum allowable concentration of contaminants on border of a sanitary protection zone of the enterprise. Now the set of techniques of determination of contaminants in a free air is accredited. However extension of the list of the analyzed indicators (which several times it is less, than the list of maximum concentration limit) for minor impurity in combustion products of firm rainfall of treatment facilities is absolutely inexpedient.

At the same time, there is open a question of tracking of potential risks as accidental volley emissions of toxicants (at an emergency), and long impact on live organisms even of very small concentration of different products of imperfect combustion of silt because of insufficient study of mechanisms of their cumulative

 influence at which influences of separate factors can not develop, and be multiplied mutually. It is so-called synergy effect of impact of contaminants on a biota, including on the person. Practically it means need of use of adequate integral indicators for an assessment of compliance of quality of a free air to requirements of ecological safety. Reactions of test organisms in system of biomonitoring which primal problem is control of the level of pollution of air environment, dangerous to a biota, can be such integral indicators of impurity of air. Main objective of systems of biomonitoring is "the early biological notification" about the dangerous level of environmental pollution.

For receiving integral indicators of impurity (in relation to emissions in air) 

scientists of the Institution of Russian Academy of Sciences Saint-Petersburg Scientific-Research Centre for Ecological Safety (SRCES RAS) by request SUE Vodokanal of St. Petersburg in January, 2011 the station of production biological monitoring of gas emissions from plant on burning of a deposit of the Southwest Treatment Facilities (STF) was developed and opened up. As test organisms, on the basis of earlier executed researches, huge African snails (pulmonary mollusks) of Achatina fulica and Achatina achatina were chosen. Such choice is caused by availability at mollusks of lung respiration, sensitivity to smells, a possibility of fastening on their sinks of fiber optic sensors for control of characteristics of cardio-activity, first of all heart rate, and also availability of the physical activity which is shown in vertical movement of a mollusk.

 

Such station of biological monitoring includes:

• terrarium in which six special modules for snails are placed;
• air feed system to indicator (on watch) and control to groups of mollusks which provides normalization of temperature, control of flows of the analyzed and pure air, pumping and dilution of the analyzed flue gas;
• the control system of detention regime of snails providing drop moistening of a body of mollusks, heating of the used water up to the temperature of 25 - 35 °C, control of constancy of values rn the pumped water, ventilation;
• the lighting regulator including the automatic mode of alternation "night - day";
• six-channel fiber-optical system of assignment of a signal of cardioactivity of mollusks and six-channel monitoring system of a verticality of a mollusk of rather rubber ball.
• Snails take place on rubber balls with a diameter of 10 cm which freely rotate on a water plane without shift. Optical fibers for assignment of a signal of cordial activity are attached to a sink of snails (drawing). For a food of snails before a ball the feeding trough is established. The snail moves on a ball as on the exercise machine - a cap, at the same time sensors measure the heart rate and a physical activity.

In station two groups of snails are placed: control group of three snails who breathe "pure" air without impurity of flue gases, and indicator group of three snails who breathe air with impurity of flue gases.

The purpose of work of station of biomonitoring - obtaining the objective information about safety of gas emissions on border of a sanitary protection zone (210 m).

The smoke arriving to indicator group of snails is diluted by only 100 times that on an air pollution level raises load of test organisms in comparison with border of a sanitary protection zone of plant on burning of a deposit by 100 times as in specific conditions dilution of content of toxicants on border of a sanitary protection zone makes about 10 thousand times.

The assessment the duty dispatcher of a current status of level of biological danger of the thrown-out flue gases is carried out on the basis of results of automatic processing and the analysis in real time a time history of heart rate and mobility of mollusks in control and indicator groups.

For descriptive reasons integral indicator quality indicators of change of degree of impurity form as individual (on separate mollusks), and (the traffic light system: "red" - an accident rate sign, "yellow" - availability of signs of threat, "blue" - a sign of restrictions in work of engineering systems, "green" - a sign of lack of the manifestations stated above).

The main options of indication of the "main traffic light" created on the personal computer of the removed dispatcher of system are provided:

 "red" - is developed in case of synchronous transition from a normality to negative "protective" reaction at all mollusks of indicator group or in case of the same sharp and synchronous reaction of increase of heart rate. Manifestation of both reactions indicates sharp increase of toxicity of flue gases to level at which even influence within several hours is dangerous that demands taking a step on detailed clarification of character and the reasons of the incident.

"Blue" - is developed if communication with the personal computer is broken and also if all mollusks of both indicator, and control groups within several hours stay the sink which is able "securities" from action of a circumambient and show lack of a physical activity. It indicates that for any reasons the system of drop moistening of mollusks ceased to work, and taking a step on recovery of its work is necessary. At automatic daily testing such situation can arise only during rather short time - no more than one hour and only during the period allocated for this testing - from 0 to 3 o'clock in the morning.

"Yellow" - arises if the bulk of mollusks of indicator group is in a condition of "protective" reaction. It can be connected with change of total concentration of oxides of carbon, sulfur and nitrogen in flue gases and can indicate both changes of the mode of burning, and uncontrollable processes in a gas feed system. In this case at a transmission through a flowing rn-cell of undiluted flue gases noticeable fluctuations of hydrogen ionization value can be observed. If hydrogen ionization value changes remain further for indefinite time, this condition of "traffic light" can serve as the direct instruction on the fact that it is required to carry out additional adjustment of a feed system of flue gases to station of biological monitoring.

The specified procedure is applicable for determination of the moment of emergency at which in the flue gases dumped in the atmosphere the content of oxides of sulfur, carbon monoxide gas, products of imperfect combustion, etc. can repeatedly increase. For the automated control of accumulation of negative changes of a functional condition of the used bioindicators at long impact on them of the diluted flue gases also comparative testing of character of the defense reaction accompanied with cardioactivity changes at mollusks from indicator and control groups at their blowing a high flow of a dry air performed every day in the range from 1 to 4 o'clock in the morning is used.

Thus, the bioelectronic monitoring system of quality of gas emissions of plant on burning of rainfall of drain waters is the unique innovation project. It can become a basis for implementation in domestic practice of the automated systems of integral biological monitoring of toxicological danger of a free air to the early notification of the population about threat of its pollution.