The purpose of this study is to establish a monitorimg method for the detection, identification and evaluation of persistent micro-pollutants in the aquatic environment.
The experimental studies on development of biological methods for concentration and estimation of the micro-pollutants in marine waters were carried out in order to improve the detection technique.
Regarding biological concentration, it could be found in this study that the activated sludge was applicable as an adsorption medium for concentration of the micro- pollutants in marine waters and its application was advantageous in the case that it could not be detect the persistent micro-pollutants by the concentration because of its minute concentration.
The activated sludge was cultivated in the specially designed apparatus to be operated continuously and automatically.
The sample water was prepared by addition of the substrate for cultivation of the activated sludge before feeding into the apparatus.

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The degradation of three kinds of oils such as alkylbenzene, A heavy oil and the Iranian heavy crude oil by a bacterial strain, Caulobacter sp., isolated from the sea water of Tokyo Bay was studied experimentally in the enriched seawater (ESW) medium. The alkylbenzene used in the present study is a mixture of n-hexylbenzene, n-heptylbenzene, n-nonylbenzene and n-pentadecane.
The maximum rate of degradation was observed after a lag period of 6 to 14 days and the bacteria were found to degrade the oils at the rates calculated to be in a range from 1.1x10-11 to 3.7x10-11 mg-oil/cell/hr for the alkyl-benzene, from 5.9 10-12 to 5.3x 10-11 mg-oil/cell/hr for A heavy oil and from 1.6 10-11 to 1.1 10-10 mg-oil/cell/hr for the Iranian heavy crude oil.
The fraction of degradation of the alkylbenzene attained to 100 percent in the low oil contents of the range below 200 mg-oil /l while the A heavy oil and the Iranian heavy crude oil were degraded at most in about 80 percent even at low oil contents.
The maximum degradation rate, rm mg-oil/l /hr, was correlated with the amount of the initial total oil per liter of ESW, S mg-oil/l, as expesssed by the following equation :rm = (rm)max(SS+Km)where (rm)max denotes the ultimate value of rm when the oil is added in large excess and Km is a saturated constant. The value of (rm)max and Km for the oils used in the present study were calculated to be as follows : in the case of alkylbenzene, (rm)max=12.3 mg-oil/l/hr and Km=950.8 mg-oil/l; in the case of the A heavy oil, (rm)max=7.63 mg-oil/l/hr and Km=1045 mg-oil/l; in the case of the Iranian heavy crude oil, (rm)max=7.25 mg-oil/l/hr and Km=496 mg-oil/l.

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The prediction or forcast of water quality of lakes is one of the important parts of water quality control techniques. In near future, there may be chances of changing of the water quality of the Lake Biwa, because of the regional development depending upon the Lake Biwa Comprehensive Project. For the quantification of the changes, the finite element model has been developed to simulate and predict the possible changes of the water quality. The deduction processes of the finite element equations from the shallow water equations and the water quality equation are fully described and some related cares are noted in this paper. The applications of the proposed method to the southern part of the Lake Biwa and the practicability of the model will be discussed together with the observed data in the comming publication.

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Microorganisms such as bacteria and/or actinomyces have been used for sludge treatment, e. g., aerobic or anaerobic digestion and composting. It is well known that some soil animals also play an important role in the decomposition of organic materials.
Resently, earth worms (Eisenia foetida) have been successfully applied to treat sledges produced in the pulp or food processing plants. It should, therefore, be possible to apply E. foetida for sewage sludge treatment.
In this research, sewage sludge compost was fed to E. foetida and the following results were obtained ;
(1) The growth, cocoon production, respiration and egesta rates were measured in the laboratory cultures and each rates was expressed as a function of fresh weight.
(2) Using these equations, the carbon balance in the growth and reproduction processes of E. foetida at 20 was investigated.
Considering the amount of carbon utilized for each process, it was suggested that E. foetida did not contribute directly to the decrease of organic materials but it might reduce them in collaboration with bacteria.
It could be assumed that the properties of organic materials were changed after consumption in such a way that is beneficial to the growth of plants.

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There is little information regarding the presence of methylmercury in the sea water, while the total mercury levels in the sea water have been determined by many investigators. Therefore, the origin of methylmercury in the marine ecology still remains obscure. Thus, in order to clarify if there exists appreciable amount of methylmercury in the sea water, we have developed a method for concentrating and measuring trace amount of methylmercury and determined the methylmercury levels in both offshore and inshore area around Japan archiperago.
When the sea water was filtered through the membrane filter (pore size 0.45, m), methylmercury concentration was about 0.2ng/L with certain variances depending on an area at which the water was sampled. On the other hand, methylmercury concentration in the suspended substances (SS) (mostly phyto-plankton) remaining on the filter showed approximately constant value of 0.2-0.3 ng/SS /L. Methylmercury concentration per unit mass of SS was 104-105 times more than of the filtered sea water.

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