Effect of long-term exposure to simazine on histopathology, hematological, and biochemical parameters in Cyprinus carpio

We investigated if residues of simazine in the natural waters would cause histological, hematological, and biochemical alterations in carps from contaminated areas in Badajoz (Spain). Some necrotic foci in kidney and liver, hepatitis, and hepatic steatosis were detected. No changes on measured hematological and biochemical parameters between fish from reference and contaminated ponds were observed. To assess if simazine exposure was the cause of these observations carps were exposed in the laboratory to simazine (45 microg/L) for 90 days. Some results obtained in the field were confirmed in laboratory, such as necrosis in kidney and liver and hepatic steatosis. Globular eosinophilic foci in kidney and a slight decrease of the hematocrit were also detected. These changes were moderate and indicative of an adaptation of the fish to the toxic stress caused by exposure to low simazine concentrations.

Utilization of chlorinated s-triazines by a new strain of Klebsiella pneumoniae

A bacterium utilizing 2-chloro-4,6-diamino-s-triazine (CAAT) as sole nitrogen source was isolated under a N2-free atmosphere and identified as Klebsiella pneumoniae. Concomitant to CAAT degradation the protein content increased and chloride was released into the medium. Under air and a N2-atmosphere no reduction of CAAT degradation resulted, though this strain is able to fix molecular nitrogen, but the decomposition accelerated under anaerobic conditions. The degradation rate increased continuously with increasing CAAT concentration. A continuous CAAT degradation without CAAT accumulation was possible up to a influx rate of 4.8 mumol.l-1h-1 (dilution rate = 0.007 h-1). K. pneumoniae A2 was also able to utilize deethylsimazine (CEAT) and deethylatrazine (CIAT) as nitrogen source. Both under aerobic and anaerobic conditions CEAT could be degraded faster than CIAT. The degradation sequence of mixed s-triazines was cyanuric acid < CAAT < CEAT < CIAT, which was reflected by the degradation times of single compounds. Complete degradation was assumed for all investigated s-triazine derivatives.