An Excel Macro to Plot the HFE-Diagram to Identify Sea Water Intrusion Phases.

A hydrochemical facies evolution diagram (HFE-D) is a multirectangular diagram, which is a useful tool in the interpretation of sea water intrusion processes. This method note describes a simple method for generating an HFE-D plot using the spreadsheet software package, Microsoft Excel. The code was applied to groundwater from the alluvial coastal plain of Grosseto (Tuscany, Italy), which is characterized by a complex salinization process in which sea water mixes with sulfate or bicarbonate recharge water.

Evaluation of surface- and ground-water pollution due to herbicides in agricultural areas of Zamora and Salamanca (Spain).

The pollution of agricultural land due to herbicides was assessed in the Guareña and Almar river basins, situated in the provinces of Zamora and Salamanca (Spain). A set of fifteen herbicides, including triazines, ureas, amides and others, was selected owing to their frequency of use, the amounts used, their toxicity and their persistence in the environment. Solid-phase extraction with polymeric cartridges, followed by HPLC with diode-array detection, were used to monitor the herbicides. This technique was chosen owing to the wide range of functionality and polarity of the analytes under study. The detection limits obtained were in the 0.004-0.025 microg/l range (lambda=220 nm). Surface and ground waters, taken from different locations in the basins, were analyzed over a 6-month period. The presence of six out of the fifteen herbicides monitored--chlortoluron, atrazine, terbutryn, alachlor, diflufenican and fluazifop-butyl--was detected in several samples at levels ranging from the detection limit to 1.2 microg/l. The relationship of these herbicides to the agricultural activities of the zone is discussed.

Intrafamilial spread of hepatitis C virus.

We studied the prevalence of antibodies against hepatitis C virus (anti-HCV) among 530 household contacts of 225 anti-HCV-positive subjects (index cases). Twenty-six (4.9%) relatives had anti-HCV, a proportion higher than that found among blood donors (175 of 22,435; 0.78%) (p less than 0.001). We did not find any differences regarding the type of relation with the index case (sexual or nonsexual). The prevalence of anti-HCV increased with the age of the relatives, with the contact time with the index case, and with the time of exposure to HCV. On the other hand, the anti-HCV was associated mainly with the existence of cirrhosis or hepatocellular carcinoma in the patient. We concluded that intrafamilial transmission may be an important mechanism in the spread of HCV.