{'fraction_non_alphanumeric': 0.0397456279809221, 'fraction_numerical': 0.00794912559618442, 'mean_word_length': 5.0576923076923075, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Trace metals in waters.

The topic of this paper is extremely broad, and to allow more useful discussion, emphasis is placed on trace (less than 1 mg/l) metals in fresh surface waters and in drinking waters. An attempt is made to give a broad overview of current knowledge, problems and research with particular reference to the following: (1) metals of interest, current standards of water quality relevant to health, and concentrations of metals in waters; (2) sources of, and other factors affecting, the concentrations of metals; (3) general problems in the measurement of metal concentrations; (4) important research topics.