<prompt> Translate the following text to EnglishLengo la majaribio ya sumu ya maji ya muda mrefu na maji machafu na misombo safi ni kukadiria kiwango cha juu cha salama au hakuna athari ya viwango vya vitu hivi.  <response>: 1 The objective of chronic aquatic toxicity tests with effluents and pure compounds is to estimate the highest safe or no-effect concentration of these substances. 