Question

research has indicated that ph is a key determinant of the rates at which heavy metals in rocks and sediment leach into waterways, and multiple studies—including one conducted by akihito mochizuki et al. in lake biwa, japan, in 2015—have found that ph positively correlates with concentrations of the heavy metal uranium (u) in natural bodies of water. with these findings in mind, a student analyzing data on concentrations of u - 238 (an isotope that accounts for more than 99% of all naturally occurring u) in water samples from four lakes with minimal anthropogenic impact in chinas qaidam basin concludes that relative to tuosu lake and xiligou lake, u - leaching is likely slower in kaluka lake and gahai lake.
based on the text and the table, is the students conclusion reasonable?
a) yes, because the data indicate that a slight variation in ph results in a large variation in u - 238 concentration only in the tuosu lake and xiligou lake samples.
b) no, because the data show only u - 238 concentrations and ph values in the samples from the four chinese lakes, making it impossible to draw conclusions about leaching rates across those lakes.
c) no, because there are no data indicating whether the ph and u - 238 values in the kaluka lake and gahai lake samples are more similar to those in the tuosu lake and xiligou lake samples or to those in the lake biwa samples.
d) yes, because the data show that ph and u - 238 values in the tuosu lake and xiligou lake samples are higher than are the ph and u - 238 values in the kaluka lake and gahai lake samples.

sample id	sampling location	ph	u - 238 (μg/l)
ts 2 - t	tuosu lake	8.87	34.6
klk 3 - m	kaluka lake	7.77	5.4
gh 1	gahai lake	7.84	16.2

Explanation:

The text indicates that pH is a key determinant of leaching rates. The table shows pH and U - 238 concentrations for four lakes. In Tuosu Lake and Xiligou Lake, there is a relatively large variation in U - 238 concentration while in Kaluka Lake and Gahai Lake, the variation is slight. The student's conclusion about leaching rates in Kaluka Lake and Gahai Lake being slower relative to Tuosu Lake and Xiligou Lake is reasonable as the data shows a correlation between pH and U - 238 concentration which is related to leaching rates.

Answer:

A. Yes, because the data indicate that a slight variation in pH results in a large variation in U - 238 concentration only in the Tuosu Lake and Xiligou Lake samples